Print stack trace on assert() failure or when calling fatal_error()

Note: this uses the __sanitizer_print_stack_trace() function from the
AddressSanitizer runtime, so it only works when AddressSanitizer is
in use.

base64.c

@@ -4,12 +4,12 @@
 #include <string.h>
 #include <stdint.h>
 #include <stdbool.h>
-#include <assert.h>
 #include <errno.h>
 
 #define LOG_MODULE "base64"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 
 enum {
     P = 1 << 6, // Padding byte (=)

client.c

@@ -4,7 +4,6 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <unistd.h>
-#include <assert.h>
 #include <getopt.h>
 #include <signal.h>
 #include <errno.h>
@@ -16,6 +15,7 @@
 #define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "client-protocol.h"
+#include "debug.h"
 #include "foot-features.h"
 #include "version.h"
 #include "xmalloc.h"

config.c

@@ -6,7 +6,6 @@
 #include <stdbool.h>
 #include <ctype.h>
 #include <unistd.h>
-#include <assert.h>
 #include <errno.h>
 #include <pwd.h>
 #include <fcntl.h>
@@ -21,6 +20,7 @@
 #define LOG_MODULE "config"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 #include "input.h"
 #include "macros.h"
 #include "tokenize.h"

csi.c

@@ -3,7 +3,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <assert.h>
 #include <errno.h>
 
 #if defined(_DEBUG)
@@ -16,6 +15,7 @@
 #define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "config.h"
+#include "debug.h"
 #include "grid.h"
 #include "selection.h"
 #include "sixel.h"

debug.c

@@ -0,0 +1,48 @@
+#include "debug.h"
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+
+#if defined(__SANITIZE_ADDRESS__) || HAS_FEATURE(address_sanitizer)
+#include <sanitizer/asan_interface.h>
+#define ASAN_ENABLED 1
+#endif
+
+static void
+print_stack_trace(void)
+{
+#ifdef ASAN_ENABLED
+    fputs("\nStack trace:\n", stderr);
+    __sanitizer_print_stack_trace();
+#endif
+}
+
+noreturn void
+fatal_error(const char *msg, int err)
+{
+    syslog(LOG_ERR, "%s: %s", msg, strerror(err));
+    errno = err;
+    perror(msg);
+    print_stack_trace();
+    abort();
+}
+
+noreturn void
+bug(const char *file, int line, const char *func, const char *fmt, ...)
+{
+    fprintf(stderr, "\n%s:%d: BUG in %s(): ", file, line, func);
+
+    va_list ap;
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    fputc('\n', stderr);
+    print_stack_trace();
+    fflush(stderr);
+    abort();
+}

debug.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include "macros.h"
+
+#ifdef NDEBUG
+    #define BUG(...) UNREACHABLE()
+#else
+    #define BUG(...) bug(__FILE__, __LINE__, __func__, __VA_ARGS__)
+#endif
+
+#undef assert
+
+#define assert(x) do { \
+    IGNORE_WARNING("-Wtautological-compare") \
+    if (unlikely(!(x))) { \
+        BUG("assertion failed: '%s'", #x); \
+    } \
+    UNIGNORE_WARNINGS \
+} while (0)
+
+#ifndef static_assert
+    #if __STDC_VERSION__ >= 201112L
+        #define static_assert(x, msg) _Static_assert((x), msg)
+    #elif GNUC_AT_LEAST(4, 6) || HAS_EXTENSION(c_static_assert)
+        #define static_assert(x, msg) __extension__ _Static_assert((x), msg)
+    #else
+        #define static_assert(x, msg)
+    #endif
+#endif
+
+noreturn void fatal_error(const char *msg, int err) COLD;
+noreturn void bug(const char *file, int line, const char *func, const char *fmt, ...) PRINTF(4) COLD;

fdm.c

@@ -5,7 +5,6 @@
 #include <inttypes.h>
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 #include <fcntl.h>
 
 #include <sys/epoll.h>
@@ -15,6 +14,7 @@
 #define LOG_MODULE "fdm"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 
 struct handler {
     int fd;

grid.c

@@ -1,11 +1,11 @@
 #include "grid.h"
 
 #include <string.h>
-#include <assert.h>
 
 #define LOG_MODULE "grid"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 #include "macros.h"
 #include "sixel.h"
 #include "util.h"

log.c

@@ -1,15 +1,15 @@
 #include "log.h"
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <stdarg.h>
-#include <string.h>
-#include <stdbool.h>
 #include <errno.h>
-#include <assert.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
 #include <unistd.h>
 
-#include <syslog.h>
+#include "debug.h"
 
 static bool colorize = false;
 static bool do_syslog = true;

macros.h

@@ -27,6 +27,21 @@
     #define HAS_BUILTIN(x) 0
 #endif
 
+#ifdef __has_feature
+    #define HAS_FEATURE(x) __has_feature(x)
+#else
+    #define HAS_FEATURE(x) 0
+#endif
+
+// __has_extension() is a Clang macro used to determine if a feature is
+// available even if not standardized in the current "-std" mode.
+#ifdef __has_extension
+    #define HAS_EXTENSION(x) __has_extension(x)
+#else
+    // Clang versions prior to 3.0 only supported __has_feature()
+    #define HAS_EXTENSION(x) HAS_FEATURE(x)
+#endif
+
 #if GNUC_AT_LEAST(3, 0) || HAS_ATTRIBUTE(unused) || defined(__TINYC__)
     #define UNUSED __attribute__((__unused__))
 #else
@@ -139,11 +154,11 @@
 #define XSTRDUP XMALLOC NONNULL_ARGS
 
