[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/open.c b/ap/os/linux/linux-3.4.x/fs/open.c
new file mode 100644
index 0000000..cf1d34f
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/open.c
@@ -0,0 +1,1144 @@
+/*
+ * linux/fs/open.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/fsnotify.h>
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/namei.h>
+#include <linux/backing-dev.h>
+#include <linux/capability.h>
+#include <linux/securebits.h>
+#include <linux/security.h>
+#include <linux/mount.h>
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <asm/uaccess.h>
+#include <linux/fs.h>
+#include <linux/personality.h>
+#include <linux/pagemap.h>
+#include <linux/syscalls.h>
+#include <linux/rcupdate.h>
+#include <linux/audit.h>
+#include <linux/falloc.h>
+#include <linux/fs_struct.h>
+#include <linux/ima.h>
+#include <linux/dnotify.h>
+
+#include "internal.h"
+
+int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
+ struct file *filp)
+{
+ int ret;
+ struct iattr newattrs;
+
+ /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
+ if (length < 0)
+ return -EINVAL;
+
+ newattrs.ia_size = length;
+ newattrs.ia_valid = ATTR_SIZE | time_attrs;
+ if (filp) {
+ newattrs.ia_file = filp;
+ newattrs.ia_valid |= ATTR_FILE;
+ }
+
+ /* Remove suid/sgid on truncate too */
+ ret = should_remove_suid(dentry);
+ if (ret)
+ newattrs.ia_valid |= ret | ATTR_FORCE;
+
+ mutex_lock(&dentry->d_inode->i_mutex);
+ ret = notify_change(dentry, &newattrs);
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ return ret;
+}
+
+static long do_sys_truncate(const char __user *pathname, loff_t length)
+{
+ struct path path;
+ struct inode *inode;
+ int error;
+
+ error = -EINVAL;
+ if (length < 0) /* sorry, but loff_t says... */
+ goto out;
+
+ error = user_path(pathname, &path);
+ if (error)
+ goto out;
+ inode = path.dentry->d_inode;
+
+ /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
+ error = -EISDIR;
+ if (S_ISDIR(inode->i_mode))
+ goto dput_and_out;
+
+ error = -EINVAL;
+ if (!S_ISREG(inode->i_mode))
+ goto dput_and_out;
+
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto dput_and_out;
+
+ error = inode_permission(inode, MAY_WRITE);
+ if (error)
+ goto mnt_drop_write_and_out;
+
+ error = -EPERM;
+ if (IS_APPEND(inode))
+ goto mnt_drop_write_and_out;
+
+ error = get_write_access(inode);
+ if (error)
+ goto mnt_drop_write_and_out;
+
+ /*
+ * Make sure that there are no leases. get_write_access() protects
+ * against the truncate racing with a lease-granting setlease().
+ */
+ error = break_lease(inode, O_WRONLY);
+ if (error)
+ goto put_write_and_out;
+
+ error = locks_verify_truncate(inode, NULL, length);
+ if (!error)
+ error = security_path_truncate(&path);
+ if (!error)
+ error = do_truncate(path.dentry, length, 0, NULL);
+
+put_write_and_out:
+ put_write_access(inode);
+mnt_drop_write_and_out:
+ mnt_drop_write(path.mnt);
+dput_and_out:
+ path_put(&path);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
+{
+ return do_sys_truncate(path, length);
+}
+
+static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
+{
+ struct inode * inode;
+ struct dentry *dentry;
+ struct file * file;
+ int error;
+
+ error = -EINVAL;
+ if (length < 0)
+ goto out;
+ error = -EBADF;
+ file = fget(fd);
+ if (!file)
+ goto out;
+
+ /* explicitly opened as large or we are on 64-bit box */
+ if (file->f_flags & O_LARGEFILE)
+ small = 0;
+
+ dentry = file->f_path.dentry;
+ inode = dentry->d_inode;
+ error = -EINVAL;
+ if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE))
+ goto out_putf;
+
+ error = -EINVAL;
+ /* Cannot ftruncate over 2^31 bytes without large file support */
+ if (small && length > MAX_NON_LFS)
+ goto out_putf;
+
+ error = -EPERM;
+ if (IS_APPEND(inode))
+ goto out_putf;
+
+ error = locks_verify_truncate(inode, file, length);
+ if (!error)
+ error = security_path_truncate(&file->f_path);
+ if (!error)
+ error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file);
+out_putf:
+ fput(file);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
