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Diffstat (limited to 'src/connect.c')
| -rw-r--r-- | src/connect.c | 1043 |
1 files changed, 1043 insertions, 0 deletions
diff --git a/src/connect.c b/src/connect.c new file mode 100644 index 0000000..37dae21 --- /dev/null +++ b/src/connect.c @@ -0,0 +1,1043 @@ +/* Establishing and handling network connections. + Copyright (C) 1995-2011, 2015, 2018 Free Software Foundation, Inc. + +This file is part of GNU Wget. + +GNU Wget is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + +GNU Wget is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with Wget. If not, see <http://www.gnu.org/licenses/>. + +Additional permission under GNU GPL version 3 section 7 + +If you modify this program, or any covered work, by linking or +combining it with the OpenSSL project's OpenSSL library (or a +modified version of that library), containing parts covered by the +terms of the OpenSSL or SSLeay licenses, the Free Software Foundation +grants you additional permission to convey the resulting work. +Corresponding Source for a non-source form of such a combination +shall include the source code for the parts of OpenSSL used as well +as that of the covered work. */ + +#include "wget.h" + +#include "exits.h" +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <assert.h> + +#include <sys/socket.h> +#include <sys/select.h> + +#ifndef WINDOWS +# ifdef __VMS +# include "vms_ip.h" +# else /* def __VMS */ +# include <netdb.h> +# endif /* def __VMS [else] */ +# include <netinet/in.h> +# ifndef __BEOS__ +# include <arpa/inet.h> +# endif +#endif /* not WINDOWS */ + +#include <errno.h> +#include <string.h> +#include <sys/time.h> + +#include "utils.h" +#include "host.h" +#include "connect.h" +#include "hash.h" + +#include <stdint.h> + +/* Define sockaddr_storage where unavailable (presumably on IPv4-only + hosts). */ + +#ifndef ENABLE_IPV6 +# ifndef HAVE_STRUCT_SOCKADDR_STORAGE +# define sockaddr_storage sockaddr_in +# endif +#endif /* ENABLE_IPV6 */ + +/* Fill SA as per the data in IP and PORT. SA shoult point to struct + sockaddr_storage if ENABLE_IPV6 is defined, to struct sockaddr_in + otherwise. */ + +static void +sockaddr_set_data (struct sockaddr *sa, const ip_address *ip, int port) +{ + switch (ip->family) + { + case AF_INET: + { + struct sockaddr_in *sin = (struct sockaddr_in *)sa; + xzero (*sin); + sin->sin_family = AF_INET; + sin->sin_port = htons (port); + sin->sin_addr = ip->data.d4; + break; + } +#ifdef ENABLE_IPV6 + case AF_INET6: + { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa; + xzero (*sin6); + sin6->sin6_family = AF_INET6; + sin6->sin6_port = htons (port); + sin6->sin6_addr = ip->data.d6; +#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID + sin6->sin6_scope_id = ip->ipv6_scope; +#endif + break; + } +#endif /* ENABLE_IPV6 */ + default: + abort (); + } +} + +/* Get the data of SA, specifically the IP address and the port. If + you're not interested in one or the other information, pass NULL as + the pointer. */ + +static void +sockaddr_get_data (const struct sockaddr *sa, ip_address *ip, int *port) +{ + switch (sa->sa_family) + { + case AF_INET: + { + struct sockaddr_in *sin = (struct sockaddr_in *)sa; + if (ip) + { + ip->family = AF_INET; + ip->data.d4 = sin->sin_addr; + } + if (port) + *port = ntohs (sin->sin_port); + break; + } +#ifdef ENABLE_IPV6 + case AF_INET6: + { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa; + if (ip) + { + ip->family = AF_INET6; + ip->data.d6 = sin6->sin6_addr; +#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID + ip->ipv6_scope = sin6->sin6_scope_id; +#endif + } + if (port) + *port = ntohs (sin6->sin6_port); + break; + } +#endif + default: + abort (); + } +} + +/* Return the size of the sockaddr structure depending on its + family. */ + +static socklen_t +sockaddr_size (const struct sockaddr *sa) +{ + switch (sa->sa_family) + { + case AF_INET: + return sizeof (struct sockaddr_in); +#ifdef ENABLE_IPV6 + case AF_INET6: + return sizeof (struct sockaddr_in6); +#endif + default: + abort (); + } +} + +/* Resolve the bind address specified via --bind-address and store it + to SA. The resolved value is stored in a static variable and + reused after the first invocation of this function. + + Returns true on success, false on failure. */ + +static bool +resolve_bind_address (struct sockaddr *sa) +{ + struct address_list *al; + + /* Make sure this is called only once. opt.bind_address doesn't + change during a Wget run. */ + static bool called, should_bind; + static ip_address ip; + if (called) + { + if (should_bind) + sockaddr_set_data (sa, &ip, 0); + return should_bind; + } + called = true; + + al = lookup_host (opt.bind_address, LH_BIND | LH_SILENT); + if (!al) + { + /* #### We should be able to print the error message here. */ + logprintf (LOG_NOTQUIET, + _("%s: unable to resolve bind address %s; disabling bind.\n"), + exec_name, quote (opt.bind_address)); + should_bind = false; + return false; + } + + /* Pick the first address in the list and use it as bind address. + Perhaps we should try multiple addresses in succession, but I + don't think that's necessary in practice. */ + ip = *address_list_address_at (al, 0); + address_list_release (al); + + sockaddr_set_data (sa, &ip, 0); + should_bind = true; + return true; +} + +struct cwt_context { + int fd; + const struct sockaddr *addr; + socklen_t addrlen; + int result; +}; + +static void +connect_with_timeout_callback (void *arg) +{ + struct cwt_context *ctx = (struct cwt_context *)arg; + ctx->result = connect (ctx->fd, ctx->addr, ctx->addrlen); +} + +/* Like connect, but specifies a timeout. If connecting takes longer + than TIMEOUT seconds, -1 is returned and errno is set to + ETIMEDOUT. */ + +static int +connect_with_timeout (int fd, const struct sockaddr *addr, socklen_t addrlen, + double timeout) +{ + struct cwt_context ctx; + ctx.fd = fd; + ctx.addr = addr; + ctx.addrlen = addrlen; + + if (run_with_timeout (timeout, connect_with_timeout_callback, &ctx)) + { + errno = ETIMEDOUT; + return -1; + } + if (ctx.result == -1 && errno == EINTR) + errno = ETIMEDOUT; + return ctx.result; +} + +/* Connect via TCP to the specified address and port. + + If PRINT is non-NULL, it is the host name to print that we're + connecting to. */ + +int +connect_to_ip (const ip_address *ip, int port, const char *print) +{ + struct sockaddr_storage ss; + struct sockaddr *sa = (struct sockaddr *)&ss; + int sock; + + /* If PRINT is non-NULL, print the "Connecting to..." line, with + PRINT being the host name we're connecting to. */ + if (print) + { + const char *txt_addr = print_address (ip); + if (0 != strcmp (print, txt_addr)) + { + char *str = NULL, *name; + + if (opt.enable_iri && (name = idn_decode ((char *) print)) != NULL) + { + str = aprintf ("%s (%s)", name, print); + xfree (name); + } + + logprintf (LOG_VERBOSE, _("Connecting to %s|%s|:%d... "), + str ? str : escnonprint_uri (print), txt_addr, port); + + xfree (str); + } + else + { + if (ip->family == AF_INET) + logprintf (LOG_VERBOSE, _("Connecting to %s:%d... "), txt_addr, port); +#ifdef ENABLE_IPV6 + else if (ip->family == AF_INET6) + logprintf (LOG_VERBOSE, _("Connecting to [%s]:%d... "), txt_addr, port); +#endif + } + } + + /* Store the sockaddr info to SA. */ + sockaddr_set_data (sa, ip, port); + + /* Create the socket of the family appropriate for the address. */ + sock = socket (sa->sa_family, SOCK_STREAM, 0); + if (sock < 0) + goto err; + +#if defined(ENABLE_IPV6) && defined(IPV6_V6ONLY) + if (opt.ipv6_only) { + int on = 1; + /* In case of error, we will go on anyway... */ + int err = setsockopt (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on)); + IF_DEBUG + if (err < 0) + DEBUGP (("Failed setting IPV6_V6ONLY: %s", strerror (errno))); + } +#endif + + /* For very small rate limits, set the buffer size (and hence, + hopefully, the kernel's TCP window size) to the per-second limit. + That way we should