cregit-Linux how code gets into the kernel

Release 4.9 fs/utimes.c

Directory: fs
#include <linux/compiler.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/utime.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>

#ifdef __ARCH_WANT_SYS_UTIME

/*
 * sys_utime() can be implemented in user-level using sys_utimes().
 * Is this for backwards compatibility?  If so, why not move it
 * into the appropriate arch directory (for those architectures that
 * need it).
 */

/* If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */

SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
{
	struct timespec tv[2];

	if (times) {
		if (get_user(tv[0].tv_sec, &times->actime) ||
		    get_user(tv[1].tv_sec, &times->modtime))
			return -EFAULT;
		tv[0].tv_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
}

#endif




static bool nsec_valid(long nsec)
{
	if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
		return true;

	return nsec >= 0 && nsec <= 999999999;
}


Contributors
PersonTokensPropCommitsCommitProp
miklos szeredimiklos szeredi2890.32%150.00%


michael kerriskmichael kerrisk39.68%150.00%


Total31100.00%2100.00%






static int utimes_common(struct path *path, struct timespec *times)
{
	int error;
	struct iattr newattrs;
	struct inode *inode = path->dentry->d_inode;
	struct inode *delegated_inode = NULL;

	error = mnt_want_write(path->mnt);
	if (error)
		goto out;

	if (times && times[0].tv_nsec == UTIME_NOW &&
		     times[1].tv_nsec == UTIME_NOW)
		times = NULL;

	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
	if (times) {
		if (times[0].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_ATIME;
		else if (times[0].tv_nsec != UTIME_NOW) {
			newattrs.ia_atime.tv_sec = times[0].tv_sec;
			newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
			newattrs.ia_valid |= ATTR_ATIME_SET;
		}

		if (times[1].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_MTIME;
		else if (times[1].tv_nsec != UTIME_NOW) {
			newattrs.ia_mtime.tv_sec = times[1].tv_sec;
			newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
			newattrs.ia_valid |= ATTR_MTIME_SET;
		}
		/*
                 * Tell setattr_prepare(), that this is an explicit time
                 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
                 * were used.
                 */
		newattrs.ia_valid |= ATTR_TIMES_SET;
	} else {
		newattrs.ia_valid |= ATTR_TOUCH;
	}
retry_deleg:
	inode_lock(inode);
	error = notify_change(path->dentry, &newattrs, &delegated_inode);
	inode_unlock(inode);
	if (delegated_inode) {
		error = break_deleg_wait(&delegated_inode);
		if (!error)
			goto retry_deleg;
	}

	mnt_drop_write(path->mnt);
out:
	return error;
}


Contributors
PersonTokensPropCommitsCommitProp
alexey dobriyanalexey dobriyan11738.49%17.69%


ulrich drepperulrich drepper7625.00%17.69%


j. bruce fieldsj. bruce fields3411.18%17.69%


miklos szeredimiklos szeredi3310.86%430.77%


michael kerriskmichael kerrisk289.21%215.38%


dave hansendave hansen113.62%17.69%


linus torvaldslinus torvalds20.66%17.69%


al viroal viro20.66%17.69%


jan karajan kara10.33%17.69%


Total304100.00%13100.00%



/*
 * do_utimes - change times on filename or file descriptor
 * @dfd: open file descriptor, -1 or AT_FDCWD
 * @filename: path name or NULL
 * @times: new times or NULL
 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
 *
 * If filename is NULL and dfd refers to an open file, then operate on
 * the file.  Otherwise look up filename, possibly using dfd as a
 * starting point.
 *
 * If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */



long do_utimes(int dfd, const char __user *filename, struct timespec *times,
	       int flags)
{
	int error = -EINVAL;

	if (times && (!nsec_valid(times[0].tv_nsec) ||
		      !nsec_valid(times[1].tv_nsec))) {
		goto out;
	}

	if (flags & ~AT_SYMLINK_NOFOLLOW)
		goto out;

	if (filename == NULL && dfd != AT_FDCWD) {
		struct fd f;

		if (flags & AT_SYMLINK_NOFOLLOW)
			goto out;

		f = fdget(dfd);
		error = -EBADF;
		if (!f.file)
			goto out;

		error = utimes_common(&f.file->f_path, times);
		fdput(f);
	} else {
		struct path path;
		int lookup_flags = 0;

		if (!(flags & AT_SYMLINK_NOFOLLOW))
			lookup_flags |= LOOKUP_FOLLOW;
retry:
		error = user_path_at(dfd, filename, lookup_flags, &path);
		if (error)
			goto out;

		error = utimes_common(&path, times);
		path_put(&path);
		if (retry_estale(error, lookup_flags)) {
			lookup_flags |= LOOKUP_REVAL;
			goto retry;
		}
	}

out:
	return error;
}


Contributors
PersonTokensPropCommitsCommitProp
miklos szeredimiklos szeredi17075.89%112.50%


jeff laytonjeff layton208.93%112.50%


al viroal viro146.25%225.00%


alexey dobriyanalexey dobriyan104.46%112.50%


ulrich drepperulrich drepper73.12%112.50%


jan blunckjan blunck20.89%112.50%


david howellsdavid howells10.45%112.50%


Total224100.00%8100.00%




SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
		struct timespec __user *, utimes, int, flags)
{
	struct timespec tstimes[2];

	if (utimes) {
		if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
			return -EFAULT;

		/* Nothing to do, we must not even check the path.  */
		if (tstimes[0].tv_nsec == UTIME_OMIT &&
		    tstimes[1].tv_nsec == UTIME_OMIT)
			return 0;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
}


SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
		struct timeval __user *, utimes)
{
	struct timeval times[2];
	struct timespec tstimes[2];

	if (utimes) {
		if (copy_from_user(&times, utimes, sizeof(times)))
			return -EFAULT;

		/* This test is needed to catch all invalid values.  If we
                   would test only in do_utimes we would miss those invalid
                   values truncated by the multiplication with 1000.  Note
                   that we also catch UTIME_{NOW,OMIT} here which are only
                   valid for utimensat.  */
		if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
		    times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
			return -EINVAL;

		tstimes[0].tv_sec = times[0].tv_sec;
		tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
		tstimes[1].tv_sec = times[1].tv_sec;
		tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
}


SYSCALL_DEFINE2(utimes, char __user *, filename,
		struct timeval __user *, utimes)
{
	return sys_futimesat(AT_FDCWD, filename, utimes);
}

Overall Contributors
PersonTokensPropCommitsCommitProp
ulrich drepperulrich drepper32232.39%14.35%


alexey dobriyanalexey dobriyan25325.45%14.35%


miklos szeredimiklos szeredi23223.34%521.74%


heiko carstensheiko carstens585.84%28.70%


j. bruce fieldsj. bruce fields343.42%14.35%


michael kerriskmichael kerrisk313.12%28.70%


jeff laytonjeff layton202.01%14.35%


al viroal viro191.91%417.39%


dave hansendave hansen141.41%14.35%


adrian bunkadrian bunk30.30%14.35%


david howellsdavid howells30.30%14.35%


jan blunckjan blunck20.20%14.35%


linus torvaldslinus torvalds20.20%14.35%


jan karajan kara10.10%14.35%


Total994100.00%23100.00%

  
Directory: fs