Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2568 insertions, 0 deletions

diff --git a/http.c b/http.c
new file mode 100644
index 0000000..c4b6dde
--- /dev/null
+++ b/http.c
@@ -0,0 +1,2568 @@
+#include "git-compat-util.h"
+#include "git-curl-compat.h"
+#include "http.h"
+#include "config.h"
+#include "pack.h"
+#include "sideband.h"
+#include "run-command.h"
+#include "url.h"
+#include "urlmatch.h"
+#include "credential.h"
+#include "version.h"
+#include "pkt-line.h"
+#include "gettext.h"
+#include "transport.h"
+#include "packfile.h"
+#include "protocol.h"
+#include "string-list.h"
+#include "object-store.h"
+
+static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
+static int trace_curl_data = 1;
+static int trace_curl_redact = 1;
+long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
+int active_requests;
+int http_is_verbose;
+ssize_t http_post_buffer = 16 * LARGE_PACKET_MAX;
+
+static int min_curl_sessions = 1;
+static int curl_session_count;
+static int max_requests = -1;
+static CURLM *curlm;
+static CURL *curl_default;
+
+#define PREV_BUF_SIZE 4096
+
+char curl_errorstr[CURL_ERROR_SIZE];
+
+static int curl_ssl_verify = -1;
+static int curl_ssl_try;
+static const char *curl_http_version = NULL;
+static const char *ssl_cert;
+static const char *ssl_cipherlist;
+static const char *ssl_version;
+static struct {
+	const char *name;
+	long ssl_version;
+} sslversions[] = {
+	{ "sslv2", CURL_SSLVERSION_SSLv2 },
+	{ "sslv3", CURL_SSLVERSION_SSLv3 },
+	{ "tlsv1", CURL_SSLVERSION_TLSv1 },
+#ifdef GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_0
+	{ "tlsv1.0", CURL_SSLVERSION_TLSv1_0 },
+	{ "tlsv1.1", CURL_SSLVERSION_TLSv1_1 },
+	{ "tlsv1.2", CURL_SSLVERSION_TLSv1_2 },
+#endif
+#ifdef GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_3
+	{ "tlsv1.3", CURL_SSLVERSION_TLSv1_3 },
+#endif
+};
+static const char *ssl_key;
+static const char *ssl_capath;
+static const char *curl_no_proxy;
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
+static const char *ssl_pinnedkey;
+#endif
+static const char *ssl_cainfo;
+static long curl_low_speed_limit = -1;
+static long curl_low_speed_time = -1;
+static int curl_ftp_no_epsv;
+static const char *curl_http_proxy;
+static const char *http_proxy_authmethod;
+
+static const char *http_proxy_ssl_cert;
+static const char *http_proxy_ssl_key;
+static const char *http_proxy_ssl_ca_info;
+static struct credential proxy_cert_auth = CREDENTIAL_INIT;
+static int proxy_ssl_cert_password_required;
+
+static struct {
+	const char *name;
+	long curlauth_param;
+} proxy_authmethods[] = {
+	{ "basic", CURLAUTH_BASIC },
+	{ "digest", CURLAUTH_DIGEST },
+	{ "negotiate", CURLAUTH_GSSNEGOTIATE },
+	{ "ntlm", CURLAUTH_NTLM },
+	{ "anyauth", CURLAUTH_ANY },
+	/*
+	 * CURLAUTH_DIGEST_IE has no corresponding command-line option in
+	 * curl(1) and is not included in CURLAUTH_ANY, so we leave it out
+	 * here, too
+	 */
+};
+#ifdef CURLGSSAPI_DELEGATION_FLAG
+static const char *curl_deleg;
+static struct {
+	const char *name;
+	long curl_deleg_param;
+} curl_deleg_levels[] = {
+	{ "none", CURLGSSAPI_DELEGATION_NONE },
+	{ "policy", CURLGSSAPI_DELEGATION_POLICY_FLAG },
+	{ "always", CURLGSSAPI_DELEGATION_FLAG },
+};
+#endif
+
+static struct credential proxy_auth = CREDENTIAL_INIT;
+static const char *curl_proxyuserpwd;
+static const char *curl_cookie_file;
+static int curl_save_cookies;
+struct credential http_auth = CREDENTIAL_INIT;
+static int http_proactive_auth;
+static const char *user_agent;
+static int curl_empty_auth = -1;
+
+enum http_follow_config http_follow_config = HTTP_FOLLOW_INITIAL;
+
+static struct credential cert_auth = CREDENTIAL_INIT;
+static int ssl_cert_password_required;
+static unsigned long http_auth_methods = CURLAUTH_ANY;
+static int http_auth_methods_restricted;
+/* Modes for which empty_auth cannot actually help us. */
+static unsigned long empty_auth_useless =
+	CURLAUTH_BASIC
+	| CURLAUTH_DIGEST_IE
+	| CURLAUTH_DIGEST;
+
+static struct curl_slist *pragma_header;
+static struct curl_slist *no_pragma_header;
+static struct string_list extra_http_headers = STRING_LIST_INIT_DUP;
+
+static struct curl_slist *host_resolutions;
+
+static struct active_request_slot *active_queue_head;
+
+static char *cached_accept_language;
+
+static char *http_ssl_backend;
+
+static int http_schannel_check_revoke = 1;
+/*
+ * With the backend being set to `schannel`, setting sslCAinfo would override
+ * the Certificate Store in cURL v7.60.0 and later, which is not what we want
+ * by default.
+ */
+static int http_schannel_use_ssl_cainfo;
+
+size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+{
+	size_t size = eltsize * nmemb;
+	struct buffer *buffer = buffer_;
+
+	if (size > buffer->buf.len - buffer->posn)
+		size = buffer->buf.len - buffer->posn;
+	memcpy(ptr, buffer->buf.buf + buffer->posn, size);
+	buffer->posn += size;
+
+	return size / eltsize;
+}
+
+int seek_buffer(void *clientp, curl_off_t offset, int origin)
+{
+	struct buffer *buffer = clientp;
+
+	if (origin != SEEK_SET)
+		BUG("seek_buffer only handles SEEK_SET");
+	if (offset < 0 || offset >= buffer->buf.len) {
+		error("curl seek would be outside of buffer");
+		return CURL_SEEKFUNC_FAIL;
+	}
+
+	buffer->posn = offset;
+	return CURL_SEEKFUNC_OK;
+}
+
+size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
+{
+	size_t size = eltsize * nmemb;
+	struct strbuf *buffer = buffer_;
+
+	strbuf_add(buffer, ptr, size);
+	return nmemb;
+}
+
+size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf)
+{
+	return nmemb;
+}
+
+static void closedown_active_slot(struct active_request_slot *slot)
+{
+	active_requests--;
+	slot->in_use = 0;
+}
+
+static void finish_active_slot(struct active_request_slot *slot)
+{
+	closedown_active_slot(slot);
+	curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE, &slot->http_code);
+
+	if (slot->finished)
+		(*slot->finished) = 1;
+
+	/* Store slot results so they can be read after the slot is reused */
+	if (slot->results) {
+		slot->results->curl_result = slot->curl_result;
+		slot->results->http_code = slot->http_code;
+		curl_easy_getinfo(slot->curl, CURLINFO_HTTPAUTH_AVAIL,
+				  &slot->results->auth_avail);
+
+		curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CONNECTCODE,
+			&slot->results->http_connectcode);
+	}
+
+	/* Run callback if appropriate */
+	if (slot->callback_func)
+		slot->callback_func(slot->callback_data);
+}
+
+static void xmulti_remove_handle(struct active_request_slot *slot)
+{
+	curl_multi_remove_handle(curlm, slot->curl);
+}
+
+static void process_curl_messages(void)
+{
+	int num_messages;
+	struct active_request_slot *slot;
+	CURLMsg *curl_message = curl_multi_info_read(curlm, &num_messages);
+
+	while (curl_message != NULL) {
+		if (curl_message->msg == CURLMSG_DONE) {
+			int curl_result = curl_message->data.result;
+			slot = active_queue_head;
+			while (slot != NULL &&
+			       slot->curl != curl_message->easy_handle)
+				slot = slot->next;
+			if (slot) {
+				xmulti_remove_handle(slot);
+				slot->curl_result = curl_result;
+				finish_active_slot(slot);
+			} else {
+				fprintf(stderr, "Received DONE message for unknown request!\n");
+			}
+		} else {
+			fprintf(stderr, "Unknown CURL message received: %d\n",
+				(int)curl_message->msg);
+		}
+		curl_message = curl_multi_info_read(curlm, &num_messages);
+	}
+}
+
+static int http_options(const char *var, const char *value, void *cb)
+{
+	if (!strcmp("http.version", var)) {
+		return git_config_string(&curl_http_version, var, value);
+	}
+	if (!strcmp("http.sslverify", var)) {
+		curl_ssl_verify = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcmp("http.sslcipherlist", var))
+		return git_config_string(&ssl_cipherlist, var, value);
+	if (!strcmp("http.sslversion", var))
+		return git_config_string(&ssl_version, var, value);
+	if (!strcmp("http.sslcert", var))
+		return git_config_pathname(&ssl_cert, var, value);
+	if (!strcmp("http.sslkey", var))
+		return git_config_pathname(&ssl_key, var, value);
+	if (!strcmp("http.sslcapath", var))
+		return git_config_pathname(&ssl_capath, var, value);
+	if (!strcmp("http.sslcainfo", var))
+		return git_config_pathname(&ssl_cainfo, var, value);
+	if (!strcmp("http.sslcertpasswordprotected", var)) {
+		ssl_cert_password_required = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcmp("http.ssltry", var)) {
+		curl_ssl_try = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcmp("http.sslbackend", var)) {
+		free(http_ssl_backend);
+		http_ssl_backend = xstrdup_or_null(value);
+		return 0;
+	}
+
+	if (!strcmp("http.schannelcheckrevoke", var)) {
+		http_schannel_check_revoke = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.schannelusesslcainfo", var)) {
