commit 7392333a9cf5eac64aa28c36007e3e8831afc306
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date: Tue Feb 14 13:51:08 2023 +0100
vbt: Format back-traces from libvarnish
This is done in a VSB to match what the panic code is currently doing.
When libunwind is used but fails to produce a back-trace, there is now
a fallback to the original libexecinfo-based implementation (suggested
by @asadsa92).
diff --git a/include/Makefile.am b/include/Makefile.am
index 1a68ab4a3..ad4bc2555 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -88,8 +88,8 @@ nobase_pkginclude_HEADERS += \
# Private headers
nobase_noinst_HEADERS = \
compat/daemon.h \
- vfl.h \
libvcc.h \
+ vbt.h \
vcc_interface.h \
vcli_serve.h \
vcs_version.h \
@@ -99,6 +99,7 @@ nobase_noinst_HEADERS = \
vend.h \
vev.h \
vfil.h \
+ vfl.h \
vin.h \
vjsn.h \
vlu.h \
diff --git a/include/vbt.h b/include/vbt.h
new file mode 100644
index 000000000..bd3a384b9
--- /dev/null
+++ b/include/vbt.h
@@ -0,0 +1,33 @@
+/*-
+ * Copyright (c) 2022 Varnish Software AS
+ * All rights reserved.
+ *
+ * Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+struct vsb;
+
+void VBT_format(struct vsb *);
diff --git a/lib/libvarnish/Makefile.am b/lib/libvarnish/Makefile.am
index d06f1b5b2..221091110 100644
--- a/lib/libvarnish/Makefile.am
+++ b/lib/libvarnish/Makefile.am
@@ -18,6 +18,7 @@ libvarnish_la_SOURCES = \
vbh.c \
vas.c \
vav.c \
+ vbt.c \
vcli_proto.c \
vcli_serve.c \
vct.c \
@@ -46,6 +47,11 @@ libvarnish_la_SOURCES = \
libvarnish_la_LIBADD = @PCRE2_LIBS@ $(LIBM)
+if WITH_UNWIND
+libvarnish_la_CFLAGS += -DUNW_LOCAL_ONLY $(LIBUNWIND_CFLAGS)
+libvarnish_la_LIBADD += $(LIBUNWIND_LIBS)
+endif
+
TESTS = \
vav_test \
vbh_test \
diff --git a/lib/libvarnish/vbt.c b/lib/libvarnish/vbt.c
new file mode 100644
index 000000000..4a2da2c27
--- /dev/null
+++ b/lib/libvarnish/vbt.c
@@ -0,0 +1,143 @@
+/*-
+ * Copyright (c) 2006 Verdens Gang AS
+ * Copyright (c) 2006-2022 Varnish Software AS
+ * All rights reserved.
+ *
+ * Author: Poul-Henning Kamp <phk at phk.freebsd.dk>
+ * Author: Guillaume Quintard <guillaume at varnish-software.com>
+ * Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#ifdef WITH_UNWIND
+# include <libunwind.h>
+#endif
+
+#include <execinfo.h>
+
+#include "vdef.h"
+#include "vas.h"
+#include "vbt.h"
+#include "vsb.h"
+
+#ifdef WITH_UNWIND
+static int
+vbt_unwind(struct vsb *vsb)
+{
+ unw_cursor_t cursor; unw_context_t uc;
+ unw_word_t ip, sp;
+ unw_word_t offp;
+ char fname[1024];
+ const char *sep;
+ int ret;
+
+ ret = unw_getcontext(&uc);
+ if (ret != 0) {
+ VSB_printf(vsb, "Backtrace not available "
+ "(unw_getcontext returned %d)\n", ret);
+ return (-1);
+ }
+ ret = unw_init_local(&cursor, &uc);
+ if (ret != 0) {
+ VSB_printf(vsb, "Backtrace not available "
+ "(unw_init_local returned %d)\n", ret);
+ return (-1);
+ }
+ while (unw_step(&cursor) > 0) {
+ fname[0] = '\0';
+ sep = "";
+ if (!unw_get_reg(&cursor, UNW_REG_IP, &ip)) {
+ VSB_printf(vsb, "ip=0x%lx", (long) ip);
+ sep = " ";
+ }
+ if (!unw_get_reg(&cursor, UNW_REG_SP, &sp)) {
+ VSB_printf(vsb, "%ssp=0x%lx", sep, (long) sp);
+ sep = " ";
+ }
+ if (!unw_get_proc_name(&cursor, fname, sizeof(fname), &offp)) {
+ VSB_printf(vsb, "%s<%s+0x%lx>",
+ sep, fname[0] ? fname : "<unknown>", (long)offp);
+ }
+ VSB_putc(vsb, '\n');
+ }
+
+ return (0);
+}
+#endif
+
+#define BACKTRACE_LEVELS 20
+
+static void
+vbt_execinfo(struct vsb *vsb)
+{
+ void *array[BACKTRACE_LEVELS];
+ size_t size;
+ size_t i;
+ char **strings;
+ char *p;
+ char buf[32];
+
+ size = backtrace (array, BACKTRACE_LEVELS);
+ if (size > BACKTRACE_LEVELS) {
+ VSB_printf(vsb, "Backtrace not available (ret=%zu)\n", size);
+ return;
+ }
+ for (i = 0; i < size; i++) {
+ bprintf(buf, "%p", array[i]);
+ VSB_printf(vsb, "%s: ", buf);
+ strings = backtrace_symbols(&array[i], 1);
+ if (strings == NULL || strings[0] == NULL) {
+ VSB_cat(vsb, "(?)");
+ } else {
+ p = strings[0];
+ if (!memcmp(buf, p, strlen(buf))) {
+ p += strlen(buf);
+ if (*p == ':')
+ p++;
+ while (*p == ' ')
+ p++;
+ }
+ VSB_cat(vsb, p);
+ }
+ VSB_cat(vsb, "\n");
+ free(strings);
+ }
+}
+
+void
+VBT_format(struct vsb *vsb)
+{
+
+#ifdef WITH_UNWIND
+ if (!vbt_unwind(vsb))
+ return;
+ VSB_cat(vsb, "Falling back to execinfo backtrace\n");
+#endif
+ vbt_execinfo(vsb);
+}