Add support for using standard regular expression library.

2 files changed, 139 insertions, 12 deletions

diff --git a/configure.in b/configure.in
index b4d83d2..fbaa423 100644
--- a/configure.in
+++ b/configure.in
@@ -19,21 +19,29 @@ AC_ARG_ENABLE(debug,
         [Compile binaries in debug mode]))
 
 if test "$enable_debug" = "yes"; then
-  CFLAGS="$CFLAGS -g -O0 -Wall"
-  AC_DEFINE_UNQUOTED(_DEBUG, 1, [In debug mode])
-  echo "enabling debug compile mode"
+    CFLAGS="$CFLAGS -g -O0 -Wall"
+    AC_DEFINE_UNQUOTED(_DEBUG, 1, [In debug mode])
+    echo "enabling debug compile mode"
 fi
 
 # Some checks for libraries
 AC_CHECK_LIB(bsnmp, snmp_close, , 
     [echo "Couldn't find the bsnmp library"; exit 1])
-AC_CHECK_LIB(pcre, pcre_compile, , 
-    [echo "Couldn't find the pcre library"; exit 1])
-    
+
 # Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS("pcre.h", , 
-    [echo "Couldn't find pcre headers"; exit 1])
+
+AC_ARG_ENABLE(pcre,
+        AC_HELP_STRING([--with-pcre],
+        [Use PCRE instead of the default regular expression library]))
+        
+if test "$enable_pcre" = "yes"; then
+    AC_CHECK_LIB(pcre, pcre_compile, , 
+        [echo "Couldn't find the pcre library"; exit 1])
+    AC_CHECK_HEADERS("pcre.h", , 
+        [echo "Couldn't find pcre headers"; exit 1])
+    AC_DEFINE_UNQUOTED(WITH_PCRE, 1, [Use PCRE regular expression library])
+fi
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
diff --git a/src/bsnmp-regex.c b/src/bsnmp-regex.c
index 091fbf8..cf06114 100644
--- a/src/bsnmp-regex.c
+++ b/src/bsnmp-regex.c
@@ -12,7 +12,12 @@
 #include <fcntl.h>
 
 #include <bsnmp/snmpmod.h>
+
+#ifdef WITH_PCRE
 #include <pcre.h>
+#else
+#include <regex.h>
+#endif
 
 #include "regex_tree.h"
 #include "regex_oid.h"
@@ -43,8 +48,12 @@ struct data_entry {
     int                     type;
     char                    *descr;
 
+#ifdef WITH_PCRE
     pcre                    *regex;
     pcre_extra              *extra;
+#else
+    regex_t                 regex;
+#endif
     char                    *result;
 
     uint64_t                last_update;
@@ -139,6 +148,53 @@ getcurrticks ()
     return t;
 }
 
+#ifndef WITH_PCRE
+
+static const char*
+regex_msg (int code)
+{
+    ASSERT (code != 0);
+
+    switch (code) {
+    case REG_NOMATCH:
+        return "The regexec() function failed to match";
+    case REG_BADPAT:
+        return "invalid regular expression";
+    case REG_ECOLLATE:
+        return "invalid collating element";
+    case REG_ECTYPE:
+        return "invalid character class";
+    case REG_EESCAPE:
+        return "'\' applied to unescapable character";
+    case REG_ESUBREG:
+        return "invalid backreference number";
+    case REG_EBRACK:
+        return "brackets '[ ]' not balanced";
+    case REG_EPAREN:
+        return "parentheses '( )' not balanced";
+    case REG_EBRACE:
+        return "braces '{ }' not balanced";
+    case REG_BADBR:
+        return "invalid repetition count(s) in '{ }'";
+    case REG_ERANGE:
+        return "invalid character range in '[ ]'";
+    case REG_ESPACE:
+        return "ran out of memory";
+    case REG_BADRPT:
+        return "'?', '*', or '+' operand invalid";
+    case REG_EMPTY:
+        return "empty (sub)expression";
+    case REG_ILLSEQ:
+        return "illegal byte sequence (bad multibyte character)";
+
+    case REG_ASSERT:
+    case REG_INVARG:
+    default:
+        return "internal or unknown error";
+    }
+}
+
+#endif /* WITH_PCRE */
 