+		http_schannel_use_ssl_cainfo = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.minsessions", var)) {
+		min_curl_sessions = git_config_int(var, value);
+		if (min_curl_sessions > 1)
+			min_curl_sessions = 1;
+		return 0;
+	}
+	if (!strcmp("http.maxrequests", var)) {
+		max_requests = git_config_int(var, value);
+		return 0;
+	}
+	if (!strcmp("http.lowspeedlimit", var)) {
+		curl_low_speed_limit = (long)git_config_int(var, value);
+		return 0;
+	}
+	if (!strcmp("http.lowspeedtime", var)) {
+		curl_low_speed_time = (long)git_config_int(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.noepsv", var)) {
+		curl_ftp_no_epsv = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcmp("http.proxy", var))
+		return git_config_string(&curl_http_proxy, var, value);
+
+	if (!strcmp("http.proxyauthmethod", var))
+		return git_config_string(&http_proxy_authmethod, var, value);
+
+	if (!strcmp("http.proxysslcert", var))
+		return git_config_string(&http_proxy_ssl_cert, var, value);
+
+	if (!strcmp("http.proxysslkey", var))
+		return git_config_string(&http_proxy_ssl_key, var, value);
+
+	if (!strcmp("http.proxysslcainfo", var))
+		return git_config_string(&http_proxy_ssl_ca_info, var, value);
+
+	if (!strcmp("http.proxysslcertpasswordprotected", var)) {
+		proxy_ssl_cert_password_required = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.cookiefile", var))
+		return git_config_pathname(&curl_cookie_file, var, value);
+	if (!strcmp("http.savecookies", var)) {
+		curl_save_cookies = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.postbuffer", var)) {
+		http_post_buffer = git_config_ssize_t(var, value);
+		if (http_post_buffer < 0)
+			warning(_("negative value for http.postBuffer; defaulting to %d"), LARGE_PACKET_MAX);
+		if (http_post_buffer < LARGE_PACKET_MAX)
+			http_post_buffer = LARGE_PACKET_MAX;
+		return 0;
+	}
+
+	if (!strcmp("http.useragent", var))
+		return git_config_string(&user_agent, var, value);
+
+	if (!strcmp("http.emptyauth", var)) {
+		if (value && !strcmp("auto", value))
+			curl_empty_auth = -1;
+		else
+			curl_empty_auth = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (!strcmp("http.delegation", var)) {
+#ifdef CURLGSSAPI_DELEGATION_FLAG
+		return git_config_string(&curl_deleg, var, value);
+#else
+		warning(_("Delegation control is not supported with cURL < 7.22.0"));
+		return 0;
+#endif
+	}
+
+	if (!strcmp("http.pinnedpubkey", var)) {
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
+		return git_config_pathname(&ssl_pinnedkey, var, value);
+#else
+		warning(_("Public key pinning not supported with cURL < 7.39.0"));
+		return 0;
+#endif
+	}
+
+	if (!strcmp("http.extraheader", var)) {
+		if (!value) {
+			return config_error_nonbool(var);
+		} else if (!*value) {
+			string_list_clear(&extra_http_headers, 0);
+		} else {
+			string_list_append(&extra_http_headers, value);
+		}
+		return 0;
+	}
+
+	if (!strcmp("http.curloptresolve", var)) {
+		if (!value) {
+			return config_error_nonbool(var);
+		} else if (!*value) {
+			curl_slist_free_all(host_resolutions);
+			host_resolutions = NULL;
+		} else {
+			host_resolutions = curl_slist_append(host_resolutions, value);
+		}
+		return 0;
+	}
+
+	if (!strcmp("http.followredirects", var)) {
+		if (value && !strcmp(value, "initial"))
+			http_follow_config = HTTP_FOLLOW_INITIAL;
+		else if (git_config_bool(var, value))
+			http_follow_config = HTTP_FOLLOW_ALWAYS;
+		else
+			http_follow_config = HTTP_FOLLOW_NONE;
+		return 0;
+	}
+
+	/* Fall back on the default ones */
+	return git_default_config(var, value, cb);
+}
+
+static int curl_empty_auth_enabled(void)
+{
+	if (curl_empty_auth >= 0)
+		return curl_empty_auth;
+
+	/*
+	 * In the automatic case, kick in the empty-auth
+	 * hack as long as we would potentially try some
+	 * method more exotic than "Basic" or "Digest".
+	 *
+	 * But only do this when this is our second or
+	 * subsequent request, as by then we know what
+	 * methods are available.
+	 */
+	if (http_auth_methods_restricted &&
+	    (http_auth_methods & ~empty_auth_useless))
+		return 1;
+	return 0;
+}
+
+static void init_curl_http_auth(CURL *result)
+{
+	if (!http_auth.username || !*http_auth.username) {
+		if (curl_empty_auth_enabled())
+			curl_easy_setopt(result, CURLOPT_USERPWD, ":");
+		return;
+	}
+
+	credential_fill(&http_auth);
+
+	curl_easy_setopt(result, CURLOPT_USERNAME, http_auth.username);
+	curl_easy_setopt(result, CURLOPT_PASSWORD, http_auth.password);
+}
+
+/* *var must be free-able */
+static void var_override(const char **var, char *value)
+{
+	if (value) {
+		free((void *)*var);
+		*var = xstrdup(value);
+	}
+}
+
+static void set_proxyauth_name_password(CURL *result)
+{
+		curl_easy_setopt(result, CURLOPT_PROXYUSERNAME,
+			proxy_auth.username);
+		curl_easy_setopt(result, CURLOPT_PROXYPASSWORD,
+			proxy_auth.password);
+}
+
+static void init_curl_proxy_auth(CURL *result)
+{
+	if (proxy_auth.username) {
+		if (!proxy_auth.password)
+			credential_fill(&proxy_auth);
+		set_proxyauth_name_password(result);
+	}
+
+	var_override(&http_proxy_authmethod, getenv("GIT_HTTP_PROXY_AUTHMETHOD"));
+
+	if (http_proxy_authmethod) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(proxy_authmethods); i++) {
+			if (!strcmp(http_proxy_authmethod, proxy_authmethods[i].name)) {
+				curl_easy_setopt(result, CURLOPT_PROXYAUTH,
+						proxy_authmethods[i].curlauth_param);
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(proxy_authmethods)) {
+			warning("unsupported proxy authentication method %s: using anyauth",
+					http_proxy_authmethod);
+			curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+		}
+	}
+	else
+		curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+}
+
+static int has_cert_password(void)
+{
+	if (ssl_cert == NULL || ssl_cert_password_required != 1)
+		return 0;
+	if (!cert_auth.password) {
+		cert_auth.protocol = xstrdup("cert");
+		cert_auth.host = xstrdup("");
+		cert_auth.username = xstrdup("");
+		cert_auth.path = xstrdup(ssl_cert);
+		credential_fill(&cert_auth);
+	}
+	return 1;
+}
+
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_KEYPASSWD
+static int has_proxy_cert_password(void)
+{
+	if (http_proxy_ssl_cert == NULL || proxy_ssl_cert_password_required != 1)
+		return 0;
+	if (!proxy_cert_auth.password) {
+		proxy_cert_auth.protocol = xstrdup("cert");
+		proxy_cert_auth.host = xstrdup("");
+		proxy_cert_auth.username = xstrdup("");
+		proxy_cert_auth.path = xstrdup(http_proxy_ssl_cert);
+		credential_fill(&proxy_cert_auth);
+	}
+	return 1;
+}
+#endif
+
+#ifdef GITCURL_HAVE_CURLOPT_TCP_KEEPALIVE
+static void set_curl_keepalive(CURL *c)
+{
+	curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1);
+}
+
+#else
+static int sockopt_callback(void *client, curl_socket_t fd, curlsocktype type)
+{
+	int ka = 1;
+	int rc;
+	socklen_t len = (socklen_t)sizeof(ka);
+
+	if (type != CURLSOCKTYPE_IPCXN)
+		return 0;
+
+	rc = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&ka, len);
+	if (rc < 0)
+		warning_errno("unable to set SO_KEEPALIVE on socket");
+
+	return CURL_SOCKOPT_OK;
+}
+
+static void set_curl_keepalive(CURL *c)
+{
+	curl_easy_setopt(c, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
+}
+#endif
+
+/* Return 1 if redactions have been made, 0 otherwise. */
+static int redact_sensitive_header(struct strbuf *header, size_t offset)
+{
+	int ret = 0;
+	const char *sensitive_header;
+
+	if (trace_curl_redact &&
+	    (skip_iprefix(header->buf + offset, "Authorization:", &sensitive_header) ||
+	     skip_iprefix(header->buf + offset, "Proxy-Authorization:", &sensitive_header))) {
+		/* The first token is the type, which is OK to log */
+		while (isspace(*sensitive_header))
+			sensitive_header++;
+		while (*sensitive_header && !isspace(*sensitive_header))
+			sensitive_header++;
+		/* Everything else is opaque and possibly sensitive */
+		strbuf_setlen(header,  sensitive_header - header->buf);
+		strbuf_addstr(header, " <redacted>");
+		ret = 1;
+	} else if (trace_curl_redact &&
+		   skip_iprefix(header->buf + offset, "Cookie:", &sensitive_header)) {
+		struct strbuf redacted_header = STRBUF_INIT;
+		const char *cookie;
+
+		while (isspace(*sensitive_header))
+			sensitive_header++;
+
+		cookie = sensitive_header;
+
+		while (cookie) {
+			char *equals;
+			char *semicolon = strstr(cookie, "; ");
+			if (semicolon)
+				*semicolon = 0;
+			equals = strchrnul(cookie, '=');
+			if (!equals) {
+				/* invalid cookie, just append and continue */
+				strbuf_addstr(&redacted_header, cookie);
+				continue;
+			}
+			strbuf_add(&redacted_header, cookie, equals - cookie);
+			strbuf_addstr(&redacted_header, "=<redacted>");
+			if (semicolon) {
+				/*
+				 * There are more cookies. (Or, for some
+				 * reason, the input string ends in "; ".)
