Implement sigtimedwait

HBLvim · Aug 26, 2019 · d5f9309 · d5f9309
1 parent 68e7dd8
commit d5f9309
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Showing 4 changed files with 55 additions and 1 deletion.
diff --git a/kernel/calls.c b/kernel/calls.c
@@ -107,6 +107,7 @@ syscall_t syscall_table[] = {
     [174] = (syscall_t) sys_rt_sigaction,
     [175] = (syscall_t) sys_rt_sigprocmask,
     [176] = (syscall_t) sys_rt_sigpending,
+    [177] = (syscall_t) sys_rt_sigtimedwait,
     [179] = (syscall_t) sys_rt_sigsuspend,
     [180] = (syscall_t) sys_pread,
     [181] = (syscall_t) sys_pwrite,

diff --git a/kernel/signal.c b/kernel/signal.c
@@ -55,7 +55,7 @@ static void deliver_signal_unlocked(struct task *task, int sig, struct siginfo_
     sigqueue->info.sig = sig;
     list_add_tail(&task->queue, &sigqueue->queue);
 
-    if (sigset_has(task->blocked, sig) && signal_is_blockable(sig))
+    if (sigset_has(task->blocked & ~task->waiting, sig) && signal_is_blockable(sig))
         return;
 
     if (task != current) {
@@ -584,6 +584,57 @@ int_t sys_pause() {
     return _EINTR;
 }
 
+int_t sys_rt_sigtimedwait(addr_t set_addr, addr_t info_addr, addr_t timeout_addr, uint_t set_size) {
+    if (set_size != sizeof(sigset_t_))
+        return _EINVAL;
+    sigset_t_ set;
+    if (user_get(set_addr, set))
+        return _EFAULT;
+    struct timespec timeout;
+    if (timeout_addr != 0) {
+        struct timespec_ fake_timeout;
+        if (user_get(timeout_addr, fake_timeout))
+            return _EFAULT;
+        timeout.tv_sec = fake_timeout.sec;
+        timeout.tv_nsec = fake_timeout.nsec;
+    }
+    STRACE("sigtimedwait(%#llx, %#x, %#x) = ...\n", (long long) set, info_addr, timeout_addr);
+
+    lock(&current->sighand->lock);
+    assert(current->waiting == 0);
+    current->waiting = set;
+    int err;
+    do {
+        err = wait_for(&current->pause, &current->sighand->lock, timeout_addr == 0 ? NULL : &timeout);
+    } while (err != 0);
+    current->waiting = 0;
+    if (err == _ETIMEDOUT) {
+        unlock(&current->sighand->lock);
+        STRACE("sigtimedwait timed out\n");
+        return _EAGAIN;
+    }
+
+    struct sigqueue *sigqueue;
+    bool found = false;
+    list_for_each_entry(&current->queue, sigqueue, queue) {
+        if (sigset_has(set, sigqueue->info.sig)) {
+            found = true;
+            list_remove(&sigqueue->queue);
+            break;
+        }
+    }
+    if (!found)
+        return _EINTR;
+    struct siginfo_ info = sigqueue->info;
+    free(sigqueue);
+    if (info_addr != 0)
+        if (user_put(info_addr, info))
+            return _EFAULT;
+    unlock(&current->sighand->lock);
+    STRACE("done sigtimedwait = %d\n", info.sig);
+    return info.sig;
+}
+
 int do_kill(pid_t_ pid, dword_t sig, pid_t_ tgid) {
     STRACE("kill(%d, %d)", pid, sig);
     if (sig >= NUM_SIGS)

diff --git a/kernel/signal.h b/kernel/signal.h
@@ -171,6 +171,7 @@ dword_t sys_sigaltstack(addr_t ss, addr_t old_ss);
 
 int_t sys_rt_sigsuspend(addr_t mask_addr, uint_t size);
 int_t sys_pause(void);
+int_t sys_rt_sigtimedwait(addr_t set_addr, addr_t info_addr, addr_t timeout_addr, uint_t set_size);
 
 dword_t sys_kill(pid_t_ pid, dword_t sig);
 dword_t sys_tkill(pid_t_ tid, dword_t sig);

diff --git a/kernel/task.h b/kernel/task.h
@@ -40,6 +40,7 @@ struct task {
     struct sighand *sighand;
     sigset_t_ blocked;
     sigset_t_ pending;
+    sigset_t_ waiting; // if nonzero, an ongoing call to sigtimedwait is waiting on these
     struct list queue;
     cond_t pause; // please don't signal this
     // private