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util_run_program: restore signal mask before executing event RUN commands

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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>
This commit is contained in:
Jeremy Kerr 2009-09-05 17:48:23 +10:00 committed by Kay Sievers
parent 9e6273c713
commit d412a68573
7 changed files with 20 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
libudev/libudev-private.h
View 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);

7
libudev/libudev-util-private.c
View 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 */

2
udev/test-udev.c
View 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);

4
udev/udev-event.c
View 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;
}

4
udev/udev-rules.c
View 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 {

3
udev/udev.h
View 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);

6
udev/udevd.c
View 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");