+				 */
+				strbuf_addstr(&redacted_header, "; ");
+				cookie = semicolon + strlen("; ");
+			} else {
+				cookie = NULL;
+			}
+		}
+
+		strbuf_setlen(header, sensitive_header - header->buf);
+		strbuf_addbuf(header, &redacted_header);
+		ret = 1;
+	}
+	return ret;
+}
+
+/* Redact headers in info */
+static void redact_sensitive_info_header(struct strbuf *header)
+{
+	const char *sensitive_header;
+
+	/*
+	 * curl's h2h3 prints headers in info, e.g.:
+	 *   h2h3 [<header-name>: <header-val>]
+	 */
+	if (trace_curl_redact &&
+	    skip_iprefix(header->buf, "h2h3 [", &sensitive_header)) {
+		if (redact_sensitive_header(header, sensitive_header - header->buf)) {
+			/* redaction ate our closing bracket */
+			strbuf_addch(header, ']');
+		}
+	}
+}
+
+static void curl_dump_header(const char *text, unsigned char *ptr, size_t size, int hide_sensitive_header)
+{
+	struct strbuf out = STRBUF_INIT;
+	struct strbuf **headers, **header;
+
+	strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+		text, (long)size, (long)size);
+	trace_strbuf(&trace_curl, &out);
+	strbuf_reset(&out);
+	strbuf_add(&out, ptr, size);
+	headers = strbuf_split_max(&out, '\n', 0);
+
+	for (header = headers; *header; header++) {
+		if (hide_sensitive_header)
+			redact_sensitive_header(*header, 0);
+		strbuf_insertstr((*header), 0, text);
+		strbuf_insertstr((*header), strlen(text), ": ");
+		strbuf_rtrim((*header));
+		strbuf_addch((*header), '\n');
+		trace_strbuf(&trace_curl, (*header));
+	}
+	strbuf_list_free(headers);
+	strbuf_release(&out);
+}
+
+static void curl_dump_data(const char *text, unsigned char *ptr, size_t size)
+{
+	size_t i;
+	struct strbuf out = STRBUF_INIT;
+	unsigned int width = 60;
+
+	strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+		text, (long)size, (long)size);
+	trace_strbuf(&trace_curl, &out);
+
+	for (i = 0; i < size; i += width) {
+		size_t w;
+
+		strbuf_reset(&out);
+		strbuf_addf(&out, "%s: ", text);
+		for (w = 0; (w < width) && (i + w < size); w++) {
+			unsigned char ch = ptr[i + w];
+
+			strbuf_addch(&out,
+				       (ch >= 0x20) && (ch < 0x80)
+				       ? ch : '.');
+		}
+		strbuf_addch(&out, '\n');
+		trace_strbuf(&trace_curl, &out);
+	}
+	strbuf_release(&out);
+}
+
+static void curl_dump_info(char *data, size_t size)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_add(&buf, data, size);
+
+	redact_sensitive_info_header(&buf);
+	trace_printf_key(&trace_curl, "== Info: %s", buf.buf);
+
+	strbuf_release(&buf);
+}
+
+static int curl_trace(CURL *handle, curl_infotype type, char *data, size_t size, void *userp)
+{
+	const char *text;
+	enum { NO_FILTER = 0, DO_FILTER = 1 };
+
+	switch (type) {
+	case CURLINFO_TEXT:
+		curl_dump_info(data, size);
+		break;
+	case CURLINFO_HEADER_OUT:
+		text = "=> Send header";
+		curl_dump_header(text, (unsigned char *)data, size, DO_FILTER);
+		break;
+	case CURLINFO_DATA_OUT:
+		if (trace_curl_data) {
+			text = "=> Send data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
+		break;
+	case CURLINFO_SSL_DATA_OUT:
+		if (trace_curl_data) {
+			text = "=> Send SSL data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
+		break;
+	case CURLINFO_HEADER_IN:
+		text = "<= Recv header";
+		curl_dump_header(text, (unsigned char *)data, size, NO_FILTER);
+		break;
+	case CURLINFO_DATA_IN:
+		if (trace_curl_data) {
+			text = "<= Recv data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
+		break;
+	case CURLINFO_SSL_DATA_IN:
+		if (trace_curl_data) {
+			text = "<= Recv SSL data";
+			curl_dump_data(text, (unsigned char *)data, size);
+		}
+		break;
+
+	default:		/* we ignore unknown types by default */
+		return 0;
+	}
+	return 0;
+}
+
+void http_trace_curl_no_data(void)
+{
+	trace_override_envvar(&trace_curl, "1");
+	trace_curl_data = 0;
+}
+
+void setup_curl_trace(CURL *handle)
+{
+	if (!trace_want(&trace_curl))
+		return;
+	curl_easy_setopt(handle, CURLOPT_VERBOSE, 1L);
+	curl_easy_setopt(handle, CURLOPT_DEBUGFUNCTION, curl_trace);
+	curl_easy_setopt(handle, CURLOPT_DEBUGDATA, NULL);
+}
+
+static void proto_list_append(struct strbuf *list, const char *proto)
+{
+	if (!list)
+		return;
+	if (list->len)
+		strbuf_addch(list, ',');
+	strbuf_addstr(list, proto);
+}
+
+static long get_curl_allowed_protocols(int from_user, struct strbuf *list)
+{
+	long bits = 0;
+
+	if (is_transport_allowed("http", from_user)) {
+		bits |= CURLPROTO_HTTP;
+		proto_list_append(list, "http");
+	}
+	if (is_transport_allowed("https", from_user)) {
+		bits |= CURLPROTO_HTTPS;
+		proto_list_append(list, "https");
+	}
+	if (is_transport_allowed("ftp", from_user)) {
+		bits |= CURLPROTO_FTP;
+		proto_list_append(list, "ftp");
+	}
+	if (is_transport_allowed("ftps", from_user)) {
+		bits |= CURLPROTO_FTPS;
+		proto_list_append(list, "ftps");
+	}
+
+	return bits;
+}
+
+#ifdef GIT_CURL_HAVE_CURL_HTTP_VERSION_2
+static int get_curl_http_version_opt(const char *version_string, long *opt)
+{
+	int i;
+	static struct {
+		const char *name;
+		long opt_token;
+	} choice[] = {
+		{ "HTTP/1.1", CURL_HTTP_VERSION_1_1 },
+		{ "HTTP/2", CURL_HTTP_VERSION_2 }
+	};
+
+	for (i = 0; i < ARRAY_SIZE(choice); i++) {
+		if (!strcmp(version_string, choice[i].name)) {
+			*opt = choice[i].opt_token;
+			return 0;
+		}
+	}
+
+	warning("unknown value given to http.version: '%s'", version_string);
+	return -1; /* not found */
+}
+
+#endif
+
+static CURL *get_curl_handle(void)
+{
+	CURL *result = curl_easy_init();
+
+	if (!result)
+		die("curl_easy_init failed");
+
+	if (!curl_ssl_verify) {
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 0);
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 0);
+	} else {
+		/* Verify authenticity of the peer's certificate */
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYPEER, 1);
+		/* The name in the cert must match whom we tried to connect */
+		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
+	}
+
+#ifdef GIT_CURL_HAVE_CURL_HTTP_VERSION_2
+    if (curl_http_version) {
+		long opt;
+		if (!get_curl_http_version_opt(curl_http_version, &opt)) {
+			/* Set request use http version */
+			curl_easy_setopt(result, CURLOPT_HTTP_VERSION, opt);
+		}
+    }
+#endif
+
+	curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
+	curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
+
+#ifdef CURLGSSAPI_DELEGATION_FLAG
+	if (curl_deleg) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(curl_deleg_levels); i++) {
+			if (!strcmp(curl_deleg, curl_deleg_levels[i].name)) {
+				curl_easy_setopt(result, CURLOPT_GSSAPI_DELEGATION,
+						curl_deleg_levels[i].curl_deleg_param);
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(curl_deleg_levels))
+			warning("Unknown delegation method '%s': using default",
+				curl_deleg);
+	}
+#endif
+
+	if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
+	    !http_schannel_check_revoke) {
+#ifdef GIT_CURL_HAVE_CURLSSLOPT_NO_REVOKE
+		curl_easy_setopt(result, CURLOPT_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
+#else
+		warning(_("CURLSSLOPT_NO_REVOKE not supported with cURL < 7.44.0"));
+#endif
+	}
+
+	if (http_proactive_auth)
+		init_curl_http_auth(result);
+
+	if (getenv("GIT_SSL_VERSION"))
+		ssl_version = getenv("GIT_SSL_VERSION");
+	if (ssl_version && *ssl_version) {
+		int i;
+		for (i = 0; i < ARRAY_SIZE(sslversions); i++) {
+			if (!strcmp(ssl_version, sslversions[i].name)) {
+				curl_easy_setopt(result, CURLOPT_SSLVERSION,
+						 sslversions[i].ssl_version);
+				break;
+			}
+		}
+		if (i == ARRAY_SIZE(sslversions))
+			warning("unsupported ssl version %s: using default",
+				ssl_version);
+	}
+
+	if (getenv("GIT_SSL_CIPHER_LIST"))
+		ssl_cipherlist = getenv("GIT_SSL_CIPHER_LIST");
+	if (ssl_cipherlist != NULL && *ssl_cipherlist)
+		curl_easy_setopt(result, CURLOPT_SSL_CIPHER_LIST,
+				ssl_cipherlist);
+
+	if (ssl_cert)
+		curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
+	if (has_cert_password())
+		curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
+	if (ssl_key)
+		curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
+	if (ssl_capath)
+		curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
+	if (ssl_pinnedkey)
+		curl_easy_setopt(result, CURLOPT_PINNEDPUBLICKEY, ssl_pinnedkey);
+#endif
+	if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
+	    !http_schannel_use_ssl_cainfo) {
+		curl_easy_setopt(result, CURLOPT_CAINFO, NULL);
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_CAINFO
+		curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, NULL);
+#endif
+	} else if (ssl_cainfo != NULL || http_proxy_ssl_ca_info != NULL) {
+		if (ssl_cainfo)
+			curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_CAINFO
+		if (http_proxy_ssl_ca_info)
+			curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, http_proxy_ssl_ca_info);
+#endif
+	}
+
+	if (curl_low_speed_limit > 0 && curl_low_speed_time > 0) {
+		curl_easy_setopt(result, CURLOPT_LOW_SPEED_LIMIT,
+				 curl_low_speed_limit);
+		curl_easy_setopt(result, CURLOPT_LOW_SPEED_TIME,
+				 curl_low_speed_time);
+	}
+
+	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
+	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
+
+#ifdef GIT_CURL_HAVE_CURLOPT_PROTOCOLS_STR
+	{
+		struct strbuf buf = STRBUF_INIT;
+
+		get_curl_allowed_protocols(0, &buf);
+		curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS_STR, buf.buf);
+		strbuf_reset(&buf);
+
+		get_curl_allowed_protocols(-1, &buf);
+		curl_easy_setopt(result, CURLOPT_PROTOCOLS_STR, buf.buf);
+		strbuf_release(&buf);
+	}
+#else
+	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
+			 get_curl_allowed_protocols(0, NULL));
+	curl_easy_setopt(result, CURLOPT_PROTOCOLS,
+			 get_curl_allowed_protocols(-1, NULL));
+#endif
+
+	if (getenv("GIT_CURL_VERBOSE"))
+		http_trace_curl_no_data();
+	setup_curl_trace(result);
+	if (getenv("GIT_TRACE_CURL_NO_DATA"))
+		trace_curl_data = 0;
+	if (!git_env_bool("GIT_TRACE_REDACT", 1))
+		trace_curl_redact = 0;
+
+	curl_easy_setopt(result, CURLOPT_USERAGENT,
+		user_agent ? user_agent : git_user_agent());
+
+	if (curl_ftp_no_epsv)
+		curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
+
+	if (curl_ssl_try)
+		curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
+
+	/*
+	 * CURL also examines these variables as a fallback; but we need to query
+	 * them here in order to decide whether to prompt for missing password (cf.
+	 * init_curl_proxy_auth()).
+	 *
+	 * Unlike many other common environment variables, these are historically
+	 * lowercase only. It appears that CURL did not know this and implemented
+	 * only uppercase variants, which was later corrected to take both - with
+	 * the exception of http_proxy, which is lowercase only also in CURL. As
+	 * the lowercase versions are the historical quasi-standard, they take
+	 * precedence here, as in CURL.
+	 */
+	if (!curl_http_proxy) {
+		if (http_auth.protocol && !strcmp(http_auth.protocol, "https")) {
+			var_override(&curl_http_proxy, getenv("HTTPS_PROXY"));
+			var_override(&curl_http_proxy, getenv("https_proxy"));
+		} else {
+			var_override(&curl_http_proxy, getenv("http_proxy"));
+		}
+		if (!curl_http_proxy) {
+			var_override(&curl_http_proxy, getenv("ALL_PROXY"));
+			var_override(&curl_http_proxy, getenv("all_proxy"));
+		}
+	}
+
+	if (curl_http_proxy && curl_http_proxy[0] == '\0') {
+		/*
+		 * Handle case with the empty http.proxy value here to keep
+		 * common code clean.
+		 * NB: empty option disables proxying at all.
+		 */
+		curl_easy_setopt(result, CURLOPT_PROXY, "");
+	} else if (curl_http_proxy) {
+		if (starts_with(curl_http_proxy, "socks5h"))
+			curl_easy_setopt(result,
+				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5_HOSTNAME);
+		else if (starts_with(curl_http_proxy, "socks5"))
+			curl_easy_setopt(result,
+				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5);
+		else if (starts_with(curl_http_proxy, "socks4a"))
+			curl_easy_setopt(result,
+				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4A);
+		else if (starts_with(curl_http_proxy, "socks"))
+			curl_easy_setopt(result,
+				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_KEYPASSWD
+		else if (starts_with(curl_http_proxy, "https")) {
+			curl_easy_setopt(result, CURLOPT_PROXYTYPE, CURLPROXY_HTTPS);
+
+			if (http_proxy_ssl_cert)
+				curl_easy_setopt(result, CURLOPT_PROXY_SSLCERT, http_proxy_ssl_cert);
+
+			if (http_proxy_ssl_key)
+				curl_easy_setopt(result, CURLOPT_PROXY_SSLKEY, http_proxy_ssl_key);
+
+			if (has_proxy_cert_password())
+				curl_easy_setopt(result, CURLOPT_PROXY_KEYPASSWD, proxy_cert_auth.password);
+		}
+#endif
+		if (strstr(curl_http_proxy, "://"))
+			credential_from_url(&proxy_auth, curl_http_proxy);
+		else {
+			struct strbuf url = STRBUF_INIT;
+			strbuf_addf(&url, "http://%s", curl_http_proxy);
+			credential_from_url(&proxy_auth, url.buf);
+			strbuf_release(&url);
+		}
+
+		if (!proxy_auth.host)
+			die("Invalid proxy URL '%s'", curl_http_proxy);
+
+		curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
+		var_override(&curl_no_proxy, getenv("NO_PROXY"));
+		var_override(&curl_no_proxy, getenv("no_proxy"));
+		curl_easy_setopt(result, CURLOPT_NOPROXY, curl_no_proxy);
+	}
+	init_curl_proxy_auth(result);
+
+	set_curl_keepalive(result);
+
+	return result;
+}
+
+static void set_from_env(const char **var, const char *envname)
+{
+	const char *val = getenv(envname);
+	if (val)
+		*var = val;
+}
+
+void http_init(struct remote *remote, const char *url, int proactive_auth)
+{
+	char *low_speed_limit;
+	char *low_speed_time;
+	char *normalized_url;
+	struct urlmatch_config config = URLMATCH_CONFIG_INIT;
+
+	config.section = "http";
+	config.key = NULL;
+	config.collect_fn = http_options;
+	config.cascade_fn = git_default_config;
+	config.cb = NULL;
+
+	http_is_verbose = 0;
+	normalized_url = url_normalize(url, &config.url);
+
+	git_config(urlmatch_config_entry, &config);
+	free(normalized_url);
+	string_list_clear(&config.vars, 1);
+
+#ifdef GIT_CURL_HAVE_CURLSSLSET_NO_BACKENDS
+	if (http_ssl_backend) {
+		const curl_ssl_backend **backends;
+		struct strbuf buf = STRBUF_INIT;
+		int i;
+
+		switch (curl_global_sslset(-1, http_ssl_backend, &backends)) {
+		case CURLSSLSET_UNKNOWN_BACKEND:
+			strbuf_addf(&buf, _("Unsupported SSL backend '%s'. "
+					    "Supported SSL backends:"),
+					    http_ssl_backend);
+			for (i = 0; backends[i]; i++)
+				strbuf_addf(&buf, "\n\t%s", backends[i]->name);
+			die("%s", buf.buf);
+		case CURLSSLSET_NO_BACKENDS:
+			die(_("Could not set SSL backend to '%s': "
+			      "cURL was built without SSL backends"),
+			    http_ssl_backend);
+		case CURLSSLSET_TOO_LATE:
+			die(_("Could not set SSL backend to '%s': already set"),
+			    http_ssl_backend);
+		case CURLSSLSET_OK:
+			break; /* Okay! */
+		}
+	}
+#endif
+
+	if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK)
+		die("curl_global_init failed");
+
+	http_proactive_auth = proactive_auth;
+
+	if (remote && remote->http_proxy)
+		curl_http_proxy = xstrdup(remote->http_proxy);
+
+	if (remote)
+		var_override(&http_proxy_authmethod, remote->http_proxy_authmethod);
+
+	pragma_header = curl_slist_append(http_copy_default_headers(),
+		"Pragma: no-cache");
+	no_pragma_header = curl_slist_append(http_copy_default_headers(),
+		"Pragma:");
+
+	{
+		char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
+		if (http_max_requests)
+			max_requests = atoi(http_max_requests);
+	}
+
+	curlm = curl_multi_init();
+	if (!curlm)
+		die("curl_multi_init failed");
+
+	if (getenv("GIT_SSL_NO_VERIFY"))
+		curl_ssl_verify = 0;
+
+	set_from_env(&ssl_cert, "GIT_SSL_CERT");
+	set_from_env(&ssl_key, "GIT_SSL_KEY");
+	set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
+	set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
+
+	set_from_env(&user_agent, "GIT_HTTP_USER_AGENT");
+
+	low_speed_limit = getenv("GIT_HTTP_LOW_SPEED_LIMIT");
+	if (low_speed_limit)
+		curl_low_speed_limit = strtol(low_speed_limit, NULL, 10);
+	low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
+	if (low_speed_time)
+		curl_low_speed_time = strtol(low_speed_time, NULL, 10);
+
+	if (curl_ssl_verify == -1)
+		curl_ssl_verify = 1;
+
+	curl_session_count = 0;
+	if (max_requests < 1)
+		max_requests = DEFAULT_MAX_REQUESTS;
+
+	set_from_env(&http_proxy_ssl_cert, "GIT_PROXY_SSL_CERT");
+	set_from_env(&http_proxy_ssl_key, "GIT_PROXY_SSL_KEY");
+	set_from_env(&http_proxy_ssl_ca_info, "GIT_PROXY_SSL_CAINFO");
+
+	if (getenv("GIT_PROXY_SSL_CERT_PASSWORD_PROTECTED"))
+		proxy_ssl_cert_password_required = 1;
+
+	if (getenv("GIT_CURL_FTP_NO_EPSV"))
+		curl_ftp_no_epsv = 1;
+
+	if (url) {
+		credential_from_url(&http_auth, url);
+		if (!ssl_cert_password_required &&
+		    getenv("GIT_SSL_CERT_PASSWORD_PROTECTED") &&
+		    starts_with(url, "https://"))
+			ssl_cert_password_required = 1;
+	}
+
+	curl_default = get_curl_handle();
+}
+
+void http_cleanup(void)
+{
+	struct active_request_slot *slot = active_queue_head;
+
+	while (slot != NULL) {
+		struct active_request_slot *next = slot->next;
+		if (slot->curl) {
+			xmulti_remove_handle(slot);
+			curl_easy_cleanup(slot->curl);
+		}
+		free(slot);
+		slot = next;
+	}
+	active_queue_head = NULL;
+
+	curl_easy_cleanup(curl_default);
+
+	curl_multi_cleanup(curlm);
+	curl_global_cleanup();
+
+	string_list_clear(&extra_http_headers, 0);
+
+	curl_slist_free_all(pragma_header);
+	pragma_header = NULL;
+
+	curl_slist_free_all(no_pragma_header);
+	no_pragma_header = NULL;
+
+	curl_slist_free_all(host_resolutions);
+	host_resolutions = NULL;
+
+	if (curl_http_proxy) {
+		free((void *)curl_http_proxy);
+		curl_http_proxy = NULL;
+	}
+
+	if (proxy_auth.password) {
+		memset(proxy_auth.password, 0, strlen(proxy_auth.password));
+		FREE_AND_NULL(proxy_auth.password);
+	}
+
+	free((void *)curl_proxyuserpwd);
+	curl_proxyuserpwd = NULL;
+
+	free((void *)http_proxy_authmethod);
+	http_proxy_authmethod = NULL;
+
+	if (cert_auth.password) {
+		memset(cert_auth.password, 0, strlen(cert_auth.password));
+		FREE_AND_NULL(cert_auth.password);
+	}
+	ssl_cert_password_required = 0;
+
+	if (proxy_cert_auth.password) {
+		memset(proxy_cert_auth.password, 0, strlen(proxy_cert_auth.password));
+		FREE_AND_NULL(proxy_cert_auth.password);
+	}
+	proxy_ssl_cert_password_required = 0;
+
+	FREE_AND_NULL(cached_accept_language);
+}
+
+struct active_request_slot *get_active_slot(void)
+{
+	struct active_request_slot *slot = active_queue_head;
+	struct active_request_slot *newslot;
+
+	int num_transfers;
+
+	/* Wait for a slot to open up if the queue is full */
+	while (active_requests >= max_requests) {
+		curl_multi_perform(curlm, &num_transfers);
+		if (num_transfers < active_requests)
+			process_curl_messages();
+	}
+
+	while (slot != NULL && slot->in_use)
+		slot = slot->next;
+
+	if (!slot) {
+		newslot = xmalloc(sizeof(*newslot));
+		newslot->curl = NULL;
+		newslot->in_use = 0;
+		newslot->next = NULL;
+
+		slot = active_queue_head;
+		if (!slot) {
+			active_queue_head = newslot;
+		} else {
+			while (slot->next != NULL)
+				slot = slot->next;
+			slot->next = newslot;
+		}
+		slot = newslot;
+	}
+
+	if (!slot->curl) {
+		slot->curl = curl_easy_duphandle(curl_default);
+		curl_session_count++;
+	}
+
+	active_requests++;
+	slot->in_use = 1;
+	slot->results = NULL;
+	slot->finished = NULL;
+	slot->callback_data = NULL;
+	slot->callback_func = NULL;
+	curl_easy_setopt(slot->curl, CURLOPT_COOKIEFILE, curl_cookie_file);
+	if (curl_save_cookies)
+		curl_easy_setopt(slot->curl, CURLOPT_COOKIEJAR, curl_cookie_file);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
+	curl_easy_setopt(slot->curl, CURLOPT_RESOLVE, host_resolutions);
+	curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
+	curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 0);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_RANGE, NULL);
+
+	/*
+	 * Default following to off unless "ALWAYS" is configured; this gives
+	 * callers a sane starting point, and they can tweak for individual
+	 * HTTP_FOLLOW_* cases themselves.