 /* -----------------------------------------------------------------------------
  * MATCHING
@@ -186,7 +242,11 @@ process_match (struct data_entry *data, char *result)
 
 static char*
 process_result (struct data_entry *data, char *line, int len,
-                int *ovector, int substrings)
+#ifdef WITH_PCRE
+    int *ovector, int substrings)
+#else
+    regmatch_t *pm)
+#endif
 {
     char *result;
     char *p, *t;
@@ -208,6 +268,7 @@ process_result (struct data_entry *data, char *line, int len,
                 continue;
             idx = p[0] - '0';
             ASSERT (idx >= 0 && idx <= 9);
+#ifdef WITH_PCRE
             if (idx < substrings) {
                 ASSERT (ovector[(idx * 2) + 1] >= ovector[idx * 2]);
                 ASSERT (ovector[(idx * 2) + 1] < len);
@@ -215,6 +276,15 @@ process_result (struct data_entry *data, char *line, int len,
                 rlen += (ovector[(idx * 2) + 1]) - (ovector[idx * 2]);
                 rlen += 1;
             }
+#else /* WITH_PCRE */
+            if (pm[idx].rm_so != -1 && pm[idx].rm_eo != -1) {
+                ASSERT (pm[idx].rm_eo >= pm[idx].rm_so);
+                ASSERT (pm[idx].rm_eo < len);
+                ASSERT (pm[idx].rm_so < len);
+                rlen += (pm[idx].rm_eo - pm[idx].rm_so);
+                rlen += 1;
+            }
+#endif /* WITH_PCRE */
         }
     }
 
@@ -229,11 +299,20 @@ process_result (struct data_entry *data, char *line, int len,
             p++;
             if (isdigit(p[0])) {
                 idx = p[0] - '0';
+#ifdef WITH_PCRE
                 if (idx < substrings) {
                     l = (ovector[(idx * 2) + 1]) - (ovector[idx * 2]);
                     memcpy (t, line + (ovector[idx * 2]), l);
                     t += l;
                 }
+#else /* WITH_PCRE */
+                if (pm[idx].rm_so != -1 && pm[idx].rm_eo != -1) {
+                    l = pm[idx].rm_eo - pm[idx].rm_so;
+                    memcpy (t, line + pm[idx].rm_so, l);
+                    t += l;
+                }
+#endif /* WITH _PCRE */
+
                 continue;
             }
         }
@@ -249,16 +328,22 @@ static void
 process_log (char *line, int len)
 {
     struct data_entry *data;
-    int ovector[30];
     char *result;
     int r;
 
+#ifdef WITH_PCRE
+    int ovector[30];
+#else
+    regmatch_t pm[10];
+#endif
+
     for (data = TAILQ_FIRST (&entries); data;
          data = TAILQ_NEXT (data, link)) {
 
-        memset (ovector, 0, sizeof (ovector));
         result = NULL;
 
+#ifdef WITH_PCRE
+        memset (ovector, 0, sizeof (ovector));
         r = pcre_exec (data->regex, data->extra, line, len, 0,
                        PCRE_NOTEMPTY | PCRE_NO_UTF8_CHECK, ovector, 30);
 
@@ -273,6 +358,19 @@ process_log (char *line, int len)
         }
 
         result = process_result (data, line, len, ovector, r);
+
+#else
+        r = regexec (&(data->regex), line, 10, pm, 0);
+        if (r == REG_NOMATCH)
+            continue;
+        else if (r != 0) {
+            emsg ("internal error in matching code: %d", r);
+            return;
+        }
+
+        result = process_result (data, line, len, pm);
+#endif
+
         process_match (data, result);
         free (result);
     }
@@ -402,10 +500,15 @@ open_fifo ()
 static void
 config_free (struct data_entry *data)
 {
+#ifdef WITH_PCRE
     if (data->regex)
         free (data->regex);
     if (data->extra)
         free (data->extra);
+#else
+    regfree (&(data->regex));
+#endif
+
     free (data);
 }
 
@@ -423,9 +526,14 @@ static int
 config_entry (struct data_entry *data, char *name, char type, char *regex,
               char *result, char *flags, int line)
 {
+#ifdef WITH_PCRE
     const char *errptr;
     int erroffset;
     int options = 0;
+#else
+    int options = REG_EXTENDED;
+    int r;
+#endif
 
     ASSERT (regex);
     ASSERT (flags);
@@ -452,7 +560,11 @@ config_entry (struct data_entry *data, char *name, char type, char *regex,
     for (; *flags; flags++) {
         switch (flags[0]) {
         case 'i':
+#ifdef WITH_PCRE
             options |= PCRE_CASELESS;
+#else
+            options |= REG_ICASE;
+#endif
             break;
         default:
             emsg ("[line %d] invalid flag: %c", line, flags[0]);
@@ -464,14 +576,21 @@ config_entry (struct data_entry *data, char *name, char type, char *regex,
     data->descr = name;
 
     /* Parse the regex */
+#ifdef WITH_PCRE
     data->regex = pcre_compile (regex, options, &errptr, &erroffset, NULL);
     if (!data->regex) {
         emsg ("[line %d] invalid regular expression: %s", line, errptr);
         return -1;
     }
-
     /* Optimize the regex, ignore errors */
     data->extra = pcre_study (data->regex, 0, &errptr);
+#else
+    r = regcomp (&(data->regex), regex, options);
+    if (r != 0) {
+        emsg ("[line %d] invalid regular expression: %s", line, regex_msg (r));
+        return -1;
+    }
+#endif
 
     /* Replacement data */
     if (data->type != TYPE_COUNTER && !result) {