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-rw-r--r--src/libudev/libudev-util.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/src/libudev/libudev-util.c b/src/libudev/libudev-util.c
new file mode 100644
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--- /dev/null
+++ b/src/libudev/libudev-util.c
@@ -0,0 +1,214 @@
+/* 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 whitelist, plain ascii, hex-escaping and valid utf8 */
+size_t util_replace_chars(char *str, const char *white) {
+ size_t i = 0, replaced = 0;
+
+ assert(str);
+
+ while (str[i] != '\0') {
+ int len;
+
+ if (whitelisted_char_for_devnode(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 && strchr(white, ' ')) {
+ 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);
+}