never have to sleep for more than 1s between + network reads. */ + if (opt.limit_rate && opt.limit_rate < 8192) + { + int bufsize = opt.limit_rate; + if (bufsize < 512) + bufsize = 512; /* avoid pathologically small values */ +#ifdef SO_RCVBUF + if (setsockopt (sock, SOL_SOCKET, SO_RCVBUF, + (void *) &bufsize, (socklen_t) sizeof (bufsize))) + logprintf (LOG_NOTQUIET, _("setsockopt SO_RCVBUF failed: %s\n"), + strerror (errno)); +#endif + /* When we add limit_rate support for writing, which is useful + for POST, we should also set SO_SNDBUF here. */ + } + + if (opt.bind_address) + { + /* Bind the client side of the socket to the requested + address. */ + struct sockaddr_storage bind_ss; + struct sockaddr *bind_sa = (struct sockaddr *)&bind_ss; + if (resolve_bind_address (bind_sa)) + { + if (bind (sock, bind_sa, sockaddr_size (bind_sa)) < 0) + goto err; + } + } + + /* Connect the socket to the remote endpoint. */ + if (connect_with_timeout (sock, sa, sockaddr_size (sa), + opt.connect_timeout) < 0) + goto err; + + /* Success. */ + assert (sock >= 0); + if (print) + logprintf (LOG_VERBOSE, _("connected.\n")); + DEBUGP (("Created socket %d.\n", sock)); + return sock; + + err: + { + /* Protect errno from possible modifications by close and + logprintf. */ + int save_errno = errno; + if (sock >= 0) + { +#ifdef WIN32 + /* If the connection timed out, fd_close will hang in Gnulib's + close_fd_maybe_socket, inside the call to WSAEnumNetworkEvents. */ + if (errno != ETIMEDOUT) +#endif + fd_close (sock); + } + if (print) + logprintf (LOG_NOTQUIET, _("failed: %s.\n"), strerror (errno)); + errno = save_errno; + return -1; + } +} + +/* Connect via TCP to a remote host on the specified port. + + HOST is resolved as an Internet host name. If HOST resolves to + more than one IP address, they are tried in the order returned by + DNS until connecting to one of them succeeds. */ + +int +connect_to_host (const char *host, int port) +{ + int i, start, end; + int sock; + + struct address_list *al = lookup_host (host, 0); + + retry: + if (!al) + { + logprintf (LOG_NOTQUIET, + _("%s: unable to resolve host address %s\n"), + exec_name, quote (host)); + return E_HOST; + } + + address_list_get_bounds (al, &start, &end); + for (i = start; i < end; i++) + { + const ip_address *ip = address_list_address_at (al, i); + sock = connect_to_ip (ip, port, host); + if (sock >= 0) + { + /* Success. */ + address_list_set_connected (al); + address_list_release (al); + return sock; + } + + /* The attempt to connect has failed. Continue with the loop + and try next address. */ + + address_list_set_faulty (al, i); + } + + /* Failed to connect to any of the addresses in AL. */ + + if (address_list_connected_p (al)) + { + /* We connected to AL before, but cannot do so now. That might + indicate that our DNS cache entry for HOST has expired. */ + address_list_release (al); + al = lookup_host (host, LH_REFRESH); + goto retry; + } + address_list_release (al); + + return -1; +} + +/* Create a socket, bind it to local interface BIND_ADDRESS on port + *PORT, set up a listen backlog, and return the resulting socket, or + -1 in case of error. + + BIND_ADDRESS is the address of the interface to bind to. If it is + NULL, the socket is bound to the default address. PORT should + point to the port number that will be used for the binding. If + that number is 0, the system will choose a suitable port, and the + chosen value will be written to *PORT. + + Calling accept() on such a socket waits for and accepts incoming + TCP connections. */ + +int +bind_local (const ip_address *bind_address, int *port) +{ + int sock; + struct sockaddr_storage ss; + struct sockaddr *sa = (struct sockaddr *)&ss; + + /* For setting options with setsockopt. */ + int setopt_val = 1; + void *setopt_ptr = (void *)&setopt_val; + socklen_t setopt_size = sizeof (setopt_val); + + sock = socket (bind_address->family, SOCK_STREAM, 0); + if (sock < 0) + return -1; + +#ifdef SO_REUSEADDR + if (setsockopt (sock, SOL_SOCKET, SO_REUSEADDR, setopt_ptr, setopt_size)) + logprintf (LOG_NOTQUIET, _("setsockopt SO_REUSEADDR failed: %s\n"), + strerror (errno)); +#endif + + xzero (ss); + sockaddr_set_data (sa, bind_address, *port); + if (bind (sock, sa, sockaddr_size (sa)) < 0) + { + fd_close (sock); + return -1; + } + DEBUGP (("Local socket fd %d bound.