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Diffstat (limited to 'src/libudev/libudev-util.c')
| -rw-r--r-- | src/libudev/libudev-util.c | 214 |
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 index 0000000..7e21719 --- /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); +} |