--- /dev/null
+/*
+ * 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/fdtable.h>
+#include <linux/capability.h>
+#include <linux/dnotify.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/security.h>
+#include <linux/ptrace.h>
+#include <linux/signal.h>
+#include <linux/rcupdate.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <linux/shmem_fs.h>
+
+#include <asm/poll.h>
+#include <asm/siginfo.h>
+#include <asm/uaccess.h>
+
+#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
+
+static int setfl(int fd, struct file * filp, unsigned long arg)
+{
+ struct inode * inode = file_inode(filp);
+ int error = 0;
+
+ /*
+ * O_APPEND cannot be cleared if the file is marked as append-only
+ * and the file is open for write.
+ */
+ if (((arg ^ filp->f_flags) & 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 (!inode_owner_or_capable(inode))
+ 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->check_flags)
+ error = filp->f_op->check_flags(arg);
+ if (error)
+ return error;
+
+ /*
+ * ->fasync() is responsible for setting the FASYNC bit.
+ */
+ if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
+ error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
+ if (error < 0)
+ goto out;
+ if (error > 0)
+ error = 0;
+ }
+ spin_lock(&filp->f_lock);
+ filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
+ spin_unlock(&filp->f_lock);
+
+ out:
+ return error;
+}
+
+static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
+ int force)
+{
+ write_lock_irq(&filp->f_owner.lock);
+ if (force || !filp->f_owner.pid) {
+ put_pid(filp->f_owner.pid);
+ filp->f_owner.pid = get_pid(pid);
+ filp->f_owner.pid_type = type;
+
+ if (pid) {
+ const struct cred *cred = current_cred();
+ filp->f_owner.uid = cred->uid;
+ filp->f_owner.euid = cred->euid;
+ }
+ }
+ write_unlock_irq(&filp->f_owner.lock);
+}
+
+void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
+ int force)
+{
+ security_file_set_fowner(filp);
+ f_modown(filp, pid, type, force);
+}
+EXPORT_SYMBOL(__f_setown);
+
+void f_setown(struct file *filp, unsigned long arg, int force)
+{
+ enum pid_type type;
+ struct pid *pid;
+ int who = arg;
+ type = PIDTYPE_PID;
+ if (who < 0) {
+ type = PIDTYPE_PGID;
+ who = -who;
+ }
+ rcu_read_lock();
+ pid = find_vpid(who);
+ __f_setown(filp, pid, type, force);
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(f_setown);
+
+void f_delown(struct file *filp)
+{
+ f_modown(filp, NULL, PIDTYPE_PID, 1);
+}
+
+pid_t f_getown(struct file *filp)
+{
+ pid_t pid;
+ read_lock(&filp->f_owner.lock);
+ pid = pid_vnr(filp->f_owner.pid);
+ if (filp->f_owner.pid_type == PIDTYPE_PGID)
+ pid = -pid;
+ read_unlock(&filp->f_owner.lock);
+ return pid;
+}
+
+static int f_setown_ex(struct file *filp, unsigned long arg)
+{
+ struct f_owner_ex __user *owner_p = (void __user *)arg;
+ struct f_owner_ex owner;
+ struct pid *pid;
+ int type;
+ int ret;
+
+ ret = copy_from_user(&owner, owner_p, sizeof(owner));
+ if (ret)
+ return -EFAULT;
+
+ switch (owner.type) {
+ case F_OWNER_TID:
+ type = PIDTYPE_MAX;
+ break;
+
+ case F_OWNER_PID:
+ type = PIDTYPE_PID;
+ break;
+
+ case F_OWNER_PGRP:
+ type = PIDTYPE_PGID;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ rcu_read_lock();
+ pid = find_vpid(owner.pid);
+ if (owner.pid && !pid)
+ ret = -ESRCH;
+ else
+ __f_setown(filp, pid, type, 1);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static int f_getown_ex(struct file *filp, unsigned long arg)
+{
+ struct f_owner_ex __user *owner_p = (void __user *)arg;
+ struct f_owner_ex owner;
+ int ret = 0;
+
+ read_lock(&filp->f_owner.lock);
+ owner.pid = pid_vnr(filp->f_owner.pid);
+ switch (filp->f_owner.pid_type) {
+ case PIDTYPE_MAX:
+ owner.type = F_OWNER_TID;
+ break;
+
+ case PIDTYPE_PID:
+ owner.type = F_OWNER_PID;
+ break;
+
+ case PIDTYPE_PGID:
+ owner.type = F_OWNER_PGRP;
+ break;
+
+ default:
+ WARN_ON(1);
+ ret = -EINVAL;
+ break;
+ }
+ read_unlock(&filp->f_owner.lock);
+
+ if (!ret) {
+ ret = copy_to_user(owner_p, &owner, sizeof(owner));
+ if (ret)
+ ret = -EFAULT;
+ }
+ return ret;
+}
