libudev-util.c revision 1328f66ad16b5afeb5684858c27e121a46c1959e
/***
This file is part of systemd.
Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
systemd 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.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <ctype.h>
#include <fcntl.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <sys/stat.h>
#include <sys/param.h>
#include "libudev.h"
#include "libudev-private.h"
/**
* SECTION:libudev-util
* @short_description: utils
*
* Utilities useful when dealing with devices and device node names.
*/
int util_delete_path(struct udev *udev, const char *path)
{
char p[UTIL_PATH_SIZE];
char *pos;
int err = 0;
if (path[0] == '/')
while(path[1] == '/')
path++;
util_strscpy(p, sizeof(p), path);
pos = strrchr(p, '/');
if (pos == p || pos == NULL)
return 0;
for (;;) {
*pos = '\0';
pos = strrchr(p, '/');
/* don't remove the last one */
if ((pos == p) || (pos == NULL))
break;
err = rmdir(p);
if (err < 0) {
if (errno == ENOENT)
err = 0;
break;
}
}
return err;
}
uid_t util_lookup_user(struct udev *udev, const char *user)
{
char *endptr;
struct passwd pwbuf;
struct passwd *pw;
uid_t uid;
size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char *buf = alloca(buflen);
if (strcmp(user, "root") == 0)
return 0;
uid = strtoul(user, &endptr, 10);
if (endptr[0] == '\0')
return uid;
errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
if (pw != NULL)
return pw->pw_uid;
if (errno == 0 || errno == ENOENT || errno == ESRCH)
udev_err(udev, "specified user '%s' unknown\n", user);
else
udev_err(udev, "error resolving user '%s': %m\n", user);
return 0;
}
gid_t util_lookup_group(struct udev *udev, const char *group)
{
char *endptr;
struct group grbuf;
struct group *gr;
gid_t gid = 0;
size_t buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char *buf = NULL;
if (strcmp(group, "root") == 0)
return 0;
gid = strtoul(group, &endptr, 10);
if (endptr[0] == '\0')
return gid;
gid = 0;
for (;;) {
char *newbuf;
newbuf = realloc(buf, buflen);
if (!newbuf)
break;
buf = newbuf;
errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
if (gr != NULL) {
gid = gr->gr_gid;
} else if (errno == ERANGE) {
buflen *= 2;
continue;
} else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
udev_err(udev, "specified group '%s' unknown\n", group);
} else {
udev_err(udev, "error resolving group '%s': %m\n", group);
}
break;
}
free(buf);
return gid;
}
/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
int util_resolve_subsys_kernel(struct udev *udev, const char *string,
char *result, size_t maxsize, int read_value)
{
char temp[UTIL_PATH_SIZE];
char *subsys;
char *sysname;
struct udev_device *dev;
char *attr;
if (string[0] != '[')
return -1;
util_strscpy(temp, sizeof(temp), string);
subsys = &temp[1];
sysname = strchr(subsys, '/');
if (sysname == NULL)
return -1;
sysname[0] = '\0';
sysname = &sysname[1];
attr = strchr(sysname, ']');
if (attr == NULL)
return -1;
attr[0] = '\0';
attr = &attr[1];
if (attr[0] == '/')
attr = &attr[1];
if (attr[0] == '\0')
attr = NULL;
if (read_value && attr == NULL)
return -1;
dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
if (dev == NULL)
return -1;
if (read_value) {
const char *val;
val = udev_device_get_sysattr_value(dev, attr);
if (val != NULL)
util_strscpy(result, maxsize, val);
else
result[0] = '\0';
udev_dbg(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
} else {
size_t l;
char *s;
s = result;
l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
