From: Roy Marples <roy@marples.name>
Date: Fri, 21 Feb 2014 15:51:42 +0000 (+0000)
Subject: If there are no file actions or dangerous attributes then use
X-Git-Tag: v6.3.0~5
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=11a06bb9b129a3dd3c872e142bd3334cf560bb54;p=thirdparty%2Fdhcpcd.git

If there are no file actions or dangerous attributes then use
vfork(2) instead of fork(2) in our compat posix_spawn(3) function.
---

diff --git a/compat/posix_spawn.c b/compat/posix_spawn.c
index 822425e7..0cb142e5 100644
--- a/compat/posix_spawn.c
+++ b/compat/posix_spawn.c
@@ -74,21 +74,31 @@ posix_spawnattr_handle(const posix_spawnattr_t *attrp)
 	return 0;
 }
 
+inline static int
+is_vfork_safe(short int flags)
+{
+	return !(flags & (POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK));
+}
+
 int
-posix_spawn(pid_t *pid, const char * path,
-	__unused void *arg,
+posix_spawn(pid_t *pid, const char *path,
+	const posix_spawn_file_actions_t *file_actions,
 	const posix_spawnattr_t *attrp,
 	char *const argv[], char *const envp[])
 {
+	short int flags;
 	pid_t p;
 	volatile int error;
 
 	error = 0;
+	flags = attrp ? attrp->posix_attr_flags : 0;
+	if (file_actions == NULL && is_vfork_safe(flags))
+		p = vfork();
+	else
 #ifdef THERE_IS_NO_FORK
-	/* Pray we can sanely modify signal foo */
-	p = vfork();
+		return ENOSYS;
 #else
-	p = fork();
+		p = fork();
 #endif
 	switch (p) {
 	case -1:
diff --git a/compat/posix_spawn.h b/compat/posix_spawn.h
index fe6958c4..ccfb0f0c 100644
--- a/compat/posix_spawn.h
+++ b/compat/posix_spawn.h
@@ -38,8 +38,13 @@ typedef struct {
 	sigset_t posix_attr_sigdefault;
 } posix_spawnattr_t;
 
-int posix_spawn(pid_t *, const char *, void *, const posix_spawnattr_t *,
-	char *const [], char *const []);
+typedef struct {
+//	int unused;
+} posix_spawn_file_actions_t;
+
+int posix_spawn(pid_t *, const char *,
+    const posix_spawn_file_actions_t *, const posix_spawnattr_t *,
+    char *const [], char *const []);
 int posix_spawnattr_init(posix_spawnattr_t *);
 int posix_spawnattr_setflags(posix_spawnattr_t *, short);
 int posix_spawnattr_setsigmask(posix_spawnattr_t *, const sigset_t *);