#include "pthread_impl.h"
+#include "stdio_impl.h"
+#include <sys/mman.h>
-#define pthread_self __pthread_self
-
-static void docancel(struct pthread *self)
+static void dummy_0()
{
- struct __ptcb cb = { .__next = self->cancelbuf };
- __pthread_unwind_next(&cb);
}
+weak_alias(dummy_0, __acquire_ptc);
+weak_alias(dummy_0, __release_ptc);
+weak_alias(dummy_0, __pthread_tsd_run_dtors);
-static void cancel_handler(int sig, siginfo_t *si, void *ctx)
+_Noreturn void pthread_exit(void *result)
{
- struct pthread *self = pthread_self();
- self->cancel = 1;
- if (self->canceldisable || (!self->cancelasync && !self->cancelpoint))
- return;
- docancel(self);
-}
+ pthread_t self = pthread_self();
+ int n;
-/* "rsyscall" is a mechanism by which a thread can synchronously force all
- * other threads to perform an arbitrary syscall. It is necessary to work
- * around the non-conformant implementation of setuid() et al on Linux,
- * which affect only the calling thread and not the whole process. This
- * implementation performs some tricks with signal delivery to work around
- * the fact that it does not keep any list of threads in userspace. */
-
-static struct {
- volatile int lock, hold, blocks, cnt;
- unsigned long arg[6];
- int nr;
- int err;
-} rs;
-
-static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
-{
- if (rs.cnt == libc.threads_minus_1) return;
+ self->result = result;
- if (syscall6(rs.nr, rs.arg[0], rs.arg[1], rs.arg[2],
- rs.arg[3], rs.arg[4], rs.arg[5]) < 0 && !rs.err) rs.err=errno;
+ while (self->cancelbuf) {
+ void (*f)(void *) = self->cancelbuf->__f;
+ void *x = self->cancelbuf->__x;
+ self->cancelbuf = self->cancelbuf->__next;
+ f(x);
+ }
- a_inc(&rs.cnt);
- __wake(&rs.cnt, 1, 1);
- while(rs.hold)
- __wait(&rs.hold, 0, 1, 1);
- a_dec(&rs.cnt);
- if (!rs.cnt) __wake(&rs.cnt, 1, 1);
-}
+ __pthread_tsd_run_dtors();
-static int rsyscall(int nr, long a, long b, long c, long d, long e, long f)
-{
- int i, ret;
- sigset_t set = { 0 };
- struct pthread *self = pthread_self();
- sigaddset(&set, SIGSYSCALL);
-
- LOCK(&rs.lock);
- while ((i=rs.blocks))
- __wait(&rs.blocks, 0, i, 1);
-
- __libc_sigprocmask(SIG_BLOCK, &set, 0);
-
- rs.nr = nr;
- rs.arg[0] = a; rs.arg[1] = b;
- rs.arg[2] = c; rs.arg[3] = d;
- rs.arg[4] = d; rs.arg[5] = f;
- rs.hold = 1;
- rs.err = 0;
- rs.cnt = 0;
-
- /* Dispatch signals until all threads respond */
- for (i=libc.threads_minus_1; i; i--)
- sigqueue(self->pid, SIGSYSCALL, (union sigval){0});
- while ((i=rs.cnt) < libc.threads_minus_1) {
- sigqueue(self->pid, SIGSYSCALL, (union sigval){0});
- __wait(&rs.cnt, 0, i, 1);
- }
+ __lock(self->exitlock);
- /* Handle any lingering signals with no-op */
- __libc_sigprocmask(SIG_UNBLOCK, &set, 0);
+ /* Mark this thread dead before decrementing count */
+ __lock(self->killlock);
+ self->dead = 1;
+ __unlock(self->killlock);
- /* Resume other threads' signal handlers and wait for them */
- rs.hold = 0;
- __wake(&rs.hold, -1, 0);
- while((i=rs.cnt)) __wait(&rs.cnt, 0, i, 1);
+ do n = libc.threads_minus_1;
+ while (n && a_cas(&libc.threads_minus_1, n, n-1)!=n);
+ if (!n) exit(0);
- if (rs.err) errno = rs.err, ret = -1;