if (attr != NULL)
util_strpcpyl(&s, l, "/", attr, NULL);
udev_dbg(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
}
udev_device_unref(dev);
return 0;
}
ssize_t util_get_sys_core_link_value(struct udev *udev, const char *slink, const char *syspath, char *value, size_t size)
{
char path[UTIL_PATH_SIZE];
char target[UTIL_PATH_SIZE];
ssize_t len;
const char *pos;
util_strscpyl(path, sizeof(path), syspath, "/", slink, NULL);
len = readlink(path, target, sizeof(target));
if (len <= 0 || len == (ssize_t)sizeof(target))
return -1;
target[len] = '\0';
pos = strrchr(target, '/');
if (pos == NULL)
return -1;
pos = &pos[1];
return util_strscpy(value, size, pos);
}
int util_resolve_sys_link(struct udev *udev, char *syspath, size_t size)
{
char link_target[UTIL_PATH_SIZE];
ssize_t len;
int i;
int back;
char *base = NULL;
len = readlink(syspath, link_target, sizeof(link_target));
if (len <= 0 || len == (ssize_t)sizeof(link_target))
return -1;
link_target[len] = '\0';
for (back = 0; startswith(&link_target[back * 3], "../"); back++)
;
for (i = 0; i <= back; i++) {
base = strrchr(syspath, '/');
if (base == NULL)
return -EINVAL;
base[0] = '\0';
}
if (base == NULL)
return -EINVAL;
util_strscpyl(base, size - (base - syspath), "/", &link_target[back * 3], NULL);
return 0;
}
int util_log_priority(const char *priority)
{
char *endptr;
int prio;
prio = strtol(priority, &endptr, 10);
if (endptr[0] == '\0' || isspace(endptr[0]))
return prio;
if (startswith(priority, "err"))
return LOG_ERR;
if (startswith(priority, "info"))
return LOG_INFO;
if (startswith(priority, "debug"))
return LOG_DEBUG;
return 0;
}
size_t util_path_encode(const char *src, char *dest, size_t size)
{
size_t i, j;
for (i = 0, j = 0; src[i] != '\0'; i++) {
if (src[i] == '/') {
if (j+4 >= size) {
j = 0;
break;
}
memcpy(&dest[j], "\\x2f", 4);
j += 4;
} else if (src[i] == '\\') {
if (j+4 >= size) {
j = 0;
break;
}
memcpy(&dest[j], "\\x5c", 4);
j += 4;
} else {
if (j+1 >= size) {
j = 0;
break;
}
dest[j] = src[i];
j++;
}
}
dest[j] = '\0';
return j;
}
void util_remove_trailing_chars(char *path, char c)
{
size_t len;
if (path == NULL)
return;
len = strlen(path);
while (len > 0 && path[len-1] == c)
path[--len] = '\0';
}
/*
* Concatenates strings. In any case, terminates in _all_ cases with '\0'
* and moves the @dest pointer forward to the added '\0'. Returns the
* remaining size, and 0 if the string was truncated.
*/
size_t util_strpcpy(char **dest, size_t size, const char *src)
{
size_t len;
len = strlen(src);
if (len >= size) {
if (size > 1)
*dest = mempcpy(*dest, src, size-1);
size = 0;
} else {
if (len > 0) {
*dest = mempcpy(*dest, src, len);
size -= len;
}
}
*dest[0] = '\0';
return size;
}
size_t util_strpcpyf(char **dest, size_t size, const char *src, ...)
{
va_list va;
int i;
va_start(va, src);
i = vsnprintf(*dest, size, src, va);
if (i < (int)size) {
*dest += i;
size -= i;
} else {
*dest += size;
size = 0;
}
va_end(va);
*dest[0] = '\0';
return size;
}
/* concatenates list of strings, moves dest forward */
size_t util_strpcpyl(char **dest, size_t size, const char *src, ...)
{
va_list va;
va_start(va, src);
do {
size = util_strpcpy(dest, size, src);
src = va_arg(va, char *);
} while (src != NULL);
va_end(va);
return size;
}
/* copies string */
size_t util_strscpy(char *dest, size_t size, const char *src)
{
char *s;
s = dest;
return util_strpcpy(&s, size, src);
}
/* concatenates list of strings */
size_t util_strscpyl(char *dest, size_t size, const char *src, ...)
