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![Ulrich Drepper](/assets/img/avatar_default.png)
Implement utimensat(2) which is an extension to futimesat(2) in that it a) supports nano-second resolution for the timestamps b) allows to selectively ignore the atime/mtime value c) allows to selectively use the current time for either atime or mtime d) supports changing the atime/mtime of a symlink itself along the lines of the BSD lutimes(3) functions For this change the internally used do_utimes() functions was changed to accept a timespec time value and an additional flags parameter. Additionally the sys_utime function was changed to match compat_sys_utime which already use do_utimes instead of duplicating the work. Also, the completely missing futimensat() functionality is added. We have such a function in glibc but we have to resort to using /proc/self/fd/* which not everybody likes (chroot etc). Test application (the syscall number will need per-arch editing): #include <errno.h> #include <fcntl.h> #include <time.h> #include <sys/time.h> #include <stddef.h> #include <syscall.h> #define __NR_utimensat 280 #define UTIME_NOW ((1l << 30) - 1l) #define UTIME_OMIT ((1l << 30) - 2l) int main(void) { int status = 0; int fd = open("ttt", O_RDWR|O_CREAT|O_EXCL, 0666); if (fd == -1) error (1, errno, "failed to create test file \"ttt\""); struct stat64 st1; if (fstat64 (fd, &st1) != 0) error (1, errno, "fstat failed"); struct timespec t[2]; t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); struct stat64 st2; if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0] = st1.st_atim; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_OMIT; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("atim not set"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("mtim changed from zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 0; t[0].tv_nsec = UTIME_OMIT; t[1] = st1.st_mtim; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != st1.st_atim.tv_sec || st2.st_atim.tv_nsec != st1.st_atim.tv_nsec) { puts ("mtim changed from original time"); status = 1; } if (st2.st_mtim.tv_sec != st1.st_mtim.tv_sec || st2.st_mtim.tv_nsec != st1.st_mtim.tv_nsec) { puts ("mtim not set"); status = 1; } if (status != 0) goto out; sleep (2); t[0].tv_sec = 0; t[0].tv_nsec = UTIME_NOW; t[1].tv_sec = 0; t[1].tv_nsec = UTIME_NOW; if (syscall(__NR_utimensat, AT_FDCWD, "ttt", t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); struct timeval tv; gettimeofday(&tv,NULL); if (st2.st_atim.tv_sec <= st1.st_atim.tv_sec || st2.st_atim.tv_sec > tv.tv_sec) { puts ("atim not set to NOW"); status = 1; } if (st2.st_mtim.tv_sec <= st1.st_mtim.tv_sec || st2.st_mtim.tv_sec > tv.tv_sec) { puts ("mtim not set to NOW"); status = 1; } if (symlink ("ttt", "tttsym") != 0) error (1, errno, "cannot create symlink"); t[0].tv_sec = 0; t[0].tv_nsec = 0; t[1].tv_sec = 0; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, AT_FDCWD, "tttsym", t, AT_SYMLINK_NOFOLLOW) != 0) error (1, errno, "utimensat failed"); if (lstat64 ("tttsym", &st2) != 0) error (1, errno, "lstat failed"); if (st2.st_atim.tv_sec != 0 || st2.st_atim.tv_nsec != 0) { puts ("symlink atim not reset to zero"); status = 1; } if (st2.st_mtim.tv_sec != 0 || st2.st_mtim.tv_nsec != 0) { puts ("symlink mtim not reset to zero"); status = 1; } if (status != 0) goto out; t[0].tv_sec = 1; t[0].tv_nsec = 0; t[1].tv_sec = 1; t[1].tv_nsec = 0; if (syscall(__NR_utimensat, fd, NULL, t, 0) != 0) error (1, errno, "utimensat failed"); if (fstat64 (fd, &st2) != 0) error (1, errno, "fstat failed"); if (st2.st_atim.tv_sec != 1 || st2.st_atim.tv_nsec != 0) { puts ("atim not reset to one"); status = 1; } if (st2.st_mtim.tv_sec != 1 || st2.st_mtim.tv_nsec != 0) { puts ("mtim not reset to one"); status = 1; } if (status == 0) puts ("all OK"); out: close (fd); unlink ("ttt"); unlink ("tttsym"); return status; } [akpm@linux-foundation.org: add missing i386 syscall table entry] Signed-off-by: Ulrich Drepper <drepper@redhat.com> Cc: Alexey Dobriyan <adobriyan@openvz.org> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
180 lines
4.8 KiB
C
180 lines
4.8 KiB
C
#include <linux/compiler.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/linkage.h>
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#include <linux/namei.h>
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#include <linux/sched.h>
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#include <linux/stat.h>
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#include <linux/utime.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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#ifdef __ARCH_WANT_SYS_UTIME
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/*
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* sys_utime() can be implemented in user-level using sys_utimes().