+{
+ long ret = do_sys_ftruncate(fd, length, 1);
+ /* avoid REGPARM breakage on x86: */
+ asmlinkage_protect(2, ret, fd, length);
+ return ret;
+}
+
+/* LFS versions of truncate are only needed on 32 bit machines */
+#if BITS_PER_LONG == 32
+SYSCALL_DEFINE(truncate64)(const char __user * path, loff_t length)
+{
+ return do_sys_truncate(path, length);
+}
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_truncate64(long path, loff_t length)
+{
+ return SYSC_truncate64((const char __user *) path, length);
+}
+SYSCALL_ALIAS(sys_truncate64, SyS_truncate64);
+#endif
+
+SYSCALL_DEFINE(ftruncate64)(unsigned int fd, loff_t length)
+{
+ long ret = do_sys_ftruncate(fd, length, 0);
+ /* avoid REGPARM breakage on x86: */
+ asmlinkage_protect(2, ret, fd, length);
+ return ret;
+}
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_ftruncate64(long fd, loff_t length)
+{
+ return SYSC_ftruncate64((unsigned int) fd, length);
+}
+SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64);
+#endif
+#endif /* BITS_PER_LONG == 32 */
+
+
+int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ long ret;
+
+ if (offset < 0 || len <= 0)
+ return -EINVAL;
+
+ /* Return error if mode is not supported */
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+ return -EOPNOTSUPP;
+
+ /* Punch hole must have keep size set */
+ if ((mode & FALLOC_FL_PUNCH_HOLE) &&
+ !(mode & FALLOC_FL_KEEP_SIZE))
+ return -EOPNOTSUPP;
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EBADF;
+
+ /* It's not possible punch hole on append only file */
+ if (mode & FALLOC_FL_PUNCH_HOLE && IS_APPEND(inode))
+ return -EPERM;
+
+ if (IS_IMMUTABLE(inode))
+ return -EPERM;
+
+ /*
+ * Revalidate the write permissions, in case security policy has
+ * changed since the files were opened.
+ */
+ ret = security_file_permission(file, MAY_WRITE);
+ if (ret)
+ return ret;
+
+ if (S_ISFIFO(inode->i_mode))
+ return -ESPIPE;
+
+ /*
+ * Let individual file system decide if it supports preallocation
+ * for directories or not.
+ */
+ if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+ return -ENODEV;
+
+ /* Check for wrap through zero too */
+ if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
+ return -EFBIG;
+
+ if (!file->f_op->fallocate)
+ return -EOPNOTSUPP;
+
+ return file->f_op->fallocate(file, mode, offset, len);
+}
+
+SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len)
+{
+ struct file *file;
+ int error = -EBADF;
+
+ file = fget(fd);
+ if (file) {
+ error = do_fallocate(file, mode, offset, len);
+ fput(file);
+ }
+
+ return error;
+}
+
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+asmlinkage long SyS_fallocate(long fd, long mode, loff_t offset, loff_t len)
+{
+ return SYSC_fallocate((int)fd, (int)mode, offset, len);
+}
+SYSCALL_ALIAS(sys_fallocate, SyS_fallocate);
+#endif
+
+/*
+ * access() needs to use the real uid/gid, not the effective uid/gid.
+ * We do this by temporarily clearing all FS-related capabilities and
+ * switching the fsuid/fsgid around to the real ones.
+ */
+SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+{
+ const struct cred *old_cred;
+ struct cred *override_cred;
+ struct path path;
+ struct inode *inode;
+ int res;
+
+ if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
+ return -EINVAL;
+
+ override_cred = prepare_creds();
+ if (!override_cred)
+ return -ENOMEM;
+
+ override_cred->fsuid = override_cred->uid;
+ override_cred->fsgid = override_cred->gid;
+
+ if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+ /* Clear the capabilities if we switch to a non-root user */
+ if (override_cred->uid)
+ cap_clear(override_cred->cap_effective);
+ else
+ override_cred->cap_effective =
+ override_cred->cap_permitted;
+ }
+
+ old_cred = override_creds(override_cred);
+
+ res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+ if (res)
+ goto out;
+
+ inode = path.dentry->d_inode;
+
+ if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
+ /*
+ * MAY_EXEC on regular files is denied if the fs is mounted
+ * with the "noexec" flag.