{
va_list va;
char *s;
va_start(va, src);
s = dest;
do {
size = util_strpcpy(&s, size, src);
src = va_arg(va, char *);
} while (src != NULL);
va_end(va);
return size;
}
/* count of characters used to encode one unicode char */
static int utf8_encoded_expected_len(const char *str)
{
unsigned char c = (unsigned char)str[0];
if (c < 0x80)
return 1;
if ((c & 0xe0) == 0xc0)
return 2;
if ((c & 0xf0) == 0xe0)
return 3;
if ((c & 0xf8) == 0xf0)
return 4;
if ((c & 0xfc) == 0xf8)
return 5;
if ((c & 0xfe) == 0xfc)
return 6;
return 0;
}
/* decode one unicode char */
static int utf8_encoded_to_unichar(const char *str)
{
int unichar;
int len;
int i;
len = utf8_encoded_expected_len(str);
switch (len) {
case 1:
return (int)str[0];
case 2:
unichar = str[0] & 0x1f;
break;
case 3:
unichar = (int)str[0] & 0x0f;
break;
case 4:
unichar = (int)str[0] & 0x07;
break;
case 5:
unichar = (int)str[0] & 0x03;
break;
case 6:
unichar = (int)str[0] & 0x01;
break;
default:
return -1;
}
for (i = 1; i < len; i++) {
if (((int)str[i] & 0xc0) != 0x80)
return -1;
unichar <<= 6;
unichar |= (int)str[i] & 0x3f;
}
return unichar;
}
/* expected size used to encode one unicode char */
static int utf8_unichar_to_encoded_len(int unichar)
{
if (unichar < 0x80)
return 1;
if (unichar < 0x800)
return 2;
if (unichar < 0x10000)
return 3;
if (unichar < 0x200000)
return 4;
if (unichar < 0x4000000)
return 5;
return 6;
}
/* check if unicode char has a valid numeric range */
static int utf8_unichar_valid_range(int unichar)
{
if (unichar > 0x10ffff)
return 0;
if ((unichar & 0xfffff800) == 0xd800)
return 0;
if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
return 0;
if ((unichar & 0xffff) == 0xffff)
return 0;
return 1;
}
/* validate one encoded unicode char and return its length */
static int utf8_encoded_valid_unichar(const char *str)
{
int len;
int unichar;
int i;
len = utf8_encoded_expected_len(str);
if (len == 0)
return -1;
/* ascii is valid */
if (len == 1)
return 1;
/* check if expected encoded chars are available */
for (i = 0; i < len; i++)
if ((str[i] & 0x80) != 0x80)
return -1;
unichar = utf8_encoded_to_unichar(str);
/* check if encoded length matches encoded value */
if (utf8_unichar_to_encoded_len(unichar) != len)
return -1;
/* check if value has valid range */
if (!utf8_unichar_valid_range(unichar))
return -1;
return len;
}
int util_replace_whitespace(const char *str, char *to, size_t len)
{
size_t i, j;
/* strip trailing whitespace */
len = strnlen(str, len);
while (len && isspace(str[len-1]))
len--;
/* strip leading whitespace */
i = 0;
while (isspace(str[i]) && (i < len))
i++;
j = 0;
while (i < len) {
/* substitute multiple whitespace with a single '_' */
if (isspace(str[i])) {
while (isspace(str[i]))
i++;
to[j++] = '_';
}
to[j++] = str[i++];
}
to[j] = '\0';
return 0;
}
static int is_whitelisted(char c, const char *white)
{
if ((c >= '0' && c <= '9') ||
(c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
strchr("#+-.:=@_", c) != NULL ||
(white != NULL && strchr(white, c) != NULL))
return 1;
return 0;
}
/* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
int util_replace_chars(char *str, const char *white)
{
size_t i = 0;
int replaced = 0;
while (str[i] != '\0') {
int len;
if (is_whitelisted(str[i], white)) {
i++;
continue;
}
/* accept hex encoding */
if (str[i] == '\\' && str[i+1] == 'x') {
i += 2;
continue;
}
/* accept valid utf8 */
len = utf8_encoded_valid_unichar(&str[i]);
if (len > 1) {
i += len;
continue;
}
/* if space is allowed, replace whitespace with ordinary space */
if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
str[i] = ' ';
i++;
replaced++;
continue;
}
/* everything else is replaced with '_' */
str[i] = '_';
i++;
replaced++;
}
return replaced;
}
/**
* udev_util_encode_string:
* @str: input string to be encoded
* @str_enc: output string to store the encoded input string
* @len: maximum size of the output string, which may be
* four times as long as the input string
*
* Encode all potentially unsafe characters of a string to the
* corresponding 2 char hex value prefixed by '\x'.
