136 lines
3.9 KiB
C
136 lines
3.9 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <ctype.h>
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#include <errno.h>
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#include "sd-device.h"
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#include "device-nodes.h"
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#include "libudev-util.h"
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#include "string-util.h"
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#include "strxcpyx.h"
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#include "utf8.h"
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/**
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* SECTION:libudev-util
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* @short_description: utils
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*
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* Utilities useful when dealing with devices and device node names.
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*/
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/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
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int util_resolve_subsys_kernel(const char *string, char *result, size_t maxsize, bool read_value) {
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char temp[UTIL_PATH_SIZE], *subsys, *sysname, *attr;
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_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
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const char *val;
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int r;
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if (string[0] != '[')
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return -EINVAL;
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strscpy(temp, sizeof(temp), string);
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subsys = &temp[1];
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sysname = strchr(subsys, '/');
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if (!sysname)
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return -EINVAL;
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sysname[0] = '\0';
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sysname = &sysname[1];
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attr = strchr(sysname, ']');
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if (!attr)
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return -EINVAL;
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attr[0] = '\0';
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attr = &attr[1];
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if (attr[0] == '/')
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attr = &attr[1];
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if (attr[0] == '\0')
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attr = NULL;
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if (read_value && !attr)
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return -EINVAL;
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r = sd_device_new_from_subsystem_sysname(&dev, subsys, sysname);
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if (r < 0)
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return r;
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if (read_value) {
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r = sd_device_get_sysattr_value(dev, attr, &val);
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if (r < 0 && r != -ENOENT)
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return r;
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if (r == -ENOENT)
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result[0] = '\0';
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else
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strscpy(result, maxsize, val);
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log_debug("value '[%s/%s]%s' is '%s'", subsys, sysname, attr, result);
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} else {
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r = sd_device_get_syspath(dev, &val);
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if (r < 0)
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return r;
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strscpyl(result, maxsize, val, attr ? "/" : NULL, attr ?: NULL, NULL);
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log_debug("path '[%s/%s]%s' is '%s'", subsys, sysname, strempty(attr), result);
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}
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return 0;
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}
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/* allow chars in allow list, plain ascii, hex-escaping and valid utf8 */
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size_t util_replace_chars(char *str, const char *allow) {
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size_t i = 0, replaced = 0;
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assert(str);
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while (str[i] != '\0') {
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int len;
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if (allow_listed_char_for_devnode(str[i], allow)) {
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i++;
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continue;
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}
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/* accept hex encoding */
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if (str[i] == '\\' && str[i+1] == 'x') {
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i += 2;
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continue;
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}
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/* accept valid utf8 */
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len = utf8_encoded_valid_unichar(str + i, (size_t) -1);
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if (len > 1) {
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i += len;
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continue;
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}
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/* if space is allowed, replace whitespace with ordinary space */
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if (isspace(str[i]) && allow && strchr(allow, ' ')) {
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str[i] = ' ';
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i++;
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replaced++;
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continue;
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}
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/* everything else is replaced with '_' */
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str[i] = '_';
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i++;
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replaced++;
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}
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return replaced;
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}
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/**
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* udev_util_encode_string:
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* @str: input string to be encoded
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* @str_enc: output string to store the encoded input string
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* @len: maximum size of the output string, which may be
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* four times as long as the input string
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*
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* Encode all potentially unsafe characters of a string to the
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* corresponding 2 char hex value prefixed by '\x'.
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*
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* Returns: 0 if the entire string was copied, non-zero otherwise.
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**/
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_public_ int udev_util_encode_string(const char *str, char *str_enc, size_t len) {
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return encode_devnode_name(str, str_enc, len);
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}
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