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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/shared/wall.c
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/shared/wall.c')
-rw-r--r--src/shared/wall.c187
1 files changed, 187 insertions, 0 deletions
diff --git a/src/shared/wall.c b/src/shared/wall.c
new file mode 100644
index 0000000..d5900ef
--- /dev/null
+++ b/src/shared/wall.c
@@ -0,0 +1,187 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "sd-login.h"
+
+#include "errno-util.h"
+#include "fd-util.h"
+#include "hostname-util.h"
+#include "io-util.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "terminal-util.h"
+#include "user-util.h"
+#include "utmp-wtmp.h"
+#include "wall.h"
+
+#if ENABLE_UTMP || ENABLE_LOGIND
+
+#define TIMEOUT_USEC (50 * USEC_PER_MSEC)
+
+static int write_to_terminal(const char *tty, const char *message) {
+ _cleanup_close_ int fd = -EBADF;
+
+ assert(tty);
+ assert(message);
+
+ fd = open(tty, O_WRONLY|O_NONBLOCK|O_NOCTTY|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+ if (!isatty(fd))
+ return -ENOTTY;
+
+ return loop_write_full(fd, message, SIZE_MAX, TIMEOUT_USEC);
+}
+
+static int wall_utmp(
+ const char *message,
+ bool (*match_tty)(const char *tty, bool is_local, void *userdata),
+ void *userdata) {
+
+#if ENABLE_UTMP
+ _unused_ _cleanup_(utxent_cleanup) bool utmpx = false;
+ struct utmpx *u;
+ int r = 0;
+
+ assert(message);
+
+ /* libc's setutxent() unfortunately doesn't inform us about success, i.e. whether /var/run/utmp
+ * exists. Hence we have to check manually first. */
+ if (access(_PATH_UTMPX, F_OK) < 0) {
+ if (errno == ENOENT)
+ return -ENOPROTOOPT;
+
+ return -errno;
+ }
+
+ utmpx = utxent_start();
+
+ while ((u = getutxent())) {
+ _cleanup_free_ char *p = NULL;
+ const char *tty_path;
+ bool is_local;
+
+ if (u->ut_type != USER_PROCESS || isempty(u->ut_user))
+ continue;
+
+ /* This access is fine, because strlen("/dev/") < 32 (UT_LINESIZE) */
+ if (path_startswith(u->ut_line, "/dev/"))
+ tty_path = u->ut_line;
+ else {
+ if (asprintf(&p, "/dev/%.*s", (int) sizeof(u->ut_line), u->ut_line) < 0)
+ return -ENOMEM;
+
+ tty_path = p;
+ }
+
+ /* It seems that the address field is always set for remote logins. For local logins and
+ * other local entries, we get [0,0,0,0]. */
+ is_local = eqzero(u->ut_addr_v6);
+
+ if (!match_tty || match_tty(tty_path, is_local, userdata))
+ RET_GATHER(r, write_to_terminal(tty_path, message));
+ }
+
+ return r;
+
+#else
+ return -ENOPROTOOPT;
+#endif
+}
+
+static int wall_logind(
+ const char *message,
+ bool (*match_tty)(const char *tty, bool is_local, void *userdata),
+ void *userdata) {
+
+#if ENABLE_LOGIND
+ _cleanup_strv_free_ char **sessions = NULL;
+ int r;
+
+ assert(message);
+
+ r = sd_get_sessions(&sessions);
+ if (r <= 0)
+ return r;
+
+ r = 0;
+
+ STRV_FOREACH(s, sessions) {
+ _cleanup_free_ char *tty_path = NULL, *tty = NULL, *rhost = NULL;
+ bool is_local;
+ int q;
+
+ q = sd_session_get_tty(*s, &tty);
+ if (IN_SET(q, -ENXIO, -ENODATA))
+ continue;
+ if (q < 0)
+ return RET_GATHER(r, q);
+
+ tty_path = strjoin("/dev/", tty);
+ if (!tty_path)
+ return -ENOMEM;
+
+ (void) sd_session_get_remote_host(*s, &rhost);
+ is_local = !rhost;
+
+ if (!match_tty || match_tty(tty_path, is_local, userdata))
+ RET_GATHER(r, write_to_terminal(tty_path, message));
+ }
+
+ return r;
+
+#else
+ return -ENOPROTOOPT;
+#endif
+}
+
+int wall(
+ const char *message,
+ const char *username,
+ const char *origin_tty,
+ bool (*match_tty)(const char *tty, bool is_local, void *userdata),
+ void *userdata) {
+
+ _cleanup_free_ char *text = NULL, *hostname = NULL, *username_alloc = NULL, *stdin_tty = NULL;
+ int r;
+
+ assert(message);
+
+ hostname = gethostname_malloc();
+ if (!hostname)
+ return -ENOMEM;
+
+ if (!username) {
+ username_alloc = getlogname_malloc();
+ if (!username_alloc)
+ return -ENOMEM;
+
+ username = username_alloc;
+ }
+
+ if (!origin_tty) {
+ (void) getttyname_harder(STDIN_FILENO, &stdin_tty);
+ origin_tty = stdin_tty;
+ }
+
+ if (asprintf(&text,
+ "\r\n"
+ "Broadcast message from %s@%s%s%s (%s):\r\n\r\n"
+ "%s\r\n\r\n",
+ username, hostname,
+ origin_tty ? " on " : "", strempty(origin_tty),
+ FORMAT_TIMESTAMP(now(CLOCK_REALTIME)),
+ message) < 0)
+ return -ENOMEM;
+
+ r = wall_utmp(text, match_tty, userdata);
+ if (r == -ENOPROTOOPT)
+ r = wall_logind(text, match_tty, userdata);
+
+ return r == -ENOPROTOOPT ? 0 : r;
+}
+
+#endif