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udevd: simplify signal mask handling 

We used to block all signals, and restore the original signal mask before exec'ing
external processes.

Now we just block the signals we care about and unconditionally unblock all signals
before exec'ing.
This commit is contained in:
Tom Gundersen 2015-06-02 17:07:21 +02:00
parent a39423c2ef
commit 8314de1d81
6 changed files with 29 additions and 46 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
src/test/test-udev.c
View File

@ -28,6 +28,7 @@
#include "missing.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "udev.h"
#include "udev-util.h"
@ -79,7 +80,6 @@ int main(int argc, char *argv[]) {
char syspath[UTIL_PATH_SIZE];
const char *devpath;
const char *action;
sigset_t mask, sigmask_orig;
int err;
err = fake_filesystems();
@ -93,8 +93,6 @@ int main(int argc, char *argv[]) {
log_debug("version %s", VERSION);
mac_selinux_init("/dev");
sigprocmask(SIG_SETMASK, NULL, &sigmask_orig);
action = argv[1];
if (action == NULL) {
log_error("action missing");
@ -118,8 +116,7 @@ int main(int argc, char *argv[]) {
event = udev_event_new(dev);
sigfillset(&mask);
sigprocmask(SIG_SETMASK, &mask, &sigmask_orig);
assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, SIGHUP, SIGCHLD, -1) == 0);
/* do what devtmpfs usually provides us */
if (udev_device_get_devnode(dev) != NULL) {
@ -142,11 +139,9 @@ int main(int argc, char *argv[]) {
udev_event_execute_rules(event,
3 * USEC_PER_SEC, USEC_PER_SEC,
NULL,
rules,
&sigmask_orig);
rules);
udev_event_execute_run(event,
3 * USEC_PER_SEC, USEC_PER_SEC,
NULL);
3 * USEC_PER_SEC, USEC_PER_SEC);
out:
mac_selinux_finish();

24
src/udev/udev-event.c
View File

@ -385,7 +385,7 @@ out:
}
static int spawn_exec(struct udev_event *event,
const char *cmd, char *const argv[], char **envp, const sigset_t *sigmask,
const char *cmd, char *const argv[], char **envp,
int fd_stdout, int fd_stderr) {
_cleanup_close_ int fd = -1;
@ -413,9 +413,8 @@ static int spawn_exec(struct udev_event *event,
/* terminate child in case parent goes away */
prctl(PR_SET_PDEATHSIG, SIGTERM);
/* restore original udev sigmask before exec */
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, NULL);
/* restore sigmask before exec */
(void) reset_signal_mask();
execve(argv[0], argv, envp);
@ -699,7 +698,7 @@ out:
int udev_event_spawn(struct udev_event *event,
usec_t timeout_usec,
usec_t timeout_warn_usec,
const char *cmd, char **envp, const sigset_t *sigmask,
const char *cmd, char **envp,
char *result, size_t ressize) {
int outpipe[2] = {-1, -1};
int errpipe[2] = {-1, -1};
@ -749,7 +748,7 @@ int udev_event_spawn(struct udev_event *event,
log_debug("starting '%s'", cmd);
spawn_exec(event, cmd, argv, envp, sigmask,
spawn_exec(event, cmd, argv, envp,
outpipe[WRITE_END], errpipe[WRITE_END]);
_exit(2 );
@ -811,8 +810,7 @@ static int rename_netif(struct udev_event *event) {
void udev_event_execute_rules(struct udev_event *event,
usec_t timeout_usec, usec_t timeout_warn_usec,
struct udev_list *properties_list,
struct udev_rules *rules,
const sigset_t *sigmask) {
struct udev_rules *rules) {
struct udev_device *dev = event->dev;
if (udev_device_get_subsystem(dev) == NULL)
@ -828,8 +826,7 @@ void udev_event_execute_rules(struct udev_event *event,
udev_rules_apply_to_event(rules, event,
timeout_usec, timeout_warn_usec,
properties_list,
sigmask);
properties_list);
if (major(udev_device_get_devnum(dev)) != 0)
udev_node_remove(dev);
@ -847,8 +844,7 @@ void udev_event_execute_rules(struct udev_event *event,
udev_rules_apply_to_event(rules, event,
timeout_usec, timeout_warn_usec,
properties_list,
sigmask);
properties_list);
/* rename a new network interface, if needed */
if (udev_device_get_ifindex(dev) > 0 && streq(udev_device_get_action(dev), "add") &&
@ -911,7 +907,7 @@ void udev_event_execute_rules(struct udev_event *event,
}
}
void udev_event_execute_run(struct udev_event *event, usec_t timeout_usec, usec_t timeout_warn_usec, const sigset_t *sigmask) {
void udev_event_execute_run(struct udev_event *event, usec_t timeout_usec, usec_t timeout_warn_usec) {
struct udev_list_entry *list_entry;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&event->run_list)) {
@ -934,7 +930,7 @@ void udev_event_execute_run(struct udev_event *event, usec_t timeout_usec, usec_
udev_event_apply_format(event, cmd, program, sizeof(program));
envp = udev_device_get_properties_envp(event->dev);
udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, sigmask, NULL, 0);
udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, NULL, 0);
}
}
}

