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-rw-r--r--fs/open.c1657
1 files changed, 1657 insertions, 0 deletions
diff --git a/fs/open.c b/fs/open.c
new file mode 100644
index 0000000000..54723fceb7
--- /dev/null
+++ b/fs/open.c
@@ -0,0 +1,1657 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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 <linux/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 <linux/compat.h>
+#include <linux/mnt_idmapping.h>
+#include <linux/filelock.h>
+
+#include "internal.h"
+
+int do_truncate(struct mnt_idmap *idmap, 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, and file capabilities on truncate too */
+ ret = dentry_needs_remove_privs(idmap, dentry);
+ if (ret < 0)
+ return ret;
+ if (ret)
+ newattrs.ia_valid |= ret | ATTR_FORCE;
+
+ inode_lock(dentry->d_inode);
+ /* Note any delegations or leases have already been broken: */
+ ret = notify_change(idmap, dentry, &newattrs, NULL);
+ inode_unlock(dentry->d_inode);
+ return ret;
+}
+
+long vfs_truncate(const struct path *path, loff_t length)
+{
+ struct mnt_idmap *idmap;
+ struct inode *inode;
+ long error;
+
+ inode = path->dentry->d_inode;
+
+ /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
+ if (S_ISDIR(inode->i_mode))
+ return -EISDIR;
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+
+ error = mnt_want_write(path->mnt);
+ if (error)
+ goto out;
+
+ idmap = mnt_idmap(path->mnt);
+ error = inode_permission(idmap, 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 = security_path_truncate(path);
+ if (!error)
+ error = do_truncate(idmap, path->dentry, length, 0, NULL);
+
+put_write_and_out:
+ put_write_access(inode);
+mnt_drop_write_and_out:
+ mnt_drop_write(path->mnt);
+out:
+ return error;
+}
+EXPORT_SYMBOL_GPL(vfs_truncate);
+
+long do_sys_truncate(const char __user *pathname, loff_t length)
+{
+ unsigned int lookup_flags = LOOKUP_FOLLOW;
+ struct path path;
+ int error;
+
+ if (length < 0) /* sorry, but loff_t says... */
+ return -EINVAL;
+
+retry:
+ error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+ if (!error) {
+ error = vfs_truncate(&path, length);
+ path_put(&path);
+ }
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ return error;
+}
+
+SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
+{
+ return do_sys_truncate(path, length);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
+{
+ return do_sys_truncate(path, length);
+}
+#endif
+
+long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
+{
+ struct inode *inode;
+ struct dentry *dentry;
+ struct fd f;
+ int error;
+
+ error = -EINVAL;
+ if (length < 0)
+ goto out;
+ error = -EBADF;
+ f = fdget(fd);
+ if (!f.file)
+ goto out;
+
+ /* explicitly opened as large or we are on 64-bit box */
+ if (f.file->f_flags & O_LARGEFILE)
+ small = 0;
+
+ dentry = f.file->f_path.dentry;
+ inode = dentry->d_inode;
+ error = -EINVAL;
+ if (!S_ISREG(inode->i_mode) || !(f.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;
+ /* Check IS_APPEND on real upper inode */
+ if (IS_APPEND(file_inode(f.file)))
+ goto out_putf;
+ sb_start_write(inode->i_sb);
+ error = security_file_truncate(f.file);
+ if (!error)
+ error = do_truncate(file_mnt_idmap(f.file), dentry, length,
+ ATTR_MTIME | ATTR_CTIME, f.file);
+ sb_end_write(inode->i_sb);
+out_putf:
+ fdput(f);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
+{
+ return do_sys_ftruncate(fd, length, 1);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
+{
+ return do_sys_ftruncate(fd, length, 1);
+}
+#endif
+
+/* LFS versions of truncate are only needed on 32 bit machines */
+#if BITS_PER_LONG == 32
+SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
+{
+ return do_sys_truncate(path, length);
+}
+
+SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
+{
+ return do_sys_ftruncate(fd, length, 0);
+}
+#endif /* BITS_PER_LONG == 32 */
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64)
+COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
+ compat_arg_u64_dual(length))
+{
+ return ksys_truncate(pathname, compat_arg_u64_glue(length));
+}
+#endif
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64)
+COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd,
+ compat_arg_u64_dual(length))
+{
+ return ksys_ftruncate(fd, compat_arg_u64_glue(length));
+}
+#endif
+
+int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
+{
+ struct inode *inode = file_inode(file);
+ long ret;
+
+ if (offset < 0 || len <= 0)
+ return -EINVAL;
+
+ /* Return error if mode is not supported */
+ if (mode & ~FALLOC_FL_SUPPORTED_MASK)
+ return -EOPNOTSUPP;
+
