This adds a 4 argument version of fchmodat (fchmodat4) that supports a flag argument, as specified by POSIX. It supports the same two flags as fchownat: AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH.
Signed-off-by: Andrew Ayer <[email protected]> --- fs/open.c | 23 ++++++++++++++++++++--- include/linux/syscalls.h | 2 ++ 2 files changed, 22 insertions(+), 3 deletions(-) diff --git a/fs/open.c b/fs/open.c index 4b3e1ed..6f661f9 100644 --- a/fs/open.c +++ b/fs/open.c @@ -469,6 +469,9 @@ static int chmod_common(struct path *path, umode_t mode) struct iattr newattrs; int error; + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + error = mnt_want_write(path->mnt); if (error) return error; @@ -506,9 +509,22 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode) { + return sys_fchmodat4(dfd, filename, mode, 0); +} + +SYSCALL_DEFINE4(fchmodat4, int, dfd, const char __user *, filename, + umode_t, mode, int, flag) +{ struct path path; - int error; - unsigned int lookup_flags = LOOKUP_FOLLOW; + int error = -EINVAL; + unsigned 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) { @@ -519,12 +535,13 @@ retry: goto retry; } } +out: return error; } SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) { - return sys_fchmodat(AT_FDCWD, filename, mode); + return sys_fchmodat4(AT_FDCWD, filename, mode, 0); } static int chown_common(struct path *path, uid_t user, gid_t group) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 40ed9e9..32811df 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -747,6 +747,8 @@ asmlinkage long sys_futimesat(int dfd, const char __user *filename, asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode); asmlinkage long sys_fchmodat(int dfd, const char __user * filename, umode_t mode); +asmlinkage long sys_fchmodat4(int dfd, const char __user *filename, + umode_t mode, int flag); asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, int flag); asmlinkage long sys_openat(int dfd, const char __user *filename, int flags, -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
