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authorGravatar Denis Vlasenko <vda.linux@googlemail.com>2009-01-31 19:26:12 +0000
committerGravatar Denis Vlasenko <vda.linux@googlemail.com>2009-01-31 19:26:12 +0000
commit9ec0ecbfdde2396c4c1c91b4a040ccb006f424c2 (patch)
tree1a5d4a1c3f542afe6ed737f297c1a77e822e593f /init
parent4ae8a05b131836184eb32c440a6bf814ff81b069 (diff)
downloadbusybox-9ec0ecbfdde2396c4c1c91b4a040ccb006f424c2.tar.gz
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init: remove wait() loop on restart, it may be dangerous
Diffstat (limited to 'init')
-rw-r--r--init/init.c37
1 files changed, 22 insertions, 15 deletions
diff --git a/init/init.c b/init/init.c
index 7ba8b67ec..68e624294 100644
--- a/init/init.c
+++ b/init/init.c
@@ -418,14 +418,16 @@ static pid_t run(const struct init_action *a)
_exit(-1);
}
-static struct init_action *mark_terminated(int pid)
+static struct init_action *mark_terminated(pid_t pid)
{
struct init_action *a;
- for (a = init_action_list; a; a = a->next) {
- if (a->pid == pid) {
- a->pid = 0;
- return a;
+ if (pid > 0) {
+ for (a = init_action_list; a; a = a->next) {
+ if (a->pid == pid) {
+ a->pid = 0;
+ return a;
+ }
}
}
return NULL;
@@ -444,7 +446,7 @@ static void waitfor(pid_t pid)
mark_terminated(wpid);
/* Unsafe. SIGTSTP handler might have wait'ed it already */
/*if (wpid == pid) break;*/
- /* More reliable */
+ /* More reliable: */
if (kill(pid, 0))
break;
}
@@ -697,11 +699,11 @@ static void halt_reboot_pwoff(int sig)
*/
static void stop_handler(int sig UNUSED_PARAM)
{
- int saved_errno;
smallint saved_bb_got_signal;
+ int saved_errno;
- saved_errno = errno;
saved_bb_got_signal = bb_got_signal;
+ saved_errno = errno;
signal(SIGCONT, record_signo);
while (1) {
@@ -714,14 +716,13 @@ static void stop_handler(int sig UNUSED_PARAM)
* code which is resilient against this.
*/
wpid = wait_any_nohang(NULL);
- if (wpid > 0)
- mark_terminated(wpid);
+ mark_terminated(wpid);
sleep(1);
}
signal(SIGCONT, SIG_DFL);
- bb_got_signal = saved_bb_got_signal;
errno = saved_errno;
+ bb_got_signal = saved_bb_got_signal;
}
/* Handler for QUIT - exec "restart" action,
@@ -747,8 +748,14 @@ static void restart_handler(int sig UNUSED_PARAM)
if (open_stdio_to_tty(a->terminal)) {
dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
- while (wait(NULL) > 0)
- continue;
+ /* Theoretically should be safe.
+ * But in practice, kernel bugs may leave
+ * unkillable processes, and wait() may block forever.
+ * Oh well. Hoping "new" init won't be too surprised
+ * by having children it didn't create.
+ */
+ //while (wait(NULL) > 0)
+ // continue;
init_exec(a->command);
}
/* Open or exec failed */
@@ -990,14 +997,14 @@ int init_main(int argc UNUSED_PARAM, char **argv)
got_sigs |= check_delayed_sigs();
+ if (got_sigs)
+ goto dont_block;
/* Wait for any child process to exit.
* NB: "delayed" signals will also interrupt this wait(),
* bb_signals_recursive_norestart() set them up for that.
* This guarantees we won't be stuck here
* till next orphan dies.
*/
- if (got_sigs)
- goto dont_block;
wpid = wait(NULL);
while (wpid > 0) {
struct init_action *a = mark_terminated(wpid);