From: Roy Marples <roy@marples.name>
Date: Sun, 11 Nov 2012 00:25:58 +0000 (+0000)
Subject: Log posix_spawn(2) errors better.
X-Git-Tag: v5.99.3~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9530feed8ab30c96f639b521bed1d6ef982df018;p=thirdparty%2Fdhcpcd.git

Log posix_spawn(2) errors better.

In our compat shim, use fork(2) if we have it, otherwise vfork(2).
This makes us a lot better in terms of reliability, but sucks for
reporting errors.
---

diff --git a/compat/posix_spawn.c b/compat/posix_spawn.c
index 3de3f301..00f0cb3d 100644
--- a/compat/posix_spawn.c
+++ b/compat/posix_spawn.c
@@ -26,9 +26,7 @@
  */
 
 /* This implementation of posix_spawn is only suitable for the needs of dhcpcd
- * but it could easily be extended to other applications.
- * Also, it does rely on the system being able to modify signals safely within
- * the vfork process which is undefined behaviour, but seems sane in testing. */
+ * but it could easily be extended to other applications. */
 
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -86,7 +84,12 @@ posix_spawn(pid_t *pid, const char * path,
 	volatile int error;
 
 	error = 0;
+#ifdef THERE_IS_NO_FORK
+	/* Pray we can sanely modify signal foo */
 	p = vfork();
+#else
+	p = fork();
+#endif
 	switch (p) {
 	case -1:
 		return errno;
diff --git a/configure.c b/configure.c
index 78b470c9..03e24555 100644
--- a/configure.c
+++ b/configure.c
@@ -101,8 +101,10 @@ exec_script(char *const *argv, char *const *env)
 	posix_spawnattr_setsigmask(&attr, &dhcpcd_sigset);
 	errno = 0;
 	i = posix_spawn(&pid, argv[0], NULL, &attr, argv, env);
-	if (i)
+	if (i) {
+		errno = i;
 		return -1;
+	}
 	return pid;
 }
 
@@ -422,10 +424,9 @@ run_script_reason(const struct interface *iface, const char *reason)
 	env[++elen] = '\0';
 
 	pid = exec_script(argv, env);
-	if (pid == -1) {
-		syslog(LOG_ERR, "exec_script: %m");
-		status = -1;
-	} else if (pid != 0) {
+	if (pid == -1)
+		syslog(LOG_ERR, "exec_script: %s: %m", argv[0]);
+	else if (pid != 0) {
 		/* Wait for the script to finish */
 		while (waitpid(pid, &status, 0) == -1) {
 			if (errno != EINTR) {
@@ -462,7 +463,7 @@ run_script_reason(const struct interface *iface, const char *reason)
 	while (*ep)
 		free(*ep++);
 	free(env);
-	return status;
+	return WEXITSTATUS(status);
 }
 
 static struct rt *