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-rw-r--r--fs/fcntl.c601
1 files changed, 601 insertions, 0 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
new file mode 100644
index 000000000000..c1708066bf55
--- /dev/null
+++ b/fs/fcntl.c
@@ -0,0 +1,601 @@
+/*
+ * linux/fs/fcntl.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+#include <linux/syscalls.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/dnotify.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/security.h>
+#include <linux/ptrace.h>
+
+#include <asm/poll.h>
+#include <asm/siginfo.h>
+#include <asm/uaccess.h>
+
+void fastcall set_close_on_exec(unsigned int fd, int flag)
+{
+ struct files_struct *files = current->files;
+ spin_lock(&files->file_lock);
+ if (flag)
+ FD_SET(fd, files->close_on_exec);
+ else
+ FD_CLR(fd, files->close_on_exec);
+ spin_unlock(&files->file_lock);
+}
+
+static inline int get_close_on_exec(unsigned int fd)
+{
+ struct files_struct *files = current->files;
+ int res;
+ spin_lock(&files->file_lock);
+ res = FD_ISSET(fd, files->close_on_exec);
+ spin_unlock(&files->file_lock);
+ return res;
+}
+
+/*
+ * locate_fd finds a free file descriptor in the open_fds fdset,
+ * expanding the fd arrays if necessary. Must be called with the
+ * file_lock held for write.
+ */
+
+static int locate_fd(struct files_struct *files,
+ struct file *file, unsigned int orig_start)
+{
+ unsigned int newfd;
+ unsigned int start;
+ int error;
+
+ error = -EINVAL;
+ if (orig_start >= current->signal->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->signal->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 int dupfd(struct file *file, unsigned int start)
+{
+ struct files_struct * files = current->files;
+ int fd;
+
+ spin_lock(&files->file_lock);
+ fd = locate_fd(files, file, start);
+ if (fd >= 0) {
+ FD_SET(fd, files->open_fds);
+ FD_CLR(fd, files->close_on_exec);
+ spin_unlock(&files->file_lock);
+ fd_install(fd, file);
+ } else {
+ spin_unlock(&files->file_lock);
+ fput(file);
+ }
+
+ return fd;
+}
+
+asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
+{
+ int err = -EBADF;
+ struct file * file, *tofree;
+ struct files_struct * files = current->files;
+
+ spin_lock(&files->file_lock);
+ if (!(file = fcheck(oldfd)))
+ goto out_unlock;
+ err = newfd;
+ if (newfd == oldfd)
+ goto out_unlock;
+ err = -EBADF;
+ if (newfd >= current->signal->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);
+ spin_unlock(&files->file_lock);
+
+ if (tofree)
+ filp_close(tofree, files);
+ err = newfd;
+out:
+ return err;
+out_unlock:
+ spin_unlock(&files->file_lock);
+ goto out;
+
+out_fput:
+ spin_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 | O_NOATIME)
+
+static int setfl(int fd, struct file * filp, unsigned long arg)
+{
+ struct inode * inode = filp->f_dentry->d_inode;
+ int error = 0;
+
+ /* O_APPEND cannot be cleared if the file is marked as append-only */
+ if (!(arg & O_APPEND) && IS_APPEND(inode))
+ return -EPERM;
+
+ /* O_NOATIME can only be set by the owner or superuser */
+ if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
+ if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
+ return -EPERM;
+
+ /* required for strict SunOS emulation */
+ if (O_NONBLOCK != O_NDELAY)
+ if (arg & O_NDELAY)
+ arg |= O_NONBLOCK;
+
+ if (arg & O_DIRECT) {
+ if (!filp->f_mapping || !filp->f_mapping->a_ops ||
+ !filp->f_mapping->a_ops->direct_IO)
+ return -EINVAL;
+ }
+
+ if (filp->f_op && filp->f_op->check_flags)
+ error = filp->f_op->check_flags(arg);
+ if (error)
+ return error;
+
+ lock_kernel();
+ 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)
+ goto out;
+ }
+ }
+
+ filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
+ out:
+ unlock_kernel();
+ return error;
+}
+
+static void f_modown(struct file *filp, unsigned long pid,
+ uid_t uid, uid_t euid, int force)
+{
+ write_lock_irq(&filp->f_owner.lock);
+ if (force || !filp->f_owner.pid) {
+ filp->f_owner.pid = pid;
+ filp->f_owner.uid = uid;
+ filp->f_owner.euid = euid;
+ }
+ write_unlock_irq(&filp->f_owner.lock);
+}
+
+int f_setown(struct file *filp, unsigned long arg, int force)
+{
+ int err;
+
+ err = security_file_set_fowner(filp);
+ if (err)
+ return err;
+
+ f_modown(filp, arg, current->uid, current->euid, force);
