diff options
-rw-r--r-- | src/internal/libc.h | 3 | ||||
-rw-r--r-- | src/internal/pthread_impl.h | 6 | ||||
-rw-r--r-- | src/thread/__rsyscall.c | 114 | ||||
-rw-r--r-- | src/thread/pthread_create.c | 8 | ||||
-rw-r--r-- | src/thread/synccall.c | 109 | ||||
-rw-r--r-- | src/unistd/setegid.c | 4 | ||||
-rw-r--r-- | src/unistd/seteuid.c | 4 | ||||
-rw-r--r-- | src/unistd/setgid.c | 2 | ||||
-rw-r--r-- | src/unistd/setregid.c | 2 | ||||
-rw-r--r-- | src/unistd/setresgid.c | 2 | ||||
-rw-r--r-- | src/unistd/setresuid.c | 2 | ||||
-rw-r--r-- | src/unistd/setreuid.c | 2 | ||||
-rw-r--r-- | src/unistd/setuid.c | 2 |
13 files changed, 130 insertions, 130 deletions
diff --git a/src/internal/libc.h b/src/internal/libc.h index 638ea527..906de2ca 100644 --- a/src/internal/libc.h +++ b/src/internal/libc.h @@ -42,7 +42,8 @@ void __lockfile(FILE *); #define LOCK(x) (libc.threads_minus_1 ? (__lock(x),1) : ((void)(x),1)) #define UNLOCK(x) (*(volatile int *)(x)=0) -int __rsyscall(int, long, long, long, long, long, long); +void __synccall(void (*)(void *), void *); +int __setxid(int, int, int, int); extern char **__environ; #define environ __environ diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index 2089c857..e6089f02 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -80,7 +80,7 @@ struct __timer { #define SIGTIMER 32 #define SIGCANCEL 33 -#define SIGSYSCALL 34 +#define SIGSYNCCALL 34 #define SIGPT_SET ((sigset_t *)(unsigned long [1+(sizeof(long)==4)]){ \ [sizeof(long)==4] = 3UL<<(32*(sizeof(long)>4)) }) @@ -98,8 +98,8 @@ int __timedwait_cp(volatile int *, int, clockid_t, const struct timespec *, int) void __wait(volatile int *, volatile int *, int, int); void __wake(volatile int *, int, int); -void __rsyscall_lock(); -void __rsyscall_unlock(); +void __synccall_lock(); +void __synccall_unlock(); #define DEFAULT_STACK_SIZE (16384-PAGE_SIZE) #define DEFAULT_GUARD_SIZE PAGE_SIZE diff --git a/src/thread/__rsyscall.c b/src/thread/__rsyscall.c deleted file mode 100644 index e885d9e7..00000000 --- a/src/thread/__rsyscall.c +++ /dev/null @@ -1,114 +0,0 @@ -#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); - - __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1}, &set, 8); - - if (!rs.init) { - struct sigaction sa = { - .sa_flags = SA_SIGINFO | SA_RESTART, - .sa_sigaction = rsyscall_handler, - .sa_mask = set - }; - sigfillset(&sa.sa_mask); - sa.sa_sigaction = rsyscall_handler; - __libc_sigaction(SIGSYSCALL, &sa, 0); - rs.init = 1; - } - - 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 */ - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, &set, 8); - - /* 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); -} diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index d60c2a4d..856015ff 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -3,8 +3,8 @@ static void dummy_0() { } -weak_alias(dummy_0, __rsyscall_lock); -weak_alias(dummy_0, __rsyscall_unlock); +weak_alias(dummy_0, __synccall_lock); +weak_alias(dummy_0, __synccall_unlock); weak_alias(dummy_0, __pthread_tsd_run_dtors); #ifdef __pthread_unwind_next @@ -99,12 +99,12 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo new->tlsdesc[1] = (uintptr_t)new; stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15); - __rsyscall_lock(); + __synccall_lock(); a_inc(&libc.threads_minus_1); ret = __uniclone(stack, start, new); - __rsyscall_unlock(); + __synccall_unlock(); if (ret < 0) { a_dec(&libc.threads_minus_1); diff --git a/src/thread/synccall.c b/src/thread/synccall.c new file mode 100644 index 00000000..7c4f92bf --- /dev/null +++ b/src/thread/synccall.c @@ -0,0 +1,109 @@ +#include "pthread_impl.h" +#include <semaphore.h> + +static struct chain { + struct chain *next; + sem_t sem, sem2; +} *head; + +static void (*callback)(void *), *context; +static int chainlen; +static sem_t chainlock, chaindone; +static pthread_rwlock_t lock = PTHREAD_RWLOCK_INITIALIZER; + +static void handler(int sig, siginfo_t *si, void *ctx) +{ + struct chain ch; + pthread_t self = __pthread_self(); + int old_errno = errno; + + if (chainlen == libc.threads_minus_1) return; + + sigqueue(self->pid, SIGSYNCCALL, (union sigval){0}); + + /* Threads which have already decremented themselves from the + * thread