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#include "pthread_impl.h"
#include <semaphore.h>
#include <unistd.h>
static struct chain {
struct chain *next;
sem_t sem, sem2;
} *head, *cur;
static void (*callback)(void *), *context;
static int chainlen;
static sem_t chainlock, chaindone;
static void handler(int sig, siginfo_t *si, void *ctx)
{
struct chain ch;
int old_errno = errno;
if (chainlen == libc.threads_minus_1) return;
sigqueue(getpid(), SIGSYNCCALL, (union sigval){0});
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)
{
struct sigaction sa;
struct chain *next;
sigset_t oldmask;
if (!libc.threads_minus_1) {
func(ctx);
return;
}
__inhibit_ptc();
__block_all_sigs(&oldmask);
sem_init(&chaindone, 0, 0);
sem_init(&chainlock, 0, 1);
chainlen = 0;
head = 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);
sigqueue(getpid(), SIGSYNCCALL, (union sigval){0});
while (sem_wait(&chaindone));
sa.sa_flags = 0;
sa.sa_handler = SIG_IGN;
__libc_sigaction(SIGSYNCCALL, &sa, 0);
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);
}
__restore_sigs(&oldmask);
__release_ptc();
}
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