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 3de3f3018c8b7c0f4e1e7b053221bae64c4d6212..00f0cb3d5ee6855b6abfc8cc2c20f76a07898c83 100644 (file)
--- 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 78b470c9fa597f9b31018e935f59cca540c45432..03e245554dae1055c6f2beefa8d19f1ff6a6a0fc 100644 (file)
--- 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 *