*
* Returns: 0 if the entire string was copied, non-zero otherwise.
**/
_public_ int udev_util_encode_string(const char *str, char *str_enc, size_t len)
{
size_t i, j;
if (str == NULL || str_enc == NULL)
return -1;
for (i = 0, j = 0; str[i] != '\0'; i++) {
int seqlen;
seqlen = utf8_encoded_valid_unichar(&str[i]);
if (seqlen > 1) {
if (len-j < (size_t)seqlen)
goto err;
memcpy(&str_enc[j], &str[i], seqlen);
j += seqlen;
i += (seqlen-1);
} else if (str[i] == '\\' || !is_whitelisted(str[i], NULL)) {
if (len-j < 4)
goto err;
sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
j += 4;
} else {
if (len-j < 1)
goto err;
str_enc[j] = str[i];
j++;
}
}
if (len-j < 1)
goto err;
str_enc[j] = '\0';
return 0;
err:
return -1;
}
/*
* http://sites.google.com/site/murmurhash/
*
* All code is released to the public domain. For business purposes,
* Murmurhash is under the MIT license.
*
*/
static unsigned int murmur_hash2(const char *key, int len, unsigned int seed)
{
/*
* 'm' and 'r' are mixing constants generated offline.
* They're not really 'magic', they just happen to work well.
*/
const unsigned int m = 0x5bd1e995;
const int r = 24;
/* initialize the hash to a 'random' value */
unsigned int h = seed ^ len;
/* mix 4 bytes at a time into the hash */
const unsigned char * data = (const unsigned char *)key;
while(len >= 4) {
unsigned int k = *(unsigned int *)data;
k *= m;
k ^= k >> r;
k *= m;
h *= m;
h ^= k;
data += 4;
len -= 4;
}
/* handle the last few bytes of the input array */
switch(len) {
case 3:
h ^= data[2] << 16;
case 2:
h ^= data[1] << 8;
case 1:
h ^= data[0];
h *= m;
};
/* do a few final mixes of the hash to ensure the last few bytes are well-incorporated */
h ^= h >> 13;
h *= m;
h ^= h >> 15;
return h;
}
unsigned int util_string_hash32(const char *str)
{
return murmur_hash2(str, strlen(str), 0);
}
/* get a bunch of bit numbers out of the hash, and set the bits in our bit field */
uint64_t util_string_bloom64(const char *str)
{
uint64_t bits = 0;
unsigned int hash = util_string_hash32(str);
bits |= 1LLU << (hash & 63);
bits |= 1LLU << ((hash >> 6) & 63);
bits |= 1LLU << ((hash >> 12) & 63);
bits |= 1LLU << ((hash >> 18) & 63);
return bits;
}
ssize_t print_kmsg(const char *fmt, ...)
{
int fd;
va_list ap;
char text[1024];
ssize_t len;
ssize_t ret;
fd = open("/dev/kmsg", O_WRONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return -errno;
len = snprintf(text, sizeof(text), "<30>systemd-udevd[%u]: ", getpid());
va_start(ap, fmt);
len += vsnprintf(text + len, sizeof(text) - len, fmt, ap);
va_end(ap);
ret = write(fd, text, len);
if (ret < 0)
ret = -errno;
close(fd);
return ret;
}