Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/fcntl.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | #include <linux/syscalls.h> |
| 8 | #include <linux/init.h> |
| 9 | #include <linux/mm.h> |
| 10 | #include <linux/fs.h> |
| 11 | #include <linux/file.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 12 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | #include <linux/dnotify.h> |
| 14 | #include <linux/smp_lock.h> |
| 15 | #include <linux/slab.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/security.h> |
| 18 | #include <linux/ptrace.h> |
Jesper Juhl | 7ed20e1 | 2005-05-01 08:59:14 -0700 | [diff] [blame] | 19 | #include <linux/signal.h> |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 20 | #include <linux/rcupdate.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | |
| 22 | #include <asm/poll.h> |
| 23 | #include <asm/siginfo.h> |
| 24 | #include <asm/uaccess.h> |
| 25 | |
| 26 | void fastcall set_close_on_exec(unsigned int fd, int flag) |
| 27 | { |
| 28 | struct files_struct *files = current->files; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 29 | struct fdtable *fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | spin_lock(&files->file_lock); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 31 | fdt = files_fdtable(files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | if (flag) |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 33 | FD_SET(fd, fdt->close_on_exec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | else |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 35 | FD_CLR(fd, fdt->close_on_exec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | spin_unlock(&files->file_lock); |
| 37 | } |
| 38 | |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame^] | 39 | static int get_close_on_exec(unsigned int fd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | { |
| 41 | struct files_struct *files = current->files; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 42 | struct fdtable *fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | int res; |
Dipankar Sarma | b835996 | 2005-09-09 13:04:14 -0700 | [diff] [blame] | 44 | rcu_read_lock(); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 45 | fdt = files_fdtable(files); |
| 46 | res = FD_ISSET(fd, fdt->close_on_exec); |
Dipankar Sarma | b835996 | 2005-09-09 13:04:14 -0700 | [diff] [blame] | 47 | rcu_read_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | return res; |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * locate_fd finds a free file descriptor in the open_fds fdset, |
| 53 | * expanding the fd arrays if necessary. Must be called with the |
| 54 | * file_lock held for write. |
| 55 | */ |
| 56 | |
| 57 | static int locate_fd(struct files_struct *files, |
| 58 | struct file *file, unsigned int orig_start) |
| 59 | { |
| 60 | unsigned int newfd; |
| 61 | unsigned int start; |
| 62 | int error; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 63 | struct fdtable *fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
| 65 | error = -EINVAL; |
| 66 | if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
| 67 | goto out; |
| 68 | |
| 69 | repeat: |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 70 | fdt = files_fdtable(files); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | /* |
| 72 | * Someone might have closed fd's in the range |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 73 | * orig_start..fdt->next_fd |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | */ |
| 75 | start = orig_start; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 76 | if (start < fdt->next_fd) |
| 77 | start = fdt->next_fd; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | |
| 79 | newfd = start; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 80 | if (start < fdt->max_fdset) { |
| 81 | newfd = find_next_zero_bit(fdt->open_fds->fds_bits, |
| 82 | fdt->max_fdset, start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | error = -EMFILE; |
| 86 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
| 87 | goto out; |
| 88 | |
| 89 | error = expand_files(files, newfd); |
| 90 | if (error < 0) |
| 91 | goto out; |
| 92 | |
| 93 | /* |
| 94 | * If we needed to expand the fs array we |
| 95 | * might have blocked - try again. |
| 96 | */ |
| 97 | if (error) |
| 98 | goto repeat; |
| 99 | |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 100 | /* |
| 101 | * We reacquired files_lock, so we are safe as long as |
| 102 | * we reacquire the fdtable pointer and use it while holding |
| 103 | * the lock, no one can free it during that time. |
| 104 | */ |
| 105 | fdt = files_fdtable(files); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 106 | if (start <= fdt->next_fd) |
| 107 | fdt->next_fd = newfd + 1; |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 108 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | error = newfd; |
| 110 | |
| 111 | out: |
| 112 | return error; |
| 113 | } |
| 114 | |
| 115 | static int dupfd(struct file *file, unsigned int start) |
| 116 | { |
| 117 | struct files_struct * files = current->files; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 118 | struct fdtable *fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | int fd; |
| 120 | |
| 121 | spin_lock(&files->file_lock); |
| 122 | fd = locate_fd(files, file, start); |
| 123 | if (fd >= 0) { |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 124 | /* locate_fd() may have expanded fdtable, load the ptr */ |
| 125 | fdt = files_fdtable(files); |
| 126 | FD_SET(fd, fdt->open_fds); |
| 127 | FD_CLR(fd, fdt->close_on_exec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | spin_unlock(&files->file_lock); |
| 129 | fd_install(fd, file); |
| 130 | } else { |
| 131 | spin_unlock(&files->file_lock); |
| 132 | fput(file); |
| 133 | } |
| 134 | |
| 135 | return fd; |
| 136 | } |
| 137 | |
| 138 | asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) |
| 139 | { |
| 140 | int err = -EBADF; |
| 141 | struct file * file, *tofree; |
| 142 | struct files_struct * files = current->files; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 143 | struct fdtable *fdt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | |
| 145 | spin_lock(&files->file_lock); |
| 146 | if (!(file = fcheck(oldfd))) |
| 147 | goto out_unlock; |
| 148 | err = newfd; |
| 149 | if (newfd == oldfd) |
| 150 | goto out_unlock; |
| 151 | err = -EBADF; |
| 152 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
| 153 | goto out_unlock; |
| 154 | get_file(file); /* We are now finished with oldfd */ |
| 155 | |
| 156 | err = expand_files(files, newfd); |
| 157 | if (err < 0) |
| 158 | goto out_fput; |
| 159 | |
| 160 | /* To avoid races with open() and dup(), we will mark the fd as |
| 161 | * in-use in the open-file bitmap throughout the entire dup2() |
| 162 | * process. This is quite safe: do_close() uses the fd array |
| 163 | * entry, not the bitmap, to decide what work needs to be |
| 164 | * done. --sct */ |
| 165 | /* Doesn't work. open() might be there first. --AV */ |
| 166 | |
| 167 | /* Yes. It's a race. In user space. Nothing sane to do */ |
| 168 | err = -EBUSY; |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 169 | fdt = files_fdtable(files); |
| 170 | tofree = fdt->fd[newfd]; |
| 171 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 172 | goto out_fput; |
| 173 | |
Dipankar Sarma | ab2af1f | 2005-09-09 13:04:13 -0700 | [diff] [blame] | 174 | rcu_assign_pointer(fdt->fd[newfd], file); |
Dipankar Sarma | badf166 | 2005-09-09 13:04:10 -0700 | [diff] [blame] | 175 | FD_SET(newfd, fdt->open_fds); |
| 176 | FD_CLR(newfd, fdt->close_on_exec); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | spin_unlock(&files->file_lock); |
| 178 | |
| 179 | if (tofree) |
| 180 | filp_close(tofree, files); |
| 181 | err = newfd; |
| 182 | out: |
| 183 | return err; |
| 184 | out_unlock: |
| 185 | spin_unlock(&files->file_lock); |
| 186 | goto out; |
| 187 | |
| 188 | out_fput: |
| 189 | spin_unlock(&files->file_lock); |
| 190 | fput(file); |
| 191 | goto out; |
| 192 | } |
| 193 | |
| 194 | asmlinkage long sys_dup(unsigned int fildes) |
| 195 | { |
| 196 | int ret = -EBADF; |
| 197 | struct file * file = fget(fildes); |
| 198 | |
| 199 | if (file) |
| 200 | ret = dupfd(file, 0); |
| 201 | return ret; |
| 202 | } |
| 203 | |
| 204 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) |
| 205 | |
| 206 | static int setfl(int fd, struct file * filp, unsigned long arg) |
| 207 | { |
| 208 | struct inode * inode = filp->f_dentry->d_inode; |
| 209 | int error = 0; |
| 210 | |
| 211 | /* O_APPEND cannot be cleared if the file is marked as append-only */ |
| 212 | if (!(arg & O_APPEND) && IS_APPEND(inode)) |
| 213 | return -EPERM; |
| 214 | |
| 215 | /* O_NOATIME can only be set by the owner or superuser */ |
| 216 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) |
| 217 | if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER)) |
| 218 | return -EPERM; |
| 219 | |
| 220 | /* required for strict SunOS emulation */ |
| 221 | if (O_NONBLOCK != O_NDELAY) |
| 222 | if (arg & O_NDELAY) |
| 223 | arg |= O_NONBLOCK; |
| 224 | |
| 225 | if (arg & O_DIRECT) { |
| 226 | if (!filp->f_mapping || !filp->f_mapping->a_ops || |
| 227 | !filp->f_mapping->a_ops->direct_IO) |
| 228 | return -EINVAL; |
| 229 | } |
| 230 | |
| 231 | if (filp->f_op && filp->f_op->check_flags) |
| 232 | error = filp->f_op->check_flags(arg); |
| 233 | if (error) |
| 234 | return error; |
| 235 | |
| 236 | lock_kernel(); |
| 237 | if ((arg ^ filp->f_flags) & FASYNC) { |
| 238 | if (filp->f_op && filp->f_op->fasync) { |
| 239 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
| 240 | if (error < 0) |
| 241 | goto out; |
| 242 | } |
| 243 | } |
| 244 | |
| 245 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
| 246 | out: |
| 247 | unlock_kernel(); |
| 248 | return error; |
| 249 | } |
| 250 | |
| 251 | static void f_modown(struct file *filp, unsigned long pid, |
| 252 | uid_t uid, uid_t euid, int force) |
| 253 | { |
| 254 | write_lock_irq(&filp->f_owner.lock); |
| 255 | if (force || !filp->f_owner.pid) { |
| 256 | filp->f_owner.pid = pid; |
| 257 | filp->f_owner.uid = uid; |
| 258 | filp->f_owner.euid = euid; |
| 259 | } |
| 260 | write_unlock_irq(&filp->f_owner.lock); |
| 261 | } |
| 262 | |
| 263 | int f_setown(struct file *filp, unsigned long arg, int force) |
| 264 | { |
| 265 | int err; |
| 266 | |
| 267 | err = security_file_set_fowner(filp); |
| 268 | if (err) |
| 269 | return err; |
| 270 | |
| 271 | f_modown(filp, arg, current->uid, current->euid, force); |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | EXPORT_SYMBOL(f_setown); |
| 276 | |
| 277 | void f_delown(struct file *filp) |
| 278 | { |
| 279 | f_modown(filp, 0, 0, 0, 1); |
| 280 | } |
| 281 | |
| 282 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
| 283 | struct file *filp) |
| 284 | { |
| 285 | long err = -EINVAL; |
| 286 | |
| 287 | switch (cmd) { |
| 288 | case F_DUPFD: |
| 289 | get_file(filp); |
| 290 | err = dupfd(filp, arg); |
| 291 | break; |
| 292 | case F_GETFD: |
| 293 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; |
| 294 | break; |
| 295 | case F_SETFD: |
| 296 | err = 0; |
| 297 | set_close_on_exec(fd, arg & FD_CLOEXEC); |
| 298 | break; |
| 299 | case F_GETFL: |
| 300 | err = filp->f_flags; |
| 301 | break; |
| 302 | case F_SETFL: |
| 303 | err = setfl(fd, filp, arg); |
| 304 | break; |
| 305 | case F_GETLK: |
| 306 | err = fcntl_getlk(filp, (struct flock __user *) arg); |
| 307 | break; |
| 308 | case F_SETLK: |
| 309 | case F_SETLKW: |
Peter Staubach | c293621 | 2005-07-27 11:45:09 -0700 | [diff] [blame] | 310 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | break; |
| 312 | case F_GETOWN: |
| 313 | /* |
| 314 | * XXX If f_owner is a process group, the |
| 315 | * negative return value will get converted |
| 316 | * into an error. Oops. If we keep the |
| 317 | * current syscall conventions, the only way |
| 318 | * to fix this will be in libc. |
| 319 | */ |
| 320 | err = filp->f_owner.pid; |
| 321 | force_successful_syscall_return(); |
| 322 | break; |
| 323 | case F_SETOWN: |
| 324 | err = f_setown(filp, arg, 1); |
| 325 | break; |
| 326 | case F_GETSIG: |
| 327 | err = filp->f_owner.signum; |
| 328 | break; |
| 329 | case F_SETSIG: |
| 330 | /* arg == 0 restores default behaviour. */ |
Jesper Juhl | 7ed20e1 | 2005-05-01 08:59:14 -0700 | [diff] [blame] | 331 | if (!valid_signal(arg)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 332 | break; |
| 333 | } |
| 334 | err = 0; |
| 335 | filp->f_owner.signum = arg; |
| 336 | break; |
| 337 | case F_GETLEASE: |
| 338 | err = fcntl_getlease(filp); |
| 339 | break; |
| 340 | case F_SETLEASE: |
| 341 | err = fcntl_setlease(fd, filp, arg); |
| 342 | break; |
| 343 | case F_NOTIFY: |
| 344 | err = fcntl_dirnotify(fd, filp, arg); |
| 345 | break; |
| 346 | default: |
| 347 | break; |
| 348 | } |
| 349 | return err; |
| 350 | } |
| 351 | |
| 352 | asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg) |
| 353 | { |
| 354 | struct file *filp; |
| 355 | long err = -EBADF; |
| 356 | |
| 357 | filp = fget(fd); |
| 358 | if (!filp) |
| 359 | goto out; |
| 360 | |
| 361 | err = security_file_fcntl(filp, cmd, arg); |
| 362 | if (err) { |
| 363 | fput(filp); |
| 364 | return err; |
| 365 | } |
| 366 | |
| 367 | err = do_fcntl(fd, cmd, arg, filp); |
| 368 | |
| 369 | fput(filp); |
| 370 | out: |
| 371 | return err; |
| 372 | } |
| 373 | |
| 374 | #if BITS_PER_LONG == 32 |
| 375 | asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg) |
| 376 | { |
| 377 | struct file * filp; |
| 378 | long err; |
| 379 | |
| 380 | err = -EBADF; |
| 381 | filp = fget(fd); |
| 382 | if (!filp) |
| 383 | goto out; |
| 384 | |
| 385 | err = security_file_fcntl(filp, cmd, arg); |
| 386 | if (err) { |
| 387 | fput(filp); |
| 388 | return err; |
| 389 | } |
| 390 | err = -EBADF; |
| 391 | |
| 392 | switch (cmd) { |
| 393 | case F_GETLK64: |
| 394 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); |
| 395 | break; |
| 396 | case F_SETLK64: |
| 397 | case F_SETLKW64: |
Peter Staubach | c293621 | 2005-07-27 11:45:09 -0700 | [diff] [blame] | 398 | err = fcntl_setlk64(fd, filp, cmd, |
| 399 | (struct flock64 __user *) arg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | break; |
| 401 | default: |
| 402 | err = do_fcntl(fd, cmd, arg, filp); |
| 403 | break; |
| 404 | } |
| 405 | fput(filp); |
| 406 | out: |
| 407 | return err; |
| 408 | } |
| 409 | #endif |
| 410 | |
| 411 | /* Table to convert sigio signal codes into poll band bitmaps */ |
| 412 | |
| 413 | static long band_table[NSIGPOLL] = { |
| 414 | POLLIN | POLLRDNORM, /* POLL_IN */ |
| 415 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ |
| 416 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ |
| 417 | POLLERR, /* POLL_ERR */ |
| 418 | POLLPRI | POLLRDBAND, /* POLL_PRI */ |
| 419 | POLLHUP | POLLERR /* POLL_HUP */ |
| 420 | }; |
| 421 | |
| 422 | static inline int sigio_perm(struct task_struct *p, |
| 423 | struct fown_struct *fown, int sig) |
| 424 | { |
| 425 | return (((fown->euid == 0) || |
| 426 | (fown->euid == p->suid) || (fown->euid == p->uid) || |
| 427 | (fown->uid == p->suid) || (fown->uid == p->uid)) && |
| 428 | !security_file_send_sigiotask(p, fown, sig)); |
| 429 | } |
| 430 | |
| 431 | static void send_sigio_to_task(struct task_struct *p, |
| 432 | struct fown_struct *fown, |
| 433 | int fd, |
| 434 | int reason) |
| 435 | { |
| 436 | if (!sigio_perm(p, fown, fown->signum)) |
| 437 | return; |
| 438 | |
| 439 | switch (fown->signum) { |
| 440 | siginfo_t si; |
| 441 | default: |
| 442 | /* Queue a rt signal with the appropriate fd as its |
| 443 | value. We use SI_SIGIO as the source, not |
| 444 | SI_KERNEL, since kernel signals always get |
| 445 | delivered even if we can't queue. Failure to |
| 446 | queue in this case _should_ be reported; we fall |
| 447 | back to SIGIO in that case. --sct */ |
| 448 | si.si_signo = fown->signum; |
| 449 | si.si_errno = 0; |
| 450 | si.si_code = reason; |
| 451 | /* Make sure we are called with one of the POLL_* |
| 452 | reasons, otherwise we could leak kernel stack into |
| 453 | userspace. */ |
| 454 | if ((reason & __SI_MASK) != __SI_POLL) |
| 455 | BUG(); |
| 456 | if (reason - POLL_IN >= NSIGPOLL) |
| 457 | si.si_band = ~0L; |
| 458 | else |
| 459 | si.si_band = band_table[reason - POLL_IN]; |
| 460 | si.si_fd = fd; |
Oleg Nesterov | 850d6fb | 2006-01-08 01:03:29 -0800 | [diff] [blame] | 461 | if (!group_send_sig_info(fown->signum, &si, p)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | break; |
| 463 | /* fall-through: fall back on the old plain SIGIO signal */ |
| 464 | case 0: |
Oleg Nesterov | 850d6fb | 2006-01-08 01:03:29 -0800 | [diff] [blame] | 465 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 466 | } |
| 467 | } |
| 468 | |
| 469 | void send_sigio(struct fown_struct *fown, int fd, int band) |
| 470 | { |
| 471 | struct task_struct *p; |
| 472 | int pid; |
| 473 | |
| 474 | read_lock(&fown->lock); |
| 475 | pid = fown->pid; |
| 476 | if (!pid) |
| 477 | goto out_unlock_fown; |
| 478 | |
| 479 | read_lock(&tasklist_lock); |
| 480 | if (pid > 0) { |
| 481 | p = find_task_by_pid(pid); |
| 482 | if (p) { |
| 483 | send_sigio_to_task(p, fown, fd, band); |
| 484 | } |
| 485 | } else { |
| 486 | do_each_task_pid(-pid, PIDTYPE_PGID, p) { |
| 487 | send_sigio_to_task(p, fown, fd, band); |
| 488 | } while_each_task_pid(-pid, PIDTYPE_PGID, p); |
| 489 | } |
| 490 | read_unlock(&tasklist_lock); |
| 491 | out_unlock_fown: |
| 492 | read_unlock(&fown->lock); |
| 493 | } |
| 494 | |
| 495 | static void send_sigurg_to_task(struct task_struct *p, |
| 496 | struct fown_struct *fown) |
| 497 | { |
| 498 | if (sigio_perm(p, fown, SIGURG)) |
Oleg Nesterov | 850d6fb | 2006-01-08 01:03:29 -0800 | [diff] [blame] | 499 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | } |
| 501 | |
| 502 | int send_sigurg(struct fown_struct *fown) |
| 503 | { |
| 504 | struct task_struct *p; |
| 505 | int pid, ret = 0; |
| 506 | |
| 507 | read_lock(&fown->lock); |
| 508 | pid = fown->pid; |
| 509 | if (!pid) |
| 510 | goto out_unlock_fown; |
| 511 | |
| 512 | ret = 1; |
| 513 | |
| 514 | read_lock(&tasklist_lock); |
| 515 | if (pid > 0) { |
| 516 | p = find_task_by_pid(pid); |
| 517 | if (p) { |
| 518 | send_sigurg_to_task(p, fown); |
| 519 | } |
| 520 | } else { |
| 521 | do_each_task_pid(-pid, PIDTYPE_PGID, p) { |
| 522 | send_sigurg_to_task(p, fown); |
| 523 | } while_each_task_pid(-pid, PIDTYPE_PGID, p); |
| 524 | } |
| 525 | read_unlock(&tasklist_lock); |
| 526 | out_unlock_fown: |
| 527 | read_unlock(&fown->lock); |
| 528 | return ret; |
| 529 | } |
| 530 | |
| 531 | static DEFINE_RWLOCK(fasync_lock); |
| 532 | static kmem_cache_t *fasync_cache; |
| 533 | |
| 534 | /* |
| 535 | * fasync_helper() is used by some character device drivers (mainly mice) |
| 536 | * to set up the fasync queue. It returns negative on error, 0 if it did |
| 537 | * no changes and positive if it added/deleted the entry. |
| 538 | */ |
| 539 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) |
| 540 | { |
| 541 | struct fasync_struct *fa, **fp; |
| 542 | struct fasync_struct *new = NULL; |
| 543 | int result = 0; |
| 544 | |
| 545 | if (on) { |
| 546 | new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL); |
| 547 | if (!new) |
| 548 | return -ENOMEM; |
| 549 | } |
| 550 | write_lock_irq(&fasync_lock); |
| 551 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| 552 | if (fa->fa_file == filp) { |
| 553 | if(on) { |
| 554 | fa->fa_fd = fd; |
| 555 | kmem_cache_free(fasync_cache, new); |
| 556 | } else { |
| 557 | *fp = fa->fa_next; |
| 558 | kmem_cache_free(fasync_cache, fa); |
| 559 | result = 1; |
| 560 | } |
| 561 | goto out; |
| 562 | } |
| 563 | } |
| 564 | |
| 565 | if (on) { |
| 566 | new->magic = FASYNC_MAGIC; |
| 567 | new->fa_file = filp; |
| 568 | new->fa_fd = fd; |
| 569 | new->fa_next = *fapp; |
| 570 | *fapp = new; |
| 571 | result = 1; |
| 572 | } |
| 573 | out: |
| 574 | write_unlock_irq(&fasync_lock); |
| 575 | return result; |
| 576 | } |
| 577 | |
| 578 | EXPORT_SYMBOL(fasync_helper); |
| 579 | |
| 580 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) |
| 581 | { |
| 582 | while (fa) { |
| 583 | struct fown_struct * fown; |
| 584 | if (fa->magic != FASYNC_MAGIC) { |
| 585 | printk(KERN_ERR "kill_fasync: bad magic number in " |
| 586 | "fasync_struct!\n"); |
| 587 | return; |
| 588 | } |
| 589 | fown = &fa->fa_file->f_owner; |
| 590 | /* Don't send SIGURG to processes which have not set a |
| 591 | queued signum: SIGURG has its own default signalling |
| 592 | mechanism. */ |
| 593 | if (!(sig == SIGURG && fown->signum == 0)) |
| 594 | send_sigio(fown, fa->fa_fd, band); |
| 595 | fa = fa->fa_next; |
| 596 | } |
| 597 | } |
| 598 | |
| 599 | EXPORT_SYMBOL(__kill_fasync); |
| 600 | |
| 601 | void kill_fasync(struct fasync_struct **fp, int sig, int band) |
| 602 | { |
| 603 | /* First a quick test without locking: usually |
| 604 | * the list is empty. |
| 605 | */ |
| 606 | if (*fp) { |
| 607 | read_lock(&fasync_lock); |
| 608 | /* reread *fp after obtaining the lock */ |
| 609 | __kill_fasync(*fp, sig, band); |
| 610 | read_unlock(&fasync_lock); |
| 611 | } |
| 612 | } |
| 613 | EXPORT_SYMBOL(kill_fasync); |
| 614 | |
| 615 | static int __init fasync_init(void) |
| 616 | { |
| 617 | fasync_cache = kmem_cache_create("fasync_cache", |
| 618 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL); |
| 619 | return 0; |
| 620 | } |
| 621 | |
| 622 | module_init(fasync_init) |