| /* |
| * regcomp and regexec -- regsub and regerror are elsewhere |
| * @(#)regexp.c 1.3 of 18 April 87 |
| * |
| * Copyright (c) 1986 by University of Toronto. |
| * Written by Henry Spencer. Not derived from licensed software. |
| * |
| * Permission is granted to anyone to use this software for any |
| * purpose on any computer system, and to redistribute it freely, |
| * subject to the following restrictions: |
| * |
| * 1. The author is not responsible for the consequences of use of |
| * this software, no matter how awful, even if they arise |
| * from defects in it. |
| * |
| * 2. The origin of this software must not be misrepresented, either |
| * by explicit claim or by omission. |
| * |
| * 3. Altered versions must be plainly marked as such, and must not |
| * be misrepresented as being the original software. |
| * |
| * Beware that some of this code is subtly aware of the way operator |
| * precedence is structured in regular expressions. Serious changes in |
| * regular-expression syntax might require a total rethink. |
| * |
| * This code was modified by Ethan Sommer to work within the kernel |
| * (it now uses kmalloc etc..) |
| * |
| * Modified slightly by Matthew Strait to use more modern C. |
| */ |
| |
| #include "regexp.h" |
| #include "regmagic.h" |
| |
| /* added by ethan and matt. Lets it work in both kernel and user space. |
| (So iptables can use it, for instance.) Yea, it goes both ways... */ |
| #if __KERNEL__ |
| #define malloc(foo) kmalloc(foo,GFP_ATOMIC) |
| #else |
| #define printk(format,args...) printf(format,##args) |
| #endif |
| |
| void regerror(char * s) |
| { |
| printk("<3>Regexp: %s\n", s); |
| /* NOTREACHED */ |
| } |
| |
| /* |
| * The "internal use only" fields in regexp.h are present to pass info from |
| * compile to execute that permits the execute phase to run lots faster on |
| * simple cases. They are: |
| * |
| * regstart char that must begin a match; '\0' if none obvious |
| * reganch is the match anchored (at beginning-of-line only)? |
| * regmust string (pointer into program) that match must include, or NULL |
| * regmlen length of regmust string |
| * |
| * Regstart and reganch permit very fast decisions on suitable starting points |
| * for a match, cutting down the work a lot. Regmust permits fast rejection |
| * of lines that cannot possibly match. The regmust tests are costly enough |
| * that regcomp() supplies a regmust only if the r.e. contains something |
| * potentially expensive (at present, the only such thing detected is * or + |
| * at the start of the r.e., which can involve a lot of backup). Regmlen is |
| * supplied because the test in regexec() needs it and regcomp() is computing |
| * it anyway. |
| */ |
| |
| /* |
| * Structure for regexp "program". This is essentially a linear encoding |
| * of a nondeterministic finite-state machine (aka syntax charts or |
| * "railroad normal form" in parsing technology). Each node is an opcode |
| * plus a "next" pointer, possibly plus an operand. "Next" pointers of |
| * all nodes except BRANCH implement concatenation; a "next" pointer with |
| * a BRANCH on both ends of it is connecting two alternatives. (Here we |
| * have one of the subtle syntax dependencies: an individual BRANCH (as |
| * opposed to a collection of them) is never concatenated with anything |
| * because of operator precedence.) The operand of some types of node is |
| * a literal string; for others, it is a node leading into a sub-FSM. In |
| * particular, the operand of a BRANCH node is the first node of the branch. |
| * (NB this is *not* a tree structure: the tail of the branch connects |
| * to the thing following the set of BRANCHes.) The opcodes are: |
| */ |
| |
| /* definition number opnd? meaning */ |
| #define END 0 /* no End of program. */ |
| #define BOL 1 /* no Match "" at beginning of line. */ |
| #define EOL 2 /* no Match "" at end of line. */ |
| #define ANY 3 /* no Match any one character. */ |