+ return 0;
+}
+
+EXPORT_SYMBOL(f_setown);
+
+void f_delown(struct file *filp)
+{
+ f_modown(filp, 0, 0, 0, 1);
+}
+
+static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
+ struct file *filp)
+{
+ long err = -EINVAL;
+
+ switch (cmd) {
+ case F_DUPFD:
+ get_file(filp);
+ err = dupfd(filp, arg);
+ break;
+ case F_GETFD:
+ err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
+ break;
+ case F_SETFD:
+ err = 0;
+ set_close_on_exec(fd, arg & FD_CLOEXEC);
+ break;
+ case F_GETFL:
+ err = filp->f_flags;
+ break;
+ case F_SETFL:
+ err = setfl(fd, filp, arg);
+ break;
+ case F_GETLK:
+ err = fcntl_getlk(filp, (struct flock __user *) arg);
+ break;
+ case F_SETLK:
+ case F_SETLKW:
+ err = fcntl_setlk(filp, cmd, (struct flock __user *) 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;
+ force_successful_syscall_return();
+ break;
+ case F_SETOWN:
+ err = f_setown(filp, arg, 1);
+ 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:
+ 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 = security_file_fcntl(filp, cmd, arg);
+ if (err) {
+ fput(filp);
+ return err;
+ }
+
+ 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;
+
+ err = security_file_fcntl(filp, cmd, arg);
+ if (err) {
+ fput(filp);
+ return err;
+ }
+ err = -EBADF;
+
+ switch (cmd) {
+ case F_GETLK64:
+ err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
+ break;
+ case F_SETLK64:
+ case F_SETLKW64:
+ err = fcntl_setlk64(filp, cmd, (struct flock64 __user *) 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 inline int sigio_perm(struct task_struct *p,
+ struct fown_struct *fown, int sig)
+{
+ return (((fown->euid == 0) ||
+ (fown->euid == p->suid) || (fown->euid == p->uid) ||
+ (fown->uid == p->suid) || (fown->uid == p->uid)) &&
+ !security_file_send_sigiotask(p, fown, sig));
+}
+
+static void send_sigio_to_task(struct task_struct *p,
+ struct fown_struct *fown,
+ int fd,
+ int reason)
+{
+ if (!sigio_perm(p, fown, fown->signum))
+ 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_group_sig_info(SIGIO, SEND_SIG_PRIV, p);
+ }
+}
+
+void send_sigio(struct fown_struct *fown, int fd, int band)
+{
+ struct task_struct *p;
+ int pid;
+
+ read_lock(&fown->lock);
+ pid = fown->pid;
+ if (!pid)
+ goto out_unlock_fown;
+
+ read_lock(&tasklist_lock);
+ if (pid > 0) {
+ p = find_task_by_pid(pid);
+ if (p) {
+ send_sigio_to_task(p, fown, fd, band);
+ }
+ } else {
+ do_each_task_pid(-pid, PIDTYPE_PGID, p) {
+ send_sigio_to_task(p, fown, fd, band);
+ } while_each_task_pid(-pid, PIDTYPE_PGID, p);
+ }
+ read_unlock(&tasklist_lock);
+ out_unlock_fown:
+ read_unlock(&fown->lock);
+}
+
+static void send_sigurg_to_task(struct task_struct *p,
+ struct fown_struct *fown)
+{
+ if (sigio_perm(p, fown, SIGURG))
+ send_group_sig_info(SIGURG, SEND_SIG_PRIV, p);
+}
+
+int send_sigurg(struct fown_struct *fown)
+{
+ struct task_struct *p;
+ int pid, ret = 0;
+
+ read_lock(&fown->lock);
+ pid = fown->pid;
+ if (!pid)
+ goto out_unlock_fown;
+
+ ret = 1;
+
+ read_lock(&tasklist_lock);
+ if (pid > 0) {
+ p = find_task_by_pid(pid);
+ if (p) {
+ send_sigurg_to_task(p, fown);
+ }
+ } else {
+ do_each_task_pid(-pid, PIDTYPE_PGID, p) {
+ send_sigurg_to_task(p, fown);
+ } while_each_task_pid(-pid, PIDTYPE_PGID, p);
+ }
+ read_unlock(&tasklist_lock);
+ out_unlock_fown:
+ read_unlock(&fown->lock);
+ return ret;
+}
+
+static DEFINE_RWLOCK(fasync_lock);
+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;
+}
+
+EXPORT_SYMBOL(fasync_helper);
+
+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 (!(sig == SIGURG && fown->signum == 0))
+ send_sigio(fown, fa->fa_fd, band);
+ fa = fa->fa_next;
+ }
+}
+
+EXPORT_SYMBOL(__kill_fasync);
+
+void kill_fasync(struct fasync_struct **fp, int sig, int band)
+{
+ /* First a quick test without locking: usually
+ * the list is empty.
+ */
+ if (*fp) {
+ read_lock(&fasync_lock);
+ /* reread *fp after obtaining the lock */
+ __kill_fasync(*fp, sig, band);
+ read_unlock(&fasync_lock);
+ }
+}
+EXPORT_SYMBOL(kill_fasync);
+
+static int __init fasync_init(void)
+{
+ fasync_cache = kmem_cache_create("fasync_cache",
+ sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL);
+ return 0;
+}
+
+module_init(fasync_init)
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-24 13:10:42 +0000