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process-util: don't install atfork() handler more than once

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This commit is contained in:
Lennart Poettering 2018-02-26 20:50:57 +01:00
parent 340c01be7c
commit 5d71bac3b9
1 changed files with 13 additions and 4 deletions
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17
src/basic/process-util.c
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@ -1166,6 +1166,7 @@ extern int __register_atfork(void (*prepare) (void), void (*parent) (void), void
extern void* __dso_handle __attribute__ ((__weak__));
pid_t getpid_cached(void) {
static bool installed = false;
pid_t current_value;
/* getpid_cached() is much like getpid(), but caches the value in local memory, to avoid having to invoke a
@ -1186,10 +1187,18 @@ pid_t getpid_cached(void) {
new_pid = raw_getpid();
if (__register_atfork(NULL, NULL, reset_cached_pid, __dso_handle) != 0) {
/* OOM? Let's try again later */
cached_pid = CACHED_PID_UNSET;
return new_pid;
if (!installed) {
/* __register_atfork() either returns 0 or -ENOMEM, in its glibc implementation. Since it's
* only half-documented (glibc doesn't document it but LSB does — though only superficially)
* we'll check for errors only in the most generic fashion possible. */
if (__register_atfork(NULL, NULL, reset_cached_pid, __dso_handle) != 0) {
/* OOM? Let's try again later */
cached_pid = CACHED_PID_UNSET;
return new_pid;
}
installed = true;
}
cached_pid = new_pid;