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Make locks more reliable

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This change switches most of the core locks to be re-entrant, in order
to reduce the chance of deadlocking code that does, clever things with
asynchronous signal handlers. This change implements it it in pthreads
so we're one step closer to having a standardized threading primitives
This commit is contained in:
Justine Tunney 2022-06-11 01:59:26 -07:00
parent 5ea618f0af
commit c260345e06
35 changed files with 369 additions and 258 deletions
Download patch file Download diff file Expand all files Collapse all files

15
libc/stdio/fflush_unlocked.c
View file

@ -21,6 +21,7 @@
#include "libc/bits/pushpop.h"
#include "libc/calls/calls.h"
#include "libc/errno.h"
#include "libc/intrin/pthread.h"
#include "libc/intrin/spinlock.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
@ -40,7 +41,7 @@ int fflush_unlocked(FILE *f) {
int rc = 0;
size_t i;
if (!f) {
_spinlock(&__fflush.lock);
pthread_mutex_lock(&__fflush.lock);
for (i = __fflush.handles.i; i; --i) {
if ((f = __fflush.handles.p[i - 1])) {
if (fflush(f) == -1) {
@ -48,7 +49,7 @@ int fflush_unlocked(FILE *f) {
}
}
}
_spunlock(&__fflush.lock);
pthread_mutex_unlock(&__fflush.lock);
} else if (f->fd != -1) {
if (__fflush_impl(f) == -1) {
rc = -1;
@ -63,7 +64,7 @@ textstartup int __fflush_register(FILE *f) {
int rc;
size_t i;
struct StdioFlush *sf;
_spinlock(&__fflush.lock);
pthread_mutex_lock(&__fflush.lock);
sf = &__fflush;
if (!sf->handles.p) {
sf->handles.p = sf->handles_initmem;
@ -73,19 +74,19 @@ textstartup int __fflush_register(FILE *f) {
for (i = sf->handles.i; i; --i) {
if (!sf->handles.p[i - 1]) {
sf->handles.p[i - 1] = f;
_spunlock(&__fflush.lock);
pthread_mutex_unlock(&__fflush.lock);
return 0;
}
}
rc = append(&sf->handles, &f);
_spunlock(&__fflush.lock);
pthread_mutex_unlock(&__fflush.lock);
return rc;
}
void __fflush_unregister(FILE *f) {
size_t i;
struct StdioFlush *sf;
_spinlock(&__fflush.lock);
pthread_mutex_lock(&__fflush.lock);
sf = &__fflush;
sf = pushpop(sf);
for (i = sf->handles.i; i; --i) {
@ -94,5 +95,5 @@ void __fflush_unregister(FILE *f) {
break;
}
}
_spunlock(&__fflush.lock);
pthread_mutex_unlock(&__fflush.lock);
}