I noticed that regex invoked alloca with unbounded size. Rather
than use the allocsa module I thought it better to stick to glibc
style, and define __libc_use_alloca when _LIBC isn't defined.
I installed this (and filed glibc bug 1245):
2005-08-25 Paul Eggert <[EMAIL PROTECTED]>
* config/srclist.txt: Add glibc bug 1245.
* lib/regexec.c (set_regs): Don't alloca with an unbounded size.
alloca modernization/simplification for regex.
* lib/regex.c: Remove portability cruft for alloca. This no longer
needs to be at the start of the file, and can be moved into
regex_internal.h and simplified.
* lib/regex_internal.h: Include <alloca.h>.
(__libc_use_alloca) [!defined _LIBC]: New macro.
* lib/regexec.c (build_trtable): Remove "#ifdef _LIBC",
since the code now works outside glibc.
--- config/srclist.txt.~1.86.~ 2005-08-25 13:39:57.000000000 -0700
+++ config/srclist.txt 2005-08-25 22:55:59.000000000 -0700
@@ -105,6 +105,7 @@ $LIBCSRC/stdlib/getsubopt.c lib gpl
#$LIBCSRC/posix/regcomp.c lib gpl
#
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1238
+# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1245
#$LIBCSRC/posix/regex.c lib gpl
#
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1201
@@ -128,6 +129,7 @@ $LIBCSRC/stdlib/getsubopt.c lib gpl
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1221
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1237
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1241
+# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1245
#$LIBCSRC/posix/regex_internal.h lib gpl
#
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1216
@@ -137,6 +139,7 @@ $LIBCSRC/stdlib/getsubopt.c lib gpl
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1231
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1237
# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1241
+# http://sources.redhat.com/bugzilla/show_bug.cgi?id=1245
#$LIBCSRC/posix/regexec.c lib gpl
#
# c89 changes $LIBCSRC/string/strdup.c lib gpl
--- lib/regex.c 24 Aug 2005 23:43:01 -0000 1.91
+++ lib/regex.c 26 Aug 2005 05:41:47 -0000
@@ -21,30 +21,6 @@
#include "config.h"
#endif
-#ifdef _AIX
-#pragma alloca
-#else
-# ifndef allocax /* predefined by HP cc +Olibcalls */
-# ifdef __GNUC__
-# define alloca(size) __builtin_alloca (size)
-# else
-# if HAVE_ALLOCA_H
-# include <alloca.h>
-# else
-# ifdef __hpux
- void *alloca ();
-# else
-# if !defined __OS2__ && !defined WIN32
- char *alloca ();
-# else
-# include <malloc.h> /* OS/2 defines alloca in here */
-# endif
-# endif
-# endif
-# endif
-# endif
-#endif
-
#ifdef _LIBC
/* We have to keep the namespace clean. */
# define regfree(preg) __regfree (preg)
--- lib/regex_internal.h 25 Aug 2005 20:39:57 -0000 1.4
+++ lib/regex_internal.h 26 Aug 2005 05:41:47 -0000
@@ -431,6 +431,21 @@ static unsigned char re_string_fetch_byt
#define re_string_skip_bytes(pstr,idx) ((pstr)->cur_idx += (idx))
#define re_string_set_index(pstr,idx) ((pstr)->cur_idx = (idx))
+#include <alloca.h>
+
+#ifndef __LIBC
+# if HAVE_ALLOCA
+/* The OS usually guarantees only one guard page at the bottom of the stack,
+ and a page size can be as small as 4096 bytes. So we cannot safely
+ allocate anything larger than 4096 bytes. Also care for the possibility
+ of a few compiler-allocated temporary stack slots. */
+# define __libc_use_alloca(n) ((n) < 4032)
