Adding upstream version 255.4.upstream/255.4

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

1 files changed, 209 insertions, 0 deletions

diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c
new file mode 100644
index 0000000..e743033
--- /dev/null
+++ b/src/basic/hostname-util.c
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "env-file.h"
+#include "hostname-util.h"
+#include "os-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+char* get_default_hostname(void) {
+        int r;
+
+        const char *e = secure_getenv("SYSTEMD_DEFAULT_HOSTNAME");
+        if (e) {
+                if (hostname_is_valid(e, 0))
+                        return strdup(e);
+                log_debug("Invalid hostname in $SYSTEMD_DEFAULT_HOSTNAME, ignoring: %s", e);
+        }
+
+        _cleanup_free_ char *f = NULL;
+        r = parse_os_release(NULL, "DEFAULT_HOSTNAME", &f);
+        if (r < 0)
+                log_debug_errno(r, "Failed to parse os-release, ignoring: %m");
+        else if (f) {
+                if (hostname_is_valid(f, 0))
+                        return TAKE_PTR(f);
+                log_debug("Invalid hostname in os-release, ignoring: %s", f);
+        }
+
+        return strdup(FALLBACK_HOSTNAME);
+}
+
+int gethostname_full(GetHostnameFlags flags, char **ret) {
+        _cleanup_free_ char *buf = NULL, *fallback = NULL;
+        struct utsname u;
+        const char *s;
+
+        assert(ret);
+
+        assert_se(uname(&u) >= 0);
+
+        s = u.nodename;
+        if (isempty(s) || streq(s, "(none)") ||
+            (!FLAGS_SET(flags, GET_HOSTNAME_ALLOW_LOCALHOST) && is_localhost(s)) ||
+            (FLAGS_SET(flags, GET_HOSTNAME_SHORT) && s[0] == '.')) {
+                if (!FLAGS_SET(flags, GET_HOSTNAME_FALLBACK_DEFAULT))
+                        return -ENXIO;
+
+                s = fallback = get_default_hostname();
+                if (!s)
+                        return -ENOMEM;
+
+                if (FLAGS_SET(flags, GET_HOSTNAME_SHORT) && s[0] == '.')
+                        return -ENXIO;
+        }
+
+        if (FLAGS_SET(flags, GET_HOSTNAME_SHORT))
+                buf = strdupcspn(s, ".");
+        else
+                buf = strdup(s);
+        if (!buf)
+                return -ENOMEM;
+
+        *ret = TAKE_PTR(buf);
+        return 0;
+}
+
+bool valid_ldh_char(char c) {
+        /* "LDH" → "Letters, digits, hyphens", as per RFC 5890, Section 2.3.1 */
+
+        return ascii_isalpha(c) ||
+                ascii_isdigit(c) ||
+                c == '-';
+}
+
+bool hostname_is_valid(const char *s, ValidHostnameFlags flags) {
+        unsigned n_dots = 0;
+        const char *p;
+        bool dot, hyphen;
+
+        /* Check if s looks like a valid hostname or FQDN. This does not do full DNS validation, but only
+         * checks if the name is composed of allowed characters and the length is not above the maximum
+         * allowed by Linux (c.f. dns_name_is_valid()). A trailing dot is allowed if
+         * VALID_HOSTNAME_TRAILING_DOT flag is set and at least two components are present in the name. Note
+         * that due to the restricted charset and length this call is substantially more conservative than
+         * dns_name_is_valid(). Doesn't accept empty hostnames, hostnames with leading dots, and hostnames
+         * with multiple dots in a sequence. Doesn't allow hyphens at the beginning or end of label. */
+
+        if (isempty(s))
+                return false;
+
+        if (streq(s, ".host")) /* Used by the container logic to denote the "root container" */
+                return FLAGS_SET(flags, VALID_HOSTNAME_DOT_HOST);
+
+        for (p = s, dot = hyphen = true; *p; p++)
+                if (*p == '.') {
+                        if (dot || hyphen)
+                                return false;
+
+                        dot = true;
+                        hyphen = false;
+                        n_dots++;
+
+                } else if (*p == '-') {
+                        if (dot)
+                                return false;
+
+                        dot = false;
+                        hyphen = true;
+
+                } else {
+                        if (!valid_ldh_char(*p))
+                                return false;
+
+                        dot = false;
+                        hyphen = false;
+                }
+
+        if (dot && (n_dots < 2 || !FLAGS_SET(flags, VALID_HOSTNAME_TRAILING_DOT)))
+                return false;
+        if (hyphen)
+                return false;
+
+        if (p-s > HOST_NAME_MAX) /* Note that HOST_NAME_MAX is 64 on Linux, but DNS allows domain names up to
+                                  * 255 characters */
+                return false;
+
+        return true;
+}
+
+char* hostname_cleanup(char *s) {
+        char *p, *d;
+        bool dot, hyphen;
+
+        assert(s);
+
+        for (p = s, d = s, dot = hyphen = true; *p && d - s < HOST_NAME_MAX; p++)
+                if (*p == '.') {
+                        if (dot || hyphen)
+                                continue;
+
+                        *(d++) = '.';
+                        dot = true;
+                        hyphen = false;
+
+                } else if (*p == '-') {
+                        if (dot)
+                                continue;
+
+                        *(d++) = '-';
+                        dot = false;
+                        hyphen = true;
+
+                } else if (valid_ldh_char(*p)) {
+                        *(d++) = *p;
+                        dot = false;
+                        hyphen = false;
+                }
+
+        if (d > s && IN_SET(d[-1], '-', '.'))
+                /* The dot can occur at most once, but we might have multiple
+                 * hyphens, hence the loop */
+                d--;
+        *d = 0;
+
+        return s;
+}
+
+bool is_localhost(const char *hostname) {
+        assert(hostname);
+
+        /* This tries to identify local host and domain names
+         * described in RFC6761 plus the redhatism of localdomain */
+
+        return STRCASE_IN_SET(
+                        hostname,
+                        "localhost",
+                        "localhost.",
+                        "localhost.localdomain",
+                        "localhost.localdomain.") ||
+                endswith_no_case(hostname, ".localhost") ||
+                endswith_no_case(hostname, ".localhost.") ||
+                endswith_no_case(hostname, ".localhost.localdomain") ||
+                endswith_no_case(hostname, ".localhost.localdomain.");
+}
+
+int get_pretty_hostname(char **ret) {
+        _cleanup_free_ char *n = NULL;
+        int r;
+
+        assert(ret);
+
+        r = parse_env_file(NULL, "/etc/machine-info", "PRETTY_HOSTNAME", &n);
+        if (r < 0)
+                return r;
+
+        if (isempty(n))
+                return -ENXIO;
+
+        *ret = TAKE_PTR(n);
+        return 0;
+}