count must not act. Block further receipt of signals + * and return. */ + if (self->dead) { + memset(&((ucontext_t *)ctx)->uc_sigmask, -1, 8); + errno = old_errno; + return; + } + + sem_init(&ch.sem, 0, 0); + sem_init(&ch.sem2, 0, 0); + + while (sem_wait(&chainlock)); + ch.next = head; + head = &ch; + if (++chainlen == libc.threads_minus_1) sem_post(&chaindone); + sem_post(&chainlock); + + while (sem_wait(&ch.sem)); + callback(context); + sem_post(&ch.sem2); + while (sem_wait(&ch.sem)); + + errno = old_errno; +} + +void __synccall(void (*func)(void *), void *ctx) +{ + pthread_t self; + struct sigaction sa; + struct chain *cur, *next; + uint64_t oldmask; + + pthread_rwlock_wrlock(&lock); + + __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1}, &oldmask, 8); + + if (!libc.threads_minus_1) { + func(ctx); + return; + } + + sem_init(&chaindone, 0, 0); + sem_init(&chainlock, 0, 1); + chainlen = 0; + callback = func; + context = ctx; + + sa.sa_flags = SA_SIGINFO | SA_RESTART; + sa.sa_sigaction = handler; + sigfillset(&sa.sa_mask); + __libc_sigaction(SIGSYNCCALL, &sa, 0); + + self = __pthread_self(); + sigqueue(self->pid, SIGSYNCCALL, (union sigval){0}); + while (sem_wait(&chaindone)); + + for (cur=head; cur; cur=cur->next) { + sem_post(&cur->sem); + while (sem_wait(&cur->sem2)); + } + func(ctx); + + for (cur=head; cur; cur=next) { + next = cur->next; + sem_post(&cur->sem); + } + + sa.sa_flags = 0; + sa.sa_handler = SIG_IGN; + __libc_sigaction(SIGSYNCCALL, &sa, 0); + + __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &oldmask, 0, 8); + + pthread_rwlock_unlock(&lock); +} + +void __synccall_lock() +{ + pthread_rwlock_rdlock(&lock); +} + +void __synccall_unlock() +{ + pthread_rwlock_unlock(&lock); +} diff --git a/src/unistd/setegid.c b/src/unistd/setegid.c index 85348842..e6da2573 100644 --- a/src/unistd/setegid.c +++ b/src/unistd/setegid.c @@ -1,6 +1,8 @@ #include <unistd.h> +#include "libc.h" +#include "syscall.h" int setegid(gid_t egid) { - return setregid(-1, egid); + return __setxid(SYS_setresgid, -1, egid, -1); } diff --git a/src/unistd/seteuid.c b/src/unistd/seteuid.c index 0aaa86e0..ef8b9df4 100644 --- a/src/unistd/seteuid.c +++ b/src/unistd/seteuid.c @@ -1,6 +1,8 @@ #include <unistd.h> +#include "syscall.h" +#include "libc.h" int seteuid(uid_t euid) { - return setreuid(-1, euid); + return __setxid(SYS_setresuid, -1, euid, -1); } diff --git a/src/unistd/setgid.c b/src/unistd/setgid.c index 87b2717e..bae4616a 100644 --- a/src/unistd/setgid.c +++ b/src/unistd/setgid.c @@ -4,5 +4,5 @@ int setgid(gid_t gid) { - return __rsyscall(SYS_setgid, gid, 0, 0, 0, 0, 0); + return __setxid(SYS_setgid, gid, 0, 0); } diff --git a/src/unistd/setregid.c b/src/unistd/setregid.c index 665b5556..f5a8972a 100644 --- a/src/unistd/setregid.c +++ b/src/unistd/setregid.c @@ -4,5 +4,5 @@ int setregid(gid_t rgid, gid_t egid) { - return __rsyscall(SYS_setregid, rgid, egid, 0, 0, 0, 0); + return __setxid(SYS_setregid, rgid, egid, 0); } diff --git a/src/unistd/setresgid.c b/src/unistd/setresgid.c index 9b9fe50b..b9af540a 100644 --- a/src/unistd/setresgid.c +++ b/src/unistd/setresgid.c @@ -5,5 +5,5 @@ int setresgid(gid_t rgid, gid_t egid, gid_t sgid) { - return __rsyscall(SYS_setresgid, rgid, egid, sgid, 0, 0, 0); + return __setxid(SYS_setresgid, rgid, egid, sgid); } diff --git a/src/unistd/setresuid.c b/src/unistd/setresuid.c index 497f7592..83692b4c 100644 --- a/src/unistd/setresuid.c +++ b/src/unistd/setresuid.c @@ -5,5 +5,5 @@ int setresuid(uid_t ruid, uid_t euid, uid_t suid) { - return __rsyscall(SYS_setresuid, ruid, euid, suid, 0, 0, 0); + return __setxid(SYS_setresuid, ruid, euid, suid); } diff --git a/src/unistd/setreuid.c b/src/unistd/setreuid.c index 93d68c03..3fcc59e2 100644 --- a/src/unistd/setreuid.c +++ b/src/unistd/setreuid.c @@ -4,5 +4,5 @@ int setreuid(uid_t ruid, uid_t euid) { - return __rsyscall(SYS_setreuid, ruid, euid, 0, 0, 0, 0); + return __setxid(SYS_setreuid, ruid, euid, 0); } diff --git a/src/unistd/setuid.c b/src/unistd/setuid.c index e778c7f3..602ecbbf 100644 --- a/src/unistd/setuid.c +++ b/src/unistd/setuid.c @@ -4,5 +4,5 @@ int setuid(uid_t uid) { - return __rsyscall(SYS_setuid, uid, 0, 0, 0, 0, 0); + return __setxid(SYS_setuid, uid, 0, 0); } |