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* Is this for backwards compatibility? If so, why not move it
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* into the appropriate arch directory (for those architectures that
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* need it).
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*/
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/* If times==NULL, set access and modification to current time,
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* must be owner or have write permission.
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* Else, update from *times, must be owner or super user.
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*/
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asmlinkage long sys_utime(char __user *filename, struct utimbuf __user *times)
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{
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struct timespec tv[2];
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if (times) {
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if (get_user(tv[0].tv_sec, ×->actime) ||
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get_user(tv[1].tv_sec, ×->modtime))
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return -EFAULT;
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tv[0].tv_nsec = 0;
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tv[1].tv_nsec = 0;
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}
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return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
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}
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#endif
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/* If times==NULL, set access and modification to current time,
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* must be owner or have write permission.
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* Else, update from *times, must be owner or super user.
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*/
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long do_utimes(int dfd, char __user *filename, struct timespec *times, int flags)
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{
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int error;
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struct nameidata nd;
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struct dentry *dentry;
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struct inode *inode;
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struct iattr newattrs;
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struct file *f = NULL;
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error = -EINVAL;
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if (flags & ~AT_SYMLINK_NOFOLLOW)
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goto out;
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if (filename == NULL && dfd != AT_FDCWD) {
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error = -EINVAL;
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if (flags & AT_SYMLINK_NOFOLLOW)
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goto out;
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error = -EBADF;
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f = fget(dfd);
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if (!f)
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goto out;
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dentry = f->f_path.dentry;
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} else {
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error = __user_walk_fd(dfd, filename, (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW, &nd);
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if (error)
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goto out;
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dentry = nd.dentry;
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}
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inode = dentry->d_inode;
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error = -EROFS;
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if (IS_RDONLY(inode))
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goto dput_and_out;
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/* Don't worry, the checks are done in inode_change_ok() */
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newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
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if (times) {
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error = -EPERM;
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if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
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goto dput_and_out;
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if (times[0].tv_nsec == UTIME_OMIT)
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newattrs.ia_valid &= ~ATTR_ATIME;
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else if (times[0].tv_nsec != UTIME_NOW) {
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newattrs.ia_atime.tv_sec = times[0].tv_sec;
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newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
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newattrs.ia_valid |= ATTR_ATIME_SET;
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}
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if (times[1].tv_nsec == UTIME_OMIT)
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newattrs.ia_valid &= ~ATTR_MTIME;
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else if (times[1].tv_nsec != UTIME_NOW) {
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newattrs.ia_mtime.tv_sec = times[1].tv_sec;
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newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
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newattrs.ia_valid |= ATTR_MTIME_SET;
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}
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} else {
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error = -EACCES;
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if (IS_IMMUTABLE(inode))
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goto dput_and_out;
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if (current->fsuid != inode->i_uid &&
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(error = vfs_permission(&nd, MAY_WRITE)) != 0)
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goto dput_and_out;
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}
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mutex_lock(&inode->i_mutex);
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error = notify_change(dentry, &newattrs);
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mutex_unlock(&inode->i_mutex);
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dput_and_out:
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if (f)
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fput(f);
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else
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path_release(&nd);
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out:
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return error;
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}
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asmlinkage long sys_utimensat(int dfd, char __user *filename, struct timespec __user *utimes, int flags)
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{
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struct timespec tstimes[2];
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if (utimes) {
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if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
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return -EFAULT;
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if ((tstimes[0].tv_nsec == UTIME_OMIT ||
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tstimes[0].tv_nsec == UTIME_NOW) &&
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tstimes[0].tv_sec != 0)
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return -EINVAL;
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if ((tstimes[1].tv_nsec == UTIME_OMIT ||
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tstimes[1].tv_nsec == UTIME_NOW) &&
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tstimes[1].tv_sec != 0)
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return -EINVAL;
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/* Nothing to do, we must not even check the path. */
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if (tstimes[0].tv_nsec == UTIME_OMIT &&
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tstimes[1].tv_nsec == UTIME_OMIT)
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return 0;
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}
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return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
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}
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asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
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{
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struct timeval times[2];
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struct timespec tstimes[2];
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if (utimes) {
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if (copy_from_user(×, utimes, sizeof(times)))
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return -EFAULT;
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/* This test is needed to catch all invalid values. If we
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would test only in do_utimes we would miss those invalid
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values truncated by the multiplication with 1000. Note
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that we also catch UTIME_{NOW,OMIT} here which are only
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valid for utimensat. */
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if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
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times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
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return -EINVAL;
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tstimes[0].tv_sec = times[0].tv_sec;
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tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
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tstimes[1].tv_sec = times[1].tv_sec;
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tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
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}
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return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
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}
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asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
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{
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return sys_futimesat(AT_FDCWD, filename, utimes);
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}
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