+	 */
+	if (http_follow_config == HTTP_FOLLOW_ALWAYS)
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+	else
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 0);
+
+	curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
+	if (http_auth.password || curl_empty_auth_enabled())
+		init_curl_http_auth(slot->curl);
+
+	return slot;
+}
+
+int start_active_slot(struct active_request_slot *slot)
+{
+	CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
+	int num_transfers;
+
+	if (curlm_result != CURLM_OK &&
+	    curlm_result != CURLM_CALL_MULTI_PERFORM) {
+		warning("curl_multi_add_handle failed: %s",
+			curl_multi_strerror(curlm_result));
+		active_requests--;
+		slot->in_use = 0;
+		return 0;
+	}
+
+	/*
+	 * We know there must be something to do, since we just added
+	 * something.
+	 */
+	curl_multi_perform(curlm, &num_transfers);
+	return 1;
+}
+
+struct fill_chain {
+	void *data;
+	int (*fill)(void *);
+	struct fill_chain *next;
+};
+
+static struct fill_chain *fill_cfg;
+
+void add_fill_function(void *data, int (*fill)(void *))
+{
+	struct fill_chain *new_fill = xmalloc(sizeof(*new_fill));
+	struct fill_chain **linkp = &fill_cfg;
+	new_fill->data = data;
+	new_fill->fill = fill;
+	new_fill->next = NULL;
+	while (*linkp)
+		linkp = &(*linkp)->next;
+	*linkp = new_fill;
+}
+
+void fill_active_slots(void)
+{
+	struct active_request_slot *slot = active_queue_head;
+
+	while (active_requests < max_requests) {
+		struct fill_chain *fill;
+		for (fill = fill_cfg; fill; fill = fill->next)
+			if (fill->fill(fill->data))
+				break;
+
+		if (!fill)
+			break;
+	}
+
+	while (slot != NULL) {
+		if (!slot->in_use && slot->curl != NULL
+			&& curl_session_count > min_curl_sessions) {
+			curl_easy_cleanup(slot->curl);
+			slot->curl = NULL;
+			curl_session_count--;
+		}
+		slot = slot->next;
+	}
+}
+
+void step_active_slots(void)
+{
+	int num_transfers;
+	CURLMcode curlm_result;
+
+	do {
+		curlm_result = curl_multi_perform(curlm, &num_transfers);
+	} while (curlm_result == CURLM_CALL_MULTI_PERFORM);
+	if (num_transfers < active_requests) {
+		process_curl_messages();
+		fill_active_slots();
+	}
+}
+
+void run_active_slot(struct active_request_slot *slot)
+{
+	fd_set readfds;
+	fd_set writefds;
+	fd_set excfds;
+	int max_fd;
+	struct timeval select_timeout;
+	int finished = 0;
+
+	slot->finished = &finished;
+	while (!finished) {
+		step_active_slots();
+
+		if (slot->in_use) {
+			long curl_timeout;
+			curl_multi_timeout(curlm, &curl_timeout);
+			if (curl_timeout == 0) {
+				continue;
+			} else if (curl_timeout == -1) {
+				select_timeout.tv_sec  = 0;
+				select_timeout.tv_usec = 50000;
+			} else {
+				select_timeout.tv_sec  =  curl_timeout / 1000;
+				select_timeout.tv_usec = (curl_timeout % 1000) * 1000;
+			}
+
+			max_fd = -1;
+			FD_ZERO(&readfds);
+			FD_ZERO(&writefds);
+			FD_ZERO(&excfds);
+			curl_multi_fdset(curlm, &readfds, &writefds, &excfds, &max_fd);
+
+			/*
+			 * It can happen that curl_multi_timeout returns a pathologically
+			 * long timeout when curl_multi_fdset returns no file descriptors
+			 * to read.  See commit message for more details.
+			 */
+			if (max_fd < 0 &&
+			    (select_timeout.tv_sec > 0 ||
+			     select_timeout.tv_usec > 50000)) {
+				select_timeout.tv_sec  = 0;
+				select_timeout.tv_usec = 50000;
+			}
+
+			select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
+		}
+	}
+
+	/*
+	 * The value of slot->finished we set before the loop was used
+	 * to set our "finished" variable when our request completed.
+	 *
+	 * 1. The slot may not have been reused for another requst
+	 *    yet, in which case it still has &finished.
+	 *
+	 * 2. The slot may already be in-use to serve another request,
+	 *    which can further be divided into two cases:
+	 *
+	 * (a) If call run_active_slot() hasn't been called for that
+	 *     other request, slot->finished would have been cleared
+	 *     by get_active_slot() and has NULL.
+	 *
+	 * (b) If the request did call run_active_slot(), then the
+	 *     call would have updated slot->finished at the beginning
+	 *     of this function, and with the clearing of the member
+	 *     below, we would find that slot->finished is now NULL.
+	 *
+	 * In all cases, slot->finished has no useful information to
+	 * anybody at this point.  Some compilers warn us for
+	 * attempting to smuggle a pointer that is about to become
+	 * invalid, i.e. &finished.  We clear it here to assure them.
+	 */
+	slot->finished = NULL;
+}
+
+static void release_active_slot(struct active_request_slot *slot)
+{
+	closedown_active_slot(slot);
+	if (slot->curl) {
+		xmulti_remove_handle(slot);
+		if (curl_session_count > min_curl_sessions) {
+			curl_easy_cleanup(slot->curl);
+			slot->curl = NULL;
+			curl_session_count--;
+		}
+	}
+	fill_active_slots();
+}
+
+void finish_all_active_slots(void)
+{
+	struct active_request_slot *slot = active_queue_head;
+
+	while (slot != NULL)
+		if (slot->in_use) {
+			run_active_slot(slot);
+			slot = active_queue_head;
+		} else {
+			slot = slot->next;
+		}
+}
+
+/* Helpers for modifying and creating URLs */
+static inline int needs_quote(int ch)
+{
+	if (((ch >= 'A') && (ch <= 'Z'))
+			|| ((ch >= 'a') && (ch <= 'z'))
+			|| ((ch >= '0') && (ch <= '9'))
+			|| (ch == '/')
+			|| (ch == '-')
+			|| (ch == '.'))
+		return 0;
+	return 1;
+}
+
+static char *quote_ref_url(const char *base, const char *ref)
+{
+	struct strbuf buf = STRBUF_INIT;
+	const char *cp;
+	int ch;
+
+	end_url_with_slash(&buf, base);
+
+	for (cp = ref; (ch = *cp) != 0; cp++)
+		if (needs_quote(ch))
+			strbuf_addf(&buf, "%%%02x", ch);
+		else
+			strbuf_addch(&buf, *cp);
+
+	return strbuf_detach(&buf, NULL);
+}
+
+void append_remote_object_url(struct strbuf *buf, const char *url,
+			      const char *hex,
+			      int only_two_digit_prefix)
+{
+	end_url_with_slash(buf, url);
+
+	strbuf_addf(buf, "objects/%.*s/", 2, hex);
+	if (!only_two_digit_prefix)
+		strbuf_addstr(buf, hex + 2);
+}
+
+char *get_remote_object_url(const char *url, const char *hex,
+			    int only_two_digit_prefix)
+{
+	struct strbuf buf = STRBUF_INIT;
+	append_remote_object_url(&buf, url, hex, only_two_digit_prefix);
+	return strbuf_detach(&buf, NULL);
+}
+
+void normalize_curl_result(CURLcode *result, long http_code,
+			   char *errorstr, size_t errorlen)
+{
+	/*
+	 * If we see a failing http code with CURLE_OK, we have turned off
+	 * FAILONERROR (to keep the server's custom error response), and should
+	 * translate the code into failure here.
+	 *
+	 * Likewise, if we see a redirect (30x code), that means we turned off
+	 * redirect-following, and we should treat the result as an error.
+	 */
+	if (*result == CURLE_OK && http_code >= 300) {
+		*result = CURLE_HTTP_RETURNED_ERROR;
+		/*
+		 * Normally curl will already have put the "reason phrase"
+		 * from the server into curl_errorstr; unfortunately without
+		 * FAILONERROR it is lost, so we can give only the numeric
+		 * status code.
+		 */
+		xsnprintf(errorstr, errorlen,
+			  "The requested URL returned error: %ld",
+			  http_code);
+	}
+}
+
+static int handle_curl_result(struct slot_results *results)
+{
+	normalize_curl_result(&results->curl_result, results->http_code,
+			      curl_errorstr, sizeof(curl_errorstr));
+
+	if (results->curl_result == CURLE_OK) {
+		credential_approve(&http_auth);
+		credential_approve(&proxy_auth);
+		credential_approve(&cert_auth);
+		return HTTP_OK;
+	} else if (results->curl_result == CURLE_SSL_CERTPROBLEM) {
+		/*
+		 * We can't tell from here whether it's a bad path, bad
+		 * certificate, bad password, or something else wrong
+		 * with the certificate.  So we reject the credential to
+		 * avoid caching or saving a bad password.
