From b10941c08db89f52038e19ee8a29f26d7808a448 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 17 May 2007 20:09:24 +0200 Subject: [PATCH] volume_id: add and export string encoding function Needed for mount(8) to lookup LABEL=* in /dev/disk/by-label/*. Characters not suited for a filename will be escaped and the encoded LABEL=* string is able to find the corresponding symlink. --- extras/volume_id/lib/Makefile | 4 +- extras/volume_id/lib/exported_symbols | 1 + extras/volume_id/lib/libvolume_id.h | 1 + extras/volume_id/lib/util.c | 123 ++++++++++++++++++++++++++ extras/volume_id/lib/util.h | 3 + extras/volume_id/lib/volume_id.c | 54 +++++++++++ 6 files changed, 184 insertions(+), 2 deletions(-) diff --git a/extras/volume_id/lib/Makefile b/extras/volume_id/lib/Makefile index 17992ba02..328758d03 100644 --- a/extras/volume_id/lib/Makefile +++ b/extras/volume_id/lib/Makefile @@ -13,7 +13,7 @@ INSTALL_DATA = ${INSTALL} -m 644 INSTALL_LIB = ${INSTALL} -m 755 SHLIB_CUR = 0 -SHLIB_REV = 77 +SHLIB_REV = 78 SHLIB_AGE = 0 SHLIB = libvolume_id.so.$(SHLIB_CUR).$(SHLIB_REV).$(SHLIB_AGE) @@ -81,7 +81,7 @@ libvolume_id.a: $(HEADERS) $(OBJS) $(E) " RANLIB " $@ $(Q) $(RANLIB) $@ -$(SHLIB): $(HEADERS) $(addprefix .shlib/,$(OBJS)) +$(SHLIB): $(HEADERS) exported_symbols $(addprefix .shlib/,$(OBJS)) $(E) " CC " $@ $(Q) $(CC) -shared $(CFLAGS) -o $@ \ -Wl,-soname,libvolume_id.so.$(SHLIB_CUR),--version-script,exported_symbols \ diff --git a/extras/volume_id/lib/exported_symbols b/extras/volume_id/lib/exported_symbols index 3422152ed..05b6e52bc 100644 --- a/extras/volume_id/lib/exported_symbols +++ b/extras/volume_id/lib/exported_symbols @@ -16,6 +16,7 @@ volume_id_probe_raid; volume_id_all_probers; volume_id_get_prober_by_type; + volume_id_encode_string; volume_id_open_node; diff --git a/extras/volume_id/lib/libvolume_id.h b/extras/volume_id/lib/libvolume_id.h index c0ab29e0f..19aee68d0 100644 --- a/extras/volume_id/lib/libvolume_id.h +++ b/extras/volume_id/lib/libvolume_id.h @@ -40,6 +40,7 @@ extern int volume_id_get_uuid_raw(struct volume_id *id, const uint8_t **uuid, si extern int volume_id_get_usage(struct volume_id *id, const char **usage); extern int volume_id_get_type(struct volume_id *id, const char **type); extern int volume_id_get_type_version(struct volume_id *id, const char **type_version); +extern int volume_id_encode_string(const char *str, char *str_enc, size_t len); /* * Note: everything below will be made private or removed from diff --git a/extras/volume_id/lib/util.c b/extras/volume_id/lib/util.c index 54d9fd0d8..eaaececad 100644 --- a/extras/volume_id/lib/util.c +++ b/extras/volume_id/lib/util.c @@ -28,6 +28,129 @@ #include "libvolume_id.h" #include "util.h" +/* 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 */ +int volume_id_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; +} + void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count) { unsigned int i, j; diff --git a/extras/volume_id/lib/util.h b/extras/volume_id/lib/util.h index 1206116ce..6ed7b48b5 100644 --- a/extras/volume_id/lib/util.h +++ b/extras/volume_id/lib/util.h @@ -23,6 +23,8 @@ #include #include +#define ALLOWED_CHARS "#+-.:=@_%" + #ifndef PACKED #define PACKED __attribute__((packed)) #endif @@ -77,6 +79,7 @@ enum endian { BE = 1 }; +extern int volume_id_utf8_encoded_valid_unichar(const char *str); extern void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count); extern void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id); extern void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count); diff --git a/extras/volume_id/lib/volume_id.c b/extras/volume_id/lib/volume_id.c index 15e9cda4d..59303d5bf 100644 --- a/extras/volume_id/lib/volume_id.c +++ b/extras/volume_id/lib/volume_id.c @@ -276,6 +276,60 @@ int volume_id_get_type_version(struct volume_id *id, const char **type_version) return 1; } +static int needs_encoding(const char c) +{ + if ((c >= '0' && c <= '9') || + (c >= 'A' && c <= 'Z') || + (c >= 'a' && c <= 'z') || + strchr(ALLOWED_CHARS, c)) + return 0; + return 1; +} + +/** + * volume_id_encode_string: + * @str: Input string to be encoded. + * @str_enc: Target string to store the encoded input. + * @len: Location to store the encoded string. The target 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: 1 if the entire string was copied, 0 otherwise. + **/ +int volume_id_encode_string(const char *str, char *str_enc, size_t len) +{ + size_t i, j; + + if (str == NULL || str_enc == NULL || len == 0) + return 0; + + str_enc[0] = '\0'; + for (i = 0, j = 0; str[i] != '\0'; i++) { + int seqlen; + + seqlen = volume_id_utf8_encoded_valid_unichar(&str[i]); + if (seqlen > 1) { + memcpy(&str_enc[j], &str[i], seqlen); + j += seqlen; + i += (seqlen-1); + } else if (str[i] == '\\' || needs_encoding(str[i])) { + sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]); + j += 4; + } else { + str_enc[j] = str[i]; + j++; + } + if (j+3 >= len) + goto err; + } + str_enc[j] = '\0'; + return 1; +err: + return 0; +} + /** * volume_id_probe_raid: * @id: Probing context. -- 2.30.2