fs: pstore: remove unused hardirq.h
[linux/fpc-iii.git] / fs / signalfd.c
blob5f1ff8756595ee93bd9a13e3a3531a6a937f5d32
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * fs/signalfd.c
5 * Copyright (C) 2003 Linus Torvalds
7 * Mon Mar 5, 2007: Davide Libenzi <davidel@xmailserver.org>
8 * Changed ->read() to return a siginfo strcture instead of signal number.
9 * Fixed locking in ->poll().
10 * Added sighand-detach notification.
11 * Added fd re-use in sys_signalfd() syscall.
12 * Now using anonymous inode source.
13 * Thanks to Oleg Nesterov for useful code review and suggestions.
14 * More comments and suggestions from Arnd Bergmann.
15 * Sat May 19, 2007: Davi E. M. Arnaut <davi@haxent.com.br>
16 * Retrieve multiple signals with one read() call
17 * Sun Jul 15, 2007: Davide Libenzi <davidel@xmailserver.org>
18 * Attach to the sighand only during read() and poll().
21 #include <linux/file.h>
22 #include <linux/poll.h>
23 #include <linux/init.h>
24 #include <linux/fs.h>
25 #include <linux/sched.h>
26 #include <linux/slab.h>
27 #include <linux/kernel.h>
28 #include <linux/signal.h>
29 #include <linux/list.h>
30 #include <linux/anon_inodes.h>
31 #include <linux/signalfd.h>
32 #include <linux/syscalls.h>
33 #include <linux/proc_fs.h>
34 #include <linux/compat.h>
36 void signalfd_cleanup(struct sighand_struct *sighand)
38 wait_queue_head_t *wqh = &sighand->signalfd_wqh;
40 * The lockless check can race with remove_wait_queue() in progress,
41 * but in this case its caller should run under rcu_read_lock() and
42 * sighand_cachep is SLAB_TYPESAFE_BY_RCU, we can safely return.
44 if (likely(!waitqueue_active(wqh)))
45 return;
47 /* wait_queue_entry_t->func(POLLFREE) should do remove_wait_queue() */
48 wake_up_poll(wqh, POLLHUP | POLLFREE);
51 struct signalfd_ctx {
52 sigset_t sigmask;
55 static int signalfd_release(struct inode *inode, struct file *file)
57 kfree(file->private_data);
58 return 0;
61 static unsigned int signalfd_poll(struct file *file, poll_table *wait)
63 struct signalfd_ctx *ctx = file->private_data;
64 unsigned int events = 0;
66 poll_wait(file, &current->sighand->signalfd_wqh, wait);
68 spin_lock_irq(&current->sighand->siglock);
69 if (next_signal(&current->pending, &ctx->sigmask) ||
70 next_signal(&current->signal->shared_pending,
71 &ctx->sigmask))
72 events |= POLLIN;
73 spin_unlock_irq(&current->sighand->siglock);
75 return events;
79 * Copied from copy_siginfo_to_user() in kernel/signal.c
81 static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
82 siginfo_t const *kinfo)
84 long err;
86 BUILD_BUG_ON(sizeof(struct signalfd_siginfo) != 128);
89 * Unused members should be zero ...
91 err = __clear_user(uinfo, sizeof(*uinfo));
94 * If you change siginfo_t structure, please be sure
95 * this code is fixed accordingly.
97 err |= __put_user(kinfo->si_signo, &uinfo->ssi_signo);
98 err |= __put_user(kinfo->si_errno, &uinfo->ssi_errno);
99 err |= __put_user(kinfo->si_code, &uinfo->ssi_code);
100 switch (siginfo_layout(kinfo->si_signo, kinfo->si_code)) {
101 case SIL_KILL:
102 err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
103 err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
104 break;
105 case SIL_TIMER:
106 err |= __put_user(kinfo->si_tid, &uinfo->ssi_tid);
107 err |= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun);
108 err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
109 err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
110 break;
111 case SIL_POLL:
112 err |= __put_user(kinfo->si_band, &uinfo->ssi_band);
113 err |= __put_user(kinfo->si_fd, &uinfo->ssi_fd);
114 break;
115 case SIL_FAULT:
116 err |= __put_user((long) kinfo->si_addr, &uinfo->ssi_addr);
117 #ifdef __ARCH_SI_TRAPNO
118 err |= __put_user(kinfo->si_trapno, &uinfo->ssi_trapno);
119 #endif
120 #ifdef BUS_MCEERR_AO
122 * Other callers might not initialize the si_lsb field,
123 * so check explicitly for the right codes here.
125 if (kinfo->si_signo == SIGBUS &&
126 (kinfo->si_code == BUS_MCEERR_AR ||
127 kinfo->si_code == BUS_MCEERR_AO))
128 err |= __put_user((short) kinfo->si_addr_lsb,
129 &uinfo->ssi_addr_lsb);
130 #endif
131 break;
132 case SIL_CHLD:
133 err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
134 err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
135 err |= __put_user(kinfo->si_status, &uinfo->ssi_status);
136 err |= __put_user(kinfo->si_utime, &uinfo->ssi_utime);
137 err |= __put_user(kinfo->si_stime, &uinfo->ssi_stime);
138 break;
139 case SIL_RT:
140 default:
142 * This case catches also the signals queued by sigqueue().