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+ struct user_namespace *user_ns = current_user_ns();
+ uid_t __user *dst = (void __user *)arg;
+ uid_t src[2];
+ int err;
+
+ read_lock(&filp->f_owner.lock);
+ src[0] = from_kuid(user_ns, filp->f_owner.uid);
+ src[1] = from_kuid(user_ns, filp->f_owner.euid);
+ read_unlock(&filp->f_owner.lock);
+
+ err = put_user(src[0], &dst[0]);
+ err |= put_user(src[1], &dst[1]);
+
+ return err;
+}
+#else
+static int f_getowner_uids(struct file *filp, unsigned long arg)
+{
+ return -EINVAL;
+}
+#endif
+
+static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
+ struct file *filp)
+{
+ long err = -EINVAL;
+
+ switch (cmd) {
+ case F_DUPFD:
+ err = f_dupfd(arg, filp, 0);
+ break;
+ case F_DUPFD_CLOEXEC:
+ err = f_dupfd(arg, filp, O_CLOEXEC);
+ 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;
+#if BITS_PER_LONG != 32
+ /* 32-bit arches must use fcntl64() */
+ case F_OFD_GETLK:
+#endif
+ case F_GETLK:
+ err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
+ break;
+#if BITS_PER_LONG != 32
+ /* 32-bit arches must use fcntl64() */
+ case F_OFD_SETLK:
+ case F_OFD_SETLKW:
+#endif
+ /* Fallthrough */
+ case F_SETLK:
+ case F_SETLKW:
+ err = fcntl_setlk(fd, 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 = f_getown(filp);
+ force_successful_syscall_return();
+ break;
+ case F_SETOWN:
+ f_setown(filp, arg, 1);
+ err = 0;
+ break;
+ case F_GETOWN_EX:
+ err = f_getown_ex(filp, arg);
+ break;
+ case F_SETOWN_EX:
+ err = f_setown_ex(filp, arg);
+ break;
+ case F_GETOWNER_UIDS:
+ err = f_getowner_uids(filp, arg);
+ break;
+ case F_GETSIG:
+ err = filp->f_owner.signum;
+ break;
+ case F_SETSIG:
+ /* arg == 0 restores default behaviour. */
+ if (!valid_signal(arg)) {
+ 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;
+ case F_SETPIPE_SZ:
+ case F_GETPIPE_SZ:
+ err = pipe_fcntl(filp, cmd, arg);
+ break;
+ case F_ADD_SEALS:
+ case F_GET_SEALS:
+ err = shmem_fcntl(filp, cmd, arg);
+ break;
+ default:
+ break;
+ }
+ return err;
+}
+
+static int check_fcntl_cmd(unsigned cmd)
+{
+ switch (cmd) {
+ case F_DUPFD:
+ case F_DUPFD_CLOEXEC:
+ case F_GETFD:
+ case F_SETFD:
+ case F_GETFL:
+ return 1;
+ }
+ return 0;
+}
+
+SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
+{
+ struct fd f = fdget_raw(fd);
+ long err = -EBADF;
+
+ if (!f.file)
+ goto out;
+
+ if (unlikely(f.file->f_mode & FMODE_PATH)) {
+ if (!check_fcntl_cmd(cmd))
+ goto out1;
+ }
+
+ err = security_file_fcntl(f.file, cmd, arg);
+ if (!err)
+ err = do_fcntl(fd, cmd, arg, f.file);
+
+out1:
+ fdput(f);
+out:
+ return err;
+}
+
+#if BITS_PER_LONG == 32
+SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
+ unsigned long, arg)
+{
+ struct fd f = fdget_raw(fd);
+ long err = -EBADF;
+
+ if (!f.file)
+ goto out;
+
+ if (unlikely(f.file->f_mode & FMODE_PATH)) {
+ if (!check_fcntl_cmd(cmd))
+ goto out1;
+ }
+
+ err = security_file_fcntl(f.file, cmd, arg);
+ if (err)
+ goto out1;
+
+ switch (cmd) {
+ case F_GETLK64:
+ case F_OFD_GETLK:
+ err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
+ break;
+ case F_SETLK64:
+ case F_SETLKW64:
+ case F_OFD_SETLK:
+ case F_OFD_SETLKW:
+ err = fcntl_setlk64(fd, f.file, cmd,
+ (struct flock64 __user *) arg);
+ break;
+ default:
+ err = do_fcntl(fd, cmd, arg, f.file);
+ break;
+ }
+out1:
+ fdput(f);
+out:
+ return err;
+}
+#endif
+
+/* Table to convert sigio signal codes into poll band bitmaps */
+
+static const 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)
+{
+ const struct cred *cred;
+ int ret;
+
+ rcu_read_lock();
+ cred = __task_cred(p);
+ ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
+ uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
+ uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
+ !security_file_send_sigiotask(p, fown, sig));
+ rcu_read_unlock();
+ return ret;
+}
+
+static void send_sigio_to_task(struct task_struct *p,
+ struct fown_struct *fown,
+ int fd, int reason, int group)
+{
+ /*
+ * F_SETSIG can change ->signum lockless in parallel, make
+ * sure we read it once and use the same value throughout.