+ */
+ res = -EACCES;
+ if (path.mnt->mnt_flags & MNT_NOEXEC)
+ goto out_path_release;
+ }
+
+ res = inode_permission(inode, mode | MAY_ACCESS);
+ /* SuS v2 requires we report a read only fs too */
+ if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
+ goto out_path_release;
+ /*
+ * This is a rare case where using __mnt_is_readonly()
+ * is OK without a mnt_want/drop_write() pair. Since
+ * no actual write to the fs is performed here, we do
+ * not need to telegraph to that to anyone.
+ *
+ * By doing this, we accept that this access is
+ * inherently racy and know that the fs may change
+ * state before we even see this result.
+ */
+ if (__mnt_is_readonly(path.mnt))
+ res = -EROFS;
+
+out_path_release:
+ path_put(&path);
+out:
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ return res;
+}
+
+SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
+{
+ return sys_faccessat(AT_FDCWD, filename, mode);
+}
+
+SYSCALL_DEFINE1(chdir, const char __user *, filename)
+{
+ struct path path;
+ int error;
+
+ error = user_path_dir(filename, &path);
+ if (error)
+ goto out;
+
+ error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ if (error)
+ goto dput_and_out;
+
+ set_fs_pwd(current->fs, &path);
+
+dput_and_out:
+ path_put(&path);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE1(fchdir, unsigned int, fd)
+{
+ struct file *file;
+ struct inode *inode;
+ int error, fput_needed;
+
+ error = -EBADF;
+ file = fget_raw_light(fd, &fput_needed);
+ if (!file)
+ goto out;
+
+ inode = file->f_path.dentry->d_inode;
+
+ error = -ENOTDIR;
+ if (!S_ISDIR(inode->i_mode))
+ goto out_putf;
+
+ error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
+ if (!error)
+ set_fs_pwd(current->fs, &file->f_path);
+out_putf:
+ fput_light(file, fput_needed);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE1(chroot, const char __user *, filename)
+{
+ struct path path;
+ int error;
+
+ error = user_path_dir(filename, &path);
+ if (error)
+ goto out;
+
+ error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
+ if (error)
+ goto dput_and_out;
+
+ error = -EPERM;
+ if (!capable(CAP_SYS_CHROOT))
+ goto dput_and_out;
+ error = security_path_chroot(&path);
+ if (error)
+ goto dput_and_out;
+
+ set_fs_root(current->fs, &path);
+ error = 0;
+dput_and_out:
+ path_put(&path);
+out:
+ return error;
+}
+
+static int chmod_common(struct path *path, umode_t mode)
+{
+ struct inode *inode = path->dentry->d_inode;
+ struct iattr newattrs;
+ int error;
+
+ error = mnt_want_write(path->mnt);
+ if (error)
+ return error;
+ mutex_lock(&inode->i_mutex);
+ error = security_path_chmod(path, mode);
+ if (error)
+ goto out_unlock;
+ newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
+ newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+ error = notify_change(path->dentry, &newattrs);
+out_unlock:
+ mutex_unlock(&inode->i_mutex);
+ mnt_drop_write(path->mnt);
+ return error;
+}
+
+SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+{
+ struct file * file;
+ int err = -EBADF;
+
+ file = fget(fd);
+ if (file) {
+ audit_inode(NULL, file->f_path.dentry);
+ err = chmod_common(&file->f_path, mode);
+ fput(file);
+ }
+ return err;
+}
+
+SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
+{
+ struct path path;
+ int error;
+
+ error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+ if (!error) {
+ error = chmod_common(&path, mode);
+ path_put(&path);
+ }
+ return error;
+}
+
+SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
+{
+ return sys_fchmodat(AT_FDCWD, filename, mode);
+}
+
+static int chown_common(struct path *path, uid_t user, gid_t group)
+{
+ struct inode *inode = path->dentry->d_inode;
+ int error;
+ struct iattr newattrs;
+
+ newattrs.ia_valid = ATTR_CTIME;
+ if (user != (uid_t) -1) {
+ newattrs.ia_valid |= ATTR_UID;
+ newattrs.ia_uid = user;
+ }
+ if (group != (gid_t) -1) {
+ newattrs.ia_valid |= ATTR_GID;
+ newattrs.ia_gid = group;
+ }
+ if (!S_ISDIR(inode->i_mode))
+ newattrs.ia_valid |=
+ ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
+ mutex_lock(&inode->i_mutex);
+ error = security_path_chown(path, user, group);
+ if (!error)
+ error = notify_change(path->dentry, &newattrs);
+ mutex_unlock(&inode->i_mutex);
+
+ return error;
+}
+
+SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+ struct path path;
+ int error;
+
+ error = user_path(filename, &path);
+ if (error)
+ goto out;
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto out_release;
+ error = chown_common(&path, user, group);
+ mnt_drop_write(path.mnt);
+out_release:
+ path_put(&path);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
+ gid_t, group, int, flag)
+{
+ struct path path;
+ int error = -EINVAL;
+ int lookup_flags;
+
+ if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+ goto out;
+
+ lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (flag & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+ error = user_path_at(dfd, filename, lookup_flags, &path);
+ if (error)
+ goto out;
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto out_release;
+ error = chown_common(&path, user, group);
+ mnt_drop_write(path.mnt);
+out_release:
+ path_put(&path);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+ struct path path;
+ int error;
+
+ error = user_lpath(filename, &path);
+ if (error)
+ goto out;
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto out_release;
+ error = chown_common(&path, user, group);
+ mnt_drop_write(path.mnt);
+out_release:
+ path_put(&path);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+{
+ struct file * file;
+ int error = -EBADF;
+ struct dentry * dentry;
+
+ file = fget(fd);
+ if (!file)
+ goto out;
+
+ error = mnt_want_write_file(file);
+ if (error)
+ goto out_fput;
+ dentry = file->f_path.dentry;
+ audit_inode(NULL, dentry);
+ error = chown_common(&file->f_path, user, group);
+ mnt_drop_write_file(file);
+out_fput:
+ fput(file);
+out:
+ return error;
+}
+
+/*
+ * You have to be very careful that these write
+ * counts get cleaned up in error cases and
+ * upon __fput(). This should probably never
+ * be called outside of __dentry_open().
+ */
+static inline int __get_file_write_access(struct inode *inode,
+ struct vfsmount *mnt)
+{
+ int error;
+ error = get_write_access(inode);
+ if (error)
+ return error;
+ /*
+ * Do not take mount writer counts on
+ * special files since no writes to
+ * the mount itself will occur.
+ */
+ if (!special_file(inode->i_mode)) {
+ /*
+ * Balanced in __fput()
+ */
+ error = mnt_want_write(mnt);
+ if (error)
+ put_write_access(inode);
+ }
+ return error;
+}
+
+static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
+ struct file *f,
+ int (*open)(struct inode *, struct file *),
+ const struct cred *cred)
+{
+ static const struct file_operations empty_fops = {};
+ struct inode *inode;
+ int error;
+
+ f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
+ FMODE_PREAD | FMODE_PWRITE;
+
+ if (unlikely(f->f_flags & O_PATH))
+ f->f_mode = FMODE_PATH;
+
+ inode = dentry->d_inode;
+ if (f->f_mode & FMODE_WRITE) {
+ error = __get_file_write_access(inode, mnt);
+ if (error)
+ goto cleanup_file;
+ if (!special_file(inode->i_mode))
+ file_take_write(f);
+ }
+
+ f->f_mapping = inode->i_mapping;
+ f->f_path.dentry = dentry;
+ f->f_path.mnt = mnt;
+ f->f_pos = 0;
+ file_sb_list_add(f, inode->i_sb);
+
+ if (unlikely(f->f_mode & FMODE_PATH)) {
+ f->f_op = &empty_fops;
+ return f;
+ }
+
+ f->f_op = fops_get(inode->i_fop);
+
+ error = security_dentry_open(f, cred);
+ if (error)
+ goto cleanup_all;
+
+ error = break_lease(inode, f->f_flags);
+ if (error)
+ goto cleanup_all;
+
+ if (!open && f->f_op)
+ open = f->f_op->open;
+ if (open) {
+ error = open(inode, f);
+ if (error)
+ goto cleanup_all;
+ }
+ if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ i_readcount_inc(inode);
+
+ f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
+
+ file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
+
+ /* NB: we're sure to have correct a_ops only after f_op->open */
+ if (f->f_flags & O_DIRECT) {
+ if (!f->f_mapping->a_ops ||
+ ((!f->f_mapping->a_ops->direct_IO) &&
+ (!f->f_mapping->a_ops->get_xip_mem))) {
+ fput(f);
+ f = ERR_PTR(-EINVAL);
+ }
+ }
+
+ return f;
+
+cleanup_all:
+ fops_put(f->f_op);
+ if (f->f_mode & FMODE_WRITE) {
+ put_write_access(inode);
+ if (!special_file(inode->i_mode)) {
+ /*
+ * We don't consider this a real
+ * mnt_want/drop_write() pair
+ * because it all happenend right
+ * here, so just reset the state.