+ /* Punch hole and zero range are mutually exclusive */
+ if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
+ (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
+ return -EOPNOTSUPP;
+
+ /* Punch hole must have keep size set */
+ if ((mode & FALLOC_FL_PUNCH_HOLE) &&
+ !(mode & FALLOC_FL_KEEP_SIZE))
+ return -EOPNOTSUPP;
+
+ /* Collapse range should only be used exclusively. */
+ if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
+ (mode & ~FALLOC_FL_COLLAPSE_RANGE))
+ return -EINVAL;
+
+ /* Insert range should only be used exclusively. */
+ if ((mode & FALLOC_FL_INSERT_RANGE) &&
+ (mode & ~FALLOC_FL_INSERT_RANGE))
+ return -EINVAL;
+
+ /* Unshare range should only be used with allocate mode. */
+ if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
+ (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
+ return -EINVAL;
+
+ if (!(file->f_mode & FMODE_WRITE))
+ return -EBADF;
+
+ /*
+ * We can only allow pure fallocate on append only files
+ */
+ if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
+ return -EPERM;
+
+ if (IS_IMMUTABLE(inode))
+ return -EPERM;
+
+ /*
+ * We cannot allow any fallocate operation on an active swapfile
+ */
+ if (IS_SWAPFILE(inode))
+ return -ETXTBSY;
+
+ /*
+ * 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;
+
+ if (S_ISDIR(inode->i_mode))
+ return -EISDIR;
+
+ if (!S_ISREG(inode->i_mode) && !S_ISBLK(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;
+
+ file_start_write(file);
+ ret = file->f_op->fallocate(file, mode, offset, len);
+
+ /*
+ * Create inotify and fanotify events.
+ *
+ * To keep the logic simple always create events if fallocate succeeds.
+ * This implies that events are even created if the file size remains
+ * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
+ */
+ if (ret == 0)
+ fsnotify_modify(file);
+
+ file_end_write(file);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfs_fallocate);
+
+int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len)
+{
+ struct fd f = fdget(fd);
+ int error = -EBADF;
+
+ if (f.file) {
+ error = vfs_fallocate(f.file, mode, offset, len);
+ fdput(f);
+ }
+ return error;
+}
+
+SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
+{
+ return ksys_fallocate(fd, mode, offset, len);
+}
+
+#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE)
+COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode, compat_arg_u64_dual(offset),
+ compat_arg_u64_dual(len))
+{
+ return ksys_fallocate(fd, mode, compat_arg_u64_glue(offset),
+ compat_arg_u64_glue(len));
+}
+#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.
+ *
+ * Creating new credentials is expensive, so we try to skip doing it,
+ * which we can if the result would match what we already got.
+ */
+static bool access_need_override_creds(int flags)
+{
+ const struct cred *cred;
+
+ if (flags & AT_EACCESS)
+ return false;
+
+ cred = current_cred();
+ if (!uid_eq(cred->fsuid, cred->uid) ||
+ !gid_eq(cred->fsgid, cred->gid))
+ return true;
+
+ if (!issecure(SECURE_NO_SETUID_FIXUP)) {
+ kuid_t root_uid = make_kuid(cred->user_ns, 0);
+ if (!uid_eq(cred->uid, root_uid)) {
+ if (!cap_isclear(cred->cap_effective))
+ return true;
+ } else {
+ if (!cap_isidentical(cred->cap_effective,
+ cred->cap_permitted))
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static const struct cred *access_override_creds(void)
+{
+ const struct cred *old_cred;
+ struct cred *override_cred;
+
+ override_cred = prepare_creds();
+ if (!override_cred)
+ return NULL;
+
+ /*
+ * XXX access_need_override_creds performs checks in hopes of skipping
+ * this work. Make sure it stays in sync if making any changes in this
+ * routine.
+ */
+
+ 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 */
+ kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
+ if (!uid_eq(override_cred->uid, root_uid))
+ cap_clear(override_cred->cap_effective);
+ else
+ override_cred->cap_effective =
+ override_cred->cap_permitted;
+ }
+
+ /*
+ * The new set of credentials can *only* be used in
+ * task-synchronous circumstances, and does not need
+ * RCU freeing, unless somebody then takes a separate
+ * reference to it.
+ *
+ * NOTE! This is _only_ true because this credential
+ * is used purely for override_creds() that installs
+ * it as the subjective cred. Other threads will be
+ * accessing ->real_cred, not the subjective cred.
+ *
+ * If somebody _does_ make a copy of this (using the
+ * 'get_current_cred()' function), that will clear the
+ * non_rcu field, because now that other user may be
+ * expecting RCU freeing. But normal thread-synchronous
+ * cred accesses will keep things non-RCY.
