Merged revisions 48374 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.2

........
r48374 | tilghman | 2006-12-10 18:33:59 -0600 (Sun, 10 Dec 2006) | 5 lines

When doing a fork() and exec(), two problems existed (Issue 8086):
1) Ignored signals stayed ignored after the exec().
2) Signals could possibly fire between the fork() and exec(), causing Asterisk
signal handlers within the child to execute, which caused nasty race conditions.

........


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@48375 f38db490-d61c-443f-a65b-d21fe96a405b

8 files changed, 103 insertions, 23 deletions

diff --git a/apps/app_externalivr.c b/apps/app_externalivr.c
index a42dd9551..461e7483c 100644
--- a/apps/app_externalivr.c
+++ b/apps/app_externalivr.c
@@ -40,6 +40,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
+#include <signal.h>
 
 #include "asterisk/lock.h"
 #include "asterisk/file.h"
@@ -261,9 +262,13 @@ static int app_exec(struct ast_channel *chan, void *data)
 		.finishlist = AST_LIST_HEAD_INIT_VALUE,
 	};
 	struct ivr_localuser *u = &foo;
+	sigset_t fullset, oldset;
 
 	lu = ast_module_user_add(chan);
-	
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
+
 	u->abort_current_sound = 0;
 	u->chan = chan;
 	
@@ -312,6 +317,9 @@ static int app_exec(struct ast_channel *chan, void *data)
 		/* child process */
 		int i;
 
+		signal(SIGPIPE, SIG_DFL);
+		pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
+
 		if (ast_opt_high_priority)
 			ast_set_priority(0);
 
@@ -335,6 +343,8 @@ static int app_exec(struct ast_channel *chan, void *data)
 		int waitfds[2] = { child_errors_fd, child_commands_fd };
 		struct ast_channel *rchan;
 
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
+
 		close(child_stdin[0]);
 		child_stdin[0] = 0;
 		close(child_stdout[1]);
diff --git a/apps/app_festival.c b/apps/app_festival.c
index 6e7a4ffd4..126dde29d 100644
--- a/apps/app_festival.c
+++ b/apps/app_festival.c
@@ -130,19 +130,26 @@ static int send_waveform_to_fd(char *waveform, int length, int fd) {
 #ifdef __PPC__ 
 	char c;
 #endif
+	sigset_t fullset, oldset;
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
 
         res = fork();
         if (res < 0)
                 ast_log(LOG_WARNING, "Fork failed\n");
-        if (res)
+        if (res) {
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
                 return res;
+	}
         for (x=0;x<256;x++) {
                 if (x != fd)
                         close(x);
         }
 	if (ast_opt_high_priority)
 		ast_set_priority(0);
-
+	signal(SIGPIPE, SIG_DFL);
+	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
 /*IAS */
 #ifdef __PPC__  
 	for( x=0; x<length; x+=2)
diff --git a/apps/app_ices.c b/apps/app_ices.c
index c44b93136..8c6d5e7e5 100644
--- a/apps/app_ices.c
+++ b/apps/app_ices.c
@@ -65,15 +65,27 @@ static int icesencode(char *filename, int fd)
 {
 	int res;
 	int x;
+	sigset_t fullset, oldset;
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
+
 	res = fork();
 	if (res < 0) 
 		ast_log(LOG_WARNING, "Fork failed\n");
-	if (res)
+	if (res) {
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 		return res;
+	}
+
+	/* Stop ignoring PIPE */
+	signal(SIGPIPE, SIG_DFL);
+	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
+
 	if (ast_opt_high_priority)
 		ast_set_priority(0);
 	dup2(fd, STDIN_FILENO);
-	for (x=STDERR_FILENO + 1;x<256;x++) {
+	for (x=STDERR_FILENO + 1;x<1024;x++) {
 		if ((x != STDIN_FILENO) && (x != STDOUT_FILENO))
 			close(x);
 	}
@@ -84,7 +96,7 @@ static int icesencode(char *filename, int fd)
 	/* As a last-ditch effort, try to use PATH */
 	execlp("ices", "ices", filename, (char *)NULL);
 	ast_log(LOG_WARNING, "Execute of ices failed\n");
-	return -1;
+	_exit(0);
 }
 
