#include "pthread_impl.h"
+static void dummy_0()
+{
+}
+weak_alias(dummy_0, __rsyscall_lock);
+weak_alias(dummy_0, __rsyscall_unlock);
+
static void dummy_1(pthread_t self)
{
}
exit(0);
if (self->detached && self->map_base) {
- syscall(__NR_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
+ __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (long)(uint64_t[1]){-1},0,8);
__unmapself(self->map_base, self->map_size);
}
- syscall(SYS_exit, 0);
+ __syscall(SYS_exit, 0);
}
static void docancel(struct pthread *self)
static void cancelpt(int x)
{
struct pthread *self = __pthread_self();
- if (self->canceldisable) return;
- if ((self->cancelpoint+=x)==1 && x>=0 && self->cancel)
- docancel(self);
-}
-
-/* "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)
-{
- struct pthread *self = __pthread_self();
-
- if (!rs.hold || rs.cnt == libc.threads_minus_1) return;
-
- /* Threads which have already decremented themselves from the
- * thread count must not increment rs.cnt or otherwise act. */
- if (self->dead) {
- sigaddset(&((ucontext_t *)ctx)->uc_sigmask, SIGSYSCALL);
- return;
- }
-
- if (syscall(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;
-
- 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);
-}
-
-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.err = 0;
- rs.cnt = 0;
- rs.hold = 1;
-
- /* 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);
- }
-
- /* Handle any lingering signals with no-op */
- __libc_sigprocmask(SIG_UNBLOCK, &set, 0);
-
- /* 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);
-
- if (rs.err) errno = rs.err, ret = -1;
- else ret = syscall(nr, a, b, c, d, e, f);
-
- UNLOCK(&rs.lock);
- return ret;
+ if ((self->cancelpoint+=x)==1 && self->cancel
+ && x<2U && !self->canceldisable) docancel(self);
}
static void init_threads()
libc.lock = __lock;
libc.lockfile = __lockfile;
libc.cancelpt = cancelpt;
- libc.rsyscall = rsyscall;
+
+ sigemptyset(&sa.sa_mask);
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);
+ __libc_sigprocmask(SIG_UNBLOCK, &sa.sa_mask, 0);
}
static int start(void *p)
size_t size, guard;
struct pthread *self = pthread_self(), *new;
unsigned char *map, *stack, *tsd;
- static const pthread_attr_t default_attr;
+ const pthread_attr_t default_attr = { 0 };
- if (!self) return errno = ENOSYS;
+ if (!self) return ENOSYS;
if (!init && ++init) init_threads();
if (!attr) attr = &default_attr;
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);
+ __rsyscall_lock();
a_inc(&libc.threads_minus_1);
ret = __uniclone(stack, start, new);
- a_dec(&rs.blocks);
- if (rs.lock) __wake(&rs.blocks, 1, 1);
+ __rsyscall_unlock();
if (ret < 0) {
a_dec(&libc.threads_minus_1);
projects / musl / blobdiff