+ */
+ override_cred->non_rcu = 1;
+
+ old_cred = override_creds(override_cred);
+
+ /* override_cred() gets its own ref */
+ put_cred(override_cred);
+
+ return old_cred;
+}
+
+static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)
+{
+ struct path path;
+ struct inode *inode;
+ int res;
+ unsigned int lookup_flags = LOOKUP_FOLLOW;
+ const struct cred *old_cred = NULL;
+
+ if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
+ return -EINVAL;
+
+ if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+ return -EINVAL;
+
+ if (flags & AT_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+ if (access_need_override_creds(flags)) {
+ old_cred = access_override_creds();
+ if (!old_cred)
+ return -ENOMEM;
+ }
+
+retry:
+ res = user_path_at(dfd, filename, lookup_flags, &path);
+ if (res)
+ goto out;
+
+ inode = d_backing_inode(path.dentry);
+
+ 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_noexec(&path))
+ goto out_path_release;
+ }
+
+ res = inode_permission(mnt_idmap(path.mnt), 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);
+ if (retry_estale(res, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ if (old_cred)
+ revert_creds(old_cred);
+
+ return res;
+}
+
+SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+{
+ return do_faccessat(dfd, filename, mode, 0);
+}
+
+SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode,
+ int, flags)
+{
+ return do_faccessat(dfd, filename, mode, flags);
+}
+
+SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
+{
+ return do_faccessat(AT_FDCWD, filename, mode, 0);
+}
+
+SYSCALL_DEFINE1(chdir, const char __user *, filename)
+{
+ struct path path;
+ int error;
+ unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+retry:
+ error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
+ if (error)
+ goto out;
+
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
+ if (error)
+ goto dput_and_out;
+
+ set_fs_pwd(current->fs, &path);
+
+dput_and_out:
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ return error;
+}
+
+SYSCALL_DEFINE1(fchdir, unsigned int, fd)
+{
+ struct fd f = fdget_raw(fd);
+ int error;
+
+ error = -EBADF;
+ if (!f.file)
+ goto out;
+
+ error = -ENOTDIR;
+ if (!d_can_lookup(f.file->f_path.dentry))
+ goto out_putf;
+
+ error = file_permission(f.file, MAY_EXEC | MAY_CHDIR);
+ if (!error)
+ set_fs_pwd(current->fs, &f.file->f_path);
+out_putf:
+ fdput(f);
+out:
+ return error;
+}
+
+SYSCALL_DEFINE1(chroot, const char __user *, filename)
+{
+ struct path path;
+ int error;
+ unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+retry:
+ error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
+ if (error)
+ goto out;
+
+ error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
+ if (error)
+ goto dput_and_out;
+
+ error = -EPERM;
+ if (!ns_capable(current_user_ns(), 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);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ return error;
+}
+
+int chmod_common(const struct path *path, umode_t mode)
+{
+ struct inode *inode = path->dentry->d_inode;
+ struct inode *delegated_inode = NULL;
+ struct iattr newattrs;
+ int error;
+
+ error = mnt_want_write(path->mnt);
+ if (error)
+ return error;
+retry_deleg:
+ inode_lock(inode);
+ 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(mnt_idmap(path->mnt), path->dentry,
+ &newattrs, &delegated_inode);
+out_unlock:
+ inode_unlock(inode);
+ if (delegated_inode) {
+ error = break_deleg_wait(&delegated_inode);
+ if (!error)
+ goto retry_deleg;
+ }
+ mnt_drop_write(path->mnt);
+ return error;
+}
+
+int vfs_fchmod(struct file *file, umode_t mode)
+{
+ audit_file(file);
+ return chmod_common(&file->f_path, mode);
+}
+
+SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+{
+ struct fd f = fdget(fd);
+ int err = -EBADF;
+
+ if (f.file) {
+ err = vfs_fchmod(f.file, mode);
+ fdput(f);
+ }
+ return err;
+}
+
+static int do_fchmodat(int dfd, const char __user *filename, umode_t mode,
+ unsigned int flags)
+{
+ struct path path;
+ int error;
+ unsigned int lookup_flags;
+
+ if (unlikely(flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)))
+ return -EINVAL;
+
+ lookup_flags = (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ error = user_path_at(dfd, filename, lookup_flags, &path);
+ if (!error) {
+ error = chmod_common(&path, mode);
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ }
+ return error;
+}
+
+SYSCALL_DEFINE4(fchmodat2, int, dfd, const char __user *, filename,
+ umode_t, mode, unsigned int, flags)
+{
+ return do_fchmodat(dfd, filename, mode, flags);
+}
+
+SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
+ umode_t, mode)
+{
+ return do_fchmodat(dfd, filename, mode, 0);
+}
+
+SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
+{
+ return do_fchmodat(AT_FDCWD, filename, mode, 0);
+}
+
+/*
+ * Check whether @kuid is valid and if so generate and set vfsuid_t in
+ * ia_vfsuid.
+ *
+ * Return: true if @kuid is valid, false if not.
