Downloaded from http://slre.sourceforge.net/ and adapted for U-Boot environment.
Used to implement regex operations on environment variables. Code size is ~ 3.5 KiB on PPC.
To enable this code, define the CONFIG_REGEX option in your board config file.
Note: There are more recent versions of the SLRE library available at http://slre.googlecode.com ; unfortunately, the new code has a heavily reorked API which makes it less usable for our purposes: - the return code is strings, which are more difficult to process - we don't get any information any more which sub-string of the data was matched by the given regex - it is much more cumbersome to work with arbitrary expressions, where for example the number of substrings for capturing are not known at compile time Also, there does not seem to be any real changes or improvements of the functionality.
Because of this, we deliberately stick with the older code.
Note 2: the test code (built when SLRE_TEST is defined) was modified to allow for more extensive testing; now we can test the regexp matching on all lines on a text file (instead of the whole data in the file as a single block).
Signed-off-by: Wolfgang Denk wd@denx.de
--- Changes in v2: - no changes; most of this is imported code and is intentionally left as is - the "Alignment should match open parenthesis" check is left due to the "indent only by TABs" rule - the "line over 80 characters" warning is left due to the "never break user-visible strings" rule
README | 7 + include/slre.h | 100 ++++++++ lib/Makefile | 1 + lib/slre.c | 724 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 832 insertions(+) create mode 100644 include/slre.h create mode 100644 lib/slre.c
diff --git a/README b/README index 7f2506a..f088d28 100644 --- a/README +++ b/README @@ -930,6 +930,13 @@ The following options need to be configured:
XXX - this list needs to get updated!
+- Regular expression support: + CONFIG_REGEX + If this variable is defined, U-Boot is linked against + the SLRE (Super Light Regular Expression) library, + which adds regex support to some commands, as for + example "env grep" and "setexpr". + - Device tree: CONFIG_OF_CONTROL If this variable is defined, U-Boot will use a device tree diff --git a/include/slre.h b/include/slre.h new file mode 100644 index 0000000..4b41a4b --- /dev/null +++ b/include/slre.h @@ -0,0 +1,100 @@ +/* + * Copyright (c) 2004-2005 Sergey Lyubka valenok@gmail.com + * All rights reserved + * + * "THE BEER-WARE LICENSE" (Revision 42): + * Sergey Lyubka wrote this file. As long as you retain this notice you + * can do whatever you want with this stuff. If we meet some day, and you think + * this stuff is worth it, you can buy me a beer in return. + */ + +/* + * Downloaded Sat Nov 5 17:42:08 CET 2011 at + * http://slre.sourceforge.net/1.0/slre.h + */ + +/* + * This is a regular expression library that implements a subset of Perl RE. + * Please refer to http://slre.sourceforge.net for detailed description. + * + * Usage example (parsing HTTP request): + * + * struct slre slre; + * struct cap captures[4 + 1]; // Number of braket pairs + 1 + * ... + * + * slre_compile(&slre,"^(GET|POST) (\S+) HTTP/(\S+?)\r\n"); + * + * if (slre_match(&slre, buf, len, captures)) { + * printf("Request line length: %d\n", captures[0].len); + * printf("Method: %.*s\n", captures[1].len, captures[1].ptr); + * printf("URI: %.