diff options
| -rw-r--r-- | fs/signalfd.c | 120 |
1 files changed, 75 insertions, 45 deletions
diff --git a/fs/signalfd.c b/fs/signalfd.c index 7cfeab412b45..f1da89203a9a 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -11,6 +11,8 @@ * Now using anonymous inode source. * Thanks to Oleg Nesterov for useful code review and suggestions. * More comments and suggestions from Arnd Bergmann. + * Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br> + * Retrieve multiple signals with one read() call */ #include <linux/file.h> @@ -206,6 +208,59 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, return err ? -EFAULT: sizeof(*uinfo); } +static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info, + int nonblock) +{ + ssize_t ret; + struct signalfd_lockctx lk; + DECLARE_WAITQUEUE(wait, current); + + if (!signalfd_lock(ctx, &lk)) + return 0; + + ret = dequeue_signal(lk.tsk, &ctx->sigmask, info); + switch (ret) { + case 0: + if (!nonblock) + break; + ret = -EAGAIN; + default: + signalfd_unlock(&lk); + return ret; + } + + add_wait_queue(&ctx->wqh, &wait); + for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + ret = dequeue_signal(lk.tsk, &ctx->sigmask, info); + signalfd_unlock(&lk); + if (ret != 0) + break; + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + schedule(); + ret = signalfd_lock(ctx, &lk); + if (unlikely(!ret)) { + /* + * Let the caller read zero byte, ala socket + * recv() when the peer disconnect. This test + * must be done before doing a dequeue_signal(), + * because if the sighand has been orphaned, + * the dequeue_signal() call is going to crash + * because ->sighand will be long gone. + */ + break; + } + } + + remove_wait_queue(&ctx->wqh, &wait); + __set_current_state(TASK_RUNNING); + + return ret; +} + /* * Returns either the size of a "struct signalfd_siginfo", or zero if the * sighand we are attached to, has been orphaned. The "count" parameter @@ -215,55 +270,30 @@ static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct signalfd_ctx *ctx = file->private_data; - ssize_t res = 0; - int locked, signo; + struct signalfd_siginfo __user *siginfo; + int nonblock = file->f_flags & O_NONBLOCK; + ssize_t ret, total = 0; siginfo_t info; - struct signalfd_lockctx lk; - DECLARE_WAITQUEUE(wait, current); - if (count < sizeof(struct signalfd_siginfo)) + count /= sizeof(struct signalfd_siginfo); + if (!count) return -EINVAL; - locked = signalfd_lock(ctx, &lk); - if (!locked) - return 0; - res = -EAGAIN; - signo = dequeue_signal(lk.tsk, &ctx->sigmask, &info); - if (signo == 0 && !(file->f_flags & O_NONBLOCK)) { - add_wait_queue(&ctx->wqh, &wait); - for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - signo = dequeue_signal(lk.tsk, &ctx->sigmask, &info); - if (signo != 0) - break; - if (signal_pending(current)) { - res = -ERESTARTSYS; - break; - } - signalfd_unlock(&lk); - schedule(); - locked = signalfd_lock(ctx, &lk); - if (unlikely(!locked)) { - /* - * Let the caller read zero byte, ala socket - * recv() when the peer disconnect. This test - * must be done before doing a dequeue_signal(), - * because if the sighand has been orphaned, - * the dequeue_signal() call is going to crash. - */ - res = 0; - break; - } - } - remove_wait_queue(&ctx->wqh, &wait); - __set_current_state(TASK_RUNNING); - } - if (likely(locked)) - signalfd_unlock(&lk); - if (likely(signo)) - res = signalfd_copyinfo((struct signalfd_siginfo __user *) buf, - &info); - return res; + siginfo = (struct signalfd_siginfo __user *) buf; + + do { + ret = signalfd_dequeue(ctx, &info, nonblock); + if (unlikely(ret <= 0)) + break; + ret = signalfd_copyinfo(siginfo, &info); + if (ret < 0) + break; + siginfo++; + total += ret; + nonblock = 1; + } while (--count); + + return total ? total : ret; } static const struct file_operations signalfd_fops = { |