+ */
+static inline bool setattr_vfsuid(struct iattr *attr, kuid_t kuid)
+{
+ if (!uid_valid(kuid))
+ return false;
+ attr->ia_valid |= ATTR_UID;
+ attr->ia_vfsuid = VFSUIDT_INIT(kuid);
+ return true;
+}
+
+/*
+ * Check whether @kgid is valid and if so generate and set vfsgid_t in
+ * ia_vfsgid.
+ *
+ * Return: true if @kgid is valid, false if not.
+ */
+static inline bool setattr_vfsgid(struct iattr *attr, kgid_t kgid)
+{
+ if (!gid_valid(kgid))
+ return false;
+ attr->ia_valid |= ATTR_GID;
+ attr->ia_vfsgid = VFSGIDT_INIT(kgid);
+ return true;
+}
+
+int chown_common(const struct path *path, uid_t user, gid_t group)
+{
+ struct mnt_idmap *idmap;
+ struct user_namespace *fs_userns;
+ struct inode *inode = path->dentry->d_inode;
+ struct inode *delegated_inode = NULL;
+ int error;
+ struct iattr newattrs;
+ kuid_t uid;
+ kgid_t gid;
+
+ uid = make_kuid(current_user_ns(), user);
+ gid = make_kgid(current_user_ns(), group);
+
+ idmap = mnt_idmap(path->mnt);
+ fs_userns = i_user_ns(inode);
+
+retry_deleg:
+ newattrs.ia_vfsuid = INVALID_VFSUID;
+ newattrs.ia_vfsgid = INVALID_VFSGID;
+ newattrs.ia_valid = ATTR_CTIME;
+ if ((user != (uid_t)-1) && !setattr_vfsuid(&newattrs, uid))
+ return -EINVAL;
+ if ((group != (gid_t)-1) && !setattr_vfsgid(&newattrs, gid))
+ return -EINVAL;
+ inode_lock(inode);
+ if (!S_ISDIR(inode->i_mode))
+ newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV |
+ setattr_should_drop_sgid(idmap, inode);
+ /* Continue to send actual fs values, not the mount values. */
+ error = security_path_chown(
+ path,
+ from_vfsuid(idmap, fs_userns, newattrs.ia_vfsuid),
+ from_vfsgid(idmap, fs_userns, newattrs.ia_vfsgid));
+ if (!error)
+ error = notify_change(idmap, path->dentry, &newattrs,
+ &delegated_inode);
+ inode_unlock(inode);
+ if (delegated_inode) {
+ error = break_deleg_wait(&delegated_inode);
+ if (!error)
+ goto retry_deleg;
+ }
+ return error;
+}
+
+int do_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;
+retry:
+ 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);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ return error;
+}
+
+SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
+ gid_t, group, int, flag)
+{
+ return do_fchownat(dfd, filename, user, group, flag);
+}
+
+SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+ return do_fchownat(AT_FDCWD, filename, user, group, 0);
+}
+
+SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
+{
+ return do_fchownat(AT_FDCWD, filename, user, group,
+ AT_SYMLINK_NOFOLLOW);
+}
+
+int vfs_fchown(struct file *file, uid_t user, gid_t group)
+{
+ int error;
+
+ error = mnt_want_write_file(file);
+ if (error)
+ return error;
+ audit_file(file);
+ error = chown_common(&file->f_path, user, group);
+ mnt_drop_write_file(file);
+ return error;
+}
+
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
+{
+ struct fd f = fdget(fd);
+ int error = -EBADF;
+
+ if (f.file) {
+ error = vfs_fchown(f.file, user, group);
+ fdput(f);
+ }
+ return error;
+}
+
+SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+{
+ return ksys_fchown(fd, user, group);
+}
+
+static int do_dentry_open(struct file *f,
+ struct inode *inode,
+ int (*open)(struct inode *, struct file *))
+{
+ static const struct file_operations empty_fops = {};
+ int error;
+
+ path_get(&f->f_path);
+ f->f_inode = inode;
+ f->f_mapping = inode->i_mapping;
+ f->f_wb_err = filemap_sample_wb_err(f->f_mapping);
+ f->f_sb_err = file_sample_sb_err(f);
+
+ if (unlikely(f->f_flags & O_PATH)) {
+ f->f_mode = FMODE_PATH | FMODE_OPENED;
+ f->f_op = &empty_fops;
+ return 0;
+ }
+
+ if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
+ i_readcount_inc(inode);
+ } else if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
+ error = get_write_access(inode);
+ if (unlikely(error))
+ goto cleanup_file;
+ error = __mnt_want_write(f->f_path.mnt);
+ if (unlikely(error)) {
+ put_write_access(inode);
+ goto cleanup_file;
+ }
+ f->f_mode |= FMODE_WRITER;
+ }
+
+ /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
+ if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
+ f->f_mode |= FMODE_ATOMIC_POS;
+
+ f->f_op = fops_get(inode->i_fop);
+ if (WARN_ON(!f->f_op)) {
+ error = -ENODEV;
+ goto cleanup_all;
+ }
+
+ error = security_file_open(f);
+ if (error)
+ goto cleanup_all;
+
+ error = break_lease(file_inode(f), f->f_flags);
+ if (error)
+ goto cleanup_all;
+
+ /* normally all 3 are set; ->open() can clear them if needed */
+ f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
+ if (!open)
+ open = f->f_op->open;
+ if (open) {
+ error = open(inode, f);
+ if (error)
+ goto cleanup_all;
+ }
+ f->f_mode |= FMODE_OPENED;
+ if ((f->f_mode & FMODE_READ) &&
+ likely(f->f_op->read || f->f_op->read_iter))
+ f->f_mode |= FMODE_CAN_READ;
+ if ((f->f_mode & FMODE_WRITE) &&
+ likely(f->f_op->write || f->f_op->write_iter))
+ f->f_mode |= FMODE_CAN_WRITE;
+ if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
+ f->f_mode &= ~FMODE_LSEEK;
+ if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
+ f->f_mode |= FMODE_CAN_ODIRECT;
+
+ f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
+ f->f_iocb_flags = iocb_flags(f);
+
+ file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
+
+ if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT))
+ return -EINVAL;
+
+ /*
+ * XXX: Huge page cache doesn't support writing yet. Drop all page
+ * cache for this file before processing writes.