- else ret = syscall6(nr, a, b, c, d, e, f);
+ if (self->detached && self->map_base) {
+ if (self->detached == 2)
+ __syscall(SYS_set_tid_address, 0);
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK,
+ SIGALL_SET, 0, __SYSCALL_SSLEN);
+ __unmapself(self->map_base, self->map_size);
+ }
- UNLOCK(&rs.lock);
- return ret;
+ for (;;) __syscall(SYS_exit, 0);
}
-static void cancelpt(int x)
+void __do_cleanup_push(struct __ptcb *cb)
{
struct pthread *self = pthread_self();
- if (self->canceldisable) return;
- self->cancelpoint = x;
- if (self->cancel) docancel(self);
+ cb->__next = self->cancelbuf;
+ self->cancelbuf = cb;
}
-static void init_threads()
+void __do_cleanup_pop(struct __ptcb *cb)
{
- struct sigaction sa = { .sa_flags = SA_SIGINFO | SA_RESTART };
- libc.lock = __lock;
- libc.cancelpt = cancelpt;
- libc.rsyscall = rsyscall;
- sa.sa_sigaction = cancel_handler;
- __libc_sigaction(SIGCANCEL, &sa, 0);
- sigaddset(&sa.sa_mask, SIGSYSCALL);
- sigaddset(&sa.sa_mask, SIGCANCEL);
- sa.sa_sigaction = rsyscall_handler;
- __libc_sigaction(SIGSYSCALL, &sa, 0);
- sigprocmask(SIG_UNBLOCK, &sa.sa_mask, 0);
+ __pthread_self()->cancelbuf = cb->__next;
}
static int start(void *p)
{
- struct pthread *self = p;
+ pthread_t self = p;
+ if (self->startlock[0]) {
+ __wait(self->startlock, 0, 1, 1);
+ if (self->startlock[0]) {
+ self->detached = 2;
+ pthread_exit(0);
+ }
+ __syscall(SYS_rt_sigprocmask, SIG_SETMASK,
+ self->sigmask, 0, __SYSCALL_SSLEN);
+ }
+ if (self->unblock_cancel)
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
+ SIGPT_SET, 0, __SYSCALL_SSLEN);
pthread_exit(self->start(self->start_arg));
return 0;
}
-#undef pthread_self
-
-#define CLONE_MAGIC 0x7d0f00
-int __clone(int (*)(void *), void *, int, void *, pid_t *, void *, pid_t *);
-
#define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE)
/* pthread_key_create.c overrides this */
static const size_t dummy = 0;
weak_alias(dummy, __pthread_tsd_size);
-int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(void *), void *arg)
+static FILE *const dummy_file = 0;
+weak_alias(dummy_file, __stdin_used);
+weak_alias(dummy_file, __stdout_used);
+weak_alias(dummy_file, __stderr_used);
+
+static void init_file_lock(FILE *f)
+{
+ if (f && f->lock<0) f->lock = 0;
+}
+
+void *__copy_tls(unsigned char *);
+
+int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp, void *(*entry)(void *), void *restrict arg)
{
- static int init;
int ret;
size_t size, guard;
struct pthread *self = pthread_self(), *new;
- unsigned char *map, *stack, *tsd;
- static const pthread_attr_t default_attr;
-
- if (!self) return errno = ENOSYS;
- if (!init && ++init) init_threads();
-
- if (!attr) attr = &default_attr;
- guard = ROUND(attr->__guardsize + DEFAULT_GUARD_SIZE);
- size = guard + ROUND(attr->__stacksize + DEFAULT_STACK_SIZE);
- size += __pthread_tsd_size;
- map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
- if (!map) return EAGAIN;
- mprotect(map, guard, PROT_NONE);
-
- tsd = map + size - __pthread_tsd_size;
- new = (void *)(tsd - sizeof *new - PAGE_SIZE%sizeof *new);
+ unsigned char *map = 0, *stack = 0, *tsd = 0;