+ */
+ file_reset_write(f);
+ mnt_drop_write(mnt);
+ }
+ }
+ file_sb_list_del(f);
+ f->f_path.dentry = NULL;
+ f->f_path.mnt = NULL;
+cleanup_file:
+ put_filp(f);
+ dput(dentry);
+ mntput(mnt);
+ return ERR_PTR(error);
+}
+
+/**
+ * lookup_instantiate_filp - instantiates the open intent filp
+ * @nd: pointer to nameidata
+ * @dentry: pointer to dentry
+ * @open: open callback
+ *
+ * Helper for filesystems that want to use lookup open intents and pass back
+ * a fully instantiated struct file to the caller.
+ * This function is meant to be called from within a filesystem's
+ * lookup method.
+ * Beware of calling it for non-regular files! Those ->open methods might block
+ * (e.g. in fifo_open), leaving you with parent locked (and in case of fifo,
+ * leading to a deadlock, as nobody can open that fifo anymore, because
+ * another process to open fifo will block on locked parent when doing lookup).
+ * Note that in case of error, nd->intent.open.file is destroyed, but the
+ * path information remains valid.
+ * If the open callback is set to NULL, then the standard f_op->open()
+ * filesystem callback is substituted.
+ */
+struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
+ int (*open)(struct inode *, struct file *))
+{
+ const struct cred *cred = current_cred();
+
+ if (IS_ERR(nd->intent.open.file))
+ goto out;
+ if (IS_ERR(dentry))
+ goto out_err;
+ nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
+ nd->intent.open.file,
+ open, cred);
+out:
+ return nd->intent.open.file;
+out_err:
+ release_open_intent(nd);
+ nd->intent.open.file = ERR_CAST(dentry);
+ goto out;
+}
+EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
+
+/**
+ * nameidata_to_filp - convert a nameidata to an open filp.
+ * @nd: pointer to nameidata
+ * @flags: open flags
+ *
+ * Note that this function destroys the original nameidata
+ */
+struct file *nameidata_to_filp(struct nameidata *nd)
+{
+ const struct cred *cred = current_cred();
+ struct file *filp;
+
+ /* Pick up the filp from the open intent */
+ filp = nd->intent.open.file;
+ nd->intent.open.file = NULL;
+
+ /* Has the filesystem initialised the file for us? */
+ if (filp->f_path.dentry == NULL) {
+ path_get(&nd->path);
+ filp = __dentry_open(nd->path.dentry, nd->path.mnt, filp,
+ NULL, cred);
+ }
+ return filp;
+}
+
+/*
+ * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
+ * error.
+ */
+struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
+ const struct cred *cred)
+{
+ int error;
+ struct file *f;
+
+ validate_creds(cred);
+
+ /* We must always pass in a valid mount pointer. */
+ BUG_ON(!mnt);
+
+ error = -ENFILE;
+ f = get_empty_filp();
+ if (f == NULL) {
+ dput(dentry);
+ mntput(mnt);
+ return ERR_PTR(error);
+ }
+
+ f->f_flags = flags;
+ return __dentry_open(dentry, mnt, f, NULL, cred);
+}
+EXPORT_SYMBOL(dentry_open);
+
+static void __put_unused_fd(struct files_struct *files, unsigned int fd)
+{
+ struct fdtable *fdt = files_fdtable(files);
+ __clear_open_fd(fd, fdt);
+ if (fd < files->next_fd)
+ files->next_fd = fd;
+}
+
+void put_unused_fd(unsigned int fd)
+{
+ struct files_struct *files = current->files;
+ spin_lock(&files->file_lock);
+ __put_unused_fd(files, fd);
+ spin_unlock(&files->file_lock);
+}
+
+EXPORT_SYMBOL(put_unused_fd);
+
+/*
+ * Install a file pointer in the fd array.
