Regular expression pattern matching and replacements

1 files changed, 110 insertions, 10 deletions

diff --git a/src/bsnmp-regex.c b/src/bsnmp-regex.c
index 93b9ac2..72b12b2 100644
--- a/src/bsnmp-regex.c
+++ b/src/bsnmp-regex.c
@@ -123,7 +123,114 @@ strtrim (char* data)
 }
 
 /* -----------------------------------------------------------------------------
- * LOG READING AND MATCHING
+ * MATCHING
+ */
+
+static int
+process_match (struct data_entry *data, char *result)
+{
+fprintf (stderr, "match for %s: %s\n", data->descr, result ? result : "MATCH");
+    return 0;
+}
+
+static char*
+process_result (struct data_entry *data, char *line, int len,
+                int *ovector, int substrings)
+{
+    char *result;
+    char *p, *t;
+    int rlen, l;
+    int idx;
+
+    /* Some nice little optimizations */
+    if (!data->result)
+        return NULL;
+    if (strchr (data->result, '\\') == NULL)
+        return strdup (data->result);
+
+    /* Figure out the string length */
+    rlen = strlen (data->result) + 1;
+    for (p = data->result; *p; p++) {
+        if(p[0] == '\\') {
+            p++;
+            if(p[0] == '\\' || !isdigit(p[0]))
+                continue;
+            idx = p[0] - '0';
+            ASSERT (idx >= 0 && idx <= 9);
+            if (idx < substrings) {
+                ASSERT (ovector[(idx * 2) + 1] >= ovector[idx * 2]);
+                ASSERT (ovector[(idx * 2) + 1] < len);
+                ASSERT (ovector[idx * 2] < len);
+                rlen += (ovector[(idx * 2) + 1]) - (ovector[idx * 2]);
+                rlen += 1;
+            }
+        }
+    }
+
+    result = (char*)calloc(rlen, 1);
+    if (!result) {
+        emsg ("out of memory");
+        return NULL;
+    }
+
+    for (p = data->result, t = result; *p; p++) {
+        if (p[0] == '\\') {
+            p++;
+            if (isdigit(p[0])) {
+                idx = p[0] - '0';
+                if (idx < substrings) {
+                    l = (ovector[(idx * 2) + 1]) - (ovector[idx * 2]);
+                    memcpy (t, line + (ovector[idx * 2]), l);
+                    t += l;
+                }
+                continue;
+            }
+        }
+
+        *t++ = *p;
+    }
+
+    *t = 0;
+    return result;
+}
+
+static void
+process_log (char *line, int len)
+{
+    struct data_entry *data;
+    int ovector[30];
+    char *result;
+    int r;
+
+    for (data = TAILQ_FIRST (&entries); data;
+         data = TAILQ_NEXT (data, link)) {
+
+        memset (ovector, 0, sizeof (ovector));
+        result = NULL;
+
+        r = pcre_exec (data->regex, data->extra, line, len, 0,
+                       PCRE_NOTEMPTY | PCRE_NO_UTF8_CHECK, ovector, 30);
+
+        if (r == PCRE_ERROR_NOMATCH)
+            continue;
+        else if (r == PCRE_ERROR_NOMEMORY) {
+            emsg ("out of memory");
+            return;
+        } else if (r < 0) {
+            emsg ("internal error in matching code: %d", r);
+            return;
+        }
+
+        result = process_result (data, line, len, ovector, r);
+        process_match (data, result);
+        free (result);
+    }
+
+    fprintf (stderr, "log line: %s\n", line);
+}
+
+/* -----------------------------------------------------------------------------
+ * LOG READING
  */
 
 static void
@@ -143,12 +250,6 @@ close_fifo ()
 }
 
 static void
-process_log (char *line)
-{
-    fprintf (stderr, "log line: %s\n", line);
-}
-
-static void
 receive_log (int fd, void *data)
 {
     char *t;
@@ -187,12 +288,12 @@ receive_log (int fd, void *data)
             *t = 0;
             if (line_buffer != t && *(t - 1) == '\r')
                 *(t - 1) = 0;
+            l = (t + 1) - line_buffer;
 
             /* Send it off */
-            process_log (line_buffer);
+            process_log (line_buffer, l);
 
             /* Move data to front of buffer */
-            l = (t + 1) - line_buffer;
             ASSERT (l <= len);
             memmove (line_buffer, t + 1, (len - l) + 1);
             len -= l;
@@ -730,7 +831,6 @@ module_fini (void)
     close_fifo ();
     config_free_all ();
 
-
     return 0;
 }