Make room in the shared memory segment for a panic string

buffer.

Replace the default libvarnish assert handler with a child specific
function.

This function which fills the static panic string and copy the
result to the shared memory panicstring.

In the manager process, report the content of the panic string
when the child dies.


git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@2971 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache.h

@@ -514,6 +514,9 @@ void THR_Name(const char *name);
 void THR_SetSession(const struct sess *sp);
 const struct sess * THR_GetSession(void);
 
+/* cache_panic.c */
+void PAN_Init(void);
+
 /* cache_pipe.c */
 void PipeSession(struct sess *sp);
 
@@ -537,7 +540,6 @@ void SES_RefSrcAddr(struct sess *sp);
 void SES_Charge(struct sess *sp);
 
 /* cache_shmlog.c */
-
 void VSL_Init(void);
 #ifdef SHMLOGHEAD_MAGIC
 void VSL(enum shmlogtag tag, int id, const char *fmt, ...);

bin/varnishd/cache_main.c

@@ -94,6 +94,7 @@ child_main(void)
 
 	THR_Name("cache-main");
 
+	PAN_Init();
 	CLI_Init();
 	Fetch_Init();
 

bin/varnishd/cache_panic.c

@@ -48,6 +48,8 @@
  * (gdb) printf "%s", panicstr
  */
 char panicstr[65536];
+static struct vsb vsps, *vsp;
+
 static char *pstr = panicstr;
 
 #define fp(...)							\
@@ -240,3 +242,41 @@ panic(const char *file, int line, const char *func,
 }
 
 #endif
+
+static void
+pan_ic(const char *func, const char *file, int line, const char *cond, int err, int xxx)
+{
+	int l;
+	char *p;
+
+	if (xxx) {
+		vsb_printf(vsp,
+		    "Missing errorhandling code in %s(), %s line %d:\n"
+		    "  Condition(%s) not true.\n",
+		    func, file, line, cond);
+	} else {
+		vsb_printf(vsp,
+		    "Assert error in %s(), %s line %d:\n"
+		    "  Condition(%s) not true.\n",
+		    func, file, line, cond);
+	}
+	if (err)
+		vsb_printf(vsp,
+		    "  errno = %d (%s)\n", err, strerror(err));
+
+	VSL_Panic(&l, &p);
+	if (l < vsb_len(vsp))
+		l = vsb_len(vsp);
+	memcpy(p, panicstr, l);
+	abort();
+}
+
+
+void
+PAN_Init(void)
+{
+
+	lbv_assert = pan_ic;
+	vsp = &vsps;
+	AN(vsb_new(vsp, panicstr, sizeof panicstr, VSB_FIXEDLEN));
+}

bin/varnishd/common.h

@@ -35,6 +35,8 @@ struct sockaddr;
 /* cache_acceptor.c */
 void VCA_tweak_acceptor(struct cli *cli, const char *arg);
 
+/* shmlog.c */
+void VSL_Panic(int *len, char **ptr);
 
 /* shmlog.c */
 void VSL_MgtInit(const char *fn, unsigned size);

bin/varnishd/mgt_child.c

@@ -375,6 +375,20 @@ mgt_stop_child(void)
 
 /*--------------------------------------------------------------------*/
 
+static void
+mgt_report_panic(pid_t r)
+{
+	int l;
+	char *p;
+
+	VSL_Panic(&l, &p);
+	if (*p == '\0')
+		return;
+	REPORT(LOG_ERR, "Child (%d) Panic message: %s", r, p);
+}
+
+/*--------------------------------------------------------------------*/
+
 static int
 mgt_sigchld(const struct vev *e, int what)
 {
@@ -411,6 +425,8 @@ mgt_sigchld(const struct vev *e, int what)
 	REPORT(LOG_INFO, "%s", vsb_data(vsb));
 	vsb_delete(vsb);
 
+	mgt_report_panic(r);
+
 	child_pid = -1;
 
 	if (child_state == CH_RUNNING) {

bin/varnishd/shmlog.c

@@ -264,6 +264,20 @@ WSL(struct worker *w, enum shmlogtag tag, int id, const char *fmt, ...)
 
 /*--------------------------------------------------------------------*/
 
+void
+VSL_Panic(int *len, char **ptr)
+{
+
+	AN(len);
+	AN(ptr);
+	assert(loghead->magic == SHMLOGHEAD_MAGIC);
+	assert(loghead->hdrsize == sizeof *loghead);
+	*len = sizeof(loghead->panicstr);
+	*ptr = loghead->panicstr;
+}
+
+/*--------------------------------------------------------------------*/
+
 void
 VSL_Init(void)
 {
@@ -274,6 +288,7 @@ VSL_Init(void)
 	logstart = (unsigned char *)loghead + loghead->start;
 	MTX_INIT(&vsl_mtx);
 	loghead->starttime = TIM_real();
+	loghead->panicstr[0] = '\0';
 	memset(VSL_stats, 0, sizeof *VSL_stats);
 }
 

include/shmlog.h

@@ -63,6 +63,9 @@ struct shmloghead {
 	unsigned		ptr;
 
 	struct varnish_stats	stats;
+
+	/* Panic message buffer */
+	char			panicstr[64 * 1024];
 };
 
 /*