From 922db9aa31d3d21cbfa631ee88b7159f34319cc2 Mon Sep 17 00:00:00 2001
From: vda <vda@69ca8d6d-28ef-0310-b511-8ec308f3f277>
Date: Mon, 26 Mar 2007 13:20:04 +0000
Subject: libbb: rework NOMMU helper API so that it makes more sense and easier
to use. Doesn't compile - need two more commits.
git-svn-id: svn://busybox.net/trunk/busybox@18241 69ca8d6d-28ef-0310-b511-8ec308f3f277
---
libbb/vfork_daemon_rexec.c | 134 ++++++++++++++++++++++++++++++++++++++++++++-
libbb/xfuncs.c | 78 --------------------------
2 files changed, 133 insertions(+), 79 deletions(-)
(limited to 'libbb')
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 3185f2d39..c59b0b6fd 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -18,11 +18,68 @@
#include <paths.h>
#include "libbb.h"
-#ifdef BB_NOMMU
+/* This does a fork/exec in one call, using vfork(). Returns PID of new child,
+ * -1 for failure. Runs argv[0], searching path if that has no / in it. */
+pid_t spawn(char **argv)
+{
+ /* Compiler should not optimize stores here */
+ volatile int failed;
+ pid_t pid;
+
+ // Be nice to nommu machines.
+ failed = 0;
+ pid = vfork();
+ if (pid < 0) /* error */
+ return pid;
+ if (!pid) { /* child */
+ /* Don't use BB_EXECVP tricks here! */
+ execvp(argv[0], argv);
+
+ /* We are (maybe) sharing a stack with blocked parent,
+ * let parent know we failed and then exit to unblock parent
+ * (but don't run atexit() stuff, which would screw up parent.)
+ */
+ failed = errno;
+ _exit(0);
+ }
+ /* parent */
+ /* Unfortunately, this is not reliable: vfork()
+ * can be equivalent to fork() according to standards */
+ if (failed) {
+ errno = failed;
+ return -1;
+ }
+ return pid;
+}
+
+/* Die with an error message if we can't spawn a child process. */
+pid_t xspawn(char **argv)
+{
+ pid_t pid = spawn(argv);
+ if (pid < 0) bb_perror_msg_and_die("%s", *argv);
+ return pid;
+}
+
+
+
+#if 0 //ndef BB_NOMMU
+// Die with an error message if we can't daemonize.
+void xdaemon(int nochdir, int noclose)
+{
+ if (daemon(nochdir, noclose))
+ bb_perror_msg_and_die("daemon");
+}
+#endif
+
+#if 0 // def BB_NOMMU
void vfork_daemon_rexec(int nochdir, int noclose, char **argv)
{
int fd;
+ /* Maybe we are already re-execed and come here again? */
+ if (re_execed)
+ return;
+
setsid();
if (!nochdir)
@@ -56,3 +113,78 @@ void vfork_daemon_rexec(int nochdir, int noclose, char **argv)
}
}
#endif /* BB_NOMMU */
+
+#ifdef BB_NOMMU
+static void daemon_or_rexec(char **argv)
+{
+ pid_t pid;
+ /* Maybe we are already re-execed and come here again? */
+ if (re_execed)
+ return;
+
+ pid = vfork();
+ if (pid < 0) /* wtf? */
+ bb_perror_msg_and_die("vfork");
+ if (pid) /* parent */
+ exit(0);
+ /* child - re-exec ourself */
+ /* high-order bit of first char in argv[0] is a hidden
+ * "we have (alrealy) re-execed, don't do it again" flag */
+ argv[0][0] |= 0x80;
+ execv(CONFIG_BUSYBOX_EXEC_PATH, argv);
+ bb_perror_msg_and_die("exec %s", CONFIG_BUSYBOX_EXEC_PATH);
+}
+#else
+static void daemon_or_rexec(void)
+{
+ pid_t pid;
+ pid = fork();
+ if (pid < 0) /* wtf? */
+ bb_perror_msg_and_die("fork");
+ if (pid) /* parent */
+ exit(0);
+ /* child */
+}