+ */
+ if (f->f_mode & FMODE_WRITE) {
+ /*
+ * Paired with smp_mb() in collapse_file() to ensure nr_thps
+ * is up to date and the update to i_writecount by
+ * get_write_access() is visible. Ensures subsequent insertion
+ * of THPs into the page cache will fail.
+ */
+ smp_mb();
+ if (filemap_nr_thps(inode->i_mapping)) {
+ struct address_space *mapping = inode->i_mapping;
+
+ filemap_invalidate_lock(inode->i_mapping);
+ /*
+ * unmap_mapping_range just need to be called once
+ * here, because the private pages is not need to be
+ * unmapped mapping (e.g. data segment of dynamic
+ * shared libraries here).
+ */
+ unmap_mapping_range(mapping, 0, 0, 0);
+ truncate_inode_pages(mapping, 0);
+ filemap_invalidate_unlock(inode->i_mapping);
+ }
+ }
+
+ /*
+ * Once we return a file with FMODE_OPENED, __fput() will call
+ * fsnotify_close(), so we need fsnotify_open() here for symmetry.
+ */
+ fsnotify_open(f);
+ return 0;
+
+cleanup_all:
+ if (WARN_ON_ONCE(error > 0))
+ error = -EINVAL;
+ fops_put(f->f_op);
+ put_file_access(f);
+cleanup_file:
+ path_put(&f->f_path);
+ f->f_path.mnt = NULL;
+ f->f_path.dentry = NULL;
+ f->f_inode = NULL;
+ return error;
+}
+
+/**
+ * finish_open - finish opening a file
+ * @file: file pointer
+ * @dentry: pointer to dentry
+ * @open: open callback
+ *
+ * This can be used to finish opening a file passed to i_op->atomic_open().
+ *
+ * If the open callback is set to NULL, then the standard f_op->open()
+ * filesystem callback is substituted.
+ *
+ * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
+ * the return value of d_splice_alias(), then the caller needs to perform dput()
+ * on it after finish_open().
+ *
+ * Returns zero on success or -errno if the open failed.
+ */
+int finish_open(struct file *file, struct dentry *dentry,
+ int (*open)(struct inode *, struct file *))
+{
+ BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */
+
+ file->f_path.dentry = dentry;
+ return do_dentry_open(file, d_backing_inode(dentry), open);
+}
+EXPORT_SYMBOL(finish_open);
+
+/**
+ * finish_no_open - finish ->atomic_open() without opening the file
+ *
+ * @file: file pointer
+ * @dentry: dentry or NULL (as returned from ->lookup())
+ *
+ * This can be used to set the result of a successful lookup in ->atomic_open().
+ *
+ * NB: unlike finish_open() this function does consume the dentry reference and
+ * the caller need not dput() it.
+ *
+ * Returns "0" which must be the return value of ->atomic_open() after having
+ * called this function.
