cregit-Linux how code gets into the kernel

Release 4.10 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 <linux/uaccess.h>
#include <asm/unistd.h>


 * 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);


static bool nsec_valid(long nsec) { if (nsec == UTIME_OMIT || nsec == UTIME_NOW) return true; return nsec >= 0 && nsec <= 999999999; }


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michael kerriskmichael kerrisk39.68%150.00%

static int utimes_common(const 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; }


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j. bruce fieldsj. bruce fields3411.15%17.14%
miklos szeredimiklos szeredi3310.82%428.57%
michael kerriskmichael kerrisk289.18%214.29%
dave hansendave hansen113.61%17.14%
al viroal viro30.98%214.29%
linus torvaldslinus torvalds20.66%17.14%
jan karajan kara10.33%17.14%

/* * 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; }


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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%

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); }

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Directory: fs
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