b182e9ad6

Denys Vlasenko

2017-08-04

SUCCESS Duration: 140s

Subject

libbb: use _exit, not exit, in bb_daemonize_or_rexec()

No binary (build failed)

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

(log yok)

console-tools/openvt.c+2 -2

@@ -99,7 +99,7 @@ static int find_free_vtno(void)
	/xfunc_error_retval = 3; - do we need compat? /
	if (ioctl(fd, VT_OPENQRY, &vtno) != 0 \|\| vtno <= 0)
	bb_perror_msg_and_die("can't find open VT");
-	// Not really needed, grep for DAEMON_ONLY_SANITIZE
+	// Not really needed, grep for DAEMON_CLOSE_EXTRA_FDS
	// if (fd > 2)
	// close(fd);
	return vtno;
@@ -155,7 +155,7 @@ int openvt_main(int argc UNUSED_PARAM, char **argv)
	/* Grab new VT */
	sprintf(vtname, VC_FORMAT, vtno);
	/* (Try to) clean up stray open fds above fd 2 */
-	bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS \| DAEMON_ONLY_SANITIZE, NULL);
+	bb_daemon_helper(DAEMON_CLOSE_EXTRA_FDS);
	close(STDIN_FILENO);
	/setsid(); - BAD IDEA: after we exit, child is SIGHUPed... /
	xopen(vtname, O_RDWR);

debianutils/start_stop_daemon.c+7 -6

@@ -516,6 +516,11 @@ int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
	/* DAEMON_DEVNULL_STDIO is superfluous -
	* it's always done by bb_daemonize() */
	#else
+	/* Daemons usually call bb_daemonize_or_rexec(), but SSD can do
+	* without: SSD is not itself a daemon, it _execs_ a daemon.
+	* The usual NOMMU problem of "child can't run indefinitely,
+	* it must exec" does not bite us: we exec anyway.
+	*/
	pid_t pid = xvfork();
	if (pid != 0) {
	/* parent */
@@ -525,12 +530,8 @@ int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
	}
	/* Child */
	setsid(); /* detach from controlling tty */
-	/* Redirect stdio to /dev/null, close extra FDs.
-	* We do not actually daemonize because of DAEMON_ONLY_SANITIZE */
-	bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO
-	+ DAEMON_CLOSE_EXTRA_FDS
-	+ DAEMON_ONLY_SANITIZE,
-	NULL /* argv, unused */ );
+	/* Redirect stdio to /dev/null, close extra FDs */
+	bb_daemon_helper(DAEMON_DEVNULL_STDIO + DAEMON_CLOSE_EXTRA_FDS);
	#endif
	}
	if (opt & OPT_MAKEPID) {

include/libbb.h+1 -0

@@ -1169,6 +1169,7 @@ enum {
	#endif
	void bb_daemonize_or_rexec(int flags, char **argv) FAST_FUNC;
	void bb_sanitize_stdio(void) FAST_FUNC;
+	#define bb_daemon_helper(arg) bb_daemonize_or_rexec((arg) \| DAEMON_ONLY_SANITIZE, NULL)
	/* Clear dangerous stuff, set PATH. Return 1 if was run by different user. */
	int sanitize_env_if_suid(void) FAST_FUNC;

libbb/vfork_daemon_rexec.c+8 -2

@@ -209,6 +209,9 @@ pid_t FAST_FUNC fork_or_rexec(char **argv)
	/* Maybe we are already re-execed and come here again? */
	if (re_execed)
	return 0;
+
+	/* fflush_all(); ? - so far all callers had no buffered output to flush */
+
	pid = xvfork();
	if (pid) /* parent */
	return pid;
@@ -245,8 +248,11 @@ void FAST_FUNC bb_daemonize_or_rexec(int flags, char **argv)
	fd = dup(fd); /* have 0,1,2 open at least to /dev/null */

	if (!(flags & DAEMON_ONLY_SANITIZE)) {
+
+	/* fflush_all(); - add it in fork_or_rexec() if necessary */
+
	if (fork_or_rexec(argv))
-	exit(EXIT_SUCCESS); /* parent */
+	_exit(EXIT_SUCCESS); /* parent */
	/* if daemonizing, detach from stdio & ctty */
	setsid();
	dup2(fd, 0);
@@ -258,7 +264,7 @@ void FAST_FUNC bb_daemonize_or_rexec(int flags, char **argv)
	* Prevent this: stop being a session leader.
	*/
	if (fork_or_rexec(argv))
-	exit(EXIT_SUCCESS); /* parent */
+	_exit(EXIT_SUCCESS); /* parent */
	}
	}
	while (fd > 2) {

loginutils/login.c+2 -2

@@ -350,8 +350,8 @@ int login_main(int argc UNUSED_PARAM, char **argv)
	/* Mandatory paranoia for suid applet:
	* ensure that fd# 0,1,2 are opened (at least to /dev/null)
	* and any extra open fd's are closed.
-	* (The name of the function is misleading. Not daemonizing here.) */
-	bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE \| DAEMON_CLOSE_EXTRA_FDS, NULL);
+	*/
+	bb_daemon_helper(DAEMON_CLOSE_EXTRA_FDS);

	username[0] = '\0';
	opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);

printutils/lpd.c+2 -3

@@ -198,9 +198,8 @@ int lpd_main(int argc UNUSED_PARAM, char *argv[])
	q = p; // next line
	}
	// helper should not talk over network.
-	// this call reopens stdio fds to "/dev/null"
-	// (no daemonization is done)
-	bb_daemonize_or_rexec(DAEMON_DEVNULL_STDIO \| DAEMON_ONLY_SANITIZE, NULL);
+	// this call reopens stdio fds to "/dev/null".
+	bb_daemon_helper(DAEMON_DEVNULL_STDIO);
	BB_EXECVP_or_die(argv);
	}