[PATCH] Use opaque struct rather than char * in regex.h

[Vladimir 'φ-coder/phcoder' Serbinenko]

Hello, all. It's a common problem when program attempts to access
unaligned pointer. On x86 this usually goes unnoticed but on other CPUs
it results in segmentation fault. -Wcast-align is a good way to check
that no such problem occurs. Unfortunately regex module breaks the
invariants by casting char * to a re_dfa_t *. Attached patch fixes it

-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko


diff --git a/lib/regcomp.c b/lib/regcomp.c
index 311f2d5..0ddff4c 100644
--- a/lib/regcomp.c
+++ b/lib/regcomp.c
@@ -778,7 +778,7 @@ re_compile_internal (regex_t *preg, const char * pattern, size_t length,
       if (dfa == NULL)
 	return REG_ESPACE;
       preg->allocated = sizeof (re_dfa_t);
-      preg->buffer = (unsigned char *) dfa;
+      preg->buffer = dfa;
     }
   preg->used = sizeof (re_dfa_t);
 
diff --git a/lib/regex.h b/lib/regex.h
index c1cd613..5317017 100644
--- a/lib/regex.h
+++ b/lib/regex.h
@@ -419,12 +419,15 @@ typedef enum
 # define __REPB_PREFIX(name) __##name
 #endif
 
+struct re_dfa_t;
+typedef struct re_dfa_t re_dfa_t;
+
 struct re_pattern_buffer
 {
   /* Space that holds the compiled pattern.  It is declared as
      'unsigned char *' because its elements are sometimes used as
      array indexes.  */
-  unsigned char *__REPB_PREFIX(buffer);
+  re_dfa_t *__REPB_PREFIX(buffer);
 
   /* Number of bytes to which 'buffer' points.  */
   __re_long_size_t __REPB_PREFIX(allocated);
diff --git a/lib/regex_internal.h b/lib/regex_internal.h
index 2b9f697..b91c5c5 100644
--- a/lib/regex_internal.h
+++ b/lib/regex_internal.h
@@ -410,8 +410,6 @@ struct re_string_t
 typedef struct re_string_t re_string_t;
 
 
-struct re_dfa_t;
-typedef struct re_dfa_t re_dfa_t;
 
 #ifndef _LIBC
 # define internal_function

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