+ unsigned flags = 0x7d8f00;
+ int do_sched = 0;
+ pthread_attr_t attr = {0};
+
+ if (!self) return ENOSYS;
+ if (!libc.threaded) {
+ for (FILE *f=libc.ofl_head; f; f=f->next)
+ init_file_lock(f);
+ init_file_lock(__stdin_used);
+ init_file_lock(__stdout_used);
+ init_file_lock(__stderr_used);
+ libc.threaded = 1;
+ }
+ if (attrp) attr = *attrp;
+
+ __acquire_ptc();
+
+ if (attr._a_stackaddr) {
+ size_t need = libc.tls_size + __pthread_tsd_size;
+ size = attr._a_stacksize + DEFAULT_STACK_SIZE;
+ stack = (void *)(attr._a_stackaddr & -16);
+ /* Use application-provided stack for TLS only when
+ * it does not take more than ~12% or 2k of the
+ * application's stack space. */
+ if (need < size/8 && need < 2048) {
+ tsd = stack - __pthread_tsd_size;
+ stack = tsd - libc.tls_size;
+ } else {
+ size = ROUND(need);
+ guard = 0;
+ }
+ } else {
+ guard = ROUND(DEFAULT_GUARD_SIZE + attr._a_guardsize);
+ size = guard + ROUND(DEFAULT_STACK_SIZE + attr._a_stacksize
+ + libc.tls_size + __pthread_tsd_size);
+ }
+
+ if (!tsd) {
+ if (guard) {
+ map = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ if (map == MAP_FAILED) goto fail;
+ if (mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)) {
+ munmap(map, size);
+ goto fail;
+ }
+ } else {
+ map = mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ if (map == MAP_FAILED) goto fail;
+ }
+ tsd = map + size - __pthread_tsd_size;
+ if (!stack) stack = tsd - libc.tls_size;
+ }
+
+ new = __copy_tls(tsd - libc.tls_size);
new->map_base = map;
new->map_size = size;
new->pid = self->pid;
new->start_arg = arg;
new->self = new;
new->tsd = (void *)tsd;
- new->detached = attr->__detach;
- new->attr = *attr;
- memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
- new->tlsdesc[1] = (uintptr_t)new;
- stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15);
-
- /* We must synchronize new thread creation with rsyscall
- * delivery. This looks to be the least expensive way: */
- a_inc(&rs.blocks);
- while (rs.lock) __wait(&rs.lock, 0, 1, 1);
+ if (attr._a_detach) {
+ new->detached = 1;
+ flags -= 0x200000;
+ }
+ if (attr._a_sched) {
+ do_sched = new->startlock[0] = 1;
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK,
+ SIGALL_SET, self->sigmask, __SYSCALL_SSLEN);
+ }
+ new->unblock_cancel = self->cancel;
+ new->canary = self->canary;
a_inc(&libc.threads_minus_1);
- ret = __clone(start, stack, CLONE_MAGIC, new,
- &new->tid, &new->tlsdesc, &new->tid);
+ ret = __clone(start, stack, flags, new, &new->tid, TP_ADJ(new), &new->tid);
- a_dec(&rs.blocks);
- if (rs.lock) __wake(&rs.blocks, 1, 1);
+ __release_ptc();
+
+ if (do_sched) {
+ __syscall(SYS_rt_sigprocmask, SIG_SETMASK,
+ new->sigmask, 0, __SYSCALL_SSLEN);
+ }
if (ret < 0) {
a_dec(&libc.threads_minus_1);
- munmap(map, size);
- return -ret;
+ if (map) munmap(map, size);
+ return EAGAIN;
}
+
+ if (do_sched) {
+ ret = __syscall(SYS_sched_setscheduler, new->tid,
+ attr._a_policy, &attr._a_prio);
+ a_store(new->startlock, ret<0 ? 2 : 0);
+ __wake(new->startlock, 1, 1);
+ if (ret < 0) return -ret;
+ }
+
*res = new;
return 0;
+fail:
+ __release_ptc();
+ return EAGAIN;
}
projects / musl / blobdiff