mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-02 22:23:52 +08:00
121 lines
3.6 KiB
C
121 lines
3.6 KiB
C
/* Detecting file changes using modification times.
|
|
Copyright (C) 2017-2023 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <file_change_detection.h>
|
|
|
|
#include <errno.h>
|
|
#include <stddef.h>
|
|
|
|
bool
|
|
__file_is_unchanged (const struct file_change_detection *left,
|
|
const struct file_change_detection *right)
|
|
{
|
|
if (left->size < 0 || right->size < 0)
|
|
/* Negative sizes are used as markers and never match. */
|
|
return false;
|
|
else if (left->size == 0 && right->size == 0)
|
|
/* Both files are empty or do not exist, so they have the same
|
|
content, no matter what the other fields indicate. */
|
|
return true;
|
|
else
|
|
return left->size == right->size
|
|
&& left->ino == right->ino
|
|
&& left->mtime.tv_sec == right->mtime.tv_sec
|
|
&& left->mtime.tv_nsec == right->mtime.tv_nsec
|
|
&& left->ctime.tv_sec == right->ctime.tv_sec
|
|
&& left->ctime.tv_nsec == right->ctime.tv_nsec;
|
|
}
|
|
libc_hidden_def (__file_is_unchanged)
|
|
|
|
void
|
|
__file_change_detection_for_stat (struct file_change_detection *file,
|
|
const struct __stat64_t64 *st)
|
|
{
|
|
if (S_ISDIR (st->st_mode))
|
|
/* Treat as empty file. */
|
|
file->size = 0;
|
|
else if (!S_ISREG (st->st_mode))
|
|
/* Non-regular files cannot be cached. */
|
|
file->size = -1;
|
|
else
|
|
{
|
|
file->size = st->st_size;
|
|
file->ino = st->st_ino;
|
|
file->mtime = (struct __timespec64) { st->st_mtim.tv_sec,
|
|
st->st_mtim.tv_nsec };
|
|
file->ctime = (struct __timespec64) { st->st_ctim.tv_sec,
|
|
st->st_ctim.tv_nsec };
|
|
}
|
|
}
|
|
libc_hidden_def (__file_change_detection_for_stat)
|
|
|
|
bool
|
|
__file_change_detection_for_path (struct file_change_detection *file,
|
|
const char *path)
|
|
{
|
|
struct __stat64_t64 st;
|
|
if (__stat64_time64 (path, &st) != 0)
|
|
switch (errno)
|
|
{
|
|
case EACCES:
|
|
case EISDIR:
|
|
case ELOOP:
|
|
case ENOENT:
|
|
case ENOTDIR:
|
|
case EPERM:
|
|
/* Ignore errors due to file system contents. Instead, treat
|
|
the file as empty. */
|
|
file->size = 0;
|
|
return true;
|
|
default:
|
|
/* Other errors are fatal. */
|
|
return false;
|
|
}
|
|
else /* stat64 was successful. */
|
|
{
|
|
__file_change_detection_for_stat (file, &st);
|
|
return true;
|
|
}
|
|
}
|
|
libc_hidden_def (__file_change_detection_for_path)
|
|
|
|
bool
|
|
__file_change_detection_for_fp (struct file_change_detection *file,
|
|
FILE *fp)
|
|
{
|
|
if (fp == NULL)
|
|
{
|
|
/* The file does not exist. */
|
|
file->size = 0;
|
|
return true;
|
|
}
|
|
else
|
|
{
|
|
struct __stat64_t64 st;
|
|
if (__fstat64_time64 (__fileno (fp), &st) != 0)
|
|
/* If we already have a file descriptor, all errors are fatal. */
|
|
return false;
|
|
else
|
|
{
|
|
__file_change_detection_for_stat (file, &st);
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
libc_hidden_def (__file_change_detection_for_fp)
|