+# else
+/* alloca is implemented with malloc, so just use malloc. */
+# define __libc_use_alloca(n) 0
+# endif
+#endif
+
#define re_malloc(t,n) ((t *) malloc ((n) * sizeof (t)))
#define re_calloc(t,n) ((t *) calloc (n, sizeof (t)))
#define re_realloc(p,t,n) ((t *) realloc (p, (n) * sizeof (t)))
--- lib/regexec.c 25 Aug 2005 20:39:57 -0000 1.8
+++ lib/regexec.c 26 Aug 2005 05:41:47 -0000
@@ -1354,6 +1354,7 @@ set_regs (const regex_t *preg, const re_
struct re_fail_stack_t *fs;
struct re_fail_stack_t fs_body = { 0, 2, NULL };
regmatch_t *prev_idx_match;
+ int prev_idx_match_malloced = 0;
#ifdef DEBUG
assert (nmatch > 1);
@@ -1372,7 +1373,18 @@ set_regs (const regex_t *preg, const re_
cur_node = dfa->init_node;
re_node_set_init_empty (&eps_via_nodes);
- prev_idx_match = (regmatch_t *) alloca (sizeof (regmatch_t) * nmatch);
+ if (__libc_use_alloca (nmatch * sizeof (regmatch_t)))
+ prev_idx_match = (regmatch_t *) alloca (nmatch * sizeof (regmatch_t));
+ else
+ {
+ prev_idx_match = re_malloc (regmatch_t, nmatch);
+ if (prev_idx_match == NULL)
+ {
+ free_fail_stack_return (fs);
+ return REG_ESPACE;
+ }
+ prev_idx_match_malloced = 1;
+ }
memcpy (prev_idx_match, pmatch, sizeof (regmatch_t) * nmatch);
for (idx = pmatch[0].rm_so; idx <= pmatch[0].rm_eo ;)
@@ -1390,6 +1402,8 @@ set_regs (const regex_t *preg, const re_
if (reg_idx == nmatch)
{
re_node_set_free (&eps_via_nodes);
+ if (prev_idx_match_malloced)
+ re_free (prev_idx_match);
return free_fail_stack_return (fs);
}
cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
@@ -1398,6 +1412,8 @@ set_regs (const regex_t *preg, const re_
else
{
re_node_set_free (&eps_via_nodes);
+ if (prev_idx_match_malloced)
+ re_free (prev_idx_match);
return REG_NOERROR;
}
}
@@ -1411,6 +1427,8 @@ set_regs (const regex_t *preg, const re_
if (BE (cur_node == -2, 0))
{
re_node_set_free (&eps_via_nodes);
+ if (prev_idx_match_malloced)
+ re_free (prev_idx_match);
free_fail_stack_return (fs);
return REG_ESPACE;
}
@@ -1420,11 +1438,15 @@ set_regs (const regex_t *preg, const re_
else
{
re_node_set_free (&eps_via_nodes);
+ if (prev_idx_match_malloced)
+ re_free (prev_idx_match);
return REG_NOMATCH;
}
}
}
re_node_set_free (&eps_via_nodes);
+ if (prev_idx_match_malloced)
+ re_free (prev_idx_match);
return free_fail_stack_return (fs);
}
@@ -3235,12 +3257,10 @@ build_trtable (re_dfa_t *dfa, re_dfastat
from `state'. `dests_node[i]' represents the nodes which i-th
destination state contains, and `dests_ch[i]' represents the
characters which i-th destination state accepts. */
-#ifdef _LIBC
if (__libc_use_alloca ((sizeof (re_node_set) + sizeof (bitset)) * SBC_MAX))
dests_node = (re_node_set *)
alloca ((sizeof (re_node_set) + sizeof (bitset)) * SBC_MAX);
else
-#endif
{
dests_node = (re_node_set *)
malloc ((sizeof (re_node_set) + sizeof (bitset)) * SBC_MAX);
@@ -3273,13 +3293,11 @@ build_trtable (re_dfa_t *dfa, re_dfastat
if (BE (err != REG_NOERROR, 0))
goto out_free;
-#ifdef _LIBC
if (__libc_use_alloca ((sizeof (re_node_set) + sizeof (bitset)) * SBC_MAX
+ ndests * 3 * sizeof (re_dfastate_t *)))
dest_states = (re_dfastate_t **)
alloca (ndests * 3 * sizeof (re_dfastate_t *));
else
-#endif
{
dest_states = (re_dfastate_t **)
malloc (ndests * 3 * sizeof (re_dfastate_t *));
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