Loop the waitpid() on EINTR, and save and restore the disposition of

SIGINT and SIGQUIT with sigaction() instead of signal() so that all bits
are preserved.

ok deraadt@ millert@

1 files changed, 12 insertions, 9 deletions

diff --git a/src/lib/libc/stdlib/system.c b/src/lib/libc/stdlib/system.c
index 3ad0bcde41..de32d4328f 100644
--- a/src/lib/libc/stdlib/system.c
+++ b/src/lib/libc/stdlib/system.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: system.c,v 1.10 2015/09/14 08:51:07 guenther Exp $ */
+/*      $OpenBSD: system.c,v 1.11 2015/10/23 04:44:41 guenther Exp $ */
 /*
  * Copyright (c) 1988 The Regents of the University of California.
  * All rights reserved.
@@ -30,6 +30,7 @@
 
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <errno.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -40,8 +41,8 @@ extern char **environ;
 int
 system(const char *command)
 {
-        pid_t pid;
-        sig_t intsave, quitsave;
+        pid_t pid, cpid;
+        struct sigaction intsave, quitsave;
         sigset_t mask, omask;
         int pstat;
         char *argp[] = {"sh", "-c", NULL, NULL};
@@ -54,7 +55,7 @@ system(const char *command)
         sigemptyset(&mask);
         sigaddset(&mask, SIGCHLD);
         sigprocmask(SIG_BLOCK, &mask, &omask);
-        switch (pid = vfork()) {
+        switch (cpid = vfork()) {
         case -1:                        /* error */
                 sigprocmask(SIG_SETMASK, &omask, NULL);
                 return(-1);
@@ -64,12 +65,14 @@ system(const char *command)
                 _exit(127);
         }
 
-        intsave = signal(SIGINT, SIG_IGN);
-        quitsave = signal(SIGQUIT, SIG_IGN);
-        pid = waitpid(pid, &pstat, 0);
+        sigaction(SIGINT, NULL, &intsave);
+        sigaction(SIGQUIT, NULL, &quitsave);
+        do {
+                pid = waitpid(cpid, &pstat, 0);
+        } while (pid == -1 && errno == EINTR);
         sigprocmask(SIG_SETMASK, &omask, NULL);
-        (void)signal(SIGINT, intsave);
-        (void)signal(SIGQUIT, quitsave);
+        sigaction(SIGINT, &intsave, NULL);
+        sigaction(SIGQUIT, &quitsave, NULL);
         return (pid == -1 ? -1 : pstat);
 }
 DEF_STRONG(system);