| #define ANYOF 4 /* str Match any character in this string. */ |
| #define ANYBUT 5 /* str Match any character not in this string. */ |
| #define BRANCH 6 /* node Match this alternative, or the next... */ |
| #define BACK 7 /* no Match "", "next" ptr points backward. */ |
| #define EXACTLY 8 /* str Match this string. */ |
| #define NOTHING 9 /* no Match empty string. */ |
| #define STAR 10 /* node Match this (simple) thing 0 or more times. */ |
| #define PLUS 11 /* node Match this (simple) thing 1 or more times. */ |
| #define OPEN 20 /* no Mark this point in input as start of #n. */ |
| /* OPEN+1 is number 1, etc. */ |
| #define CLOSE 30 /* no Analogous to OPEN. */ |
| |
| /* |
| * Opcode notes: |
| * |
| * BRANCH The set of branches constituting a single choice are hooked |
| * together with their "next" pointers, since precedence prevents |
| * anything being concatenated to any individual branch. The |
| * "next" pointer of the last BRANCH in a choice points to the |
| * thing following the whole choice. This is also where the |
| * final "next" pointer of each individual branch points; each |
| * branch starts with the operand node of a BRANCH node. |
| * |
| * BACK Normal "next" pointers all implicitly point forward; BACK |
| * exists to make loop structures possible. |
| * |
| * STAR,PLUS '?', and complex '*' and '+', are implemented as circular |
| * BRANCH structures using BACK. Simple cases (one character |
| * per match) are implemented with STAR and PLUS for speed |
| * and to minimize recursive plunges. |
| * |
| * OPEN,CLOSE ...are numbered at compile time. |
| */ |
| |
| /* |
| * A node is one char of opcode followed by two chars of "next" pointer. |
| * "Next" pointers are stored as two 8-bit pieces, high order first. The |
| * value is a positive offset from the opcode of the node containing it. |
| * An operand, if any, simply follows the node. (Note that much of the |
| * code generation knows about this implicit relationship.) |
| * |
| * Using two bytes for the "next" pointer is vast overkill for most things, |
| * but allows patterns to get big without disasters. |
| */ |
| #define OP(p) (*(p)) |
| #define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377)) |
| #define OPERAND(p) ((p) + 3) |
| |
| /* |
| * See regmagic.h for one further detail of program structure. |
| */ |
| |
| |
| /* |
| * Utility definitions. |
| */ |
| #ifndef CHARBITS |
| #define UCHARAT(p) ((int)*(unsigned char *)(p)) |
| #else |
| #define UCHARAT(p) ((int)*(p)&CHARBITS) |
| #endif |
| |
| #define FAIL(m) { regerror(m); return(NULL); } |
| #define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?') |
| #define META "^$.[()|?+*\\" |
| |
| /* |
| * Flags to be passed up and down. |
| */ |
| #define HASWIDTH 01 /* Known never to match null string. */ |
| #define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */ |
| #define SPSTART 04 /* Starts with * or +. */ |
| #define WORST 0 /* Worst case. */ |
| |
| /* |
| * Global work variables for regcomp(). |
| */ |
| struct match_globals { |
| char *reginput; /* String-input pointer. */ |
| char *regbol; /* Beginning of input, for ^ check. */ |
| char **regstartp; /* Pointer to startp array. */ |
| char **regendp; /* Ditto for endp. */ |
| char *regparse; /* Input-scan pointer. */ |
| int regnpar; /* () count. */ |
| char regdummy; |
| char *regcode; /* Code-emit pointer; ®dummy = don't. */ |
| long regsize; /* Code size. */ |
| }; |
| |
| /* |
| * Forward declarations for regcomp()'s friends. |
| */ |
| #ifndef STATIC |
| #define STATIC static |
| #endif |
| STATIC char *reg(struct match_globals *g, int paren,int *flagp); |
| STATIC char *regbranch(struct match_globals *g, int *flagp); |
| STATIC char *regpiece(struct match_globals *g, int *flagp); |
| STATIC char *regatom(struct match_globals *g, int *flagp); |
| STATIC char *regnode(struct match_globals *g, char op); |
| STATIC char *regnext(struct match_globals *g, char *p); |
| STATIC void regc(struct match_globals *g, char b); |
