chiark / gitweb /
util_run_program: restore signal mask before executing event RUN commands
authorJeremy Kerr <jk@ozlabs.org>
Sat, 5 Sep 2009 07:48:23 +0000 (17:48 +1000)
committerKay Sievers <kay.sievers@vrfy.org>
Mon, 7 Sep 2009 10:13:50 +0000 (12:13 +0200)
External programs triggered by events (via RUN=) will inherit udev's
signal mask, which is set to block all but SIGALRM. For most utilities,
this is OK, but if we start daemons from RUN=, we run into trouble
(especially as SIGCHLD is blocked).

This change saves the original sigmask when udev starts, and restores it
just before we exec() the external command.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
libudev/libudev-private.h
libudev/libudev-util-private.c
udev/test-udev.c
udev/udev-event.c
udev/udev-rules.c
udev/udev.h
udev/udevd.c

index b735298..e90c79c 100644 (file)
@@ -13,6 +13,7 @@
 #define _LIBUDEV_PRIVATE_H_
 
 #include <syslog.h>
+#include <signal.h>
 #include "libudev.h"
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
@@ -214,7 +215,8 @@ int util_unlink_secure(struct udev *udev, const char *filename);
 uid_t util_lookup_user(struct udev *udev, const char *user);
 gid_t util_lookup_group(struct udev *udev, const char *group);
 int util_run_program(struct udev *udev, const char *command, char **envp,
-                    char *result, size_t ressize, size_t *reslen);
+                    char *result, size_t ressize, size_t *reslen,
+                    const sigset_t *sigmask);
 int util_resolve_subsys_kernel(struct udev *udev, const char *string,
                                      char *result, size_t maxsize, int read_value);
 
index fe8f29b..dfde5a9 100644 (file)
@@ -242,7 +242,8 @@ int util_resolve_subsys_kernel(struct udev *udev, const char *string,
 }
 
 int util_run_program(struct udev *udev, const char *command, char **envp,
-                    char *result, size_t ressize, size_t *reslen)
+                    char *result, size_t ressize, size_t *reslen,
+                    const sigset_t *sigmask)
 {
        int status;
        int outpipe[2] = {-1, -1};
@@ -330,6 +331,10 @@ int util_run_program(struct udev *udev, const char *command, char **envp,
                        dup2(errpipe[WRITE_END], STDERR_FILENO);
                        close(errpipe[WRITE_END]);
                }
+
+               if (sigmask)
+                       sigprocmask(SIG_BLOCK, sigmask, NULL);
+
                execve(argv[0], argv, envp);
                if (errno == ENOENT || errno == ENOTDIR) {
                        /* may be on a filesystem which is not mounted right now */
index c6b8bf5..0806fbf 100644 (file)
@@ -103,7 +103,7 @@ int main(int argc, char *argv[])
                alarm(udev_device_get_event_timeout(dev));
 
        if (err == 0 && !event->ignore_device && udev_get_run(udev))
-               udev_event_execute_run(event);
+               udev_event_execute_run(event, NULL);
 
        udev_event_unref(event);
        udev_device_unref(dev);
index 8183793..7b4e4ac 100644 (file)
@@ -722,7 +722,7 @@ exit:
        return err;
 }
 
-int udev_event_execute_run(struct udev_event *event)
+int udev_event_execute_run(struct udev_event *event, const sigset_t *sigmask)
 {
        struct udev_list_entry *list_entry;
        int err = 0;
@@ -745,7 +745,7 @@ int udev_event_execute_run(struct udev_event *event)
 
                        udev_event_apply_format(event, cmd, program, sizeof(program));
                        envp = udev_device_get_properties_envp(event->dev);
-                       if (util_run_program(event->udev, program, envp, NULL, 0, NULL) != 0) {
+                       if (util_run_program(event->udev, program, envp, NULL, 0, NULL, sigmask) != 0) {
                                if (udev_list_entry_get_flag(list_entry))
                                        err = -1;
                        }
index a924464..20ec270 100644 (file)
@@ -749,7 +749,7 @@ static int import_program_into_properties(struct udev_device *dev, const char *p
        char *line;
 
        envp = udev_device_get_properties_envp(dev);
-       if (util_run_program(udev, program, envp, result, sizeof(result), &reslen) != 0)
+       if (util_run_program(udev, program, envp, result, sizeof(result), &reslen, NULL) != 0)
                return -1;
 
        line = result;
@@ -2206,7 +2206,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules, struct udev_event *event
                                     program,
                                     &rules->buf[rule->rule.filename_off],
                                     rule->rule.filename_line);
-                               if (util_run_program(event->udev, program, envp, result, sizeof(result), NULL) != 0) {
+                               if (util_run_program(event->udev, program, envp, result, sizeof(result), NULL, NULL) != 0) {
                                        if (cur->key.op != OP_NOMATCH)
                                                goto nomatch;
                                } else {
index 391276f..8f0a301 100644 (file)
@@ -21,6 +21,7 @@
 
 #include <sys/types.h>
 #include <sys/param.h>
+#include <signal.h>
 
 #include "libudev.h"
 #include "libudev-private.h"
@@ -67,7 +68,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules, struct udev_event *event
 struct udev_event *udev_event_new(struct udev_device *dev);
 void udev_event_unref(struct udev_event *event);
 int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules);
-int udev_event_execute_run(struct udev_event *event);
+int udev_event_execute_run(struct udev_event *event, const sigset_t *sigset);
 size_t udev_event_apply_format(struct udev_event *event, const char *src, char *dest, size_t size);
 int udev_event_apply_subsys_kernel(struct udev_event *event, const char *string,
                                   char *result, size_t maxsize, int read_value);
index 54064cb..2eb914a 100644 (file)
@@ -79,6 +79,7 @@ static bool stop_exec_queue;
 static bool reload_config;
 static int max_childs;
 static int childs;
+static sigset_t orig_sigmask;
 static struct udev_list_node event_list;
 static struct udev_list_node worker_list;
 static bool udev_exit;
@@ -292,7 +293,8 @@ static void worker_new(struct event *event)
 
                        /* execute RUN= */
                        if (err == 0 && !udev_event->ignore_device && udev_get_run(udev_event->udev))
-                               failed = udev_event_execute_run(udev_event);
+                               failed = udev_event_execute_run(udev_event,
+                                                               &orig_sigmask);
 
                        /* reset alarm */
                        alarm(0);
@@ -926,7 +928,7 @@ int main(int argc, char *argv[])
 
        /* block and listen to all signals on signalfd */
        sigfillset(&mask);
-       sigprocmask(SIG_SETMASK, &mask, NULL);
+       sigprocmask(SIG_SETMASK, &mask, &orig_sigmask);
        pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
        if (pfd[FD_SIGNAL].fd < 0) {
                fprintf(stderr, "error getting signalfd\n");