+ *
+ * The VFS is full of places where we drop the files lock between
+ * setting the open_fds bitmap and installing the file in the file
+ * array. At any such point, we are vulnerable to a dup2() race
+ * installing a file in the array before us. We need to detect this and
+ * fput() the struct file we are about to overwrite in this case.
+ *
+ * It should never happen - if we allow dup2() do it, _really_ bad things
+ * will follow.
+ */
+
+void fd_install(unsigned int fd, struct file *file)
+{
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ BUG_ON(fdt->fd[fd] != NULL);
+ rcu_assign_pointer(fdt->fd[fd], file);
+ spin_unlock(&files->file_lock);
+}
+
+EXPORT_SYMBOL(fd_install);
+
+static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
+{
+ int lookup_flags = 0;
+ int acc_mode;
+
+ if (flags & O_CREAT)
+ op->mode = (mode & S_IALLUGO) | S_IFREG;
+ else
+ op->mode = 0;
+
+ /* Must never be set by userspace */
+ flags &= ~FMODE_NONOTIFY;
+
+ /*
+ * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
+ * check for O_DSYNC if the need any syncing at all we enforce it's
+ * always set instead of having to deal with possibly weird behaviour
+ * for malicious applications setting only __O_SYNC.
+ */
+ if (flags & __O_SYNC)
+ flags |= O_DSYNC;
+
+ /*
+ * If we have O_PATH in the open flag. Then we
+ * cannot have anything other than the below set of flags
+ */
+ if (flags & O_PATH) {
+ flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
+ acc_mode = 0;
+ } else {
+ acc_mode = MAY_OPEN | ACC_MODE(flags);
+ }
+
+ op->open_flag = flags;
+
+ /* O_TRUNC implies we need access checks for write permissions */
+ if (flags & O_TRUNC)
+ acc_mode |= MAY_WRITE;
+
+ /* Allow the LSM permission hook to distinguish append
+ access from general write access. */
+ if (flags & O_APPEND)
+ acc_mode |= MAY_APPEND;
+
+ op->acc_mode = acc_mode;
+
+ op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
+
+ if (flags & O_CREAT) {
+ op->intent |= LOOKUP_CREATE;
+ if (flags & O_EXCL)
+ op->intent |= LOOKUP_EXCL;
+ }
+
+ if (flags & O_DIRECTORY)
+ lookup_flags |= LOOKUP_DIRECTORY;
+ if (!(flags & O_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ return lookup_flags;
+}
+
+/**
+ * filp_open - open file and return file pointer
+ *
+ * @filename: path to open
+ * @flags: open flags as per the open(2) second argument
+ * @mode: mode for the new file if O_CREAT is set, else ignored
+ *
+ * This is the helper to open a file from kernelspace if you really
+ * have to. But in generally you should not do this, so please move
+ * along, nothing to see here..
+ */
+struct file *filp_open(const char *filename, int flags, umode_t mode)
+{
+ struct open_flags op;
+ int lookup = build_open_flags(flags, mode, &op);
+ return do_filp_open(AT_FDCWD, filename, &op, lookup);
+}
+EXPORT_SYMBOL(filp_open);
+
+struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
+ const char *filename, int flags)
+{
+ struct open_flags op;
+ int lookup = build_open_flags(flags, 0, &op);
+ if (flags & O_CREAT)
+ return ERR_PTR(-EINVAL);
+ if (!filename && (flags & O_DIRECTORY))
+ if (!dentry->d_inode->i_op->lookup)
+ return ERR_PTR(-ENOTDIR);
+ return do_file_open_root(dentry, mnt, filename, &op, lookup);
+}
+EXPORT_SYMBOL(file_open_root);
+
+long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
+{
+ struct open_flags op;
+ int lookup = build_open_flags(flags, mode, &op);
+ char *tmp = getname(filename);
+ int fd = PTR_ERR(tmp);
+
+ if (!IS_ERR(tmp)) {
+ fd = get_unused_fd_flags(flags);
+ if (fd >= 0) {
+ struct file *f = do_filp_open(dfd, tmp, &op, lookup);
+ if (IS_ERR(f)) {
+ put_unused_fd(fd);
+ fd = PTR_ERR(f);
+ } else {
+ fsnotify_open(f);
+ fd_install(fd, f);
+ }
+ }
+ putname(tmp);
+ }
+ return fd;
+}
+
+SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
+{
+ long ret;
+
+ if (force_o_largefile())
+ flags |= O_LARGEFILE;
+
+ ret = do_sys_open(AT_FDCWD, filename, flags, mode);
+ /* avoid REGPARM breakage on x86: */
+ asmlinkage_protect(3, ret, filename, flags, mode);
+ return ret;
+}
+
+SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
+ umode_t, mode)
+{
+ long ret;
+
+ if (force_o_largefile())
+ flags |= O_LARGEFILE;
+
+ ret = do_sys_open(dfd, filename, flags, mode);
+ /* avoid REGPARM breakage on x86: */
+ asmlinkage_protect(4, ret, dfd, filename, flags, mode);
+ return ret;
+}
+
+#ifndef __alpha__
+
+/*
+ * For backward compatibility? Maybe this should be moved
+ * into arch/i386 instead?