+		 */
+		credential_reject(&cert_auth);
+		return HTTP_NOAUTH;
+#ifdef GIT_CURL_HAVE_CURLE_SSL_PINNEDPUBKEYNOTMATCH
+	} else if (results->curl_result == CURLE_SSL_PINNEDPUBKEYNOTMATCH) {
+		return HTTP_NOMATCHPUBLICKEY;
+#endif
+	} else if (missing_target(results))
+		return HTTP_MISSING_TARGET;
+	else if (results->http_code == 401) {
+		if (http_auth.username && http_auth.password) {
+			credential_reject(&http_auth);
+			return HTTP_NOAUTH;
+		} else {
+			http_auth_methods &= ~CURLAUTH_GSSNEGOTIATE;
+			if (results->auth_avail) {
+				http_auth_methods &= results->auth_avail;
+				http_auth_methods_restricted = 1;
+			}
+			return HTTP_REAUTH;
+		}
+	} else {
+		if (results->http_connectcode == 407)
+			credential_reject(&proxy_auth);
+		if (!curl_errorstr[0])
+			strlcpy(curl_errorstr,
+				curl_easy_strerror(results->curl_result),
+				sizeof(curl_errorstr));
+		return HTTP_ERROR;
+	}
+}
+
+int run_one_slot(struct active_request_slot *slot,
+		 struct slot_results *results)
+{
+	slot->results = results;
+	if (!start_active_slot(slot)) {
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "failed to start HTTP request");
+		return HTTP_START_FAILED;
+	}
+
+	run_active_slot(slot);
+	return handle_curl_result(results);
+}
+
+struct curl_slist *http_copy_default_headers(void)
+{
+	struct curl_slist *headers = NULL;
+	const struct string_list_item *item;
+
+	for_each_string_list_item(item, &extra_http_headers)
+		headers = curl_slist_append(headers, item->string);
+
+	return headers;
+}
+
+static CURLcode curlinfo_strbuf(CURL *curl, CURLINFO info, struct strbuf *buf)
+{
+	char *ptr;
+	CURLcode ret;
+
+	strbuf_reset(buf);
+	ret = curl_easy_getinfo(curl, info, &ptr);
+	if (!ret && ptr)
+		strbuf_addstr(buf, ptr);
+	return ret;
+}
+
+/*
+ * Check for and extract a content-type parameter. "raw"
+ * should be positioned at the start of the potential
+ * parameter, with any whitespace already removed.
+ *
+ * "name" is the name of the parameter. The value is appended
+ * to "out".
+ */
+static int extract_param(const char *raw, const char *name,
+			 struct strbuf *out)
+{
+	size_t len = strlen(name);
+
+	if (strncasecmp(raw, name, len))
+		return -1;
+	raw += len;
+
+	if (*raw != '=')
+		return -1;
+	raw++;
+
+	while (*raw && !isspace(*raw) && *raw != ';')
+		strbuf_addch(out, *raw++);
+	return 0;
+}
+
+/*
+ * Extract a normalized version of the content type, with any
+ * spaces suppressed, all letters lowercased, and no trailing ";"
+ * or parameters.
+ *
+ * Note that we will silently remove even invalid whitespace. For
+ * example, "text / plain" is specifically forbidden by RFC 2616,
+ * but "text/plain" is the only reasonable output, and this keeps
+ * our code simple.
+ *
+ * If the "charset" argument is not NULL, store the value of any
+ * charset parameter there.
+ *
+ * Example:
+ *   "TEXT/PLAIN; charset=utf-8" -> "text/plain", "utf-8"
+ *   "text / plain" -> "text/plain"
+ */
+static void extract_content_type(struct strbuf *raw, struct strbuf *type,
+				 struct strbuf *charset)
+{
+	const char *p;
+
+	strbuf_reset(type);
+	strbuf_grow(type, raw->len);
+	for (p = raw->buf; *p; p++) {
+		if (isspace(*p))
+			continue;
+		if (*p == ';') {
+			p++;
+			break;
+		}
+		strbuf_addch(type, tolower(*p));
+	}
+
+	if (!charset)
+		return;
+
+	strbuf_reset(charset);
+	while (*p) {
+		while (isspace(*p) || *p == ';')
+			p++;
+		if (!extract_param(p, "charset", charset))
+			return;
+		while (*p && !isspace(*p))
+			p++;
+	}
+
+	if (!charset->len && starts_with(type->buf, "text/"))
+		strbuf_addstr(charset, "ISO-8859-1");
+}
+
+static void write_accept_language(struct strbuf *buf)
+{
+	/*
+	 * MAX_DECIMAL_PLACES must not be larger than 3. If it is larger than
+	 * that, q-value will be smaller than 0.001, the minimum q-value the
+	 * HTTP specification allows. See
+	 * http://tools.ietf.org/html/rfc7231#section-5.3.1 for q-value.
+	 */
+	const int MAX_DECIMAL_PLACES = 3;
+	const int MAX_LANGUAGE_TAGS = 1000;
+	const int MAX_ACCEPT_LANGUAGE_HEADER_SIZE = 4000;
+	char **language_tags = NULL;
+	int num_langs = 0;
+	const char *s = get_preferred_languages();
+	int i;
+	struct strbuf tag = STRBUF_INIT;
+
+	/* Don't add Accept-Language header if no language is preferred. */
+	if (!s)
+		return;
+
+	/*
+	 * Split the colon-separated string of preferred languages into
+	 * language_tags array.
+	 */
+	do {
+		/* collect language tag */
+		for (; *s && (isalnum(*s) || *s == '_'); s++)
+			strbuf_addch(&tag, *s == '_' ? '-' : *s);
+
+		/* skip .codeset, @modifier and any other unnecessary parts */
+		while (*s && *s != ':')
+			s++;
+
+		if (tag.len) {
+			num_langs++;
+			REALLOC_ARRAY(language_tags, num_langs);
+			language_tags[num_langs - 1] = strbuf_detach(&tag, NULL);
+			if (num_langs >= MAX_LANGUAGE_TAGS - 1) /* -1 for '*' */
+				break;
+		}
+	} while (*s++);
+
+	/* write Accept-Language header into buf */
+	if (num_langs) {
+		int last_buf_len = 0;
+		int max_q;
+		int decimal_places;
+		char q_format[32];
+
+		/* add '*' */
+		REALLOC_ARRAY(language_tags, num_langs + 1);
+		language_tags[num_langs++] = "*"; /* it's OK; this won't be freed */
+
+		/* compute decimal_places */
+		for (max_q = 1, decimal_places = 0;
+		     max_q < num_langs && decimal_places <= MAX_DECIMAL_PLACES;
+		     decimal_places++, max_q *= 10)
+			;
+
+		xsnprintf(q_format, sizeof(q_format), ";q=0.%%0%dd", decimal_places);
+
+		strbuf_addstr(buf, "Accept-Language: ");
+
+		for (i = 0; i < num_langs; i++) {
+			if (i > 0)
+				strbuf_addstr(buf, ", ");
+
+			strbuf_addstr(buf, language_tags[i]);
+
+			if (i > 0)
+				strbuf_addf(buf, q_format, max_q - i);
+
+			if (buf->len > MAX_ACCEPT_LANGUAGE_HEADER_SIZE) {
+				strbuf_remove(buf, last_buf_len, buf->len - last_buf_len);
+				break;
+			}
+
+			last_buf_len = buf->len;
+		}
+	}
+
+	/* free language tags -- last one is a static '*' */
+	for (i = 0; i < num_langs - 1; i++)
+		free(language_tags[i]);
+	free(language_tags);
+}
+
+/*
+ * Get an Accept-Language header which indicates user's preferred languages.
+ *
+ * Examples:
+ *   LANGUAGE= -> ""
+ *   LANGUAGE=ko:en -> "Accept-Language: ko, en; q=0.9, *; q=0.1"
+ *   LANGUAGE=ko_KR.UTF-8:sr@latin -> "Accept-Language: ko-KR, sr; q=0.9, *; q=0.1"
+ *   LANGUAGE=ko LANG=en_US.UTF-8 -> "Accept-Language: ko, *; q=0.1"
+ *   LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *; q=0.1"
+ *   LANGUAGE= LANG=C -> ""
+ */
+const char *http_get_accept_language_header(void)
+{
+	if (!cached_accept_language) {
+		struct strbuf buf = STRBUF_INIT;
+		write_accept_language(&buf);
+		if (buf.len > 0)
+			cached_accept_language = strbuf_detach(&buf, NULL);
+	}
+
+	return cached_accept_language;
+}
+
+static void http_opt_request_remainder(CURL *curl, off_t pos)
+{
+	char buf[128];
+	xsnprintf(buf, sizeof(buf), "%"PRIuMAX"-", (uintmax_t)pos);
+	curl_easy_setopt(curl, CURLOPT_RANGE, buf);
+}
+
+/* http_request() targets */
+#define HTTP_REQUEST_STRBUF	0
+#define HTTP_REQUEST_FILE	1
+
+static int http_request(const char *url,
+			void *result, int target,
+			const struct http_get_options *options)
+{
+	struct active_request_slot *slot;
+	struct slot_results results;
+	struct curl_slist *headers = http_copy_default_headers();
+	struct strbuf buf = STRBUF_INIT;
+	const char *accept_language;
+	int ret;
+
+	slot = get_active_slot();
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPGET, 1);
+
+	if (!result) {
+		curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
+	} else {
+		curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+		curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, result);
+
+		if (target == HTTP_REQUEST_FILE) {
+			off_t posn = ftello(result);
+			curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
+					 fwrite);
+			if (posn > 0)
+				http_opt_request_remainder(slot->curl, posn);
+		} else
+			curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
+					 fwrite_buffer);
+	}
+
+	accept_language = http_get_accept_language_header();
+
+	if (accept_language)
+		headers = curl_slist_append(headers, accept_language);
+
+	strbuf_addstr(&buf, "Pragma:");
+	if (options && options->no_cache)
+		strbuf_addstr(&buf, " no-cache");
+	if (options && options->initial_request &&
+	    http_follow_config == HTTP_FOLLOW_INITIAL)
+		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+
+	headers = curl_slist_append(headers, buf.buf);
+
+	/* Add additional headers here */
+	if (options && options->extra_headers) {
+		const struct string_list_item *item;
+		for_each_string_list_item(item, options->extra_headers) {
+			headers = curl_slist_append(headers, item->string);
+		}
+	}
+
+	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
+	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");
+	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
+
+	ret = run_one_slot(slot, &results);
+
+	if (options && options->content_type) {
+		struct strbuf raw = STRBUF_INIT;
+		curlinfo_strbuf(slot->curl, CURLINFO_CONTENT_TYPE, &raw);
+		extract_content_type(&raw, options->content_type,
+				     options->charset);
+		strbuf_release(&raw);
+	}
+
+	if (options && options->effective_url)
+		curlinfo_strbuf(slot->curl, CURLINFO_EFFECTIVE_URL,
+				options->effective_url);
+
+	curl_slist_free_all(headers);
+	strbuf_release(&buf);
+
+	return ret;
+}
+
+/*
+ * Update the "base" url to a more appropriate value, as deduced by
+ * redirects seen when requesting a URL starting with "url".
