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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <ctype.h>
#include <errno.h>
#include "sd-device.h"
#include "device-nodes.h"
#include "libudev-util.h"
#include "string-util.h"
#include "strxcpyx.h"
#include "utf8.h"
/**
* SECTION:libudev-util
* @short_description: utils
*
* Utilities useful when dealing with devices and device node names.
*/
/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
int util_resolve_subsys_kernel(const char *string, char *result, size_t maxsize, bool read_value) {
char temp[UTIL_PATH_SIZE], *subsys, *sysname, *attr;
_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
const char *val;
int r;
if (string[0] != '[')
return -EINVAL;
strscpy(temp, sizeof(temp), string);
subsys = &temp[1];
sysname = strchr(subsys, '/');
if (!sysname)
return -EINVAL;
sysname[0] = '\0';
sysname = &sysname[1];
attr = strchr(sysname, ']');
if (!attr)
return -EINVAL;
attr[0] = '\0';
attr = &attr[1];
if (attr[0] == '/')
attr = &attr[1];
if (attr[0] == '\0')
attr = NULL;
if (read_value && !attr)
return -EINVAL;
r = sd_device_new_from_subsystem_sysname(&dev, subsys, sysname);
if (r < 0)
return r;
if (read_value) {
r = sd_device_get_sysattr_value(dev, attr, &val);
if (r < 0 && r != -ENOENT)
return r;
if (r == -ENOENT)
result[0] = '\0';
else
strscpy(result, maxsize, val);
log_debug("value '[%s/%s]%s' is '%s'", subsys, sysname, attr, result);
} else {
r = sd_device_get_syspath(dev, &val);
if (r < 0)
return r;
strscpyl(result, maxsize, val, attr ? "/" : NULL, attr ?: NULL, NULL);
log_debug("path '[%s/%s]%s' is '%s'", subsys, sysname, strempty(attr), result);
}
return 0;
}
size_t util_path_encode(const char *src, char *dest, size_t size) {
size_t i, j;
assert(src);
assert(dest);
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;
}
/*
* Copy from 'str' to 'to', while removing all leading and trailing whitespace,
* and replacing each run of consecutive whitespace with a single underscore.
* The chars from 'str' are copied up to the \0 at the end of the string, or
* at most 'len' chars. This appends \0 to 'to', at the end of the copied
* characters.
*
* If 'len' chars are copied into 'to', the final \0 is placed at len+1
* (i.e. 'to[len] = \0'), so the 'to' buffer must have at least len+1
* chars available.
*
* Note this may be called with 'str' == 'to', i.e. to replace whitespace
* in-place in a buffer. This function can handle that situation.
*
* Note that only 'len' characters are read from 'str'.
*/
size_t util_replace_whitespace(const char *str, char *to, size_t len) {
bool is_space = false;
size_t i, j;
assert(str);
assert(to);
i = strspn(str, WHITESPACE);
for (j = 0; j < len && i < len && str[i] != '\0'; i++) {
if (isspace(str[i])) {
is_space = true;
continue;
}
if (is_space) {
if (j + 1 >= len)
break;
to[j++] = '_';
is_space = false;
}
to[j++] = str[i];
}
to[j] = '\0';
return j;
}
/* allow chars in allow list, plain ascii, hex-escaping and valid utf8 */
size_t util_replace_chars(char *str, const char *allow) {
size_t i = 0, replaced = 0;
assert(str);
while (str[i] != '\0') {
int len;
if (allow_listed_char_for_devnode(str[i], allow)) {
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, (size_t) -1);
if (len > 1) {
i += len;
continue;
}
/* if space is allowed, replace whitespace with ordinary space */
if (isspace(str[i]) && allow && strchr(allow, ' ')) {
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) {
return encode_devnode_name(str, str_enc, len);
}
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