| STATIC void reginsert(struct match_globals *g, char op, char *opnd); |
| STATIC void regtail(struct match_globals *g, char *p, char *val); |
| STATIC void regoptail(struct match_globals *g, char *p, char *val); |
| |
| |
| __kernel_size_t my_strcspn(const char *s1,const char *s2) |
| { |
| char *scan1; |
| char *scan2; |
| int count; |
| |
| count = 0; |
| for (scan1 = (char *)s1; *scan1 != '\0'; scan1++) { |
| for (scan2 = (char *)s2; *scan2 != '\0';) /* ++ moved down. */ |
| if (*scan1 == *scan2++) |
| return(count); |
| count++; |
| } |
| return(count); |
| } |
| |
| /* |
| - regcomp - compile a regular expression into internal code |
| * |
| * We can't allocate space until we know how big the compiled form will be, |
| * but we can't compile it (and thus know how big it is) until we've got a |
| * place to put the code. So we cheat: we compile it twice, once with code |
| * generation turned off and size counting turned on, and once "for real". |
| * This also means that we don't allocate space until we are sure that the |
| * thing really will compile successfully, and we never have to move the |
| * code and thus invalidate pointers into it. (Note that it has to be in |
| * one piece because free() must be able to free it all.) |
| * |
| * Beware that the optimization-preparation code in here knows about some |
| * of the structure of the compiled regexp. |
| */ |
| regexp * |
| regcomp(char *exp,int *patternsize) |
| { |
| register regexp *r; |
| register char *scan; |
| register char *longest; |
| register int len; |
| int flags; |
| struct match_globals g; |
| |
| /* commented out by ethan |
| extern char *malloc(); |
| */ |
| |
| if (exp == NULL) |
| FAIL("NULL argument"); |
| |
| /* First pass: determine size, legality. */ |
| g.regparse = exp; |
| g.regnpar = 1; |
| g.regsize = 0L; |
| g.regcode = &g.regdummy; |
| regc(&g, MAGIC); |
| if (reg(&g, 0, &flags) == NULL) |
| return(NULL); |
| |
| /* Small enough for pointer-storage convention? */ |
| if (g.regsize >= 32767L) /* Probably could be 65535L. */ |
| FAIL("regexp too big"); |
| |
| /* Allocate space. */ |
| *patternsize=sizeof(regexp) + (unsigned)g.regsize; |
| r = (regexp *)malloc(sizeof(regexp) + (unsigned)g.regsize); |
| if (r == NULL) |
| FAIL("out of space"); |
| |
| /* Second pass: emit code. */ |
| g.regparse = exp; |
| g.regnpar = 1; |
| g.regcode = r->program; |
| regc(&g, MAGIC); |
| if (reg(&g, 0, &flags) == NULL) |
| return(NULL); |
| |
| /* Dig out information for optimizations. */ |
| r->regstart = '\0'; /* Worst-case defaults. */ |
| r->reganch = 0; |
| r->regmust = NULL; |
| r->regmlen = 0; |
| scan = r->program+1; /* First BRANCH. */ |
| if (OP(regnext(&g, scan)) == END) { /* Only one top-level choice. */ |
| scan = OPERAND(scan); |
| |
| /* Starting-point info. */ |
| if (OP(scan) == EXACTLY) |
| r->regstart = *OPERAND(scan); |
| else if (OP(scan) == BOL) |
| r->reganch++; |
| |
| /* |
| * If there's something expensive in the r.e., find the |
| * longest literal string that must appear and make it the |
| * regmust. Resolve ties in favor of later strings, since |
| * the regstart check works with the beginning of the r.e. |
| * and avoiding duplication strengthens checking. Not a |
| * strong reason, but sufficient in the absence of others. |
| */ |
| if (flags&SPSTART) { |
| longest = NULL; |
| len = 0; |
| for (; scan != NULL; scan = regnext(&g, scan)) |
| if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) { |
| longest = OPERAND(scan); |
| len = strlen(OPERAND(scan)); |
| } |
| r->regmust = longest; |
| r->regmlen = len; |
| } |
| } |
| |
| return(r); |
| } |
| |
| /* |
| - reg - regular expression, i.e. main body or parenthesized thing |
| * |
| * Caller must absorb opening parenthesis. |
| * |
| * Combining parenthesis handling with the base level of regular expression |
| * is a trifle forced, but the need to tie the tails of the branches to what |
| * follows makes it hard to avoid. |
| */ |
| static char * |