+ */
+SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
+{
+ return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
+}
+
+#endif
+
+/*
+ * "id" is the POSIX thread ID. We use the
+ * files pointer for this..
+ */
+int filp_close(struct file *filp, fl_owner_t id)
+{
+ int retval = 0;
+
+ if (!file_count(filp)) {
+ printk(KERN_ERR "VFS: Close: file count is 0\n");
+ return 0;
+ }
+
+ if (filp->f_op && filp->f_op->flush)
+ retval = filp->f_op->flush(filp, id);
+
+ if (likely(!(filp->f_mode & FMODE_PATH))) {
+ dnotify_flush(filp, id);
+ locks_remove_posix(filp, id);
+ }
+ fput(filp);
+ return retval;
+}
+
+EXPORT_SYMBOL(filp_close);
+
+/*
+ * Careful here! We test whether the file pointer is NULL before
+ * releasing the fd. This ensures that one clone task can't release
+ * an fd while another clone is opening it.
+ */
+SYSCALL_DEFINE1(close, unsigned int, fd)
+{
+ struct file * filp;
+ struct files_struct *files = current->files;
+ struct fdtable *fdt;
+ int retval;
+
+ spin_lock(&files->file_lock);
+ fdt = files_fdtable(files);
+ if (fd >= fdt->max_fds)
+ goto out_unlock;
+ filp = fdt->fd[fd];
+ if (!filp)
+ goto out_unlock;
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ __clear_close_on_exec(fd, fdt);
+ __put_unused_fd(files, fd);
+ spin_unlock(&files->file_lock);
+ retval = filp_close(filp, files);
+
+ /* can't restart close syscall because file table entry was cleared */
+ if (unlikely(retval == -ERESTARTSYS ||
+ retval == -ERESTARTNOINTR ||
+ retval == -ERESTARTNOHAND ||
+ retval == -ERESTART_RESTARTBLOCK))
+ retval = -EINTR;
+
+ return retval;
+
+out_unlock:
+ spin_unlock(&files->file_lock);
+ return -EBADF;
+}
+EXPORT_SYMBOL(sys_close);
+
+/*
+ * This routine simulates a hangup on the tty, to arrange that users
+ * are given clean terminals at login time.
+ */
+SYSCALL_DEFINE0(vhangup)
+{
+ if (capable(CAP_SYS_TTY_CONFIG)) {
+ tty_vhangup_self();
+ return 0;
+ }
+ return -EPERM;
+}
+
+/*
+ * Called when an inode is about to be open.
+ * We use this to disallow opening large files on 32bit systems if
+ * the caller didn't specify O_LARGEFILE. On 64bit systems we force
+ * on this flag in sys_open.
+ */
+int generic_file_open(struct inode * inode, struct file * filp)
+{
+ if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
+ return -EOVERFLOW;
+ return 0;
+}
+
+EXPORT_SYMBOL(generic_file_open);
+
+/*
+ * This is used by subsystems that don't want seekable
+ * file descriptors. The function is not supposed to ever fail, the only
+ * reason it returns an 'int' and not 'void' is so that it can be plugged
+ * directly into file_operations structure.
+ */
+int nonseekable_open(struct inode *inode, struct file *filp)
+{
+ filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
+ return 0;
+}
+
+EXPORT_SYMBOL(nonseekable_open);