Add log_context

fdqueue.c

@@ -314,6 +314,8 @@ static void call_alarm(struct sched_ent *alarm, int revents)
   
   alarm->poll.revents = revents;
   alarm->function(alarm);
+
+  strbuf_reset(&log_context);
   
   if (call_stats.totals)
     fd_func_exit(__HERE__, &call_stats);

log.c

@@ -101,6 +101,11 @@ static time_t _log_file_start_time;
 static char _log_file_buf[8192];
 static struct strbuf _log_file_strbuf = STRUCT_STRBUF_EMPTY;
 
+/* The log context is a string that can be set as a prefix to all subsequent log messages.
+ */
+static char _log_context[16];
+struct strbuf log_context = STRUCT_STRBUF_INIT_STATIC(_log_context);
+
 #ifdef ANDROID
 /* Static variables for sending log output to the Android log.
  *
@@ -206,6 +211,28 @@ static void _log_prefix_level(_log_iterator *it, int level)
   xprintf(it->xpf, "%-6.6s", levelstr);
 }
 
+static void _log_prefix_context(_log_iterator *it)
+{
+  if (it->config->show_pid)
+    xprintf(it->xpf, "[%5u] ", getpid());
+  if (it->config->show_time) {
+    if (it->tv.tv_sec == 0) {
+      xputs("NOTIME______ ", it->xpf);
+    } else {
+      char buf[50];
+      if (strftime(buf, sizeof buf, "%T", &it->tm) == 0)
+	xputs("EMPTYTIME___ ", it->xpf);
+      else
+	xprintf(it->xpf, "%s.%03u ", buf, (unsigned int)it->tv.tv_usec / 1000);
+    }
+  }
+  if (_log_context[0]) {
+    xputs("[", it->xpf);
+    xputs(_log_context, it->xpf);
+    xputs("] ", it->xpf);
+  }
+}
+
 static void _log_prefix(_log_iterator *it, int level)
 {
   if (it->config == &config_file) {
@@ -228,19 +255,7 @@ static void _log_prefix(_log_iterator *it, int level)
   }
   else
     abort();
-  if (it->config->show_pid)
-    xprintf(it->xpf, "[%5u] ", getpid());
-  if (it->config->show_time) {
-    if (it->tv.tv_sec == 0) {
-      xputs("NOTIME______ ", it->xpf);
-    } else {
-      char buf[50];
-      if (strftime(buf, sizeof buf, "%T", &it->tm) == 0)
-	xputs("EMPTYTIME___ ", it->xpf);
-      else
-	xprintf(it->xpf, "%s.%03u ", buf, (unsigned int)it->tv.tv_usec / 1000);
-    }
-  }
+  _log_prefix_context(it);
 }
 
 static void _log_prefix_whence(_log_iterator *it, struct __sourceloc whence)

log.h

@@ -54,6 +54,10 @@ void disable_log_stderr();
 void logFlush();
 void logConfigChanged();
 
+// Logging context string.
+struct strbuf;
+extern struct strbuf log_context;
+
 // Logging primitives.
 void vlogMessage(int level, struct __sourceloc whence, const char *fmt, va_list);
 int logBacktrace(int level, struct __sourceloc whence);

log_context.c

@@ -0,0 +1,27 @@
+/*
+Serval DNA logging
+Copyright 2015 Serval Project Inc.
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+*/
+
+// This compilation unit provides an initialised log_context strbuf for clients that do not provide
+// their own.
+
+#include "log.h"
+#include "strbuf.h"
+
+static char _log_context[16];
+struct strbuf log_context = STRUCT_STRBUF_INIT_STATIC(_log_context);

sourcefiles.mk

@@ -34,6 +34,7 @@ SERVAL_CLIENT_SOURCES = \
 # These objects do not belong in the Serval DNA daemon but are available for
 # client applications.
 SERVAL_LIB_SOURCES = \
+	log_context.c \
 	log_stderr.c
 
 # These source files are imported and do not depend on any local header files.
@@ -107,6 +108,7 @@ TEST_SOURCES = \
 	commandline.c \
 	main.c \
 	test_cli.c \
+	log_context.c \
 	log_stderr.c \
 	context1.c
 	

strbuf.h

@@ -110,6 +110,20 @@ struct strbuf {
  */
 #define STRUCT_STRBUF_EMPTY ((struct strbuf){NULL, NULL, NULL})
 
+/* Constant for initialising a struct strbuf to a static backing buffer:
+ *      char buf[n];
+ *      struct strbuf ssb = STRUCT_STRBUF_INIT_STATIC(buf);
+ * Immediately following this assignment, the following properties hold:
+ *      strbuf_is_empty(&ssb)
+ *      strbuf_len(&ssb) == 0
+ *      strbuf_count(&ssb) == 0
+ *      strbuf_str(&ssb) == buf
+ *      strbuf_size(sb) == n
+ *
+ * @author Andrew Bettison <andrew@servalproject.com>
+ */
+#define STRUCT_STRBUF_INIT_STATIC(B) ((struct strbuf){(B), (B) + sizeof(B) - 1, (B)})
+
 typedef struct strbuf *strbuf;
 typedef const struct strbuf *const_strbuf;