| reg(struct match_globals *g, int paren, int *flagp /* Parenthesized? */ ) |
| { |
| register char *ret; |
| register char *br; |
| register char *ender; |
| register int parno = 0; /* 0 makes gcc happy */ |
| int flags; |
| |
| *flagp = HASWIDTH; /* Tentatively. */ |
| |
| /* Make an OPEN node, if parenthesized. */ |
| if (paren) { |
| if (g->regnpar >= NSUBEXP) |
| FAIL("too many ()"); |
| parno = g->regnpar; |
| g->regnpar++; |
| ret = regnode(g, OPEN+parno); |
| } else |
| ret = NULL; |
| |
| /* Pick up the branches, linking them together. */ |
| br = regbranch(g, &flags); |
| if (br == NULL) |
| return(NULL); |
| if (ret != NULL) |
| regtail(g, ret, br); /* OPEN -> first. */ |
| else |
| ret = br; |
| if (!(flags&HASWIDTH)) |
| *flagp &= ~HASWIDTH; |
| *flagp |= flags&SPSTART; |
| while (*g->regparse == '|') { |
| g->regparse++; |
| br = regbranch(g, &flags); |
| if (br == NULL) |
| return(NULL); |
| regtail(g, ret, br); /* BRANCH -> BRANCH. */ |
| if (!(flags&HASWIDTH)) |
| *flagp &= ~HASWIDTH; |
| *flagp |= flags&SPSTART; |
| } |
| |
| /* Make a closing node, and hook it on the end. */ |
| ender = regnode(g, (paren) ? CLOSE+parno : END); |
| regtail(g, ret, ender); |
| |
| /* Hook the tails of the branches to the closing node. */ |
| for (br = ret; br != NULL; br = regnext(g, br)) |
| regoptail(g, br, ender); |
| |
| /* Check for proper termination. */ |
| if (paren && *g->regparse++ != ')') { |
| FAIL("unmatched ()"); |
| } else if (!paren && *g->regparse != '\0') { |
| if (*g->regparse == ')') { |
| FAIL("unmatched ()"); |
| } else |
| FAIL("junk on end"); /* "Can't happen". */ |
| /* NOTREACHED */ |
| } |
| |
| return(ret); |
| } |
| |
| /* |
| - regbranch - one alternative of an | operator |
| * |
| * Implements the concatenation operator. |
| */ |
| static char * |
| regbranch(struct match_globals *g, int *flagp) |
| { |
| register char *ret; |
| register char *chain; |
| register char *latest; |
| int flags; |
| |
| *flagp = WORST; /* Tentatively. */ |
| |
| ret = regnode(g, BRANCH); |
| chain = NULL; |
| while (*g->regparse != '\0' && *g->regparse != '|' && *g->regparse != ')') { |
| latest = regpiece(g, &flags); |
| if (latest == NULL) |
| return(NULL); |
| *flagp |= flags&HASWIDTH; |
| if (chain == NULL) /* First piece. */ |
| *flagp |= flags&SPSTART; |
| else |
| regtail(g, chain, latest); |
| chain = latest; |
| } |
| if (chain == NULL) /* Loop ran zero times. */ |
| (void) regnode(g, NOTHING); |
| |
| return(ret); |
| } |
| |
| /* |
| - regpiece - something followed by possible [*+?] |
| * |
| * Note that the branching code sequences used for ? and the general cases |
| * of * and + are somewhat optimized: they use the same NOTHING node as |
| * both the endmarker for their branch list and the body of the last branch. |
| * It might seem that this node could be dispensed with entirely, but the |
| * endmarker role is not redundant. |
| */ |
| static char * |
| regpiece(struct match_globals *g, int *flagp) |
| { |
| register char *ret; |
| register char op; |
| register char *next; |
| int flags; |
| |
| ret = regatom(g, &flags); |
| if (ret == NULL) |
| return(NULL); |
| |
| op = *g->regparse; |
| if (!ISMULT(op)) { |
| *flagp = flags; |
| return(ret); |
| } |
| |
| if (!(flags&HASWIDTH) && op != '?') |
| FAIL("*+ operand could be empty"); |
| *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH); |
| |
| if (op == '*' && (flags&SIMPLE)) |
| reginsert(g, STAR, ret); |
| else if (op == '*') { |
| /* Emit x* as (x&|), where & means "self". */ |
| reginsert(g, BRANCH, ret); /* Either x */ |
| regoptail(g, ret, regnode(g, BACK)); /* and loop */ |
| regoptail(g, ret, ret); /* back */ |
| regtail(g, ret, regnode(g, BRANCH)); /* or */ |
| regtail(g, ret, regnode(g, NOTHING)); /* null. */ |
| } else if (op == '+' && (flags&SIMPLE)) |
| reginsert(g, PLUS, ret); |
| else if (op == '+') { |
| /* Emit x+ as x(&|), where & means "self". */ |
| next = regnode(g, BRANCH); /* Either */ |
| regtail(g, ret, next); |