+#define daemon_or_rexec(argv) daemon_or_rexec()
+#endif
+
+
+/* Due to a #define in libbb.h on MMU systems we actually have 1 argument -
+ * char **argv "vanishes" */
+void bb_daemonize_or_rexec(int flags, char **argv)
+{
+ int fd;
+
+ fd = xopen(bb_dev_null, O_RDWR);
+
+ if (flags & DAEMON_CHDIR_ROOT)
+ xchdir("/");
+
+ if (flags & DAEMON_DEVNULL_STDIO) {
+ close(0);
+ close(1);
+ close(2);
+ }
+
+ while ((unsigned)fd < 2)
+ fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
+
+ if (!(flags & DAEMON_ONLY_SANITIZE)) {
+ daemon_or_rexec(argv);
+ /* if daemonizing, make sure we detach from stdio */
+ setsid();
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ }
+ if (fd > 2)
+ close(fd--);
+ if (flags & DAEMON_CLOSE_EXTRA_FDS)
+ while (fd > 2)
+ close(fd--); /* close everything after fd#2 */
+}
+
+void bb_sanitize_stdio(void)
+{
+ bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE, NULL);
+}
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index 1dcdbc065..14bd62a15 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -187,43 +187,6 @@ void xfflush_stdout(void)
}
}
-// This does a fork/exec in one call, using vfork(). Return PID of new child,
-// -1 for failure. Runs argv[0], searching path if that has no / in it.
-pid_t spawn(char **argv)
-{
- /* Why static? */
- static int failed;
- pid_t pid;
-
- // Be nice to nommu machines.
- failed = 0;
- pid = vfork();
- if (pid < 0) return pid;
- if (!pid) {
- BB_EXECVP(argv[0], argv);
-
- // We're sharing a stack with blocked parent, let parent know we failed
- // and then exit to unblock parent (but don't run atexit() stuff, which
- // would screw up parent.)
-
- failed = errno;
- _exit(0);
- }
- if (failed) {
- errno = failed;
- return -1;
- }
- return pid;
-}
-
-// Die with an error message if we can't spawn a child process.
-pid_t xspawn(char **argv)
-{
- pid_t pid = spawn(argv);
- if (pid < 0) bb_perror_msg_and_die("%s", *argv);
- return pid;
-}
-
// Wait for the specified child PID to exit, returning child's error return.
int wait4pid(int pid)
{
@@ -510,47 +473,6 @@ DIR *xopendir(const char *path)
return dp;
}
-#ifndef BB_NOMMU
-// Die with an error message if we can't daemonize.
-void xdaemon(int nochdir, int noclose)
-{
- if (daemon(nochdir, noclose))
- bb_perror_msg_and_die("daemon");
-}
-#endif
-
-void bb_sanitize_stdio_maybe_daemonize(int daemonize)
-{
- int fd;
- /* Mega-paranoid */
- fd = xopen(bb_dev_null, O_RDWR);
- while ((unsigned)fd < 2)
- fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
- if (daemonize) {
- pid_t pid = fork();
- if (pid < 0) /* wtf? */
- bb_perror_msg_and_die("fork");
- if (pid) /* parent */
- exit(0);
- /* child */
- /* if daemonizing, make sure we detach from stdio */
- setsid();
- dup2(fd, 0);
- dup2(fd, 1);
- dup2(fd, 2);
- }
- while (fd > 2)
- close(fd--); /* close everything after fd#2 */
-}
-void bb_sanitize_stdio(void)
-{
- bb_sanitize_stdio_maybe_daemonize(0);
-}
-void bb_daemonize(void)
-{
- bb_sanitize_stdio_maybe_daemonize(1);
-}
-
// Die with an error message if we can't open a new socket.
int xsocket(int domain, int type, int protocol)
{
--
cgit v1.2.3-55-g6feb