\n", sock)); + + /* If *PORT is 0, find out which port we've bound to. */ + if (*port == 0) + { + socklen_t addrlen = sockaddr_size (sa); + if (getsockname (sock, sa, &addrlen) < 0) + { + /* If we can't find out the socket's local address ("name"), + something is seriously wrong with the socket, and it's + unusable for us anyway because we must know the chosen + port. */ + fd_close (sock); + return -1; + } + sockaddr_get_data (sa, NULL, port); + DEBUGP (("binding to address %s using port %i.\n", + print_address (bind_address), *port)); + } + if (listen (sock, 1) < 0) + { + fd_close (sock); + return -1; + } + return sock; +} + +/* Like a call to accept(), but with the added check for timeout. + + In other words, accept a client connection on LOCAL_SOCK, and + return the new socket used for communication with the client. + LOCAL_SOCK should have been bound, e.g. using bind_local(). + + The caller is blocked until a connection is established. If no + connection is established for opt.connect_timeout seconds, the + function exits with an error status. */ + +int +accept_connection (int local_sock) +{ + int sock; + + /* We don't need the values provided by accept, but accept + apparently requires them to be present. */ + struct sockaddr_storage ss; + struct sockaddr *sa = (struct sockaddr *)&ss; + socklen_t addrlen = sizeof (ss); + + if (opt.connect_timeout) + { + int test = select_fd (local_sock, opt.connect_timeout, WAIT_FOR_READ); + if (test == 0) + errno = ETIMEDOUT; + if (test <= 0) + return -1; + } + sock = accept (local_sock, sa, &addrlen); + DEBUGP (("Accepted client at socket %d.\n", sock)); + return sock; +} + +/* Get the IP address associated with the connection on FD and store + it to IP. Return true on success, false otherwise. + + If ENDPOINT is ENDPOINT_LOCAL, it returns the address of the local + (client) side of the socket. Else if ENDPOINT is ENDPOINT_PEER, it + returns the address of the remote (peer's) side of the socket. */ + +bool +socket_ip_address (int sock, ip_address *ip, int endpoint) +{ + struct sockaddr_storage storage; + struct sockaddr *sockaddr = (struct sockaddr *) &storage; + socklen_t addrlen = sizeof (storage); + int ret; + + memset (sockaddr, 0, addrlen); + if (endpoint == ENDPOINT_LOCAL) + ret = getsockname (sock, sockaddr, &addrlen); + else if (endpoint == ENDPOINT_PEER) + ret = getpeername (sock, sockaddr, &addrlen); + else + abort (); + if (ret < 0) + return false; + + memset(ip, 0, sizeof(ip_address)); + ip->family = sockaddr->sa_family; + switch (sockaddr->sa_family) + { +#ifdef ENABLE_IPV6 + case AF_INET6: + { + struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&storage; + ip->data.d6 = sa6->sin6_addr; +#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID + ip->ipv6_scope = sa6->sin6_scope_id; +#endif + DEBUGP (("conaddr is: %s\n", print_address (ip))); + return true; + } +#endif + case AF_INET: + { + struct sockaddr_in *sa = (struct sockaddr_in *)&storage; + ip->data.d4 = sa->sin_addr; + DEBUGP (("conaddr is: %s\n", print_address (ip))); + return true; + } + default: + abort (); + } +} + +/* Get the socket family of connection on FD and store + Return family type on success, -1 otherwise. + + If ENDPOINT is ENDPOINT_LOCAL, it returns the sock family of the local + (client) side of the socket. Else if ENDPOINT is ENDPOINT_PEER, it + returns the sock family of the remote (peer's) side of the socket. */ + +int +socket_family (int sock, int endpoint) +{ + struct sockaddr_storage storage; + struct sockaddr *sockaddr = (struct sockaddr *) &storage; + socklen_t addrlen = sizeof (storage); + int ret; + + memset (sockaddr, 0, addrlen); + + if (endpoint == ENDPOINT_LOCAL) + ret = getsockname (sock, sockaddr, &addrlen); + else if (endpoint == ENDPOINT_PEER) + ret = getpeername (sock, sockaddr, &addrlen); + else + abort (); + + if (ret < 0) + return -1; + + return sockaddr->sa_family; +} + +/* Return true if the error from the connect code can be considered + retryable. Wget normally retries after errors, but the exception + are the "unsupported protocol" type errors (possible on IPv4/IPv6 + dual family systems) and "connection refused". */ + +bool +retryable_socket_connect_error (int err) +{ + /* Have to guard against some of these values not being defined. + Cannot use a switch statement because some of the values might be + equal. */ + if (false +#ifdef EAFNOSUPPORT + || err == EAFNOSUPPORT +#endif +#ifdef EPFNOSUPPORT + || err == EPFNOSUPPORT +#endif +#ifdef ESOCKTNOSUPPORT /* no, "sockt" is not a typo! */ + || err == ESOCKTNOSUPPORT +#endif +#ifdef EPROTONOSUPPORT + || err == EPROTONOSUPPORT +#endif +#ifdef ENOPROTOOPT + || err == ENOPROTOOPT +#endif + /* Apparently, older versions of Linux and BSD used EINVAL + instead of EAFNOSUPPORT and such. */ + || err == EINVAL + ) + return false; + + if (!opt.retry_connrefused) + if (err == ECONNREFUSED +#ifdef ENETUNREACH + || err == ENETUNREACH /* network is unreachable */ +#endif +#ifdef EHOSTUNREACH + || err == EHOSTUNREACH /* host is unreachable */ +#endif + ) + return false; + + return true; +} + +/* Wait for a single descriptor to become available, timing out after + MAXTIME seconds. Returns 1 if FD is available, 0 for timeout and + -1 for error. The argument WAIT_FOR can be a combination of + WAIT_FOR_READ and WAIT_FOR_WRITE. + + This is a mere convenience wrapper around the select call, and + should be taken as such (for example, it doesn't implement Wget's + 0-timeout-means-no-timeout semantics.) */ + +int +select_fd (int fd, double maxtime, int wait_for) +{ + fd_set fdset; + fd_set *rd = NULL, *wr = NULL; + struct timeval tmout; + int result; + + if (fd >= FD_SETSIZE) + { + logprintf (LOG_NOTQUIET, _("Too many fds open. Cannot use select on a fd >= %d\n"), FD_SETSIZE); + exit (WGET_EXIT_GENERIC_ERROR); + } + FD_ZERO (&fdset); + FD_SET (fd, &fdset); + if (wait_for & WAIT_FOR_READ) + rd = &fdset; + if (wait_for & WAIT_FOR_WRITE) + wr = &fdset; + + tmout.tv_sec = (long) maxtime; + tmout.tv_usec = 1000000 * (maxtime - (long) maxtime); + + do + { + result = select (fd + 1, rd, wr, NULL, &tmout); +#ifdef WINDOWS + /* gnulib select() converts blocking sockets to nonblocking in windows. + wget uses blocking sockets so we must convert them back to blocking. */ + set_windows_fd_as_blocking_socket (fd); +#endif + } + while (result < 0 && errno == EINTR); + + return result; +} + +/* Return true iff the connection to the remote site established + through SOCK is still open. + + Specifically, this function returns true if SOCK is not ready for + reading. This is because, when the connection closes, the socket + is ready for reading because EOF is about to be delivered. A side + effect of this method is that sockets that have pending data are + considered non-open. This is actually a good thing for callers of + this function, where such pending data can only be unwanted + leftover from a previous request. */ + +bool +test_socket_open (int sock) +{ + fd_set check_set; + struct timeval to; + int ret = 0; + + if (sock >= FD_SETSIZE) + { + logprintf (LOG_NOTQUIET, _("Too many fds open. Cannot use select on a fd >= %d\n"), FD_SETSIZE); + exit (WGET_EXIT_GENERIC_ERROR); + } + /* Check if we still have a valid (non-EOF) connection. From Andrew + * Maholski's code in the Unix Socket FAQ. */ + + FD_ZERO (&check_set); + FD_SET (sock, &check_set); + + /* Wait one microsecond */ + to.tv_sec = 0; + to.tv_usec = 1; + + ret = select (sock + 1, &check_set, NULL, NULL, &to); +#ifdef WINDOWS +/* gnulib select() converts blocking sockets to nonblocking in windows. +wget uses blocking sockets