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authorSzabolcs Nagy <nsz@port70.net>2016-11-24 01:44:49 +0100
committerRich Felker <dalias@aerifal.cx>2016-12-16 23:26:29 -0500
commit7a4c25d78030b3a43ed5c8dd1a456f73cb990f44 (patch)
treee4855beab38f5f84fd4b5d35f88748bdae78b454 /src
parentadfe682eb0d77c6afc751f5e407d9da39623c24e (diff)
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handle ^ and $ in BRE subexpression start and end as anchors
In BRE, ^ is an anchor at the beginning of an expression, optionally it may be an anchor at the beginning of a subexpression and must be treated as a literal otherwise. Previously musl treated ^ in subexpressions as literal, but at least glibc and gnu sed treats it as an anchor and that's the more useful behaviour: it can always be escaped to get back the literal meaning. Same for $ at the end of a subexpression. Portable BRE should not rely on this, but there are sed commands in build scripts which do. This changes the meaning of the BREs: \(^a\) \(a\|^b\) \(a$\) \(a$\|b\)
Diffstat (limited to 'src')
-rw-r--r--src/regex/regcomp.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/src/regex/regcomp.c b/src/regex/regcomp.c
index 65f2fd0b..5a7b53a7 100644
--- a/src/regex/regcomp.c
+++ b/src/regex/regcomp.c
@@ -401,8 +401,8 @@ typedef struct {
tre_ast_node_t *n;
/* Position in the regexp pattern after a parse function returns. */
const char *s;
- /* The first character of the regexp. */
- const char *re;
+ /* The first character of the last subexpression parsed. */
+ const char *start;
/* Current submatch ID. */
int submatch_id;
/* Current position (number of literal). */
@@ -876,14 +876,14 @@ static reg_errcode_t parse_atom(tre_parse_ctx_t *ctx, const char *s)
break;
case '^':
/* '^' has a special meaning everywhere in EREs, and at beginning of BRE. */
- if (!ere && s != ctx->re)
+ if (!ere && s != ctx->start)
goto parse_literal;
node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_BOL, -1);
s++;
break;
case '$':
- /* '$' is special everywhere in EREs, and in the end of the string in BREs. */
- if (!ere && s[1])
+ /* '$' is special everywhere in EREs, and at the end of a BRE subexpression. */
+ if (!ere && s[1] && (s[1]!='\\'|| (s[2]!=')' && s[2]!='|')))
goto parse_literal;
node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_EOL, -1);
s++;
@@ -944,7 +944,7 @@ static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
{
tre_ast_node_t *nbranch=0, *nunion=0;
int ere = ctx->cflags & REG_EXTENDED;
- const char *s = ctx->re;
+ const char *s = ctx->start;
int subid = 0;
int depth = 0;
reg_errcode_t err;
@@ -962,6 +962,7 @@ static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
s++;
depth++;
nbranch = nunion = 0;
+ ctx->start = s;
continue;
}
if ((!ere && *s == '\\' && s[1] == ')') ||
@@ -994,8 +995,8 @@ static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
if (*s=='\\')
s++;
- /* handle ^* at the start of a complete BRE. */
- if (!ere && s==ctx->re+1 && s[-1]=='^')
+ /* handle ^* at the start of a BRE. */
+ if (!ere && s==ctx->start+1 && s[-1]=='^')
break;
/* extension: multiple consecutive *+?{,} is unspecified,
@@ -1038,8 +1039,10 @@ static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
if (c == '\\' && s[1] == '|') {
s+=2;
+ ctx->start = s;
} else if (c == '|') {
s++;
+ ctx->start = s;
} else {
if (c == '\\') {
if (!depth) return REG_EPAREN;
@@ -2705,7 +2708,7 @@ regcomp(regex_t *restrict preg, const char *restrict regex, int cflags)
memset(&parse_ctx, 0, sizeof(parse_ctx));
parse_ctx.mem = mem;
parse_ctx.stack = stack;
- parse_ctx.re = regex;
+ parse_ctx.start = regex;
parse_ctx.cflags = cflags;
parse_ctx.max_backref = -1;
errcode = tre_parse(&parse_ctx);