+ *
+ * The "asked" parameter is a URL that we asked curl to access, and must begin
+ * with "base".
+ *
+ * The "got" parameter is the URL that curl reported to us as where we ended
+ * up.
+ *
+ * Returns 1 if we updated the base url, 0 otherwise.
+ *
+ * Our basic strategy is to compare "base" and "asked" to find the bits
+ * specific to our request. We then strip those bits off of "got" to yield the
+ * new base. So for example, if our base is "http://example.com/foo.git",
+ * and we ask for "http://example.com/foo.git/info/refs", we might end up
+ * with "https://other.example.com/foo.git/info/refs". We would want the
+ * new URL to become "https://other.example.com/foo.git".
+ *
+ * Note that this assumes a sane redirect scheme. It's entirely possible
+ * in the example above to end up at a URL that does not even end in
+ * "info/refs".  In such a case we die. There's not much we can do, such a
+ * scheme is unlikely to represent a real git repository, and failing to
+ * rewrite the base opens options for malicious redirects to do funny things.
+ */
+static int update_url_from_redirect(struct strbuf *base,
+				    const char *asked,
+				    const struct strbuf *got)
+{
+	const char *tail;
+	size_t new_len;
+
+	if (!strcmp(asked, got->buf))
+		return 0;
+
+	if (!skip_prefix(asked, base->buf, &tail))
+		BUG("update_url_from_redirect: %s is not a superset of %s",
+		    asked, base->buf);
+
+	new_len = got->len;
+	if (!strip_suffix_mem(got->buf, &new_len, tail))
+		die(_("unable to update url base from redirection:\n"
+		      "  asked for: %s\n"
+		      "   redirect: %s"),
+		    asked, got->buf);
+
+	strbuf_reset(base);
+	strbuf_add(base, got->buf, new_len);
+
+	return 1;
+}
+
+static int http_request_reauth(const char *url,
+			       void *result, int target,
+			       struct http_get_options *options)
+{
+	int ret = http_request(url, result, target, options);
+
+	if (ret != HTTP_OK && ret != HTTP_REAUTH)
+		return ret;
+
+	if (options && options->effective_url && options->base_url) {
+		if (update_url_from_redirect(options->base_url,
+					     url, options->effective_url)) {
+			credential_from_url(&http_auth, options->base_url->buf);
+			url = options->effective_url->buf;
+		}
+	}
+
+	if (ret != HTTP_REAUTH)
+		return ret;
+
+	/*
+	 * The previous request may have put cruft into our output stream; we
+	 * should clear it out before making our next request.
+	 */
+	switch (target) {
+	case HTTP_REQUEST_STRBUF:
+		strbuf_reset(result);
+		break;
+	case HTTP_REQUEST_FILE:
+		if (fflush(result)) {
+			error_errno("unable to flush a file");
+			return HTTP_START_FAILED;
+		}
+		rewind(result);
+		if (ftruncate(fileno(result), 0) < 0) {
+			error_errno("unable to truncate a file");
+			return HTTP_START_FAILED;
+		}
+		break;
+	default:
+		BUG("Unknown http_request target");
+	}
+
+	credential_fill(&http_auth);
+
+	return http_request(url, result, target, options);
+}
+
+int http_get_strbuf(const char *url,
+		    struct strbuf *result,
+		    struct http_get_options *options)
+{
+	return http_request_reauth(url, result, HTTP_REQUEST_STRBUF, options);
+}
+
+/*
+ * Downloads a URL and stores the result in the given file.
+ *
+ * If a previous interrupted download is detected (i.e. a previous temporary
+ * file is still around) the download is resumed.
+ */
+int http_get_file(const char *url, const char *filename,
+		  struct http_get_options *options)
+{
+	int ret;
+	struct strbuf tmpfile = STRBUF_INIT;
+	FILE *result;
+
+	strbuf_addf(&tmpfile, "%s.temp", filename);
+	result = fopen(tmpfile.buf, "a");
+	if (!result) {
+		error("Unable to open local file %s", tmpfile.buf);
+		ret = HTTP_ERROR;
+		goto cleanup;
+	}
+
+	ret = http_request_reauth(url, result, HTTP_REQUEST_FILE, options);
+	fclose(result);
+
+	if (ret == HTTP_OK && finalize_object_file(tmpfile.buf, filename))
+		ret = HTTP_ERROR;
+cleanup:
+	strbuf_release(&tmpfile);
+	return ret;
+}
+
+int http_fetch_ref(const char *base, struct ref *ref)
+{
+	struct http_get_options options = {0};
+	char *url;
+	struct strbuf buffer = STRBUF_INIT;
+	int ret = -1;
+
+	options.no_cache = 1;
+
+	url = quote_ref_url(base, ref->name);
+	if (http_get_strbuf(url, &buffer, &options) == HTTP_OK) {
+		strbuf_rtrim(&buffer);
+		if (buffer.len == the_hash_algo->hexsz)
+			ret = get_oid_hex(buffer.buf, &ref->old_oid);
+		else if (starts_with(buffer.buf, "ref: ")) {
+			ref->symref = xstrdup(buffer.buf + 5);
+			ret = 0;
+		}
+	}
+
+	strbuf_release(&buffer);
+	free(url);
+	return ret;
+}
+
+/* Helpers for fetching packs */
+static char *fetch_pack_index(unsigned char *hash, const char *base_url)
+{
+	char *url, *tmp;
+	struct strbuf buf = STRBUF_INIT;
+
+	if (http_is_verbose)
+		fprintf(stderr, "Getting index for pack %s\n", hash_to_hex(hash));
+
+	end_url_with_slash(&buf, base_url);
+	strbuf_addf(&buf, "objects/pack/pack-%s.idx", hash_to_hex(hash));
+	url = strbuf_detach(&buf, NULL);
+
+	strbuf_addf(&buf, "%s.temp", sha1_pack_index_name(hash));
+	tmp = strbuf_detach(&buf, NULL);
+
+	if (http_get_file(url, tmp, NULL) != HTTP_OK) {
+		error("Unable to get pack index %s", url);
+		FREE_AND_NULL(tmp);
+	}
+
+	free(url);
+	return tmp;
+}
+
+static int fetch_and_setup_pack_index(struct packed_git **packs_head,
+	unsigned char *sha1, const char *base_url)
+{
+	struct packed_git *new_pack;
+	char *tmp_idx = NULL;
+	int ret;
+
+	if (has_pack_index(sha1)) {
+		new_pack = parse_pack_index(sha1, sha1_pack_index_name(sha1));
+		if (!new_pack)
+			return -1; /* parse_pack_index() already issued error message */
+		goto add_pack;
+	}
+
+	tmp_idx = fetch_pack_index(sha1, base_url);
+	if (!tmp_idx)
+		return -1;
+
+	new_pack = parse_pack_index(sha1, tmp_idx);
+	if (!new_pack) {
+		unlink(tmp_idx);
+		free(tmp_idx);
+
+		return -1; /* parse_pack_index() already issued error message */
+	}
+
+	ret = verify_pack_index(new_pack);
+	if (!ret) {
+		close_pack_index(new_pack);
+		ret = finalize_object_file(tmp_idx, sha1_pack_index_name(sha1));
+	}
+	free(tmp_idx);
+	if (ret)
+		return -1;
+
+add_pack:
+	new_pack->next = *packs_head;
+	*packs_head = new_pack;
+	return 0;
+}
+
+int http_get_info_packs(const char *base_url, struct packed_git **packs_head)
+{
+	struct http_get_options options = {0};
+	int ret = 0;
+	char *url;
+	const char *data;
+	struct strbuf buf = STRBUF_INIT;
+	struct object_id oid;
+
+	end_url_with_slash(&buf, base_url);
+	strbuf_addstr(&buf, "objects/info/packs");
+	url = strbuf_detach(&buf, NULL);
+
+	options.no_cache = 1;
+	ret = http_get_strbuf(url, &buf, &options);
+	if (ret != HTTP_OK)
+		goto cleanup;
+
+	data = buf.buf;
+	while (*data) {
+		if (skip_prefix(data, "P pack-", &data) &&
+		    !parse_oid_hex(data, &oid, &data) &&
+		    skip_prefix(data, ".pack", &data) &&
+		    (*data == '\n' || *data == '\0')) {
+			fetch_and_setup_pack_index(packs_head, oid.hash, base_url);
+		} else {
+			data = strchrnul(data, '\n');
+		}
+		if (*data)
+			data++; /* skip past newline */
+	}
+
+cleanup:
+	free(url);
+	return ret;
+}
+
+void release_http_pack_request(struct http_pack_request *preq)
+{
+	if (preq->packfile) {
+		fclose(preq->packfile);
+		preq->packfile = NULL;
+	}
+	preq->slot = NULL;
+	strbuf_release(&preq->tmpfile);
+	free(preq->url);
+	free(preq);
+}
+
+static const char *default_index_pack_args[] =
+	{"index-pack", "--stdin", NULL};
+
+int finish_http_pack_request(struct http_pack_request *preq)
+{
+	struct child_process ip = CHILD_PROCESS_INIT;
+	int tmpfile_fd;
+	int ret = 0;
+
+	fclose(preq->packfile);
+	preq->packfile = NULL;
+
+	tmpfile_fd = xopen(preq->tmpfile.buf, O_RDONLY);
+
+	ip.git_cmd = 1;
+	ip.in = tmpfile_fd;
+	strvec_pushv(&ip.args, preq->index_pack_args ?