 static int ices_exec(struct ast_channel *chan, void *data)
diff --git a/apps/app_mp3.c b/apps/app_mp3.c
index 667de67ad..55d50f011 100644
--- a/apps/app_mp3.c
+++ b/apps/app_mp3.c
@@ -64,15 +64,25 @@ static int mp3play(char *filename, int fd)
 {
 	int res;
 	int x;
+	sigset_t fullset, oldset;
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
+
 	res = fork();
 	if (res < 0) 
 		ast_log(LOG_WARNING, "Fork failed\n");
-	if (res)
+	if (res) {
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 		return res;
+	}
 	if (ast_opt_high_priority)
 		ast_set_priority(0);
+	signal(SIGPIPE, SIG_DFL);
+	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
+
 	dup2(fd, STDOUT_FILENO);
-	for (x=0;x<256;x++) {
+	for (x=STDERR_FILENO + 1;x<256;x++) {
 		if (x != STDOUT_FILENO)
 			close(x);
 	}
@@ -94,7 +104,7 @@ static int mp3play(char *filename, int fd)
 	    execlp("mpg123", "mpg123", "-q", "-s", "-f", "8192", "--mono", "-r", "8000", filename, (char *)NULL);
 	}
 	ast_log(LOG_WARNING, "Execute of mpg123 failed\n");
-	return -1;
+	_exit(0);
 }
 
 static int timed_read(int fd, void *data, int datalen, int timeout)
diff --git a/apps/app_nbscat.c b/apps/app_nbscat.c
index 346584346..5f3000404 100644
--- a/apps/app_nbscat.c
+++ b/apps/app_nbscat.c
@@ -68,16 +68,26 @@ static int NBScatplay(int fd)
 {
 	int res;
 	int x;
+	sigset_t fullset, oldset;
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
+
 	res = fork();
 	if (res < 0) 
 		ast_log(LOG_WARNING, "Fork failed\n");
-	if (res)
+	if (res) {
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 		return res;
+	}
+	signal(SIGPIPE, SIG_DFL);
+	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
+
 	if (ast_opt_high_priority)
 		ast_set_priority(0);
 
 	dup2(fd, STDOUT_FILENO);
-	for (x=0;x<256;x++) {
+	for (x = STDERR_FILENO + 1; x < 1024; x++) {
 		if (x != STDOUT_FILENO)
 			close(x);
 	}
@@ -85,7 +95,7 @@ static int NBScatplay(int fd)
 	execl(NBSCAT, "nbscat8k", "-d", (char *)NULL);
 	execl(LOCAL_NBSCAT, "nbscat8k", "-d", (char *)NULL);
 	ast_log(LOG_WARNING, "Execute of nbscat8k failed\n");
-	return -1;
+	_exit(0);
 }
 
 static int timed_read(int fd, void *data, int datalen)
diff --git a/apps/app_zapras.c b/apps/app_zapras.c
index de682f72c..c3ccf30d9 100644
--- a/apps/app_zapras.c
+++ b/apps/app_zapras.c
@@ -82,11 +82,23 @@ static pid_t spawn_ras(struct ast_channel *chan, char *args)
 	char *argv[PPP_MAX_ARGS];
 	int argc = 0;
 	char *stringp=NULL;
+	sigset_t fullset, oldset;
+
+	sigfillset(&fullset);
+	pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
 
 	/* Start by forking */
 	pid = fork();
-	if (pid)
+	if (pid) {
+		pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 		return pid;
+	}
+
+	/* Restore original signal handlers */
+	for (x=0;x<NSIG;x++)
+		signal(x, SIG_DFL);
+
+	pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
 
 	/* Execute RAS on File handles */
 	dup2(chan->fds[0], STDIN_FILENO);
@@ -99,10 +111,6 @@ static pid_t spawn_ras(struct ast_channel *chan, char *args)
 	for (x=STDERR_FILENO + 1;x<1024;x++) 
 		close(x);
 
