void (*lock)(volatile int *);
void (*lockfile)(FILE *);
void (*fork_handler)(int);
- int (*rsyscall)(int, long, long, long, long, long, long);
int (*atexit)(void (*)(void));
void (*fini)(void);
void (*ldso_fini)(void);
#define CANCELPT_INHIBIT CANCELPT(2)
#define CANCELPT_RESUME CANCELPT(-2)
+int __rsyscall(int, long, long, long, long, long, long);
+
extern char **__environ;
#define environ __environ
void __wait(volatile int *, volatile int *, int, int);
void __wake(volatile int *, int, int);
+void __rsyscall_lock();
+void __rsyscall_unlock();
+
#define DEFAULT_STACK_SIZE (16384-PAGE_SIZE)
#define DEFAULT_GUARD_SIZE PAGE_SIZE
--- /dev/null
+#include "pthread_impl.h"
+
+/* "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;
+ int init;
+} rs;
+
+static void rsyscall_handler(int sig, siginfo_t *si, void *ctx)
+{
+ struct pthread *self = __pthread_self();
+ long r;
+
+ 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) {
+ sigfillset(&((ucontext_t *)ctx)->uc_sigmask);
+ return;
+ }
+
+ r = __syscall(rs.nr, rs.arg[0], rs.arg[1],
+ rs.arg[2], rs.arg[3], rs.arg[4], rs.arg[5]);
+ if (r < 0) rs.err=-r;
+
+ 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);
+}
+
+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;
+
+ if (!libc.threads_minus_1)
+ return syscall(nr, a, b, c, d, e, f);
+
+ self = __pthread_self();
+
+ LOCK(&rs.lock);
+ while ((i=rs.blocks))
+ __wait(&rs.blocks, 0, i, 1);
+
+ sigfillset(&set);
+ __libc_sigprocmask(SIG_BLOCK, &set, &set);
+
+ if (!rs.init) {
+ struct sigaction sa = {
+ .sa_sigaction = rsyscall_handler,
+ .sa_mask = set
+ };
+ sigfillset(&sa.sa_mask);
+ sa.sa_sigaction = rsyscall_handler;
+ __libc_sigaction(SIGSYSCALL, &sa, 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, &set);
+
+ /* 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;
+}
+
+void __rsyscall_lock()
+{
+ a_inc(&rs.blocks);
+ while (rs.lock) __wait(&rs.lock, 0, 1, 1);
+}
+
+void __rsyscall_unlock()
+{
+ a_dec(&rs.blocks);
+ if (rs.lock) __wake(&rs.blocks, 1, 1);
+}
#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)
{
}
}
}
-/* "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();
- long r;
-
- 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) {
- sigfillset(&((ucontext_t *)ctx)->uc_sigmask);
- return;
- }
-
- r = __syscall(rs.nr, rs.arg[0], rs.arg[1],
- rs.arg[2], rs.arg[3], rs.arg[4], rs.arg[5]);
- if (r < 0) rs.err=-r;
-
- 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;
-}
-
static void init_threads()
{
struct sigaction sa = { .sa_flags = SA_SIGINFO | SA_RESTART };
libc.lock = __lock;
libc.lockfile = __lockfile;
libc.cancelpt = cancelpt;
- libc.rsyscall = rsyscall;
-
- sigfillset(&sa.sa_mask);
- sa.sa_sigaction = rsyscall_handler;
- __libc_sigaction(SIGSYSCALL, &sa, 0);
sigemptyset(&sa.sa_mask);
sa.sa_sigaction = cancel_handler;
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 ENOSYS;
if (!init && ++init) init_threads();
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);
int setgid(gid_t gid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setgid, gid, 0, 0, 0, 0, 0);
- return syscall(SYS_setgid, gid);
+ return __rsyscall(__NR_setgid, gid, 0, 0, 0, 0, 0);
}
int setregid(gid_t rgid, gid_t egid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setregid, rgid, egid, 0, 0, 0, 0);
- return syscall(SYS_setregid, rgid, egid);
+ return __rsyscall(__NR_setregid, rgid, egid, 0, 0, 0, 0);
}
int setresgid(gid_t rgid, gid_t egid, gid_t sgid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setresgid, rgid, egid, sgid, 0, 0, 0);
- return syscall(SYS_setresgid, rgid, egid, sgid);
+ return __rsyscall(__NR_setresgid, rgid, egid, sgid, 0, 0, 0);
}
int setresuid(uid_t ruid, uid_t euid, uid_t suid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setresuid, ruid, euid, suid, 0, 0, 0);
- return syscall(SYS_setresuid, ruid, euid, suid);
+ return __rsyscall(__NR_setresuid, ruid, euid, suid, 0, 0, 0);
}
int setreuid(uid_t ruid, uid_t euid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setreuid, ruid, euid, 0, 0, 0, 0);
- return syscall(SYS_setreuid, ruid, euid);
+ return __rsyscall(__NR_setreuid, ruid, euid, 0, 0, 0, 0);
}
int setuid(uid_t uid)
{
- if (libc.rsyscall) return libc.rsyscall(__NR_setuid, uid, 0, 0, 0, 0, 0);
- return syscall(SYS_setuid, uid);
+ return __rsyscall(__NR_setuid, uid, 0, 0, 0, 0, 0);
}
projects / musl / commitdiff