| regtail(g, regnode(g, BACK), ret); /* loop back */ |
| regtail(g, next, regnode(g, BRANCH)); /* or */ |
| regtail(g, ret, regnode(g, NOTHING)); /* null. */ |
| } else if (op == '?') { |
| /* Emit x? as (x|) */ |
| reginsert(g, BRANCH, ret); /* Either x */ |
| regtail(g, ret, regnode(g, BRANCH)); /* or */ |
| next = regnode(g, NOTHING); /* null. */ |
| regtail(g, ret, next); |
| regoptail(g, ret, next); |
| } |
| g->regparse++; |
| if (ISMULT(*g->regparse)) |
| FAIL("nested *?+"); |
| |
| return(ret); |
| } |
| |
| /* |
| - regatom - the lowest level |
| * |
| * Optimization: gobbles an entire sequence of ordinary characters so that |
| * it can turn them into a single node, which is smaller to store and |
| * faster to run. Backslashed characters are exceptions, each becoming a |
| * separate node; the code is simpler that way and it's not worth fixing. |
| */ |
| static char * |
| regatom(struct match_globals *g, int *flagp) |
| { |
| register char *ret; |
| int flags; |
| |
| *flagp = WORST; /* Tentatively. */ |
| |
| switch (*g->regparse++) { |
| case '^': |
| ret = regnode(g, BOL); |
| break; |
| case '$': |
| ret = regnode(g, EOL); |
| break; |
| case '.': |
| ret = regnode(g, ANY); |
| *flagp |= HASWIDTH|SIMPLE; |
| break; |
| case '[': { |
| register int class; |
| register int classend; |
| |
| if (*g->regparse == '^') { /* Complement of range. */ |
| ret = regnode(g, ANYBUT); |
| g->regparse++; |
| } else |
| ret = regnode(g, ANYOF); |
| if (*g->regparse == ']' || *g->regparse == '-') |
| regc(g, *g->regparse++); |
| while (*g->regparse != '\0' && *g->regparse != ']') { |
| if (*g->regparse == '-') { |
| g->regparse++; |
| if (*g->regparse == ']' || *g->regparse == '\0') |
| regc(g, '-'); |
| else { |
| class = UCHARAT(g->regparse-2)+1; |
| classend = UCHARAT(g->regparse); |
| if (class > classend+1) |
| FAIL("invalid [] range"); |
| for (; class <= classend; class++) |
| regc(g, class); |
| g->regparse++; |
| } |
| } else |
| regc(g, *g->regparse++); |
| } |
| regc(g, '\0'); |
| if (*g->regparse != ']') |
| FAIL("unmatched []"); |
| g->regparse++; |
| *flagp |= HASWIDTH|SIMPLE; |
| } |
| break; |
| case '(': |
| ret = reg(g, 1, &flags); |
| if (ret == NULL) |
| return(NULL); |
| *flagp |= flags&(HASWIDTH|SPSTART); |
| break; |
| case '\0': |
| case '|': |
| case ')': |
| FAIL("internal urp"); /* Supposed to be caught earlier. */ |
| break; |
| case '?': |
| case '+': |
| case '*': |
| FAIL("?+* follows nothing"); |
| break; |
| case '\\': |
| if (*g->regparse == '\0') |
| FAIL("trailing \\"); |
| ret = regnode(g, EXACTLY); |
| regc(g, *g->regparse++); |
| regc(g, '\0'); |
| *flagp |= HASWIDTH|SIMPLE; |
| break; |
| default: { |
| register int len; |
| register char ender; |
| |
| g->regparse--; |
| len = my_strcspn((const char *)g->regparse, (const char *)META); |
| if (len <= 0) |
| FAIL("internal disaster"); |
| ender = *(g->regparse+len); |
| if (len > 1 && ISMULT(ender)) |
| len--; /* Back off clear of ?+* operand. */ |
| *flagp |= HASWIDTH; |
| if (len == 1) |
| *flagp |= SIMPLE; |
| ret = regnode(g, EXACTLY); |
| while (len > 0) { |
| regc(g, *g->regparse++); |
| len--; |
| } |
| regc(g, '\0'); |
| } |
| break; |
| } |
| |
| return(ret); |
| } |
| |
| /* |
| - regnode - emit a node |
| */ |
| static char * /* Location. */ |
| regnode(struct match_globals *g, char op) |
| { |
| register char *ret; |
| register char *ptr; |
| |
| ret = g->regcode; |
| if (ret == &g->regdummy) { |
| g->regsize += 3; |
| return(ret); |
| } |
| |
| ptr = ret; |
| *ptr++ = op; |
| *ptr++ = '\0'; /* Null "next" pointer. */ |
| *ptr++ = '\0'; |
| g->regcode = ptr; |
| |
| return(ret); |
| } |
| |
| /* |
| - regc - emit (if appropriate) a byte of code |
| */ |
| static void |
| regc(struct match_globals *g, char b) |
| { |
| if (g->regcode != &g->regdummy) |
| *g->regcode++ = b; |
| else |
| g->regsize++; |
| } |
| |
| /* |
| - reginsert - insert an operator in front of already-emitted operand |
| * |
| * Means relocating the operand. |
