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mirror of https://github.com/systemd/systemd-stable.git synced 2024-10-31 07:51:08 +03:00
systemd-stable/libsysfs/sysfs_utils.c
2005-04-26 23:55:01 -07:00

291 lines
6.2 KiB
C

/*
* sysfs_utils.c
*
* System utility functions for libsysfs
*
* Copyright (C) IBM Corp. 2003-2005
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "libsysfs.h"
#include "sysfs.h"
/**
* sysfs_remove_trailing_slash: Removes any trailing '/' in the given path
* @path: Path to look for the trailing '/'
* Returns 0 on success 1 on error
*/
int sysfs_remove_trailing_slash(char *path)
{
size_t len;
if (!path) {
errno = EINVAL;
return 1;
}
len = strlen(path);
while (len > 0 && path[len-1] == '/')
path[--len] = '\0';
return 0;
}
/*
* sysfs_get_mnt_path: Gets the sysfs mount point.
* @mnt_path: place to put "sysfs" mount point
* @len: size of mnt_path
* returns 0 with success and -1 with error.
*/
int sysfs_get_mnt_path(char *mnt_path, size_t len)
{
static char sysfs_path[SYSFS_PATH_MAX] = "";
const char *sysfs_path_env;
/* evaluate only at the first call */
if (sysfs_path[0] == '\0') {
/* possible overrride of real mount path */
sysfs_path_env = getenv(SYSFS_PATH_ENV);
if (sysfs_path_env != NULL) {
safestrcpymax(mnt_path, sysfs_path_env, len);
sysfs_remove_trailing_slash(mnt_path);
return 0;
}
safestrcpymax(mnt_path, SYSFS_MNT_PATH, len);
}
return 0;
}
/**
* sysfs_get_name_from_path: returns last name from a "/" delimited path
* @path: path to get name from
* @name: where to put name
* @len: size of name
*/
int sysfs_get_name_from_path(const char *path, char *name, size_t len)
{
char tmp[SYSFS_PATH_MAX];
char *n = NULL;
if (!path || !name || len == 0) {
errno = EINVAL;
return -1;
}
memset(tmp, 0, SYSFS_PATH_MAX);
safestrcpy(tmp, path);
n = strrchr(tmp, '/');
if (n == NULL) {
errno = EINVAL;
return -1;
}
if (*(n+1) == '\0') {
*n = '\0';
n = strrchr(tmp, '/');
if (n == NULL) {
errno = EINVAL;
return -1;
}
}
n++;
safestrcpymax(name, n, len);
return 0;
}
/**
* sysfs_get_link: returns link source
* @path: symbolic link's path
* @target: where to put name
* @len: size of name
*/
int sysfs_get_link(const char *path, char *target, size_t len)
{
char devdir[SYSFS_PATH_MAX];
char linkpath[SYSFS_PATH_MAX];
char temp_path[SYSFS_PATH_MAX];
char *d = NULL, *s = NULL;
int slashes = 0, count = 0;
if (!path || !target || len == 0) {
errno = EINVAL;
return -1;
}
memset(devdir, 0, SYSFS_PATH_MAX);
memset(linkpath, 0, SYSFS_PATH_MAX);
memset(temp_path, 0, SYSFS_PATH_MAX);
safestrcpy(devdir, path);
if ((readlink(path, linkpath, SYSFS_PATH_MAX)) < 0) {
return -1;
}
d = linkpath;
/*
* Three cases here:
* 1. relative path => format ../..
* 2. absolute path => format /abcd/efgh
* 3. relative path _from_ this dir => format abcd/efgh
*/
switch (*d) {
case '.':
/*
* handle the case where link is of type ./abcd/xxx
*/
safestrcpy(temp_path, devdir);
if (*(d+1) == '/')
d += 2;
else if (*(d+1) == '.')
goto parse_path;
s = strrchr(temp_path, '/');
if (s != NULL) {
*(s+1) = '\0';
safestrcat(temp_path, d);
} else {
safestrcpy(temp_path, d);
}
safestrcpymax(target, temp_path, len);
break;
/*
* relative path, getting rid of leading "../.."
*/
parse_path:
while (*d == '/' || *d == '.') {
if (*d == '/')
slashes++;
d++;
}
d--;
s = &devdir[strlen(devdir)-1];
while (s != NULL && count != (slashes+1)) {
s--;
if (*s == '/')
count++;
}
safestrcpymax(s, d, (SYSFS_PATH_MAX-strlen(devdir)));
safestrcpymax(target, devdir, len);
break;
case '/':
/* absolute path - copy as is */
safestrcpymax(target, linkpath, len);
break;
default:
/* relative path from this directory */
safestrcpy(temp_path, devdir);
s = strrchr(temp_path, '/');
if (s != NULL) {
*(s+1) = '\0';
safestrcat(temp_path, linkpath);
} else {
safestrcpy(temp_path, linkpath);
}
safestrcpymax(target, temp_path, len);
}
return 0;
}
/**
* sysfs_close_list: generic list free routine
* @list: dlist to free
* Returns nothing
*/
void sysfs_close_list(struct dlist *list)
{
if (list)
dlist_destroy(list);
}
/**
* sysfs_open_directory_list: gets a list of all directories under "path"
* @path: path to read
* Returns a dlist of supported names or NULL no directories (errno is set
* in case of error
*/
struct dlist *sysfs_open_directory_list(const char *path)
{
if (!path)
return NULL;
return (read_dir_subdirs(path));
}
/**
* sysfs_path_is_dir: Check if the path supplied points to a directory
* @path: path to validate
* Returns 0 if path points to dir, 1 otherwise
*/
int sysfs_path_is_dir(const char *path)
{
struct stat astats;
if (!path) {
errno = EINVAL;
return 1;
}
if ((lstat(path, &astats)) != 0) {
dprintf("stat() failed\n");
return 1;
}
if (S_ISDIR(astats.st_mode))
return 0;
return 1;
}
/**
* sysfs_path_is_link: Check if the path supplied points to a link
* @path: path to validate
* Returns 0 if path points to link, 1 otherwise
*/
int sysfs_path_is_link(const char *path)
{
struct stat astats;
if (!path) {
errno = EINVAL;
return 1;
}
if ((lstat(path, &astats)) != 0) {
dprintf("stat() failed\n");
return 1;
}
if (S_ISLNK(astats.st_mode))
return 0;
return 1;
}
/**
* sysfs_path_is_file: Check if the path supplied points to a file
* @path: path to validate
* Returns 0 if path points to file, 1 otherwise
*/
int sysfs_path_is_file(const char *path)
{
struct stat astats;
if (!path) {
errno = EINVAL;
return 1;
}
if ((lstat(path, &astats)) != 0) {
dprintf("stat() failed\n");
return 1;
}
if (S_ISREG(astats.st_mode))
return 0;
return 1;
}