144 err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid);
145 err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid);
146 err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr);
147 err |= __put_user(kinfo->si_int, &uinfo->ssi_int);
148 break;
151 return err ? -EFAULT: sizeof(*uinfo);
154 static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
155 int nonblock)
157 ssize_t ret;
158 DECLARE_WAITQUEUE(wait, current);
160 spin_lock_irq(&current->sighand->siglock);
161 ret = dequeue_signal(current, &ctx->sigmask, info);
162 switch (ret) {
163 case 0:
164 if (!nonblock)
165 break;
166 ret = -EAGAIN;
167 default:
168 spin_unlock_irq(&current->sighand->siglock);
169 return ret;
172 add_wait_queue(&current->sighand->signalfd_wqh, &wait);
173 for (;;) {
174 set_current_state(TASK_INTERRUPTIBLE);
175 ret = dequeue_signal(current, &ctx->sigmask, info);
176 if (ret != 0)
177 break;
178 if (signal_pending(current)) {
179 ret = -ERESTARTSYS;
180 break;
182 spin_unlock_irq(&current->sighand->siglock);
183 schedule();
184 spin_lock_irq(&current->sighand->siglock);
186 spin_unlock_irq(&current->sighand->siglock);
188 remove_wait_queue(&current->sighand->signalfd_wqh, &wait);
189 __set_current_state(TASK_RUNNING);
191 return ret;
195 * Returns a multiple of the size of a "struct signalfd_siginfo", or a negative
196 * error code. The "count" parameter must be at least the size of a
197 * "struct signalfd_siginfo".
199 static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
200 loff_t *ppos)
202 struct signalfd_ctx *ctx = file->private_data;
203 struct signalfd_siginfo __user *siginfo;
204 int nonblock = file->f_flags & O_NONBLOCK;
205 ssize_t ret, total = 0;
206 siginfo_t info;
208 count /= sizeof(struct signalfd_siginfo);
209 if (!count)
210 return -EINVAL;
212 siginfo = (struct signalfd_siginfo __user *) buf;
213 do {
214 ret = signalfd_dequeue(ctx, &info, nonblock);
215 if (unlikely(ret <= 0))
216 break;
217 ret = signalfd_copyinfo(siginfo, &info);
218 if (ret < 0)
219 break;
220 siginfo++;
221 total += ret;
222 nonblock = 1;
223 } while (--count);
225 return total ? total: ret;
228 #ifdef CONFIG_PROC_FS
229 static void signalfd_show_fdinfo(struct seq_file *m, struct file *f)
231 struct signalfd_ctx *ctx = f->private_data;
232 sigset_t sigmask;
234 sigmask = ctx->sigmask;
235 signotset(&sigmask);
236 render_sigset_t(m, "sigmask:\t", &sigmask);
238 #endif
240 static const struct file_operations signalfd_fops = {
241 #ifdef CONFIG_PROC_FS
242 .show_fdinfo = signalfd_show_fdinfo,
243 #endif
244 .release = signalfd_release,
245 .poll = signalfd_poll,
246 .read = signalfd_read,
247 .llseek = noop_llseek,
250 SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
251 size_t, sizemask, int, flags)
253 sigset_t sigmask;
254 struct signalfd_ctx *ctx;
256 /* Check the SFD_* constants for consistency. */
257 BUILD_BUG_ON(SFD_CLOEXEC != O_CLOEXEC);
258 BUILD_BUG_ON(SFD_NONBLOCK != O_NONBLOCK);
260 if (flags & ~(SFD_CLOEXEC | SFD_NONBLOCK))
261 return -EINVAL;
263 if (sizemask != sizeof(sigset_t) ||
264 copy_from_user(&sigmask, user_mask, sizeof(sigmask)))
265 return -EINVAL;
266 sigdelsetmask(&sigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
267 signotset(&sigmask);
269 if (ufd == -1) {
270 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
271 if (!ctx)
272 return -ENOMEM;
274 ctx->sigmask = sigmask;
277 * When we call this, the initialization must be complete, since
278 * anon_inode_getfd() will install the fd.
280 ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,
281 O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));
282 if (ufd < 0)
283 kfree(ctx);
284 } else {
285 struct fd f = fdget(ufd);
286 if (!f.file)
287 return -EBADF;
288 ctx = f.file->private_data;
289 if (f.file->f_op != &signalfd_fops) {
290 fdput(f);
291 return -EINVAL;
293 spin_lock_irq(&current->sighand->siglock);
294 ctx->sigmask = sigmask;
295 spin_unlock_irq(&current->sighand->siglock);
297 wake_up(&current->sighand->signalfd_wqh);
298 fdput(f);
301 return ufd;
304 SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
305 size_t, sizemask)
307 return sys_signalfd4(ufd, user_mask, sizemask, 0);
310 #ifdef CONFIG_COMPAT
311 COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
312 const compat_sigset_t __user *,sigmask,
313 compat_size_t, sigsetsize,
314 int, flags)
316 sigset_t tmp;
317 sigset_t __user *ksigmask;
319 if (sigsetsize != sizeof(compat_sigset_t))
320 return -EINVAL;
321 if (get_compat_sigset(&tmp, sigmask))
322 return -EFAULT;
323 ksigmask = compat_alloc_user_space(sizeof(sigset_t));
324 if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
325 return -EFAULT;
327 return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
330 COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
331 const compat_sigset_t __user *,sigmask,
332 compat_size_t, sigsetsize)
334 return compat_sys_signalfd4(ufd, sigmask, sigsetsize, 0);
336 #endif