| */ |
| static void |
| reginsert(struct match_globals *g, char op, char* opnd) |
| { |
| register char *src; |
| register char *dst; |
| register char *place; |
| |
| if (g->regcode == &g->regdummy) { |
| g->regsize += 3; |
| return; |
| } |
| |
| src = g->regcode; |
| g->regcode += 3; |
| dst = g->regcode; |
| while (src > opnd) |
| *--dst = *--src; |
| |
| place = opnd; /* Op node, where operand used to be. */ |
| *place++ = op; |
| *place++ = '\0'; |
| *place++ = '\0'; |
| } |
| |
| /* |
| - regtail - set the next-pointer at the end of a node chain |
| */ |
| static void |
| regtail(struct match_globals *g, char *p, char *val) |
| { |
| register char *scan; |
| register char *temp; |
| register int offset; |
| |
| if (p == &g->regdummy) |
| return; |
| |
| /* Find last node. */ |
| scan = p; |
| for (;;) { |
| temp = regnext(g, scan); |
| if (temp == NULL) |
| break; |
| scan = temp; |
| } |
| |
| if (OP(scan) == BACK) |
| offset = scan - val; |
| else |
| offset = val - scan; |
| *(scan+1) = (offset>>8)&0377; |
| *(scan+2) = offset&0377; |
| } |
| |
| /* |
| - regoptail - regtail on operand of first argument; nop if operandless |
| */ |
| static void |
| regoptail(struct match_globals *g, char *p, char *val) |
| { |
| /* "Operandless" and "op != BRANCH" are synonymous in practice. */ |
| if (p == NULL || p == &g->regdummy || OP(p) != BRANCH) |
| return; |
| regtail(g, OPERAND(p), val); |
| } |
| |
| /* |
| * regexec and friends |
| */ |
| |
| |
| /* |
| * Forwards. |
| */ |
| STATIC int regtry(struct match_globals *g, regexp *prog, char *string); |
| STATIC int regmatch(struct match_globals *g, char *prog); |
| STATIC int regrepeat(struct match_globals *g, char *p); |
| |
| #ifdef DEBUG |
| int regnarrate = 0; |
| void regdump(); |
| STATIC char *regprop(char *op); |
| #endif |
| |
| /* |
| - regexec - match a regexp against a string |
| */ |
| int |
| regexec(regexp *prog, char *string) |
| { |
| register char *s; |
| struct match_globals g; |
| |
| /* Be paranoid... */ |
| if (prog == NULL || string == NULL) { |
| printk("<3>Regexp: NULL parameter\n"); |
| return(0); |
| } |
| |
| /* Check validity of program. */ |
| if (UCHARAT(prog->program) != MAGIC) { |
| printk("<3>Regexp: corrupted program\n"); |
| return(0); |
| } |
| |
| /* If there is a "must appear" string, look for it. */ |
| if (prog->regmust != NULL) { |
| s = string; |
| while ((s = strchr(s, prog->regmust[0])) != NULL) { |
| if (strncmp(s, prog->regmust, prog->regmlen) == 0) |
| break; /* Found it. */ |
| s++; |
| } |
| if (s == NULL) /* Not present. */ |
| return(0); |
| } |
| |
| /* Mark beginning of line for ^ . */ |
| g.regbol = string; |
| |
| /* Simplest case: anchored match need be tried only once. */ |
| if (prog->reganch) |
| return(regtry(&g, prog, string)); |
| |
| /* Messy cases: unanchored match. */ |
| s = string; |
| if (prog->regstart != '\0') |
| /* We know what char it must start with. */ |
| while ((s = strchr(s, prog->regstart)) != NULL) { |
| if (regtry(&g, prog, s)) |
| return(1); |
| s++; |
| } |
| else |
| /* We don't -- general case. */ |
| do { |
| if (regtry(&g, prog, s)) |
| return(1); |
| } while (*s++ != '\0'); |
| |
| /* Failure. */ |
| return(0); |
| } |
| |
| /* |
| - regtry - try match at specific point |
| */ |
| static int /* 0 failure, 1 success */ |
| regtry(struct match_globals *g, regexp *prog, char *string) |
| { |
| register int i; |
| register char **sp; |
| register char **ep; |
| |
| g->reginput = string; |
| g->regstartp = prog->startp; |
| g->regendp = prog->endp; |
| |
| sp = prog->startp; |
| ep = prog->endp; |
| for (i = NSUBEXP; i > 0; i--) { |
| *sp++ = NULL; |
| *ep++ = NULL; |
| } |
| if (regmatch(g, prog->program + 1)) { |
| prog->startp[0] = string; |
| prog->endp[0] = g->reginput; |
| return(1); |
| } else |
| return(0); |
| } |
| |
| /* |
| - regmatch - main matching routine |
| * |
| * Conceptually the strategy is simple: check to see whether the current |
