Pass a strdup'd ident string to openlog(), to ensure that reallocation

of GUC memory doesn't cause us to start emitting a bogus ident string.
Per report from Han Holl.  Also some trivial code cleanup in write_syslog.

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 62919ffb04c87fe36c268ffe387cfbe30b9bccf1..07b2d007395fdfcf3500de876c7364ee17736303 100644 (file)
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -42,7 +42,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.162 2005/08/12 21:36:59 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.163 2005/10/14 16:41:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,6 +85,7 @@ char     *Syslog_ident;
 
 static void write_syslog(int level, const char *line);
 #endif
+
 #ifdef WIN32
 static void write_eventlog(int level, const char *line);
 #endif
@@ -1152,41 +1153,51 @@ DebugFileOpen(void)
 #endif
 
 /*
- * Write a message line to syslog if the syslog option is set.
- *
- * Our problem here is that many syslog implementations don't handle
- * long messages in an acceptable manner. While this function doesn't
- * help that fact, it does work around by splitting up messages into
- * smaller pieces.
+ * Write a message line to syslog
  */
 static void
 write_syslog(int level, const char *line)
 {
    static bool openlog_done = false;
    static unsigned long seq = 0;
-   static int  syslog_fac = LOG_LOCAL0;
 
-   int         len = strlen(line);
+   int         len;
 
    if (!openlog_done)
    {
+       int     syslog_fac;
+       char   *syslog_ident;
+
        if (pg_strcasecmp(Syslog_facility, "LOCAL0") == 0)
            syslog_fac = LOG_LOCAL0;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL1") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL1") == 0)
            syslog_fac = LOG_LOCAL1;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL2") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL2") == 0)
            syslog_fac = LOG_LOCAL2;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL3") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL3") == 0)
            syslog_fac = LOG_LOCAL3;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL4") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL4") == 0)
            syslog_fac = LOG_LOCAL4;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL5") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL5") == 0)
            syslog_fac = LOG_LOCAL5;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL6") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL6") == 0)
            syslog_fac = LOG_LOCAL6;
-       if (pg_strcasecmp(Syslog_facility, "LOCAL7") == 0)
+       else if (pg_strcasecmp(Syslog_facility, "LOCAL7") == 0)
            syslog_fac = LOG_LOCAL7;
-       openlog(Syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT, syslog_fac);
+       else
+           syslog_fac = LOG_LOCAL0;
+       /*
+        * openlog() usually just stores the passed char pointer as-is,
+        * so we must give it a string that will be unchanged for the life of
+        * the process.  The Syslog_ident GUC variable does not meet this
+        * requirement, so strdup() it.  This isn't a memory leak because
+        * this code is executed at most once per process.
+        */
+       syslog_ident = strdup(Syslog_ident);
+       if (syslog_ident == NULL)           /* out of memory already!? */
+           syslog_ident = "postgres";
+
+       openlog(syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT, syslog_fac);
        openlog_done = true;
    }
 
@@ -1196,8 +1207,16 @@ write_syslog(int level, const char *line)
     */
    seq++;
 
-   /* divide into multiple syslog() calls if message is too long */
-   /* or if the message contains embedded NewLine(s) '\n' */
+   /*
+    * Our problem here is that many syslog implementations don't handle
+    * long messages in an acceptable manner. While this function doesn't
+    * help that fact, it does work around by splitting up messages into
+    * smaller pieces.
+    *
+    * We divide into multiple syslog() calls if message is too long
+    * or if the message contains embedded NewLine(s) '\n'.
+    */
+   len = strlen(line);
    if (len > PG_SYSLOG_LIMIT || strchr(line, '\n') != NULL)
    {
        int         chunk_nr = 0;
@@ -1230,8 +1249,8 @@ write_syslog(int level, const char *line)
            buf[buflen] = '\0';
 
            /* already word boundary? */
-           if (!isspace((unsigned char) line[buflen]) &&
-               line[buflen] != '\0')
+           if (line[buflen] != '\0' &&
+               !isspace((unsigned char) line[buflen]))
            {
                /* try to divide at word boundary */
                i = buflen - 1;
@@ -1259,6 +1278,7 @@ write_syslog(int level, const char *line)
    }
 }
 #endif   /* HAVE_SYSLOG */
+
 #ifdef WIN32
 /*
  * Write a message line to the windows event log