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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

3
libc/calls/g_sighandrvas.c
View file

@ -16,7 +16,8 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/intrin/pthread.h"
unsigned __sighandrvas[NSIG];
unsigned __sighandflags[NSIG];
_Alignas(64) int __sig_lock_obj;
pthread_mutex_t __sig_lock_obj;

4
libc/calls/poll-nt.c
View file

@ -43,8 +43,6 @@
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/errfuns.h"
_Alignas(64) static int poll_lock;
/**
* Polls on the New Technology.
*
@ -67,7 +65,6 @@ textwindows int sys_poll_nt(struct pollfd *fds, uint64_t nfds, uint64_t *ms) {
// do the planning
// we need to read static variables
// we might need to spawn threads and open pipes
_spinlock(&poll_lock);
__fds_lock();
for (gotinvals = failed = sn = pn = i = 0; i < nfds; ++i) {
if (fds[i].fd < 0) continue;
@ -115,7 +112,6 @@ textwindows int sys_poll_nt(struct pollfd *fds, uint64_t nfds, uint64_t *ms) {
}
}
__fds_unlock();
_spunlock(&poll_lock);
if (failed) {
// failed to create a polling solution
return failed;

4
libc/calls/sig.internal.h
View file

@ -23,11 +23,9 @@ struct Signals {
struct Signal mem[__SIG_QUEUE_LENGTH];
};
extern struct Signals __sig; // TODO(jart): Need TLS
extern long __sig_count;
extern struct Signals __sig;
void __sig_lock(void) hidden;
void __sig_unlock(void) hidden;
bool __sig_check(bool) hidden;
bool __sig_handle(bool, int, int, ucontext_t *) hidden;
int __sig_add(int, int) hidden;

30
libc/calls/siglock.c
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@ -1,30 +0,0 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/state.internal.h"
#include "libc/intrin/spinlock.h"
void __sig_lock(void) {
_spinlock(&__sig_lock_obj);
}
void __sig_unlock(void) {
_spunlock(&__sig_lock_obj);
}

12
libc/calls/state.internal.h
View file

@ -1,19 +1,21 @@
#ifndef COSMOPOLITAN_LIBC_CALLS_STATE_INTERNAL_H_
#define COSMOPOLITAN_LIBC_CALLS_STATE_INTERNAL_H_
#include "libc/intrin/spinlock.h"
#include "libc/intrin/pthread.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
hidden extern int __vforked;
hidden extern int __fds_lock_obj;
hidden extern int __sig_lock_obj;
hidden extern bool __time_critical;
hidden extern unsigned __sighandrvas[NSIG];
hidden extern unsigned __sighandflags[NSIG];
hidden extern pthread_mutex_t __sig_lock_obj;
hidden extern pthread_mutex_t __fds_lock_obj;
hidden extern const struct NtSecurityAttributes kNtIsInheritable;
void __fds_lock(void);
#define __fds_unlock() _spunlock(&__fds_lock_obj)
#define __fds_lock() pthread_mutex_lock(&__fds_lock_obj)
#define __fds_unlock() pthread_mutex_unlock(&__fds_lock_obj)
#define __sig_lock() pthread_mutex_lock(&__sig_lock_obj)
#define __sig_unlock() pthread_mutex_unlock(&__sig_lock_obj)
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */