| /* |
| * linux/fs/fcntl.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/file.h> |
| #include <linux/dnotify.h> |
| #include <linux/smp_lock.h> |
| #include <linux/slab.h> |
| #include <linux/iobuf.h> |
| |
| #include <asm/poll.h> |
| #include <asm/siginfo.h> |
| #include <asm/uaccess.h> |
| |
| extern int sock_fcntl (struct file *, unsigned int cmd, unsigned long arg); |
| extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg); |
| extern int fcntl_getlease(struct file *filp); |
| |
| void set_close_on_exec(unsigned int fd, int flag) |
| { |
| struct files_struct *files = current->files; |
| write_lock(&files->file_lock); |
| if (flag) |
| FD_SET(fd, files->close_on_exec); |
| else |
| FD_CLR(fd, files->close_on_exec); |
| write_unlock(&files->file_lock); |
| } |
| |
| static inline int get_close_on_exec(unsigned int fd) |
| { |
| struct files_struct *files = current->files; |
| int res; |
| read_lock(&files->file_lock); |
| res = FD_ISSET(fd, files->close_on_exec); |
| read_unlock(&files->file_lock); |
| return res; |
| } |
| |
| |
| /* Expand files. Return <0 on error; 0 nothing done; 1 files expanded, |
| * we may have blocked. |
| * |
| * Should be called with the files->file_lock spinlock held for write. |
| */ |
| static int expand_files(struct files_struct *files, int nr) |
| { |
| int err, expand = 0; |
| #ifdef FDSET_DEBUG |
| printk (KERN_ERR __FUNCTION__ " %d: nr = %d\n", current->pid, nr); |
| #endif |
| |
| if (nr >= files->max_fdset) { |
| expand = 1; |
| if ((err = expand_fdset(files, nr))) |
| goto out; |
| } |
| if (nr >= files->max_fds) { |
| expand = 1; |
| if ((err = expand_fd_array(files, nr))) |
| goto out; |
| } |
| err = expand; |
| out: |
| #ifdef FDSET_DEBUG |
| if (err) |
| printk (KERN_ERR __FUNCTION__ " %d: return %d\n", current->pid, err); |
| #endif |
| return err; |
| } |
| |
| /* |
| * locate_fd finds a free file descriptor in the open_fds fdset, |
| * expanding the fd arrays if necessary. The files write lock will be |
| * held on exit to ensure that the fd can be entered atomically. |
| */ |
| |
| static int locate_fd(struct files_struct *files, |
| struct file *file, int orig_start) |
| { |
| unsigned int newfd; |
| int error; |
| int start; |
| |
| write_lock(&files->file_lock); |
| |
| error = -EINVAL; |
| if (orig_start >= current->rlim[RLIMIT_NOFILE].rlim_cur) |
| goto out; |
| |
| repeat: |
| /* |
| * Someone might have closed fd's in the range |
| * orig_start..files->next_fd |
| */ |
| start = orig_start; |
| if (start < files->next_fd) |
| start = files->next_fd; |
| |
| newfd = start; |
| if (start < files->max_fdset) { |
| newfd = find_next_zero_bit(files->open_fds->fds_bits, |
| files->max_fdset, start); |
| } |
| |
| error = -EMFILE; |
| if (newfd >= current->rlim[RLIMIT_NOFILE].rlim_cur) |
| goto out; |
| |
| error = expand_files(files, newfd); |
| if (error < 0) |
| goto out; |
| |
| /* |
| * If we needed to expand the fs array we |
| * might have blocked - try again. |
| */ |
| if (error) |
| goto repeat; |
| |
| if (start <= files->next_fd) |
| files->next_fd = newfd + 1; |
| |
| error = newfd; |
| |
| out: |
| return error; |
| } |
| |
| static inline void allocate_fd(struct files_struct *files, |
| struct file *file, int fd) |
| { |
| FD_SET(fd, files->open_fds); |
| FD_CLR(fd, files->close_on_exec); |
| write_unlock(&files->file_lock); |
| fd_install(fd, file); |
| } |
| |
| static int dupfd(struct file *file, int start) |
| { |
| struct files_struct * files = current->files; |
| int ret; |
| |
| ret = locate_fd(files, file, start); |
| if (ret < 0) |
| goto out_putf; |
| allocate_fd(files, file, ret); |
| return ret; |
| |
| out_putf: |
| write_unlock(&files->file_lock); |
| fput(file); |
| return ret; |
| } |
| |
| asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) |
| { |
| int err = -EBADF; |
| struct file * file, *tofree; |
| struct files_struct * files = current->files; |
| |
| write_lock(&files->file_lock); |
| if (!(file = fcheck(oldfd))) |
| goto out_unlock; |
| err = newfd; |
| if (newfd == oldfd) |
| goto out_unlock; |
| err = -EBADF; |
| if (newfd >= current->rlim[RLIMIT_NOFILE].rlim_cur) |
| goto out_unlock; |
| get_file(file); /* We are now finished with oldfd */ |
| |
| err = expand_files(files, newfd); |
| if (err < 0) |
| goto out_fput; |
| |
| /* To avoid races with open() and dup(), we will mark the fd as |
| * in-use in the open-file bitmap throughout the entire dup2() |
| * process. This is quite safe: do_close() uses the fd array |
| * entry, not the bitmap, to decide what work needs to be |
| * done. --sct */ |
| /* Doesn't work. open() might be there first. --AV */ |
| |
| /* Yes. It's a race. In user space. Nothing sane to do */ |
| err = -EBUSY; |
| tofree = files->fd[newfd]; |
| if (!tofree && FD_ISSET(newfd, files->open_fds)) |
| goto out_fput; |
| |
| files->fd[newfd] = file; |
| FD_SET(newfd, files->open_fds); |
| FD_CLR(newfd, files->close_on_exec); |
| write_unlock(&files->file_lock); |
| |
| if (tofree) |
| filp_close(tofree, files); |
| err = newfd; |
| out: |
| return err; |
| out_unlock: |
| write_unlock(&files->file_lock); |
| goto out; |
| |
| out_fput: |
| write_unlock(&files->file_lock); |
| fput(file); |
| goto out; |
| } |
| |
| asmlinkage long sys_dup(unsigned int fildes) |
| { |
| int ret = -EBADF; |
| struct file * file = fget(fildes); |
| |
| if (file) |
| ret = dupfd(file, 0); |
| return ret; |
| } |
| |
| #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT) |
| |
| static int setfl(int fd, struct file * filp, unsigned long arg) |
| { |
| struct inode * inode = filp->f_dentry->d_inode; |
| int error; |
| |
| /* |
| * In the case of an append-only file, O_APPEND |
| * cannot be cleared |
| */ |
| if (!(arg & O_APPEND) && IS_APPEND(inode)) |
| return -EPERM; |
| |
| /* Did FASYNC state change? */ |
| if ((arg ^ filp->f_flags) & FASYNC) { |
| if (filp->f_op && filp->f_op->fasync) { |
| error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
| if (error < 0) |
| return error; |
| } |
| } |
| |
| if (arg & O_DIRECT) { |
| /* |
| * alloc_kiovec() can sleep and we are only serialized by |
| * the big kernel lock here, so abuse the i_sem to serialize |
| * this case too. We of course wouldn't need to go deep down |
| * to the inode layer, we could stay at the file layer, but |
| * we don't want to pay for the memory of a semaphore in each |
| * file structure too and we use the inode semaphore that we just |
| * pay for anyways. |
| */ |
| error = 0; |
| down(&inode->i_sem); |
| if (!filp->f_iobuf) |
| error = alloc_kiovec(1, &filp->f_iobuf); |
| up(&inode->i_sem); |
| if (error < 0) |
| return error; |
| } |
| |
| /* required for strict SunOS emulation */ |
| if (O_NONBLOCK != O_NDELAY) |
| if (arg & O_NDELAY) |
| arg |= O_NONBLOCK; |
| |
| filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
| return 0; |
| } |
| |
| static long do_fcntl(unsigned int fd, unsigned int cmd, |
| unsigned long arg, struct file * filp) |
| { |
| long err = -EINVAL; |
| |
| switch (cmd) { |
| case F_DUPFD: |
| if (arg < NR_OPEN) { |
| get_file(filp); |
| err = dupfd(filp, arg); |
| } |
| break; |
| case F_GETFD: |
| err = get_close_on_exec(fd); |
| break; |
| case F_SETFD: |
| err = 0; |
| set_close_on_exec(fd, arg&1); |
| break; |
| case F_GETFL: |
| err = filp->f_flags; |
| break; |
| case F_SETFL: |
| lock_kernel(); |
| err = setfl(fd, filp, arg); |
| unlock_kernel(); |
| break; |
| case F_GETLK: |
| err = fcntl_getlk(fd, (struct flock *) arg); |
| break; |
| case F_SETLK: |
| case F_SETLKW: |
| err = fcntl_setlk(fd, cmd, (struct flock *) arg); |
| break; |
| case F_GETOWN: |
| /* |
| * XXX If f_owner is a process group, the |
| * negative return value will get converted |
| * into an error. Oops. If we keep the |
| * current syscall conventions, the only way |
| * to fix this will be in libc. |
| */ |
| err = filp->f_owner.pid; |
| break; |
| case F_SETOWN: |
| lock_kernel(); |
| filp->f_owner.pid = arg; |
| filp->f_owner.uid = current->uid; |
| filp->f_owner.euid = current->euid; |
| err = 0; |
| if (S_ISSOCK (filp->f_dentry->d_inode->i_mode)) |
| err = sock_fcntl (filp, F_SETOWN, arg); |
| unlock_kernel(); |
| break; |
| case F_GETSIG: |
| err = filp->f_owner.signum; |
| break; |
| case F_SETSIG: |
| /* arg == 0 restores default behaviour. */ |
| if (arg < 0 || arg > _NSIG) { |
| break; |
| } |
| err = 0; |
| filp->f_owner.signum = arg; |
| break; |
| case F_GETLEASE: |
| err = fcntl_getlease(filp); |
| break; |
| case F_SETLEASE: |
| err = fcntl_setlease(fd, filp, arg); |
| break; |
| case F_NOTIFY: |
| err = fcntl_dirnotify(fd, filp, arg); |
| break; |
| default: |
| /* sockets need a few special fcntls. */ |
| err = -EINVAL; |
| if (S_ISSOCK (filp->f_dentry->d_inode->i_mode)) |
| err = sock_fcntl (filp, cmd, arg); |
| break; |
| } |
| |
| return err; |
| } |
| |
| asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg) |
| { |
| struct file * filp; |
| long err = -EBADF; |
| |
| filp = fget(fd); |
| if (!filp) |
| goto out; |
| |
| err = do_fcntl(fd, cmd, arg, filp); |
| |
| fput(filp); |
| out: |
| return err; |
| } |
| |
| #if BITS_PER_LONG == 32 |
| asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg) |
| { |
| struct file * filp; |
| long err; |
| |
| err = -EBADF; |
| filp = fget(fd); |
| if (!filp) |
| goto out; |
| |
| switch (cmd) { |
| case F_GETLK64: |
| err = fcntl_getlk64(fd, (struct flock64 *) arg); |
| break; |
| case F_SETLK64: |
| err = fcntl_setlk64(fd, cmd, (struct flock64 *) arg); |
| break; |
| case F_SETLKW64: |
| err = fcntl_setlk64(fd, cmd, (struct flock64 *) arg); |
| break; |
| default: |
| err = do_fcntl(fd, cmd, arg, filp); |
| break; |
| } |
| fput(filp); |
| out: |
| return err; |
| } |
| #endif |
| |
| /* Table to convert sigio signal codes into poll band bitmaps */ |
| |
| static long band_table[NSIGPOLL] = { |
| POLLIN | POLLRDNORM, /* POLL_IN */ |
| POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ |
| POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ |
| POLLERR, /* POLL_ERR */ |
| POLLPRI | POLLRDBAND, /* POLL_PRI */ |
| POLLHUP | POLLERR /* POLL_HUP */ |
| }; |
| |
| static void send_sigio_to_task(struct task_struct *p, |
| struct fown_struct *fown, |
| int fd, |
| int reason) |
| { |
| if ((fown->euid != 0) && |
| (fown->euid ^ p->suid) && (fown->euid ^ p->uid) && |
| (fown->uid ^ p->suid) && (fown->uid ^ p->uid)) |
| return; |
| switch (fown->signum) { |
| siginfo_t si; |
| default: |
| /* Queue a rt signal with the appropriate fd as its |
