Don't skip debug printfs in handle_sigchld() just because execve()

returned an error.

diff --git a/src/exec_pty.c b/src/exec_pty.c
index b3a4e3802e8fe56ee125dee7521f184c2267e3e2..e253e034a815ce2a5df4ee3641ece154db66de90 100644 (file)
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -1147,51 +1147,54 @@ send_status(int fd, struct command_status *cstat)
 static bool
 handle_sigchld(int backchannel, struct command_status *cstat)
 {
-    bool alive = true;
+    char signame[SIG2STR_MAX];
     int status;
     pid_t pid;
     debug_decl(handle_sigchld, SUDO_DEBUG_EXEC);
 
-    /* read command status */
+    /* Read command status. */
     do {
        pid = waitpid(cmnd_pid, &status, WUNTRACED|WNOHANG);
     } while (pid == -1 && errno == EINTR);
-    if (pid != cmnd_pid) {
-       sudo_debug_printf(SUDO_DEBUG_INFO,
+    if (pid <= 0) {
+       sudo_debug_printf(SUDO_DEBUG_DIAG,
            "waitpid returned %d, expected pid %d", pid, cmnd_pid);
+       debug_return_bool(false);
+    }
+
+    if (WIFSTOPPED(status)) {
+       if (sig2str(WSTOPSIG(status), signame) == -1)
+           snprintf(signame, sizeof(signame), "%d", WSTOPSIG(status));
+       sudo_debug_printf(SUDO_DEBUG_INFO, "command stopped, SIG%s", signame);
+    } else if (WIFSIGNALED(status)) {
+       if (sig2str(WTERMSIG(status), signame) == -1)
+           snprintf(signame, sizeof(signame), "%d", WTERMSIG(status));
+       sudo_debug_printf(SUDO_DEBUG_INFO, "command killed, SIG%s", signame);
     } else {
-       if (cstat->type != CMD_ERRNO) {
-           char signame[SIG2STR_MAX];
-
-           cstat->type = CMD_WSTATUS;
-           cstat->val = status;
-           if (WIFSTOPPED(status)) {
-               if (sig2str(WSTOPSIG(status), signame) == -1)
-                   snprintf(signame, sizeof(signame), "%d", WSTOPSIG(status));
-               sudo_debug_printf(SUDO_DEBUG_INFO,
-                   "command stopped, SIG%s", signame);
-               /* Saved the foreground pgid so we can restore it later. */
-               do {
-                   pid = tcgetpgrp(io_fds[SFD_SLAVE]);
-               } while (pid == -1 && errno == EINTR);
-               if (pid != mon_pgrp)
-                   cmnd_pgrp = pid;
-               if (send_status(backchannel, cstat) == -1)
-                   debug_return_bool(alive); /* XXX */
-           } else if (WIFSIGNALED(status)) {
-               if (sig2str(WTERMSIG(status), signame) == -1)
-                   snprintf(signame, sizeof(signame), "%d", WTERMSIG(status));
-               sudo_debug_printf(SUDO_DEBUG_INFO,
-                   "command killed, SIG%s", signame);
-           } else {
-               sudo_debug_printf(SUDO_DEBUG_INFO, "command exited: %d",
-                   WEXITSTATUS(status));
-           }
+       sudo_debug_printf(SUDO_DEBUG_INFO, "command exited: %d",
+           WEXITSTATUS(status));
+    }
+
+    /* Don't overwrite execve() failure with child exit status. */
+    if (cstat->type != CMD_ERRNO) {
+       /*
+        * Store wait status in cstat and forward to parent if stopped.
+        */
+       cstat->type = CMD_WSTATUS;
+       cstat->val = status;
+       if (WIFSTOPPED(status)) {
+           /* Save the foreground pgid so we can restore it later. */
+           do {
+               pid = tcgetpgrp(io_fds[SFD_SLAVE]);
+           } while (pid == -1 && errno == EINTR);
+           if (pid != mon_pgrp)
+           send_status(backchannel, cstat);
+           debug_return_bool(true);
        }
-       if (!WIFSTOPPED(status))
-           alive = false;
     }
-    debug_return_bool(alive);
+
+    /* It's dead, Jim. */
+    debug_return_bool(false);
 }
 
 struct monitor_closure {
@@ -1272,7 +1275,7 @@ mon_backchannel_cb(int fd, int what, void *v)
     ssize_t n;
     debug_decl(mon_backchannel_cb, SUDO_DEBUG_EXEC);
 
-    /* read command from backchannel, should be a signal */
+    /* Read command from backchannel, should be a signal. */
     n = recv(fd, &cstmp, sizeof(cstmp), MSG_WAITALL);
     if (n != sizeof(cstmp)) {
        if (n == -1) {