+		     preq->index_pack_args :
+		     default_index_pack_args);
+
+	if (preq->preserve_index_pack_stdout)
+		ip.out = 0;
+	else
+		ip.no_stdout = 1;
+
+	if (run_command(&ip)) {
+		ret = -1;
+		goto cleanup;
+	}
+
+cleanup:
+	close(tmpfile_fd);
+	unlink(preq->tmpfile.buf);
+	return ret;
+}
+
+void http_install_packfile(struct packed_git *p,
+			   struct packed_git **list_to_remove_from)
+{
+	struct packed_git **lst = list_to_remove_from;
+
+	while (*lst != p)
+		lst = &((*lst)->next);
+	*lst = (*lst)->next;
+
+	install_packed_git(the_repository, p);
+}
+
+struct http_pack_request *new_http_pack_request(
+	const unsigned char *packed_git_hash, const char *base_url) {
+
+	struct strbuf buf = STRBUF_INIT;
+
+	end_url_with_slash(&buf, base_url);
+	strbuf_addf(&buf, "objects/pack/pack-%s.pack",
+		hash_to_hex(packed_git_hash));
+	return new_direct_http_pack_request(packed_git_hash,
+					    strbuf_detach(&buf, NULL));
+}
+
+struct http_pack_request *new_direct_http_pack_request(
+	const unsigned char *packed_git_hash, char *url)
+{
+	off_t prev_posn = 0;
+	struct http_pack_request *preq;
+
+	CALLOC_ARRAY(preq, 1);
+	strbuf_init(&preq->tmpfile, 0);
+
+	preq->url = url;
+
+	strbuf_addf(&preq->tmpfile, "%s.temp", sha1_pack_name(packed_git_hash));
+	preq->packfile = fopen(preq->tmpfile.buf, "a");
+	if (!preq->packfile) {
+		error("Unable to open local file %s for pack",
+		      preq->tmpfile.buf);
+		goto abort;
+	}
+
+	preq->slot = get_active_slot();
+	curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEDATA, preq->packfile);
+	curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
+	curl_easy_setopt(preq->slot->curl, CURLOPT_URL, preq->url);
+	curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
+		no_pragma_header);
+
+	/*
+	 * If there is data present from a previous transfer attempt,
+	 * resume where it left off
+	 */
+	prev_posn = ftello(preq->packfile);
+	if (prev_posn>0) {
+		if (http_is_verbose)
+			fprintf(stderr,
+				"Resuming fetch of pack %s at byte %"PRIuMAX"\n",
+				hash_to_hex(packed_git_hash),
+				(uintmax_t)prev_posn);
+		http_opt_request_remainder(preq->slot->curl, prev_posn);
+	}
+
+	return preq;
+
+abort:
+	strbuf_release(&preq->tmpfile);
+	free(preq->url);
+	free(preq);
+	return NULL;
+}
+
+/* Helpers for fetching objects (loose) */
+static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
+			       void *data)
+{
+	unsigned char expn[4096];
+	size_t size = eltsize * nmemb;
+	int posn = 0;
+	struct http_object_request *freq = data;
+	struct active_request_slot *slot = freq->slot;
+
+	if (slot) {
+		CURLcode c = curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE,
+						&slot->http_code);
+		if (c != CURLE_OK)
+			BUG("curl_easy_getinfo for HTTP code failed: %s",
+				curl_easy_strerror(c));
+		if (slot->http_code >= 300)
+			return nmemb;
+	}
+
+	do {
+		ssize_t retval = xwrite(freq->localfile,
+					(char *) ptr + posn, size - posn);
+		if (retval < 0)
+			return posn / eltsize;
+		posn += retval;
+	} while (posn < size);
+
+	freq->stream.avail_in = size;
+	freq->stream.next_in = (void *)ptr;
+	do {
+		freq->stream.next_out = expn;
+		freq->stream.avail_out = sizeof(expn);
+		freq->zret = git_inflate(&freq->stream, Z_SYNC_FLUSH);
+		the_hash_algo->update_fn(&freq->c, expn,
+					 sizeof(expn) - freq->stream.avail_out);
+	} while (freq->stream.avail_in && freq->zret == Z_OK);
+	return nmemb;
+}
+
+struct http_object_request *new_http_object_request(const char *base_url,
+						    const struct object_id *oid)
+{
+	char *hex = oid_to_hex(oid);
+	struct strbuf filename = STRBUF_INIT;
+	struct strbuf prevfile = STRBUF_INIT;
+	int prevlocal;
+	char prev_buf[PREV_BUF_SIZE];
+	ssize_t prev_read = 0;
+	off_t prev_posn = 0;
+	struct http_object_request *freq;
+
+	CALLOC_ARRAY(freq, 1);
+	strbuf_init(&freq->tmpfile, 0);
+	oidcpy(&freq->oid, oid);
+	freq->localfile = -1;
+
+	loose_object_path(the_repository, &filename, oid);
+	strbuf_addf(&freq->tmpfile, "%s.temp", filename.buf);
+
+	strbuf_addf(&prevfile, "%s.prev", filename.buf);
+	unlink_or_warn(prevfile.buf);
+	rename(freq->tmpfile.buf, prevfile.buf);
+	unlink_or_warn(freq->tmpfile.buf);
+	strbuf_release(&filename);
+
+	if (freq->localfile != -1)
+		error("fd leakage in start: %d", freq->localfile);
+	freq->localfile = open(freq->tmpfile.buf,
+			       O_WRONLY | O_CREAT | O_EXCL, 0666);
+	/*
+	 * This could have failed due to the "lazy directory creation";
+	 * try to mkdir the last path component.
+	 */
+	if (freq->localfile < 0 && errno == ENOENT) {
+		char *dir = strrchr(freq->tmpfile.buf, '/');
+		if (dir) {
+			*dir = 0;
+			mkdir(freq->tmpfile.buf, 0777);
+			*dir = '/';
+		}
+		freq->localfile = open(freq->tmpfile.buf,
+				       O_WRONLY | O_CREAT | O_EXCL, 0666);
+	}
+
+	if (freq->localfile < 0) {
+		error_errno("Couldn't create temporary file %s",
+			    freq->tmpfile.buf);
+		goto abort;
+	}
+
+	git_inflate_init(&freq->stream);
+
+	the_hash_algo->init_fn(&freq->c);
+
+	freq->url = get_remote_object_url(base_url, hex, 0);
+
+	/*
+	 * If a previous temp file is present, process what was already
+	 * fetched.
+	 */
+	prevlocal = open(prevfile.buf, O_RDONLY);
+	if (prevlocal != -1) {
+		do {
+			prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
+			if (prev_read>0) {
+				if (fwrite_sha1_file(prev_buf,
+						     1,
+						     prev_read,
+						     freq) == prev_read) {
+					prev_posn += prev_read;
+				} else {
+					prev_read = -1;
+				}
+			}
+		} while (prev_read > 0);
+		close(prevlocal);
+	}
+	unlink_or_warn(prevfile.buf);
+	strbuf_release(&prevfile);
+
+	/*
+	 * Reset inflate/SHA1 if there was an error reading the previous temp
+	 * file; also rewind to the beginning of the local file.
+	 */
+	if (prev_read == -1) {
+		memset(&freq->stream, 0, sizeof(freq->stream));
+		git_inflate_init(&freq->stream);
+		the_hash_algo->init_fn(&freq->c);
+		if (prev_posn>0) {
+			prev_posn = 0;
+			lseek(freq->localfile, 0, SEEK_SET);
+			if (ftruncate(freq->localfile, 0) < 0) {
+				error_errno("Couldn't truncate temporary file %s",
+					    freq->tmpfile.buf);
+				goto abort;
+			}
+		}
+	}
+
+	freq->slot = get_active_slot();
+
+	curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEDATA, freq);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_FAILONERROR, 0);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_HTTPHEADER, no_pragma_header);
+
+	/*
+	 * If we have successfully processed data from a previous fetch
+	 * attempt, only fetch the data we don't already have.
+	 */
+	if (prev_posn>0) {
+		if (http_is_verbose)
+			fprintf(stderr,
+				"Resuming fetch of object %s at byte %"PRIuMAX"\n",
+				hex, (uintmax_t)prev_posn);
+		http_opt_request_remainder(freq->slot->curl, prev_posn);
+	}
+
+	return freq;
+
+abort:
+	strbuf_release(&prevfile);
+	free(freq->url);
+	free(freq);
+	return NULL;
+}
+
+void process_http_object_request(struct http_object_request *freq)
+{
+	if (!freq->slot)
+		return;
+	freq->curl_result = freq->slot->curl_result;
+	freq->http_code = freq->slot->http_code;
+	freq->slot = NULL;
+}
+
+int finish_http_object_request(struct http_object_request *freq)
+{
+	struct stat st;
+	struct strbuf filename = STRBUF_INIT;
+
+	close(freq->localfile);
+	freq->localfile = -1;
+
+	process_http_object_request(freq);
+
+	if (freq->http_code == 416) {
+		warning("requested range invalid; we may already have all the data.");
+	} else if (freq->curl_result != CURLE_OK) {
+		if (stat(freq->tmpfile.buf, &st) == 0)
+			if (st.st_size == 0)
+				unlink_or_warn(freq->tmpfile.buf);
+		return -1;
+	}
+
+	git_inflate_end(&freq->stream);
+	the_hash_algo->final_oid_fn(&freq->real_oid, &freq->c);
+	if (freq->zret != Z_STREAM_END) {
+		unlink_or_warn(freq->tmpfile.buf);
+		return -1;
+	}
+	if (!oideq(&freq->oid, &freq->real_oid)) {
+		unlink_or_warn(freq->tmpfile.buf);
+		return -1;
+	}
+	loose_object_path(the_repository, &filename, &freq->oid);
+	freq->rename = finalize_object_file(freq->tmpfile.buf, filename.buf);
+	strbuf_release(&filename);
+
+	return freq->rename;
+}
+
+void abort_http_object_request(struct http_object_request *freq)
+{
+	unlink_or_warn(freq->tmpfile.buf);
+
+	release_http_object_request(freq);
+}
+
+void release_http_object_request(struct http_object_request *freq)
+{
+	if (freq->localfile != -1) {
+		close(freq->localfile);
+		freq->localfile = -1;
+	}
+	FREE_AND_NULL(freq->url);
+	if (freq->slot) {
+		freq->slot->callback_func = NULL;
+		freq->slot->callback_data = NULL;
+		release_active_slot(freq->slot);
+		freq->slot = NULL;
+	}
+	strbuf_release(&freq->tmpfile);
+}