so we must convert them back to blocking +*/ + set_windows_fd_as_blocking_socket ( sock ); +#endif + + if ( !ret ) + /* We got a timeout, it means we're still connected. */ + return true; + else + /* Read now would not wait, it means we have either pending data + or EOF/error. */ + return false; +} + +/* Basic socket operations, mostly EINTR wrappers. */ + +static int +sock_read (int fd, char *buf, int bufsize) +{ + int res; + do + res = read (fd, buf, bufsize); + while (res == -1 && errno == EINTR); + return res; +} + +static int +sock_write (int fd, char *buf, int bufsize) +{ + int res; + do + res = write (fd, buf, bufsize); + while (res == -1 && errno == EINTR); + return res; +} + +static int +sock_poll (int fd, double timeout, int wait_for) +{ + return select_fd (fd, timeout, wait_for); +} + +static int +sock_peek (int fd, char *buf, int bufsize) +{ + int res; + do + res = recv (fd, buf, bufsize, MSG_PEEK); + while (res == -1 && errno == EINTR); + return res; +} + +static void +sock_close (int fd) +{ + close (fd); + DEBUGP (("Closed fd %d\n", fd)); +} +#undef read +#undef write +#undef close + +/* Reading and writing from the network. We build around the socket + (file descriptor) API, but support "extended" operations for things + that are not mere file descriptors under the hood, such as SSL + sockets. + + That way the user code can call fd_read(fd, ...) and we'll run read + or SSL_read or whatever is necessary. */ + +static struct hash_table *transport_map; +static unsigned int transport_map_modified_tick; + +struct transport_info { + struct transport_implementation *imp; + void *ctx; +}; + +/* Register the transport layer operations that will be used when + reading, writing, and polling FD. + + This should be used for transport layers like SSL that piggyback on + sockets. FD should otherwise be a real socket, on which you can + call getpeername, etc. */ + +void +fd_register_transport (int fd, struct transport_implementation *imp, void *ctx) +{ + struct transport_info *info; + + /* The file descriptor must be non-negative to be registered. + Negative values are ignored by fd_close(), and -1 cannot be used as + hash key. */ + assert (fd >= 0); + + info = xnew (struct transport_info); + info->imp = imp; + info->ctx = ctx; + if (!transport_map) + transport_map = hash_table_new (0, NULL, NULL); + hash_table_put (transport_map, (void *)(intptr_t) fd, info); + ++transport_map_modified_tick; +} + +/* Return context of the transport registered with + fd_register_transport. This assumes fd_register_transport was + previously called on FD. */ + +void * +fd_transport_context (int fd) +{ + struct transport_info *info = hash_table_get (transport_map, (void *)(intptr_t) fd); + return info ? info->ctx : NULL; +} + +/* When fd_read/fd_write are called multiple times in a loop, they should + remember the INFO pointer instead of fetching it every time. It is + not enough to compare FD to LAST_FD because FD might have been + closed and reopened. modified_tick ensures that changes to + transport_map will not be unnoticed. + + This is a macro because we want the static storage variables to be + per-function. */ + +#define LAZY_RETRIEVE_INFO(info) do { \ + static struct transport_info *last_info; \ + static int last_fd = -1; \ + static unsigned int last_tick; \ + if (!transport_map) \ + info = NULL; \ + else if (last_fd == fd && last_tick == transport_map_modified_tick) \ + info = last_info; \ + else \ + { \ + info = hash_table_get (transport_map, (void *)(intptr_t) fd); \ + last_fd = fd; \ + last_info = info; \ + last_tick = transport_map_modified_tick; \ + } \ +} while (0) + +static bool +poll_internal (int fd, struct transport_info *info, int wf, double timeout) +{ + if (timeout == -1) + timeout = opt.read_timeout; + if (timeout) + { + int test; + if (info && info->imp->poller) + test = info->imp->poller (fd, timeout, wf, info->ctx); + else + test = sock_poll (fd, timeout, wf); + if (test == 0) + errno = ETIMEDOUT; + if (test <= 0) + return false; + } + return true; +} + +/* Read no more than BUFSIZE bytes of data from FD, storing them to + BUF. If TIMEOUT is non-zero, the operation aborts if no data is + received after that many seconds. If TIMEOUT is -1, the value of + opt.timeout is used for TIMEOUT. */ + +int +fd_read (int fd, char *buf, int bufsize, double timeout) +{ + struct transport_info *info; + LAZY_RETRIEVE_INFO (info); + if (!poll_internal (fd, info, WAIT_FOR_READ, timeout)) + return -1; + if (info && info->imp->reader) + return info->imp->reader (fd, buf, bufsize, info->ctx); + else + return sock_read (fd, buf, bufsize); +} + +/* Like fd_read, except it provides a "preview" of the data that will + be read by subsequent calls to fd_read. Specifically, it copies no + more than BUFSIZE bytes of the currently available data to BUF and + returns the number of bytes copied. Return values and timeout + semantics are the same as those of fd_read. + + CAVEAT: Do not assume that the first subsequent call to fd_read + will retrieve the same amount of data. Reading can return more or + less data, depending on the TCP implementation and other + circumstances. However, barring an error, it can be expected that + all the peeked data will eventually be read by fd_read. */ + +int +fd_peek (int fd, char *buf, int bufsize, double timeout) +{ + struct transport_info *info; + LAZY_RETRIEVE_INFO (info); + if (!poll_internal (fd, info, WAIT_FOR_READ, timeout)) + return -1; + if (info && info->imp->peeker) + return info->imp->peeker (fd, buf, bufsize, info->ctx); + else + return sock_peek (fd, buf, bufsize); +} + +/* Write the entire contents of BUF to FD. If TIMEOUT is non-zero, + the operation aborts if no data is received after that many + seconds. If TIMEOUT is -1, the value of opt.timeout is used for + TIMEOUT. */ + +int +fd_write (int fd, char *buf, int bufsize, double timeout) +{ + int res; + struct transport_info *info; + LAZY_RETRIEVE_INFO (info); + + /* `write' may write less than LEN bytes, thus the loop keeps trying + it until all was written, or an error occurred. */ + res = 0; + while (bufsize > 0) + { + if (!poll_internal (fd, info, WAIT_FOR_WRITE, timeout)) + return -1; + if (info && info->imp->writer) + res = info->imp->writer (fd, buf, bufsize, info->ctx); + else + res = sock_write (fd, buf, bufsize); + if (res <= 0) + break; + buf += res; + bufsize -= res; + } + return res; +} + +/* Report the most recent error(s) on FD. This should only be called + after fd_* functions, such as fd_read and fd_write, and only if + they return a negative result. For errors coming from other calls + such as setsockopt or fopen, strerror should continue to be + used. + + If the transport doesn't support error messages or doesn't supply + one, strerror(errno) is returned. The returned error message + should not be used after fd_close has been called. */ + +const char * +fd_errstr (int fd) +{ + /* Don't bother with LAZY_RETRIEVE_INFO, as this will only be called + in case of error, never in a tight loop. */ + struct transport_info *info = NULL; + if (transport_map) + info = hash_table_get (transport_map, (void *)(intptr_t) fd); + + if (info && info->imp->errstr) + { + const char *err = info->imp->errstr (fd, info->ctx); + if (err) + return err; + /* else, fall through and print the system error. */ + } + return strerror (errno); +} + +/* Close the file descriptor FD. */ + +void +fd_close (int fd) +{ + struct transport_info *info; + if (fd < 0) + return; + + /* Don't use LAZY_RETRIEVE_INFO because fd_close() is only called once + per socket, so that particular optimization wouldn't work. */ + info = NULL; + if (transport_map) + info = hash_table_get (transport_map, (void *)(intptr_t) fd); + + if (info && info->imp->closer) + info->imp->closer (fd, info->ctx); + else + sock_close (fd); + + if (info) + { + hash_table_remove (transport_map, (void *)(intptr_t) fd); + xfree (info); + ++transport_map_modified_tick; + } +} |