| value. We use SI_SIGIO as the source, not |
| SI_KERNEL, since kernel signals always get |
| delivered even if we can't queue. Failure to |
| queue in this case _should_ be reported; we fall |
| back to SIGIO in that case. --sct */ |
| si.si_signo = fown->signum; |
| si.si_errno = 0; |
| si.si_code = reason; |
| /* Make sure we are called with one of the POLL_* |
| reasons, otherwise we could leak kernel stack into |
| userspace. */ |
| if ((reason & __SI_MASK) != __SI_POLL) |
| BUG(); |
| if (reason - POLL_IN >= NSIGPOLL) |
| si.si_band = ~0L; |
| else |
| si.si_band = band_table[reason - POLL_IN]; |
| si.si_fd = fd; |
| if (!send_sig_info(fown->signum, &si, p)) |
| break; |
| /* fall-through: fall back on the old plain SIGIO signal */ |
| case 0: |
| send_sig(SIGIO, p, 1); |
| } |
| } |
| |
| void send_sigio(struct fown_struct *fown, int fd, int band) |
| { |
| struct task_struct * p; |
| int pid = fown->pid; |
| |
| read_lock(&tasklist_lock); |
| if ( (pid > 0) && (p = find_task_by_pid(pid)) ) { |
| send_sigio_to_task(p, fown, fd, band); |
| goto out; |
| } |
| for_each_task(p) { |
| int match = p->pid; |
| if (pid < 0) |
| match = -p->pgrp; |
| if (pid != match) |
| continue; |
| send_sigio_to_task(p, fown, fd, band); |
| } |
| out: |
| read_unlock(&tasklist_lock); |
| } |
| |
| static rwlock_t fasync_lock = RW_LOCK_UNLOCKED; |
| static kmem_cache_t *fasync_cache; |
| |
| /* |
| * fasync_helper() is used by some character device drivers (mainly mice) |
| * to set up the fasync queue. It returns negative on error, 0 if it did |
| * no changes and positive if it added/deleted the entry. |
| */ |
| int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) |
| { |
| struct fasync_struct *fa, **fp; |
| struct fasync_struct *new = NULL; |
| int result = 0; |
| |
| if (on) { |
| new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL); |
| if (!new) |
| return -ENOMEM; |
| } |
| write_lock_irq(&fasync_lock); |
| for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
| if (fa->fa_file == filp) { |
| if(on) { |
| fa->fa_fd = fd; |
| kmem_cache_free(fasync_cache, new); |
| } else { |
| *fp = fa->fa_next; |
| kmem_cache_free(fasync_cache, fa); |
| result = 1; |
| } |
| goto out; |
| } |
| } |
| |
| if (on) { |
| new->magic = FASYNC_MAGIC; |
| new->fa_file = filp; |
| new->fa_fd = fd; |
| new->fa_next = *fapp; |
| *fapp = new; |
| result = 1; |
| } |
| out: |
| write_unlock_irq(&fasync_lock); |
| return result; |
| } |
| |
| void __kill_fasync(struct fasync_struct *fa, int sig, int band) |
| { |
| while (fa) { |
| struct fown_struct * fown; |
| if (fa->magic != FASYNC_MAGIC) { |
| printk(KERN_ERR "kill_fasync: bad magic number in " |
| "fasync_struct!\n"); |
| return; |
| } |
| fown = &fa->fa_file->f_owner; |
| /* Don't send SIGURG to processes which have not set a |
| queued signum: SIGURG has its own default signalling |
| mechanism. */ |
| if (fown->pid && !(sig == SIGURG && fown->signum == 0)) |
| send_sigio(fown, fa->fa_fd, band); |
| fa = fa->fa_next; |
| } |
| } |
| |
| void kill_fasync(struct fasync_struct **fp, int sig, int band) |
| { |
| read_lock(&fasync_lock); |
| __kill_fasync(*fp, sig, band); |
| read_unlock(&fasync_lock); |
| } |
| |
| static int __init fasync_init(void) |
| { |
| fasync_cache = kmem_cache_create("fasync cache", |
| sizeof(struct fasync_struct), 0, 0, NULL, NULL); |
| if (!fasync_cache) |
| panic("cannot create fasync slab cache"); |
| return 0; |
| } |
| |
| module_init(fasync_init) |