+ */
+int finish_no_open(struct file *file, struct dentry *dentry)
+{
+ file->f_path.dentry = dentry;
+ return 0;
+}
+EXPORT_SYMBOL(finish_no_open);
+
+char *file_path(struct file *filp, char *buf, int buflen)
+{
+ return d_path(&filp->f_path, buf, buflen);
+}
+EXPORT_SYMBOL(file_path);
+
+/**
+ * vfs_open - open the file at the given path
+ * @path: path to open
+ * @file: newly allocated file with f_flag initialized
+ */
+int vfs_open(const struct path *path, struct file *file)
+{
+ file->f_path = *path;
+ return do_dentry_open(file, d_backing_inode(path->dentry), NULL);
+}
+
+struct file *dentry_open(const struct path *path, int flags,
+ const struct cred *cred)
+{
+ int error;
+ struct file *f;
+
+ /* We must always pass in a valid mount pointer. */
+ BUG_ON(!path->mnt);
+
+ f = alloc_empty_file(flags, cred);
+ if (!IS_ERR(f)) {
+ error = vfs_open(path, f);
+ if (error) {
+ fput(f);
+ f = ERR_PTR(error);
+ }
+ }
+ return f;
+}
+EXPORT_SYMBOL(dentry_open);
+
+/**
+ * dentry_create - Create and open a file
+ * @path: path to create
+ * @flags: O_ flags
+ * @mode: mode bits for new file
+ * @cred: credentials to use
+ *
+ * Caller must hold the parent directory's lock, and have prepared
+ * a negative dentry, placed in @path->dentry, for the new file.
+ *
+ * Caller sets @path->mnt to the vfsmount of the filesystem where
+ * the new file is to be created. The parent directory and the
+ * negative dentry must reside on the same filesystem instance.
+ *
+ * On success, returns a "struct file *". Otherwise a ERR_PTR
+ * is returned.
+ */
+struct file *dentry_create(const struct path *path, int flags, umode_t mode,
+ const struct cred *cred)
+{
+ struct file *f;
+ int error;
+
+ f = alloc_empty_file(flags, cred);
+ if (IS_ERR(f))
+ return f;
+
+ error = vfs_create(mnt_idmap(path->mnt),
+ d_inode(path->dentry->d_parent),
+ path->dentry, mode, true);
+ if (!error)
+ error = vfs_open(path, f);
+
+ if (unlikely(error)) {
+ fput(f);
+ return ERR_PTR(error);
+ }
+ return f;
+}
+EXPORT_SYMBOL(dentry_create);
+
+/**
+ * kernel_file_open - open a file for kernel internal use
+ * @path: path of the file to open
+ * @flags: open flags
+ * @inode: the inode
+ * @cred: credentials for open
+ *
+ * Open a file for use by in-kernel consumers. The file is not accounted
+ * against nr_files and must not be installed into the file descriptor
+ * table.
+ *
+ * Return: Opened file on success, an error pointer on failure.
+ */
+struct file *kernel_file_open(const struct path *path, int flags,
+ struct inode *inode, const struct cred *cred)
+{
+ struct file *f;
+ int error;
+
+ f = alloc_empty_file_noaccount(flags, cred);
+ if (IS_ERR(f))
+ return f;
+
+ f->f_path = *path;
+ error = do_dentry_open(f, inode, NULL);
+ if (error) {
+ fput(f);
+ f = ERR_PTR(error);
+ }
+ return f;
+}
+EXPORT_SYMBOL_GPL(kernel_file_open);
+
+/**
+ * backing_file_open - open a backing file for kernel internal use
+ * @path: path of the file to open
+ * @flags: open flags
+ * @real_path: path of the backing file
+ * @cred: credentials for open
+ *
+ * Open a backing file for a stackable filesystem (e.g., overlayfs).
+ * @path may be on the stackable filesystem and backing inode on the
+ * underlying filesystem. In this case, we want to be able to return
+ * the @real_path of the backing inode. This is done by embedding the
+ * returned file into a container structure that also stores the path of
+ * the backing inode on the underlying filesystem, which can be
+ * retrieved using backing_file_real_path().
+ */
+struct file *backing_file_open(const struct path *path, int flags,
+ const struct path *real_path,
+ const struct cred *cred)
+{
+ struct file *f;
+ int error;
+
+ f = alloc_empty_backing_file(flags, cred);
+ if (IS_ERR(f))
+ return f;
+
+ f->f_path = *path;
+ path_get(real_path);
+ *backing_file_real_path(f) = *real_path;
+ error = do_dentry_open(f, d_inode(real_path->dentry), NULL);
+ if (error) {
+ fput(f);
+ f = ERR_PTR(error);
+ }
+
+ return f;
+}
+EXPORT_SYMBOL_GPL(backing_file_open);
+
+#define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
+#define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
+
+inline struct open_how build_open_how(int flags, umode_t mode)
+{
+ struct open_how how = {
+ .flags = flags & VALID_OPEN_FLAGS,
+ .mode = mode & S_IALLUGO,
+ };
+
+ /* O_PATH beats everything else. */
+ if (how.flags & O_PATH)
+ how.flags &= O_PATH_FLAGS;
+ /* Modes should only be set for create-like flags. */
+ if (!WILL_CREATE(how.flags))
+ how.mode = 0;
+ return how;
+}
+
+inline int build_open_flags(const struct open_how *how, struct open_flags *op)
+{
+ u64 flags = how->flags;
+ u64 strip = __FMODE_NONOTIFY | O_CLOEXEC;
+ int lookup_flags = 0;
+ int acc_mode = ACC_MODE(flags);
+
+ BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS),
+ "struct open_flags doesn't yet handle flags > 32 bits");
+
+ /*
+ * Strip flags that either shouldn't be set by userspace like
+ * FMODE_NONOTIFY or that aren't relevant in determining struct
+ * open_flags like O_CLOEXEC.