-	/* Restore original signal handlers */
-	for (x=0;x<NSIG;x++)
-		signal(x, SIG_DFL);
-
 	/* Reset all arguments */
 	memset(argv, 0, sizeof(argv));
 
diff --git a/res/res_agi.c b/res/res_agi.c
index ecac92282..a8417587f 100644
--- a/res/res_agi.c
+++ b/res/res_agi.c
@@ -240,7 +240,7 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 	int audio[2];
 	int x;
 	int res;
-	sigset_t signal_set;
+	sigset_t signal_set, old_set;
 	
 	if (!strncasecmp(script, "agi://", 6))
 		return launch_netscript(script, argv, fds, efd, opid);
@@ -282,11 +282,14 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 			return AGI_RESULT_FAILURE;
 		}
 	}
-	ast_replace_sigchld();
+
+	/* Block SIGHUP during the fork - prevents a race */
+	sigfillset(&signal_set);
+	pthread_sigmask(SIG_BLOCK, &signal_set, &old_set);
 	pid = fork();
 	if (pid < 0) {
 		ast_log(LOG_WARNING, "Failed to fork(): %s\n", strerror(errno));
-		ast_unreplace_sigchld();
+		pthread_sigmask(SIG_SETMASK, &old_set, NULL);
 		return AGI_RESULT_FAILURE;
 	}
 	if (!pid) {
@@ -314,9 +317,18 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 		} else {
 			close(STDERR_FILENO + 1);
 		}
-		
+
+		/* Before we unblock our signals, return our trapped signals back to the defaults */
+		signal(SIGHUP, SIG_DFL);
+		signal(SIGCHLD, SIG_DFL);
+		signal(SIGINT, SIG_DFL);
+		signal(SIGURG, SIG_DFL);
+		signal(SIGTERM, SIG_DFL);
+		signal(SIGPIPE, SIG_DFL);
+		signal(SIGXFSZ, SIG_DFL);
+
 		/* unblock important signal handlers */
-		if (sigfillset(&signal_set) || pthread_sigmask(SIG_UNBLOCK, &signal_set, NULL)) {
+		if (pthread_sigmask(SIG_UNBLOCK, &signal_set, NULL)) {
 			ast_log(LOG_WARNING, "unable to unblock signals for AGI script: %s\n", strerror(errno));
 			_exit(1);
 		}
@@ -332,6 +344,7 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 		fflush(stdout);
 		_exit(1);
 	}
+	pthread_sigmask(SIG_SETMASK, &old_set, NULL);
 	if (option_verbose > 2) 
 		ast_verbose(VERBOSE_PREFIX_3 "Launched AGI Script %s\n", script);
 	fds[0] = toast[0];
@@ -348,7 +361,6 @@ static enum agi_result launch_script(char *script, char *argv[], int *fds, int *
 
 	*opid = pid;
 	return AGI_RESULT_SUCCESS;
-		
 }
 
 static void setup_env(struct ast_channel *chan, char *request, int fd, int enhanced)
diff --git a/res/res_musiconhold.c b/res/res_musiconhold.c
index 267cbc92b..328b099af 100644
--- a/res/res_musiconhold.c
+++ b/res/res_musiconhold.c
@@ -340,6 +340,7 @@ static int spawn_mp3(struct mohclass *class)
 	int argc = 0;
 	DIR *dir = NULL;
 	struct dirent *de;
+	sigset_t signal_set, old_set;
 
 	
 	if (!strcasecmp(class->dir, "nodir")) {
@@ -424,6 +425,11 @@ static int spawn_mp3(struct mohclass *class)
 	if (time(NULL) - class->start < respawn_time) {
 		sleep(respawn_time - (time(NULL) - class->start));
 	}
+
+	/* Block signals during the fork() */
+	sigfillset(&signal_set);
+	pthread_sigmask(SIG_BLOCK, &signal_set, &old_set);
+
 	time(&class->start);
 	class->pid = fork();
 	if (class->pid < 0) {
@@ -438,6 +444,10 @@ static int spawn_mp3(struct mohclass *class)
 		if (ast_opt_high_priority)
 			ast_set_priority(0);
 
+		/* Reset ignored signals back to default */
+		signal(SIGPIPE, SIG_DFL);
+		pthread_sigmask(SIG_UNBLOCK, &signal_set, NULL);
+
 		close(fds[0]);
 		/* Stdout goes to pipe */
 		dup2(fds[1], STDOUT_FILENO);
@@ -464,6 +474,7 @@ static int spawn_mp3(struct mohclass *class)
 		_exit(1);
 	} else {
 		/* Parent */
+		pthread_sigmask(SIG_SETMASK, &old_set, NULL);
 		close(fds[1]);
 	}
 	return fds[0];