+ */
+ int signum = ACCESS_ONCE(fown->signum);
+
+ if (!sigio_perm(p, fown, signum))
+ return;
+
+ switch (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 = 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. */
+ BUG_ON((reason & __SI_MASK) != __SI_POLL);
+ if (reason - POLL_IN >= NSIGPOLL)
+ si.si_band = ~0L;
+ else
+ si.si_band = band_table[reason - POLL_IN];
+ si.si_fd = fd;
+ if (!do_send_sig_info(signum, &si, p, group))
+ break;
+ /* fall-through: fall back on the old plain SIGIO signal */
+ case 0:
+ do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
+ }
+}
+
+void send_sigio(struct fown_struct *fown, int fd, int band)
+{
+ struct task_struct *p;
+ enum pid_type type;
+ struct pid *pid;
+ int group = 1;
+
+ read_lock(&fown->lock);
+
+ type = fown->pid_type;
+ if (type == PIDTYPE_MAX) {
+ group = 0;
+ type = PIDTYPE_PID;
+ }
+
+ pid = fown->pid;
+ if (!pid)
+ goto out_unlock_fown;
+
+ read_lock(&tasklist_lock);
+ do_each_pid_task(pid, type, p) {
+ send_sigio_to_task(p, fown, fd, band, group);
+ } while_each_pid_task(pid, type, 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, int group)
+{
+ if (sigio_perm(p, fown, SIGURG))
+ do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
+}
+
+int send_sigurg(struct fown_struct *fown)
+{
+ struct task_struct *p;
+ enum pid_type type;
+ struct pid *pid;
+ int group = 1;
+ int ret = 0;
+
+ read_lock(&fown->lock);
+
+ type = fown->pid_type;
+ if (type == PIDTYPE_MAX) {
+ group = 0;
+ type = PIDTYPE_PID;
+ }
+
+ pid = fown->pid;
+ if (!pid)
+ goto out_unlock_fown;
+
+ ret = 1;
+
+ read_lock(&tasklist_lock);
+ do_each_pid_task(pid, type, p) {
+ send_sigurg_to_task(p, fown, group);
+ } while_each_pid_task(pid, type, p);
+ read_unlock(&tasklist_lock);
+ out_unlock_fown:
+ read_unlock(&fown->lock);
+ return ret;
+}
+
+static DEFINE_SPINLOCK(fasync_lock);
+static struct kmem_cache *fasync_cache __read_mostly;
+
+static void fasync_free_rcu(struct rcu_head *head)
+{
+ kmem_cache_free(fasync_cache,
+ container_of(head, struct fasync_struct, fa_rcu));
+}
+
+/*
+ * Remove a fasync entry. If successfully removed, return
+ * positive and clear the FASYNC flag. If no entry exists,
+ * do nothing and return 0.
+ *
+ * NOTE! It is very important that the FASYNC flag always
+ * match the state "is the filp on a fasync list".
+ *
+ */
+int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
+{
+ struct fasync_struct *fa, **fp;
+ int result = 0;
+
+ spin_lock(&filp->f_lock);
+ spin_lock(&fasync_lock);
+ for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
+ if (fa->fa_file != filp)
+ continue;
+
+ spin_lock_irq(&fa->fa_lock);
+ fa->fa_file = NULL;
+ spin_unlock_irq(&fa->fa_lock);
+
+ *fp = fa->fa_next;
+ call_rcu(&fa->fa_rcu, fasync_free_rcu);
+ filp->f_flags &= ~FASYNC;
+ result = 1;
+ break;
+ }
+ spin_unlock(&fasync_lock);
+ spin_unlock(&filp->f_lock);
+ return result;
+}
+
+struct fasync_struct *fasync_alloc(void)
+{
+ return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
+}
+
+/*
+ * NOTE! This can be used only for unused fasync entries:
+ * entries that actually got inserted on the fasync list
+ * need to be released by rcu - see fasync_remove_entry.