+ */
+ flags &= ~strip;
+
+ /*
+ * Older syscalls implicitly clear all of the invalid flags or argument
+ * values before calling build_open_flags(), but openat2(2) checks all
+ * of its arguments.
+ */
+ if (flags & ~VALID_OPEN_FLAGS)
+ return -EINVAL;
+ if (how->resolve & ~VALID_RESOLVE_FLAGS)
+ return -EINVAL;
+
+ /* Scoping flags are mutually exclusive. */
+ if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT))
+ return -EINVAL;
+
+ /* Deal with the mode. */
+ if (WILL_CREATE(flags)) {
+ if (how->mode & ~S_IALLUGO)
+ return -EINVAL;
+ op->mode = how->mode | S_IFREG;
+ } else {
+ if (how->mode != 0)
+ return -EINVAL;
+ op->mode = 0;
+ }
+
+ /*
+ * Block bugs where O_DIRECTORY | O_CREAT created regular files.
+ * Note, that blocking O_DIRECTORY | O_CREAT here also protects
+ * O_TMPFILE below which requires O_DIRECTORY being raised.
+ */
+ if ((flags & (O_DIRECTORY | O_CREAT)) == (O_DIRECTORY | O_CREAT))
+ return -EINVAL;
+
+ /* Now handle the creative implementation of O_TMPFILE. */
+ if (flags & __O_TMPFILE) {
+ /*
+ * In order to ensure programs get explicit errors when trying
+ * to use O_TMPFILE on old kernels we enforce that O_DIRECTORY
+ * is raised alongside __O_TMPFILE.
+ */
+ if (!(flags & O_DIRECTORY))
+ return -EINVAL;
+ if (!(acc_mode & MAY_WRITE))
+ return -EINVAL;
+ }
+ if (flags & O_PATH) {
+ /* O_PATH only permits certain other flags to be set. */
+ if (flags & ~O_PATH_FLAGS)
+ return -EINVAL;
+ acc_mode = 0;
+ }
+
+ /*
+ * 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;
+
+ 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;
+ flags |= O_NOFOLLOW;
+ }
+ }
+
+ if (flags & O_DIRECTORY)
+ lookup_flags |= LOOKUP_DIRECTORY;
+ if (!(flags & O_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+
+ if (how->resolve & RESOLVE_NO_XDEV)
+ lookup_flags |= LOOKUP_NO_XDEV;
+ if (how->resolve & RESOLVE_NO_MAGICLINKS)
+ lookup_flags |= LOOKUP_NO_MAGICLINKS;
+ if (how->resolve & RESOLVE_NO_SYMLINKS)
+ lookup_flags |= LOOKUP_NO_SYMLINKS;
+ if (how->resolve & RESOLVE_BENEATH)
+ lookup_flags |= LOOKUP_BENEATH;
+ if (how->resolve & RESOLVE_IN_ROOT)
+ lookup_flags |= LOOKUP_IN_ROOT;
+ if (how->resolve & RESOLVE_CACHED) {
+ /* Don't bother even trying for create/truncate/tmpfile open */
+ if (flags & (O_TRUNC | O_CREAT | __O_TMPFILE))
+ return -EAGAIN;
+ lookup_flags |= LOOKUP_CACHED;
+ }
+
+ op->lookup_flags = lookup_flags;
+ return 0;
+}
+
+/**
+ * file_open_name - open file and return file pointer
+ *
+ * @name: struct filename containing 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 *file_open_name(struct filename *name, int flags, umode_t mode)
+{
+ struct open_flags op;
+ struct open_how how = build_open_how(flags, mode);
+ int err = build_open_flags(&how, &op);
+ if (err)
+ return ERR_PTR(err);
+ return do_filp_open(AT_FDCWD, name, &op);
+}
+
+/**
+ * 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 filename *name = getname_kernel(filename);
+ struct file *file = ERR_CAST(name);
+
+ if (!IS_ERR(name)) {
+ file = file_open_name(name, flags, mode);
+ putname(name);
+ }
+ return file;
+}
+EXPORT_SYMBOL(filp_open);
+
+struct file *file_open_root(const struct path *root,
+ const char *filename, int flags, umode_t mode)
+{
+ struct open_flags op;
+ struct open_how how = build_open_how(flags, mode);
+ int err = build_open_flags(&how, &op);
+ if (err)
+ return ERR_PTR(err);
+ return do_file_open_root(root, filename, &op);
+}
+EXPORT_SYMBOL(file_open_root);
+
+static long do_sys_openat2(int dfd, const char __user *filename,
+ struct open_how *how)
+{
+ struct open_flags op;
+ int fd = build_open_flags(how, &op);
+ struct filename *tmp;
+
+ if (fd)
+ return fd;
+
+ tmp = getname(filename);
+ if (IS_ERR(tmp))
+ return PTR_ERR(tmp);
+
+ fd = get_unused_fd_flags(how->flags);
+ if (fd >= 0) {
+ struct file *f = do_filp_open(dfd, tmp, &op);
+ if (IS_ERR(f)) {
+ put_unused_fd(fd);
+ fd = PTR_ERR(f);
+ } else {
+ fd_install(fd, f);
+ }
+ }
+ putname(tmp);
+ return fd;
+}
+
+long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
+{
