X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=src%2Fwall-notify.c;h=dd37e897a03ccea27adb731e0466fea59b232f6f;hb=43c0d246c433eff4a743f695f7923a8ac88d54e8;hp=343f3d0ff37bfbb5a6798ee70158dbbed0cceb4a;hpb=5b093d27e49c3fd96d262b11b08f790dc290454e;p=wall-notify%2Fwall-notify.git

diff --git a/src/wall-notify.c b/src/wall-notify.c
index 343f3d0..dd37e89 100644
--- a/src/wall-notify.c
+++ b/src/wall-notify.c
@@ -33,6 +33,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
 #ifdef USE_UTEMPTER
@@ -60,9 +61,6 @@ static void setup_signals(void) {
     sigaction(SIGQUIT, &action, NULL);
     sigaction(SIGUSR1, &action, NULL);
     sigaction(SIGUSR2, &action, NULL);
-
-    /* Collect zombies automatically without having to call waitpid(2). */
-    signal(SIGCHLD, SIG_IGN);
 }
 
 static int open_tty(void) {
@@ -145,7 +143,16 @@ static int set_utmpx(short type, int ptm) {
 #endif
 static int login(int ptm) {
 #if defined(USE_UTEMPTER)
-    return utempter_add_record(ptm, NULL);
+    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. */
+# ifndef __linux
+    result = 1;
+# endif
+    return result;
 #elif defined(USE_UTMPX)
     return set_utmpx(USER_PROCESS, ptm);
 #else
@@ -154,7 +161,12 @@ static int login(int ptm) {
 }
 static int logout(int ptm) {
 #if defined(USE_UTEMPTER)
-    return utempter_remove_record(ptm);
+    int result = utempter_remove_record(ptm);
+    /* See above. */
+# ifndef __linux
+    result = 1;
+# endif
+    return result;
 #elif defined(USE_UTMPX)
     return set_utmpx(DEAD_PROCESS, ptm);
 #else
@@ -225,9 +237,21 @@ static void pass_buffer_to_program(const char *buffer, size_t length, char **arg
         }
         close(fds[0]);
 
-        execvp(argv[0], argv);
-        perror("execvp");
-        exit(EXIT_FAILURE);
+        /* Double fork so `wall-notify` doesn't have to wait for the
+         * notification process to terminate. We can't just use
+         * signal(SIGCHLD, SIG_IGN); because utempter on at least FreeBSD
+         * doesn't work if SIGCHLD is ignored. */
+        pid = fork();
+        if (pid < 0) {
+            perror("fork");
+            exit(EXIT_FAILURE);
+        } else if (pid == 0) {
+            execvp(argv[0], argv);
+            perror("execvp");
+            exit(EXIT_FAILURE);
+        }
+
+        exit(EXIT_SUCCESS);
     }
     /* father */
 
@@ -239,6 +263,10 @@ static void pass_buffer_to_program(const char *buffer, size_t length, char **arg
 out:
     close(fds[0]); /* read side */
     fclose(fh);
+
+    if (waitpid(pid, NULL, 0) < 0) {
+        perror("waitpid");
+    }
 }
 static void handle_wall(int fd, char **argv) {
     char buffer[4096];