11
src/udev/udev-rules.c
View File

@ -633,7 +633,7 @@ static int import_file_into_properties(struct udev_device *dev, const char *file
static int import_program_into_properties(struct udev_event *event,
usec_t timeout_usec,
usec_t timeout_warn_usec,
const char *program, const sigset_t *sigmask) {
const char *program) {
struct udev_device *dev = event->dev;
char **envp;
char result[UTIL_LINE_SIZE];
@ -641,7 +641,7 @@ static int import_program_into_properties(struct udev_event *event,
int err;
envp = udev_device_get_properties_envp(dev);
err = udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, sigmask, result, sizeof(result));
err = udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, result, sizeof(result));
if (err < 0)
return err;
@ -1895,8 +1895,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules,
struct udev_event *event,
usec_t timeout_usec,
usec_t timeout_warn_usec,
struct udev_list *properties_list,
const sigset_t *sigmask) {
struct udev_list *properties_list) {
struct token *cur;
struct token *rule;
enum escape_type esc = ESCAPE_UNSET;
@ -2132,7 +2131,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules,
rules_str(rules, rule->rule.filename_off),
rule->rule.filename_line);
if (udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, sigmask, result, sizeof(result)) < 0) {
if (udev_event_spawn(event, timeout_usec, timeout_warn_usec, program, envp, result, sizeof(result)) < 0) {
if (cur->key.op != OP_NOMATCH)
goto nomatch;
} else {
@ -2168,7 +2167,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules,
rules_str(rules, rule->rule.filename_off),
rule->rule.filename_line);
if (import_program_into_properties(event, timeout_usec, timeout_warn_usec, import, sigmask) != 0)
if (import_program_into_properties(event, timeout_usec, timeout_warn_usec, import) != 0)
if (cur->key.op != OP_NOMATCH)
goto nomatch;
break;

11
src/udev/udev.h
View File

@ -20,7 +20,6 @@
#include <sys/types.h>
#include <sys/param.h>
#include <signal.h>
#include "macro.h"
#include "sd-rtnl.h"
@ -73,8 +72,7 @@ struct udev_rules *udev_rules_unref(struct udev_rules *rules);
bool udev_rules_check_timestamp(struct udev_rules *rules);
int udev_rules_apply_to_event(struct udev_rules *rules, struct udev_event *event,
usec_t timeout_usec, usec_t timeout_warn_usec,
struct udev_list *properties_list,
const sigset_t *sigmask);
struct udev_list *properties_list);
int udev_rules_apply_static_dev_perms(struct udev_rules *rules);
/* udev-event.c */
@ -86,14 +84,13 @@ int udev_event_apply_subsys_kernel(struct udev_event *event, const char *string,
int udev_event_spawn(struct udev_event *event,
usec_t timeout_usec,
usec_t timeout_warn_usec,
const char *cmd, char **envp, const sigset_t *sigmask,
const char *cmd, char **envp,
char *result, size_t ressize);
void udev_event_execute_rules(struct udev_event *event,
usec_t timeout_usec, usec_t timeout_warn_usec,
struct udev_list *properties_list,
struct udev_rules *rules,
const sigset_t *sigset);
void udev_event_execute_run(struct udev_event *event, usec_t timeout_usec, usec_t timeout_warn_usec, const sigset_t *sigset);
struct udev_rules *rules);
void udev_event_execute_run(struct udev_event *event, usec_t timeout_usec, usec_t timeout_warn_usec);
int udev_build_argv(struct udev *udev, char *cmd, int *argc, char *argv[]);
/* udev-watch.c */

3
src/udev/udevadm-test.c
View File

@ -135,8 +135,7 @@ static int adm_test(struct udev *udev, int argc, char *argv[]) {
udev_event_execute_rules(event,
60 * USEC_PER_SEC, 20 * USEC_PER_SEC,
NULL,
rules,
&sigmask_orig);
rules);
udev_list_entry_foreach(entry, udev_device_get_properties_list_entry(dev))
printf("%s=%s\n", udev_list_entry_get_name(entry), udev_list_entry_get_value(entry));

13
src/udev/udevd.c
View File

@ -42,6 +42,8 @@
#include "sd-daemon.h"
#include "sd-event.h"
#include "signal-util.h"
#include "event-util.h"
#include "rtnl-util.h"
#include "cgroup-util.h"
@ -69,7 +71,6 @@ typedef struct Manager {
struct udev_list_node events;
char *cgroup;
pid_t pid; /* the process that originally allocated the manager object */
sigset_t sigmask_orig;
struct udev_rules *rules;
struct udev_list properties;
@ -448,12 +449,10 @@ static void worker_spawn(Manager *manager, struct event *event) {
udev_event_execute_rules(udev_event,
arg_event_timeout_usec, arg_event_timeout_warn_usec,
&manager->properties,
manager->rules,
&manager->sigmask_orig);
manager->rules);
udev_event_execute_run(udev_event,
arg_event_timeout_usec, arg_event_timeout_warn_usec,
&manager->sigmask_orig);
arg_event_timeout_usec, arg_event_timeout_warn_usec);
if (udev_event->rtnl)
/* in case rtnl was initialized */
@ -1513,7 +1512,6 @@ static int manager_new(Manager **ret) {
}
static int manager_listen(Manager *manager) {
sigset_t mask;
int r, fd_worker, one = 1;
assert(manager);
@ -1536,8 +1534,7 @@ static int manager_listen(Manager *manager) {
udev_watch_restore(manager->udev);
/* block and listen to all signals on signalfd */
sigfillset(&mask);
sigprocmask(SIG_SETMASK, &mask, &manager->sigmask_orig);
assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, SIGHUP, SIGCHLD, -1) == 0);
r = sd_event_default(&manager->event);
if (r < 0)