+ */
+void fasync_free(struct fasync_struct *new)
+{
+ kmem_cache_free(fasync_cache, new);
+}
+
+/*
+ * Insert a new entry into the fasync list. Return the pointer to the
+ * old one if we didn't use the new one.
+ *
+ * NOTE! It is very important that the FASYNC flag always
+ * match the state "is the filp on a fasync list".
+ */
+struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
+{
+ struct fasync_struct *fa, **fp;
+
+ spin_lock(&filp->f_lock);
+ spin_lock(&fasync_lock);
+ for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
+ if (fa->fa_file != filp)
+ continue;
+
+ spin_lock_irq(&fa->fa_lock);
+ fa->fa_fd = fd;
+ spin_unlock_irq(&fa->fa_lock);
+ goto out;
+ }
+
+ spin_lock_init(&new->fa_lock);
+ new->magic = FASYNC_MAGIC;
+ new->fa_file = filp;
+ new->fa_fd = fd;
+ new->fa_next = *fapp;
+ rcu_assign_pointer(*fapp, new);
+ filp->f_flags |= FASYNC;
+
+out:
+ spin_unlock(&fasync_lock);
+ spin_unlock(&filp->f_lock);
+ return fa;
+}
+
+/*
+ * Add a fasync entry. Return negative on error, positive if
+ * added, and zero if did nothing but change an existing one.
+ */
+static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
+{
+ struct fasync_struct *new;
+
+ new = fasync_alloc();
+ if (!new)
+ return -ENOMEM;
+
+ /*
+ * fasync_insert_entry() returns the old (update) entry if
+ * it existed.
+ *
+ * So free the (unused) new entry and return 0 to let the
+ * caller know that we didn't add any new fasync entries.
+ */
+ if (fasync_insert_entry(fd, filp, fapp, new)) {
+ fasync_free(new);
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * fasync_helper() is used by almost all character device drivers
+ * to set up the fasync queue, and for regular files by the file
+ * lease code. 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)
+{
+ if (!on)
+ return fasync_remove_entry(filp, fapp);
+ return fasync_add_entry(fd, filp, fapp);
+}
+
+EXPORT_SYMBOL(fasync_helper);
+
+/*
+ * rcu_read_lock() is held
+ */
+static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
+{
+ while (fa) {
+ struct fown_struct *fown;
+ unsigned long flags;
+
+ if (fa->magic != FASYNC_MAGIC) {
+ printk(KERN_ERR "kill_fasync: bad magic number in "
+ "fasync_struct!\n");
+ return;
+ }
+ spin_lock_irqsave(&fa->fa_lock, flags);
+ if (fa->fa_file) {
+ 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);
+ }
+ spin_unlock_irqrestore(&fa->fa_lock, flags);
+ fa = rcu_dereference(fa->fa_next);
+ }
+}
+
+void kill_fasync(struct fasync_struct **fp, int sig, int band)
+{
+ /* First a quick test without locking: usually
+ * the list is empty.
+ */
+ if (*fp) {
+ rcu_read_lock();
+ kill_fasync_rcu(rcu_dereference(*fp), sig, band);
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(kill_fasync);
+
+static int __init fcntl_init(void)
+{
+ /*
+ * Please add new bits here to ensure allocation uniqueness.
+ * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
+ * is defined as O_NONBLOCK on some platforms and not on others.
+ */
+ BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
+ O_RDONLY | O_WRONLY | O_RDWR |
+ O_CREAT | O_EXCL | O_NOCTTY |
+ O_TRUNC | O_APPEND | /* O_NONBLOCK | */
+ __O_SYNC | O_DSYNC | FASYNC |
+ O_DIRECT | O_LARGEFILE | O_DIRECTORY |
+ O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
+ __FMODE_EXEC | O_PATH | __O_TMPFILE |
+ __FMODE_NONOTIFY
+ ));
+
+ fasync_cache = kmem_cache_create("fasync_cache",
+ sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
+ return 0;
+}
+
+module_init(fcntl_init)
Code Review / kvmfornfv.git / blobdiff