remove superfluous braces in comment

[wall-notify/wall-notify.git] / src / wall-notify.c

diff --git a/src/wall-notify.c b/src/wall-notify.c
index bbc783b5e884514ca1f793da674ba22d71bc5415..e0d556db1386387e567bcb7967cb0fe9f1e213fb 100644 (file)
--- a/src/wall-notify.c
+++ b/src/wall-notify.c
@@ -1,7 +1,7 @@
 /*
  * Receive wall messages and pass them to a notification program via stdin.
  *
- * Copyright (C) 2014  Simon Ruderich
+ * Copyright (C) 2014-2015  Simon Ruderich
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -48,8 +48,13 @@
 #endif
 
 
+static sig_atomic_t signaled = 0;
+
+
 static void sig_handler(int signal) {
     (void)signal;
+
+    signaled = 1;
 }
 static void setup_signals(void) {
     struct sigaction action;
@@ -67,7 +72,18 @@ static void setup_signals(void) {
     sigaction(SIGUSR2, &action, NULL);
 }
 
-static int open_tty(void) {
+static int set_cloexec(int fd) {
+    int flags = fcntl(fd, F_GETFD);
+    if (flags == -1) {
+        return 0;
+    }
+    if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) {
+        return 0;
+    }
+    return 1;
+}
+
+static int open_tty(int public) {
     int ptm;
     const char *name;
 
@@ -78,15 +94,20 @@ static int open_tty(void) {
     if (grantpt(ptm) != 0) {
         return -1;
     }
+    if (!set_cloexec(ptm)) {
+        return -1;
+    }
 
     /* Prevent write access for other users so they can't use wall to send
      * messages to this program. */
-    name = ptsname(ptm);
-    if (!name) {
-        return -1;
-    }
-    if (chmod(name, S_IRUSR | S_IWUSR) != 0) {
-        return -1;
+    if (!public) {
+        name = ptsname(ptm);
+        if (!name) {
+            return -1;
+        }
+        if (chmod(name, S_IRUSR | S_IWUSR) != 0) {
+            return -1;
+        }
     }
 
     if (unlockpt(ptm) != 0) {
@@ -148,11 +169,11 @@ static int set_utmpx(short type, int ptm) {
 static int login(int ptm) {
 #if defined(USE_UTEMPTER)
     int result = utempter_add_record(ptm, NULL);
-    /* Exit value of utempter_*() is not correct on all systems, e.g.
-     * FreeBSD() always returns 0. Checking the utmpx database manually is
-     * difficult because we don't know the exact values for ut_id and ut_line,
-     * therefore we only check the return value on systems known to return a
-     * useful value. */
+    /* Exit value of utempter_*() is not correct on all systems, e.g. FreeBSD
+     * always returns 0. Checking the utmpx database manually is difficult
+     * because we don't know the exact values for ut_id and ut_line, therefore
+     * we only check the return value on systems known to return a useful
+     * value. */
 # ifndef __linux
     result = 1;
 # endif
@@ -212,14 +233,14 @@ static void drop_privileges(void) {
     gid = getgid();
 
     /* Drop all privileges. */
-    if (setresuid(uid, uid, uid) != 0) {
-        perror("setresuid");
-        exit(EXIT_FAILURE);
-    }
     if (setresgid(gid, gid, gid) != 0) {
         perror("setresgid");
         exit(EXIT_FAILURE);
     }
+    if (setresuid(uid, uid, uid) != 0) {
+        perror("setresuid");
+        exit(EXIT_FAILURE);
+    }
 
     /* Verify all privileges were dropped. */
     if (getresuid(&ruid, &euid, &suid) != 0) {
@@ -316,7 +337,7 @@ static void handle_wall(int fd, char **argv) {
     ssize_t r;
 
     assert(SSIZE_MAX <= SIZE_MAX);
-    while ((r = read(fd, buffer, sizeof(buffer))) > 0) {
+    while (!signaled && (r = read(fd, buffer, sizeof(buffer))) > 0) {
         size_t space;
         ssize_t r2;
 
@@ -359,10 +380,12 @@ static void *x11_event_loop_thread(void *unused) {
 #endif
 
 static void usage(const char *argv0) {
-    fprintf(stderr, "usage: %s [-X] <cmd args..>\n", argv0);
+    fprintf(stderr, "usage: %s [-X] [-m] [-v] <cmd args..>\n", argv0);
     fprintf(stderr, "Pass wall messages to <cmd args..>.\n");
     fprintf(stderr, "\n");
     fprintf(stderr, "-X quit when the current X session terminates\n");
+    fprintf(stderr, "-m allow messages from normal users (like `mesg y`)\n");
+    fprintf(stderr, "-v display version\n");
 #ifdef DONT_USE_X11
     fprintf(stderr, "\n");
     fprintf(stderr, "compiled without X11 support, -X disabled\n");
@@ -372,7 +395,8 @@ static void usage(const char *argv0) {
 
 
 int main(int argc, char **argv) {
-    int option, enable_x11;
+    int option, enable_x11, mesg_yes;
+    const char *argv0;
     int ptm, pts;
     char *name;
 
@@ -380,6 +404,9 @@ int main(int argc, char **argv) {
     opterr = 0;
 
     enable_x11 = 0;
+    mesg_yes = 0;
+
+    argv0 = argv[0];
 
     /*
      * Glibc violates POSIX by default and skips over non-option arguments and
@@ -388,30 +415,39 @@ int main(int argc, char **argv) {
      * the optstring with "+" fixes this behaver. This is not POSIX
      * compatible, but the option should be ignored on other systems.
      */
-    while ((option = getopt(argc, argv, "+Xh")) != -1) {
+    while ((option = getopt(argc, argv, "+Xmhv")) != -1) {
         switch (option) {
             case 'X':
                 enable_x11 = 1;
                 break;
+            case 'm':
+                mesg_yes = 1;
+                break;
             case 'h':
-                usage(argv[0]);
+                usage(argv0);
+                break;
+            case 'v':
+                printf("%s%s\n",
+                       PACKAGE_STRING,
+                       strlen(GIT_VERSION) ? " (Git " GIT_VERSION ")" : "");
+                exit(EXIT_SUCCESS);
                 break;
             default:
                 fprintf(stderr, "%s: unknown option '%s'!\n\n",
-                                argv[0], argv[optind - 1]);
-                usage(argv[0]);
+                                argv0, argv[optind - 1]);
+                usage(argv0);
                 break;
         }
     }
 
     /* No arguments remaining, abort. */
     if (!argv[optind]) {
-        usage(argv[0]);
+        usage(argv0);
     }
     /* Arguments for notification program. */
     argv += optind;
 
-    ptm = open_tty();
+    ptm = open_tty(mesg_yes);
     if (ptm < 0) {
         perror("open_tty");
         exit(EXIT_FAILURE);
@@ -428,7 +464,7 @@ int main(int argc, char **argv) {
 
     /* We need to open the slave or reading from the master yields EOF after
      * the first wall write to it. */
-    pts = open(name, O_RDWR);
+    pts = open(name, O_RDWR | O_CLOEXEC);
     if (pts < 0) {
         perror(name);
         exit(EXIT_FAILURE);