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Diffstat (limited to 'libblkid/src/encode.c')
| -rw-r--r-- | libblkid/src/encode.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/libblkid/src/encode.c b/libblkid/src/encode.c new file mode 100644 index 0000000..8213873 --- /dev/null +++ b/libblkid/src/encode.c @@ -0,0 +1,263 @@ + +/* + * encode.c - string conversion routines (mostly for compatibility with + * udev/volume_id) + * + * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org> + * Copyright (C) 2009 Karel Zak <kzak@redhat.com> + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ +#include <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <unistd.h> +#include <errno.h> +#include <string.h> +#include <ctype.h> + +#include "blkidP.h" +#include "strutils.h" + +/** + * SECTION: encode + * @title: Encoding utils + * @short_description: encode strings to safe udev-compatible formats + * + */ + +/* 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; +} + +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; +} + +/** + * blkid_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 hex value prefixed by '\x'. + * + * Returns: 0 if the entire string was copied, non-zero otherwise. + **/ +int blkid_encode_string(const char *str, char *str_enc, size_t len) +{ + size_t i, j; + + if (!str || !str_enc || !len) + 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 (j+3 >= len) + goto err; + } + if (len-j < 1) + goto err; + str_enc[j] = '\0'; + return 0; +err: + return -1; +} + +/** + * blkid_safe_string: + * @str: input string + * @str_safe: output string + * @len: size of output string + * + * Processing whitespace characters. Allows valid ascii,valid utf8. + * Replace everything else with'_' + * + * Returns: 0 on success or -1 in case of error. + */ +int blkid_safe_string(const char *str, char *str_safe, size_t len) +{ + size_t i = 0; + + if (!str || !str_safe || !len) + return -1; + + __normalize_whitespace( + (const unsigned char *) str, strnlen(str, len), + (unsigned char *) str_safe, len); + + while (i < len && str_safe[i] != '\0') { + int seqsz; + + /* accept ASCII from ' ' to '~' */ + if (str_safe[i] > 0x20 && str_safe[i] <= 0x7E) + i++; + + /* accept hex encoding */ + else if (str_safe[i] == '\\' && str_safe[i+1] == 'x') + i += 2; + + /* replace whitespace */ + else if (isspace(str_safe[i])) + str_safe[i++] = '_'; + + /* accept valid utf8 */ + else if ((seqsz = utf8_encoded_valid_unichar(&str_safe[i])) >= 1) + i += seqsz; + + /* everything else is replaced with '_' */ + else + str_safe[i++] = '_'; + } + + str_safe[len - 1] = '\0'; + return 0; +} |