+ struct open_how how = build_open_how(flags, mode);
+ return do_sys_openat2(dfd, filename, &how);
+}
+
+
+SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
+{
+ if (force_o_largefile())
+ flags |= O_LARGEFILE;
+ return do_sys_open(AT_FDCWD, filename, flags, mode);
+}
+
+SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
+ umode_t, mode)
+{
+ if (force_o_largefile())
+ flags |= O_LARGEFILE;
+ return do_sys_open(dfd, filename, flags, mode);
+}
+
+SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
+ struct open_how __user *, how, size_t, usize)
+{
+ int err;
+ struct open_how tmp;
+
+ BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0);
+ BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST);
+
+ if (unlikely(usize < OPEN_HOW_SIZE_VER0))
+ return -EINVAL;
+
+ err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize);
+ if (err)
+ return err;
+
+ audit_openat2_how(&tmp);
+
+ /* O_LARGEFILE is only allowed for non-O_PATH. */
+ if (!(tmp.flags & O_PATH) && force_o_largefile())
+ tmp.flags |= O_LARGEFILE;
+
+ return do_sys_openat2(dfd, filename, &tmp);
+}
+
+#ifdef CONFIG_COMPAT
+/*
+ * Exactly like sys_open(), except that it doesn't set the
+ * O_LARGEFILE flag.
+ */
+COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
+{
+ return do_sys_open(AT_FDCWD, filename, flags, mode);
+}
+
+/*
+ * Exactly like sys_openat(), except that it doesn't set the
+ * O_LARGEFILE flag.
+ */
+COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
+{
+ return do_sys_open(dfd, filename, flags, mode);
+}
+#endif
+
+#ifndef __alpha__
+
+/*
+ * For backward compatibility? Maybe this should be moved
+ * into arch/i386 instead?
+ */
+SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
+{
+ int flags = O_CREAT | O_WRONLY | O_TRUNC;
+
+ if (force_o_largefile())
+ flags |= O_LARGEFILE;
+ return do_sys_open(AT_FDCWD, pathname, flags, mode);
+}
+#endif
+
+/*
+ * "id" is the POSIX thread ID. We use the
+ * files pointer for this..
+ */
+static int filp_flush(struct file *filp, fl_owner_t id)
+{
+ int retval = 0;
+
+ if (CHECK_DATA_CORRUPTION(file_count(filp) == 0,
+ "VFS: Close: file count is 0 (f_op=%ps)",
+ filp->f_op)) {
+ return 0;
+ }
+
+ if (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);
+ }
+ return retval;
+}
+
+int filp_close(struct file *filp, fl_owner_t id)
+{
+ int retval;
+
+ retval = filp_flush(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)
+{
+ int retval;
+ struct file *file;
+
+ file = close_fd_get_file(fd);
+ if (!file)
+ return -EBADF;
+
+ retval = filp_flush(file, current->files);
+
+ /*
+ * We're returning to user space. Don't bother
+ * with any delayed fput() cases.
+ */
+ __fput_sync(file);
+
+ /* 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;
+}
+
+/**
+ * sys_close_range() - Close all file descriptors in a given range.
+ *
+ * @fd: starting file descriptor to close
+ * @max_fd: last file descriptor to close
+ * @flags: reserved for future extensions
+ *
+ * This closes a range of file descriptors. All file descriptors
+ * from @fd up to and including @max_fd are closed.
+ * Currently, errors to close a given file descriptor are ignored.
+ */
+SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
+ unsigned int, flags)
+{
+ return __close_range(fd, max_fd, flags);
+}
+
+/*
+ * 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);
+
+/*
+ * stream_open is used by subsystems that want stream-like file descriptors.
+ * Such file descriptors are not seekable and don't have notion of position
+ * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
+ * Contrary to file descriptors of other regular files, .read() and .write()
+ * can run simultaneously.
+ *
+ * stream_open never fails and is marked to return int so that it could be
+ * directly used as file_operations.open .
+ */
+int stream_open(struct inode *inode, struct file *filp)
+{
+ filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
+ filp->f_mode |= FMODE_STREAM;
+ return 0;
+}
+
+EXPORT_SYMBOL(stream_open);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-20 10:48:23 +0000