 #if __STDC_VERSION__ >= 201112L
-    #define NORETURN _Noreturn
+    #define noreturn _Noreturn
 #elif GNUC_AT_LEAST(3, 0)
-    #define NORETURN __attribute__((__noreturn__))
+    #define noreturn __attribute__((__noreturn__))
 #else
-    #define NORETURN
+    #define noreturn
 #endif
 
 #if CLANG_AT_LEAST(3, 6)

meson.build

@@ -106,6 +106,7 @@ version = custom_target(
 
 misc = static_library(
   'misc',
+  'debug.c', 'debug.h',
   'hsl.c', 'hsl.h',
   'log.c', 'log.h',
   'macros.h',
@@ -180,6 +181,7 @@ executable(
 executable(
   'footclient',
   'client.c', 'client-protocol.h',
+  'debug.c', 'debug.h',
   'foot-features.h',
   'log.c', 'log.h',
   'macros.h',

reaper.c

@@ -5,11 +5,12 @@
 #include <sys/epoll.h>
 #include <sys/wait.h>
 #include <sys/signalfd.h>
+#include <tllist.h>
 
 #define LOG_MODULE "reaper"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
-#include "tllist.h"
+#include "debug.h"
 
 struct child {
     pid_t pid;

search.c

@@ -593,7 +593,6 @@ execute_binding(struct seat *seat, struct terminal *term,
     case BIND_ACTION_SEARCH_EDIT_LEFT_WORD: {
         size_t diff = distance_prev_word(term);
         term->search.cursor -= diff;
-        assert(term->search.cursor >= 0);
         assert(term->search.cursor <= term->search.len);
         return false;
     }
@@ -606,7 +605,6 @@ execute_binding(struct seat *seat, struct terminal *term,
     case BIND_ACTION_SEARCH_EDIT_RIGHT_WORD: {
         size_t diff = distance_next_word(term);
         term->search.cursor += diff;
-        assert(term->search.cursor >= 0);
         assert(term->search.cursor <= term->search.len);
         return false;
     }

shm.c

@@ -2,7 +2,6 @@
 
 #include <stdio.h>
 #include <string.h>
-#include <assert.h>
 #include <errno.h>
 #include <unistd.h>
 #include <limits.h>
@@ -22,6 +21,7 @@
 #define LOG_MODULE "shm"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 #include "macros.h"
 #include "xmalloc.h"
 

sixel.c

@@ -6,6 +6,7 @@
 #define LOG_MODULE "sixel"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 #include "render.h"
 #include "hsl.h"
 #include "util.h"

slave.c

@@ -6,7 +6,6 @@
 #include <ctype.h>
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 #include <signal.h>
 #include <termios.h>
 
@@ -18,6 +17,7 @@
 #define LOG_ENABLE_DBG 0
 #include "log.h"
 
+#include "debug.h"
 #include "terminal.h"
 #include "tokenize.h"
 #include "xmalloc.h"

spawn.c

@@ -2,7 +2,6 @@
 
 #include <unistd.h>
 #include <errno.h>
-#include <assert.h>
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -11,6 +10,7 @@
 #define LOG_MODULE "spawn"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 
 bool
 spawn(struct reaper *reaper, const char *cwd, char *const argv[],

terminal.c

@@ -3,7 +3,6 @@
 #include <malloc.h>
 #include <string.h>
 #include <unistd.h>
-#include <assert.h>
 #include <errno.h>
 
 #include <sys/stat.h>
@@ -22,6 +21,7 @@
 
 #include "async.h"
 #include "config.h"
+#include "debug.h"
 #include "extract.h"
 #include "grid.h"
 #include "ime.h"

terminal.h

@@ -12,6 +12,7 @@
 #include <fcft/fcft.h>
 
 //#include "config.h"
+#include "debug.h"
 #include "fdm.h"
 #include "macros.h"
 #include "reaper.h"

uri.c

@@ -4,11 +4,11 @@
 #include <string.h>
 #include <limits.h>
 #include <unistd.h>
-#include <assert.h>
 
 #define LOG_MODULE "uri"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
+#include "debug.h"
 #include "xmalloc.h"
 
 enum {

vt.c

@@ -3,13 +3,13 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <assert.h>
 
 #define LOG_MODULE "vt"
 #define LOG_ENABLE_DBG 0
 #include "log.h"
 #include "csi.h"
 #include "dcs.h"
+#include "debug.h"
 #include "grid.h"
 #include "osc.h"
 #include "util.h"

xmalloc.c

@@ -1,21 +1,11 @@
-#include <assert.h>
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
-#include <syslog.h>
 #include "xmalloc.h"
-
+#include "debug.h"
-static NORETURN COLD void
-fatal_error(const char *msg, int err)
-{
-    syslog(LOG_ERR, "%s: %s", msg, strerror(err));
-    errno = err;
-    perror(msg);
-    abort();
-}
 
 static void *
 check_alloc(void *alloc)

xsnprintf.c

@@ -1,8 +1,8 @@
 #include "xsnprintf.h"
 
-#include <assert.h>
 #include <limits.h>
 #include <stdio.h>
+#include "debug.h"
 
 size_t
 xvsnprintf(char *buf, size_t n, const char *format, va_list ap)