| * node matches, call self recursively to see whether the rest matches, |
| * and then act accordingly. In practice we make some effort to avoid |
| * recursion, in particular by going through "ordinary" nodes (that don't |
| * need to know whether the rest of the match failed) by a loop instead of |
| * by recursion. |
| */ |
| static int /* 0 failure, 1 success */ |
| regmatch(struct match_globals *g, char *prog) |
| { |
| register char *scan = prog; /* Current node. */ |
| char *next; /* Next node. */ |
| |
| #ifdef DEBUG |
| if (scan != NULL && regnarrate) |
| fprintf(stderr, "%s(\n", regprop(scan)); |
| #endif |
| while (scan != NULL) { |
| #ifdef DEBUG |
| if (regnarrate) |
| fprintf(stderr, "%s...\n", regprop(scan)); |
| #endif |
| next = regnext(g, scan); |
| |
| switch (OP(scan)) { |
| case BOL: |
| if (g->reginput != g->regbol) |
| return(0); |
| break; |
| case EOL: |
| if (*g->reginput != '\0') |
| return(0); |
| break; |
| case ANY: |
| if (*g->reginput == '\0') |
| return(0); |
| g->reginput++; |
| break; |
| case EXACTLY: { |
| register int len; |
| register char *opnd; |
| |
| opnd = OPERAND(scan); |
| /* Inline the first character, for speed. */ |
| if (*opnd != *g->reginput) |
| return(0); |
| len = strlen(opnd); |
| if (len > 1 && strncmp(opnd, g->reginput, len) != 0) |
| return(0); |
| g->reginput += len; |
| } |
| break; |
| case ANYOF: |
| if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) == NULL) |
| return(0); |
| g->reginput++; |
| break; |
| case ANYBUT: |
| if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) != NULL) |
| return(0); |
| g->reginput++; |
| break; |
| case NOTHING: |
| case BACK: |
| break; |
| case OPEN+1: |
| case OPEN+2: |
| case OPEN+3: |
| case OPEN+4: |
| case OPEN+5: |
| case OPEN+6: |
| case OPEN+7: |
| case OPEN+8: |
| case OPEN+9: { |
| register int no; |
| register char *save; |
| |
| no = OP(scan) - OPEN; |
| save = g->reginput; |
| |
| if (regmatch(g, next)) { |
| /* |
| * Don't set startp if some later |
| * invocation of the same parentheses |
| * already has. |
| */ |
| if (g->regstartp[no] == NULL) |
| g->regstartp[no] = save; |
| return(1); |
| } else |
| return(0); |
| } |
| break; |
| case CLOSE+1: |
| case CLOSE+2: |
| case CLOSE+3: |
| case CLOSE+4: |
| case CLOSE+5: |
| case CLOSE+6: |
| case CLOSE+7: |
| case CLOSE+8: |
| case CLOSE+9: |
| { |
| register int no; |
| register char *save; |
| |
| no = OP(scan) - CLOSE; |
| save = g->reginput; |
| |
| if (regmatch(g, next)) { |
| /* |
| * Don't set endp if some later |
| * invocation of the same parentheses |
| * already has. |
| */ |
| if (g->regendp[no] == NULL) |
| g->regendp[no] = save; |
| return(1); |
| } else |
| return(0); |
| } |
| break; |
| case BRANCH: { |
| register char *save; |
| |
| if (OP(next) != BRANCH) /* No choice. */ |
| next = OPERAND(scan); /* Avoid recursion. */ |
| else { |
| do { |
| save = g->reginput; |
| if (regmatch(g, OPERAND(scan))) |
| return(1); |
| g->reginput = save; |
| scan = regnext(g, scan); |
| } while (scan != NULL && OP(scan) == BRANCH); |
| return(0); |
| /* NOTREACHED */ |
| } |
| } |
| break; |
| case STAR: |
| case PLUS: { |
| register char nextch; |
| register int no; |
| register char *save; |
| register int min; |
| |
| /* |
| * Lookahead to avoid useless match attempts |
| * when we know what character comes next. |
| */ |
| nextch = '\0'; |
| if (OP(next) == EXACTLY) |
| nextch = *OPERAND(next); |
| min = (OP(scan) == STAR) ? 0 : 1; |
| save = g->reginput; |
| no = regrepeat(g, OPERAND(scan)); |
| while (no >= min) { |
| /* If it could work, try it. */ |
| if (nextch == '\0' || *g->reginput == nextch) |
| if (regmatch(g, next)) |
| return(1); |
| /* Couldn't or didn't -- back up. */ |
| no--; |
| g->reginput = save + no; |
| } |
| return(0); |
| } |
| break; |
| case END: |
| return(1); /* Success! */ |
| break; |
| default: |
| printk("<3>Regexp: memory corruption\n"); |
| return(0); |
| break; |
| } |
| |
| scan = next; |
| } |
| |
| /* |