*s\n", captures[2].len, captures[2].ptr); + * } + * + * Supported syntax: + * ^ Match beginning of a buffer + * $ Match end of a buffer + * () Grouping and substring capturing + * [...] Match any character from set + * [^...] Match any character but ones from set + * \s Match whitespace + * \S Match non-whitespace + * \d Match decimal digit + * \r Match carriage return + * \n Match newline + * + Match one or more times (greedy) + * +? Match one or more times (non-greedy) + * * Match zero or more times (greedy) + * *? Match zero or more times (non-greedy) + * ? Match zero or once + * \xDD Match byte with hex value 0xDD + * \meta Match one of the meta character: ^$().[*+?\ + */ + +#ifndef SLRE_HEADER_DEFINED +#define SLRE_HEADER_DEFINED + +/* + * Compiled regular expression + */ +struct slre { + unsigned char code[256]; + unsigned char data[256]; + int code_size; + int data_size; + int num_caps; /* Number of bracket pairs */ + int anchored; /* Must match from string start */ + const char *err_str; /* Error string */ +}; + +/* + * Captured substring + */ +struct cap { + const char *ptr; /* Pointer to the substring */ + int len; /* Substring length */ +}; + +/* + * Compile regular expression. If success, 1 is returned. + * If error, 0 is returned and slre.err_str points to the error message. + */ +int slre_compile(struct slre *, const char *re); + +/* + * Return 1 if match, 0 if no match. + * If `captured_substrings' array is not NULL, then it is filled with the + * values of captured substrings. captured_substrings[0] element is always + * a full matched substring. The round bracket captures start from + * captured_substrings[1]. + * It is assumed that the size of captured_substrings array is enough to + * hold all captures. The caller function must make sure it is! So, the + * array_size = number_of_round_bracket_pairs + 1 + */ +int slre_match(const struct slre *, const char *buf, int buf_len, + struct cap *captured_substrings); + +#ifdef SLRE_TEST +void slre_dump(const struct slre *r, FILE *fp); +#endif /* SLRE_TEST */ +#endif /* SLRE_HEADER_DEFINED */ diff --git a/lib/Makefile b/lib/Makefile index 1bfd3ee..57a1cae 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -71,6 +71,7 @@ COBJS-y += crc32.o COBJS-y += ctype.o COBJS-y += div64.o COBJS-y += linux_string.o +COBJS-$(CONFIG_REGEX) += slre.o COBJS-y += string.o COBJS-y += time.o COBJS-$(CONFIG_BOOTP_PXE) += uuid.o diff --git a/lib/slre.c b/lib/slre.c new file mode 100644 index 0000000..8cdd192 --- /dev/null +++ b/lib/slre.c @@ -0,0 +1,724 @@ +/* + * Copyright (c) 2004-2005 Sergey Lyubka valenok@gmail.com + * All rights reserved + * + * "THE BEER-WARE LICENSE" (Revision 42): + * Sergey Lyubka wrote this file. As long as you retain this notice you + * can do whatever you want with this stuff. If we meet some day, and you think + * this stuff is worth it, you can buy me a beer in return. + */ + +/* + * Downloaded Sat Nov 5 17:43:06 CET 2011 at + * http://slre.sourceforge.net/1.0/slre.c + */ + +#ifdef SLRE_TEST +#include <stdio.h> +#include <assert.h> +#include <ctype.h> +#include <stdlib.h> +#include <string.h> +#else +#include <common.h> +#include <linux/ctype.h> +#endif /* SLRE_TEST */ + +#include <errno.h> + +#include <slre.h> + +enum {END, BRANCH, ANY, EXACT, ANYOF, ANYBUT, OPEN, CLOSE, BOL, EOL, + STAR, PLUS, STARQ, PLUSQ, QUEST, SPACE, NONSPACE, DIGIT}; + +#ifdef SLRE_TEST +static struct { + const char *name; + int narg; + const char *flags; +} opcodes[] = { + {"END", 0, ""}, /* End of code block or program */ + {"BRANCH", 2, "oo"}, /* Alternative operator, "|" */ + {"ANY", 0, ""}, /* Match any character, "." */ + {"EXACT", 2, "d"}, /* Match exact string */ + {"ANYOF", 2, "D"}, /* Match any from set, "[]" */ + {"ANYBUT", 2, "D"}, /* Match any but from set, "[^]"*/ + {"OPEN ", 1, "i"}, /* Capture start, "(" */ + {"CLOSE", 1, "i"}, /* Capture end, ")" */ + {"BOL", 0, ""}, /* Beginning of string, "^" */ + {"EOL", 0, ""}, /* End of string, "$" */ + {"STAR", 1, "o"}, /* Match zero or more times "*" */ + {"PLUS", 1, "o"}, /* Match one or more times, "+" */ + {"STARQ", 1, "o"}, /* Non-greedy STAR, "*?" */ + {"PLUSQ", 1, "o"}, /* Non-greedy PLUS, "+?" */ + {"QUEST", 1, "o"}, /* Match zero or one time, "?" */ + {"SPACE", 0, ""}, /* Match whitespace, "\s" */ + {"NONSPACE", 0, ""}, /* Match non-space, "\S" */ + {"DIGIT", 0, ""} /* Match digit, "\d" */ +}; +#endif /* SLRE_TEST */ + +/* + * Commands and operands are all unsigned char (1 byte long). All code offsets + * are relative to current address, and positive (always point forward). Data + * offsets are absolute. Commands with operands: + * + * BRANCH offset1 offset2 + * Try to match the code block that follows the BRANCH instruction + * (code block ends with END). If no match, try to match code block that + * starts at offset1. If either of these match, jump to offset2. + * + * EXACT data_offset data_length + * Try to match exact string. String is recorded in data section from + * data_offset, and has length data_length. + * + * OPEN capture_number + * CLOSE capture_number + * If the user have passed 'struct cap' array for captures, OPEN + * records the beginning of the matched substring (cap->ptr), CLOSE + * sets the length (cap->len) for respective capture_number. + * + * STAR code_offset + * PLUS code_offset + * QUEST code_offset + * *, +, ?, respectively. Try to gobble as much as possible from the + * matched buffer, until code block that follows these instructions + * matches. When the longest possible string is matched, + * jump to code_offset + * + * STARQ, PLUSQ are non-greedy versions of STAR and PLUS. + */ + +static const char *meta_chars = "|.^$*+?()[\"; + +#ifdef SLRE_TEST + +static void +print_character_set(FILE *fp, const unsigned char *p, int len) +{ + int i; + + for (i = 0; i < len; i++) { + if (i > 0) + (void) fputc(',', fp); + if (p[i] == 0) { + i++; + if (p[i] == 0) + (void) fprintf(fp, "\x%02x", p[i]); + else + (void) fprintf(fp, "%s", opcodes[p[i]].name); + } else if (isprint(p[i])) { + (void) fputc(p[i], fp); + } else { + (void) fprintf(fp, "\x%02x", p[i]); + } + } +} + +void +slre_dump(const struct slre *r, FILE *fp) +{ + int i, j, ch, op, pc; + + for (pc = 0; pc < r->code_size; pc++) { + + op = r->code[pc]; + (void) fprintf(fp, "%3d %s ", pc, opcodes[op].name); + + for (i = 0; opcodes[op].flags[i] != '\0'; i++) + switch (opcodes[op].flags[i]) { + case 'i': + (void) fprintf(fp, "%d ", r->code[pc + 1]); + pc++; + break; + case 'o': + (void) fprintf(fp, "%d ", + pc + r->code[pc + 1] - i); + pc++; + break; + case 'D': + print_character_set(fp, r->data + + r->code[pc + 1], r->code[pc + 2]); + pc += 2; + break; + case 'd': + (void) fputc('"', fp); + for (j = 0; j < r->code[pc + 2]; j++) { + ch = r->data[r->code[pc + 1] + j]; + if (isprint(ch)) { + (void) fputc(ch, fp); + } else { + (void) fprintf(fp, + "\x%02x", ch); + } + } + (void) fputc('"', fp); + pc += 2; + break; + } + + (void) fputc('\n', fp); + } +} +#endif /* SLRE_TEST */ + +static void +set_jump_offset(struct slre *r, int pc, int offset) +{ + assert(offset < r->code_size); + + if (r->code_size - offset > 0xff) + r->err_str = "Jump offset is too big"; + else + r->code[pc] = (unsigned char) (r->code_size - offset); +} + +static void +emit(struct slre *r, int code) +{ + if (r->code_size >= (int) (sizeof(r->code) / sizeof(r->code[0]))) + r->err_str = "RE is too long (code overflow)"; + else + r->code[r->code_size++] = (unsigned char) code; +} + +static void +store_char_in_data(struct slre *r, int ch) +{ + if (r->data_size >= (int) sizeof(r->data)) + r->err_str = "RE is too long (data overflow)"; + else + r->data[r->data_size++] = ch; +} + +static void +exact(struct slre *r, const char **re) +{ + int old_data_size = r->data_size; + + while (**re != '\0' && (strchr(meta_chars, **re)) == NULL) + store_char_in_data(r, *(*re)++); + + emit(r, EXACT); + emit(r, old_data_size); + emit(r, r->data_size - old_data_size); +} + +static int +get_escape_char(const char **re) +{ + int res; + + switch (*(*re)++) { + case 'n': + res = '\n'; + break; + case 'r': + res = '\r'; + break; + case 't': + res = '\t'; + break; + case '0': + res = 0; + break; + case 'S': + res = NONSPACE << 8; + break; + case 's': + res = SPACE << 8; + break; + case 'd': + res = DIGIT << 8; + break; + default: + res = (*re)[-1]; + break; + } + + return res; +} + +static void +anyof(struct slre *r, const char **re) +{ + int esc, old_data_size = r->data_size, op = ANYOF; + + if (**re == '^') { + op = ANYBUT; + (*re)++; + } + + while (**re != '\0') + + switch (*(*re)++) { + case ']': + emit(r, op); + emit(r, old_data_size); + emit(r, r->data_size - old_data_size); + return; + /* NOTREACHED */ + break; + case '\': + esc = get_escape_char(re); + if ((esc & 0xff) == 0) { + store_char_in_data(r, 0); + store_char_in_data(r, esc >> 8); + } else { + store_char_in_data(r, esc); + } + break; + default: + store_char_in_data(r, (*re)[-1]); + break; + } + + r->err_str = "No closing ']' bracket"; +} + +static void +relocate(struct slre *r, int begin, int shift) +{ + emit(r, END); + memmove(r->code + begin + shift, r->code + begin, r->code_size - begin); + r->code_size += shift; +} + +static void +quantifier(struct slre *r, int prev, int op) +{ + if (r->code[prev] == EXACT && r->code[prev + 2] > 1) { + r->code[prev + 2]--; + emit(r, EXACT); + emit(r, r->code[prev + 1] + r->code[prev + 2]); + emit(r, 1); + prev = r->code_size - 3; + } + relocate(r, prev, 2); + r->code[prev] = op; + set_jump_offset(r, prev + 1, prev); +} + +static void +exact_one_char(struct slre *r, int ch) +{ + emit(r, EXACT); + emit(r, r->data_size); + emit(r, 1); + store_char_in_data(r, ch); +} + +static void +fixup_branch(struct slre *r, int fixup) +{ + if (fixup > 0) { + emit(r, END); + set_jump_offset(r, fixup, fixup - 2); + } +} + +static void +compile(struct slre *r, const char **re) +{ + int op, esc, branch_start, last_op, fixup, cap_no, level; + + fixup = 0; + level = r->num_caps; + branch_start = last_op = r->code_size; + + for (;;) + switch (*(*re)++) { + case '\0': + (*re)--; + return; + /* NOTREACHED */ + break; + case '^': + emit(r, BOL); + break; + case '$': + emit(r, EOL); + break; + case '.': + last_op = r->code_size; + emit(r, ANY); + break; + case '[': + last_op = r->code_size; + anyof(r, re); + break; + case '\': + last_op = r->code_size; + esc = get_escape_char(re); + if (esc & 0xff00) + emit(r, esc >> 8); + else + exact_one_char(r, esc); + break; + case '(': + last_op = r->code_size; + cap_no = ++r->num_caps; + emit(r, OPEN); + emit(r, cap_no); + + compile(r, re); + if (*(*re)++ != ')') { + r->err_str = "No closing bracket"; + return; + } + + emit(r, CLOSE); + emit(r, cap_no); + break; + case ')': + (*re)--; + fixup_branch(r, fixup); + if (level == 0) { + r->err_str = "Unbalanced brackets"; + return; + } + return; + /* NOTREACHED */ + break; + case '+': + case '*': + op = (*re)[-1] == '*' ? STAR : PLUS; + if (**re == '?') { + (*re)++; + op = op == STAR ? STARQ : PLUSQ; + } + quantifier(r, last_op, op); + break; + case '?': + quantifier(r, last_op, QUEST); + break; + case '|': + fixup_branch(r, fixup); + relocate(r, branch_start, 3); + r->code[branch_start] = BRANCH; + set_jump_offset(r, branch_start + 1, branch_start); + fixup = branch_start + 2; + r->code[fixup] = 0xff; + break; + default: + (*re)--; + last_op = r->code_size; + exact(r, re); + break; + } +} + +int +slre_compile(struct slre *r, const char *re) +{ + r->err_str = NULL; + r->code_size = r->data_size = r->num_caps = r->anchored = 0; + + if (*re == '^') + r->anchored++; + + emit(r, OPEN); /* This will capture what matches full RE */ + emit(r, 0); + + while (*re != '\0') + compile(r, &re); + + if (r->code[2] == BRANCH) + fixup_branch(r, 4); + + emit(r, CLOSE); + emit(r, 0); + emit(r, END); + + return (r->err_str == NULL ? 1 : 0); +} + +static int match(const struct slre *, int, + const char *, int, int *, struct cap *); + +static void +loop_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs) +{ + int saved_offset, matched_offset; + + saved_offset = matched_offset = *ofs; + + while (match(r, pc + 2, s, len, ofs, NULL)) { + saved_offset = *ofs; + if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL)) + matched_offset = saved_offset; + *ofs = saved_offset; + } + + *ofs = matched_offset; +} + +static void +loop_non_greedy(const struct slre *r, int pc, const char *s, int len, int *ofs) +{ + int saved_offset = *ofs; + + while (match(r, pc + 2, s, len, ofs, NULL)) { + saved_offset = *ofs; + if (match(r, pc + r->code[pc + 1], s, len, ofs, NULL)) + break; + } + + *ofs = saved_offset; +} + +static int +is_any_of(const unsigned char *p, int len, const char *s, int *ofs) +{ + int i, ch; + + ch = s[*ofs]; + + for (i = 0; i < len; i++) + if (p[i] == ch) { + (*ofs)++; + return 1; + } + + return 0; +} + +static int +is_any_but(const unsigned char *p, int len, const char *s, int *ofs) +{ + int i, ch; + + ch = s[*ofs]; + + for (i = 0; i < len; i++) { + if (p[i] == ch) + return 0; + } + + (*ofs)++; + return 1; +} + +static int +match(const struct slre *r, int pc, const char *s, int len, + int *ofs, struct cap *caps) +{ + int n, saved_offset, res = 1; + + while (res && r->code[pc] != END) { + + assert(pc < r->code_size); + assert(pc < (int) (sizeof(r->code) / sizeof(r->code[0]))); + + switch (r->code[pc]) { + case BRANCH: + saved_offset = *ofs; + res = match(r, pc + 3, s, len, ofs, caps); + if (res == 0) { + *ofs = saved_offset; + res = match(r, pc + r->code[pc + 1], + s, len, ofs, caps); + } + pc += r->code[pc + 2]; + break; + case EXACT: + res = 0; + n = r->code[pc + 2]; /* String length */ + if (n <= len - *ofs && !memcmp(s + *ofs, r->data + + r->code[pc + 1], n)) { + (*ofs) += n; + res = 1; + } + pc += 3; + break; + case QUEST: + res = 1; + saved_offset = *ofs; + if (!match(r, pc + 2, s, len, ofs, caps)) + *ofs = saved_offset; + pc += r->code[pc + 1]; + break; + case STAR: + res = 1; + loop_greedy(r, pc, s, len, ofs); + pc += r->code[pc + 1]; + break; + case STARQ: + res = 1; + loop_non_greedy(r, pc, s, len, ofs); + pc += r->code[pc + 1]; + break; + case PLUS: + res = match(r, pc + 2, s, len, ofs, caps); + if (res == 0) + break; + + loop_greedy(r, pc, s, len, ofs); + pc += r->code[pc + 1]; + break; + case PLUSQ: + res = match(r, pc + 2, s, len, ofs, caps); + if (res == 0) + break; + + loop_non_greedy(r, pc, s, len, ofs); + pc += r->code[pc + 1]; + break; + case SPACE: + res = 0; + if (*ofs < len && isspace(((unsigned char *)s)[*ofs])) { + (*ofs)++; + res = 1; + } + pc++; + break; + case NONSPACE: + res = 0; + if (*ofs < len && + !isspace(((unsigned char *)s)[*ofs])) { + (*ofs)++; + res = 1; + } + pc++; + break; + case DIGIT: + res = 0; + if (*ofs < len && isdigit(((unsigned char *)s)[*ofs])) { + (*ofs)++; + res = 1; + } + pc++; + break; + case ANY: + res = 0; + if (*ofs < len) { + (*ofs)++; + res = 1; + } + pc++; + break; + case ANYOF: + res = 0; + if (*ofs < len) + res = is_any_of(r->data + r->code[pc + 1], + r->code[pc + 2], s, ofs); + pc += 3; + break; + case ANYBUT: + res = 0; + if (*ofs < len) + res = is_any_but(r->data + r->code[pc + 1], + r->code[pc + 2], s, ofs); + pc += 3; + break; + case BOL: + res = *ofs == 0 ? 1 : 0; + pc++; + break; + case EOL: + res = *ofs == len ? 1 : 0; + pc++; + break; + case OPEN: + if (caps != NULL) + caps[r->code[pc + 1]].ptr = s + *ofs; + pc += 2; + break; + case CLOSE: + if (caps != NULL) + caps[r->code[pc + 1]].len = (s + *ofs) - + caps[r->code[pc + 1]].ptr; + pc += 2; + break; + case END: + pc++; + break; + default: + printf("unknown cmd (%d) at %d\n", r->code[pc], pc); + assert(0); + break; + } + } + + return res; +} + +int +slre_match(const struct slre *r, const char *buf, int len, + struct cap *caps) +{ + int i, ofs = 0, res = 0; + + if (r->anchored) { + res = match(r, 0, buf, len, &ofs, caps); + } else { + for (i = 0; i < len && res == 0; i++) { + ofs = i; + res = match(r, 0, buf, len, &ofs, caps); + } + } + + return res; +} + +#ifdef SLRE_TEST +#define N_CAPS 5 + +int main(int argc, char *argv[]) +{ + struct slre slre; + struct cap caps[N_CAPS]; + unsigned char data[1 * 1024 * 1024]; + FILE *fp; + int i, res, len; + + if (argc < 2) { + fprintf(stderr, "Usage: %s 'slre' <file>\n", argv[0]); + return 1; + } + + fp = fopen(argv[2], "rb"); + if (fp == NULL) { + fprintf(stderr, "Error: cannot open %s:%s\n", + argv[2], strerror(errno)); + return 1; + } + + if (!slre_compile(&slre, argv[1])) { + fprintf(stderr, "Error compiling slre: %s\n", slre.err_str); + return 1; + } + + slre_dump(&slre, stderr); + + while (fgets(data, sizeof(data), fp) != NULL) { + len = strlen(data); + + if ((len > 0) && (data[len-1] == '\n')) { + data[len-1] = '\0'; + --len; + } + + printf("Data = "%s"\n", data); + + (void) memset(caps, 0, sizeof(caps)); + + res = 0; + + res = slre_match(&slre, data, len, caps); + printf("Result [%d]: %d\n", i, res); + + for (i = 0; i < N_CAPS; i++) { + if (caps[i].len > 0) { + printf("Substring %d: len=%d [%.*s]\n", i, + caps[i].len, + caps[i].len, caps[i].ptr); + } + } + printf("----------------------------------------------------\n"); + } + (void) fclose(fp); + + return 0; +} +#endif /* SLRE_TEST */