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 62919ff..07b2d00 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