| * We get here only if there's trouble -- normally "case END" is |
| * the terminating point. |
| */ |
| printk("<3>Regexp: corrupted pointers\n"); |
| return(0); |
| } |
| |
| /* |
| - regrepeat - repeatedly match something simple, report how many |
| */ |
| static int |
| regrepeat(struct match_globals *g, char *p) |
| { |
| register int count = 0; |
| register char *scan; |
| register char *opnd; |
| |
| scan = g->reginput; |
| opnd = OPERAND(p); |
| switch (OP(p)) { |
| case ANY: |
| count = strlen(scan); |
| scan += count; |
| break; |
| case EXACTLY: |
| while (*opnd == *scan) { |
| count++; |
| scan++; |
| } |
| break; |
| case ANYOF: |
| while (*scan != '\0' && strchr(opnd, *scan) != NULL) { |
| count++; |
| scan++; |
| } |
| break; |
| case ANYBUT: |
| while (*scan != '\0' && strchr(opnd, *scan) == NULL) { |
| count++; |
| scan++; |
| } |
| break; |
| default: /* Oh dear. Called inappropriately. */ |
| printk("<3>Regexp: internal foulup\n"); |
| count = 0; /* Best compromise. */ |
| break; |
| } |
| g->reginput = scan; |
| |
| return(count); |
| } |
| |
| /* |
| - regnext - dig the "next" pointer out of a node |
| */ |
| static char* |
| regnext(struct match_globals *g, char *p) |
| { |
| register int offset; |
| |
| if (p == &g->regdummy) |
| return(NULL); |
| |
| offset = NEXT(p); |
| if (offset == 0) |
| return(NULL); |
| |
| if (OP(p) == BACK) |
| return(p-offset); |
| else |
| return(p+offset); |
| } |
| |
| #ifdef DEBUG |
| |
| STATIC char *regprop(); |
| |
| /* |
| - regdump - dump a regexp onto stdout in vaguely comprehensible form |
| */ |
| void |
| regdump(regexp *r) |
| { |
| register char *s; |
| register char op = EXACTLY; /* Arbitrary non-END op. */ |
| register char *next; |
| /* extern char *strchr(); */ |
| |
| |
| s = r->program + 1; |
| while (op != END) { /* While that wasn't END last time... */ |
| op = OP(s); |
| printf("%2d%s", s-r->program, regprop(s)); /* Where, what. */ |
| next = regnext(s); |
| if (next == NULL) /* Next ptr. */ |
| printf("(0)"); |
| else |
| printf("(%d)", (s-r->program)+(next-s)); |
| s += 3; |
| if (op == ANYOF || op == ANYBUT || op == EXACTLY) { |
| /* Literal string, where present. */ |
| while (*s != '\0') { |
| putchar(*s); |
| s++; |
| } |
| s++; |
| } |
| putchar('\n'); |
| } |
| |
| /* Header fields of interest. */ |
| if (r->regstart != '\0') |
| printf("start `%c' ", r->regstart); |
| if (r->reganch) |
| printf("anchored "); |
| if (r->regmust != NULL) |
| printf("must have \"%s\"", r->regmust); |
| printf("\n"); |
| } |
| |
| /* |
| - regprop - printable representation of opcode |
| */ |
| static char * |
| regprop(char *op) |
| { |
| #define BUFLEN 50 |
| register char *p; |
| static char buf[BUFLEN]; |
| |
| strcpy(buf, ":"); |
| |
| switch (OP(op)) { |
| case BOL: |
| p = "BOL"; |
| break; |
| case EOL: |
| p = "EOL"; |
| break; |
| case ANY: |
| p = "ANY"; |
| break; |
| case ANYOF: |
| p = "ANYOF"; |
| break; |
| case ANYBUT: |
| p = "ANYBUT"; |
| break; |
| case BRANCH: |
| p = "BRANCH"; |
| break; |
| case EXACTLY: |
| p = "EXACTLY"; |
| break; |
| case NOTHING: |
| p = "NOTHING"; |
| break; |
| case BACK: |
| p = "BACK"; |
| break; |
| case END: |
| p = "END"; |
| break; |
| case OPEN+1: |
| case OPEN+2: |
| case OPEN+3: |
| case OPEN+4: |
| case OPEN+5: |
| case OPEN+6: |
| case OPEN+7: |
| case OPEN+8: |
| case OPEN+9: |
| snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "OPEN%d", OP(op)-OPEN); |
| p = NULL; |
| break; |
| case CLOSE+1: |
| case CLOSE+2: |
| case CLOSE+3: |
| case CLOSE+4: |
| case CLOSE+5: |
| case CLOSE+6: |
| case CLOSE+7: |
| case CLOSE+8: |
| case CLOSE+9: |
| snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "CLOSE%d", OP(op)-CLOSE); |
| p = NULL; |
| break; |
| case STAR: |
| p = "STAR"; |
| break; |
| case PLUS: |
| p = "PLUS"; |
| break; |
| default: |
| printk("<3>Regexp: corrupted opcode\n"); |
| break; |
| } |
| if (p != NULL) |
| strncat(buf, p, BUFLEN-strlen(buf)); |
| return(buf); |
| } |
| #endif |
| |
| |