Add option libbfd support for tracing code

CONFIG_WPA_TRACE=y and CONFIG_WPA_TRACE_BFD=y can now be used to get
even more complete symbols (func/file/line and inline functions) for
backtraces.

hostapd/Makefile

@@ -51,6 +51,13 @@ CFLAGS += -DHOSTAPD
 ifdef CONFIG_WPA_TRACE
 CFLAGS += -DWPA_TRACE
 OBJS += ../src/utils/trace.o
+LDFLAGS += -rdynamic
+CFLAGS += -funwind-tables
+ifdef CONFIG_WPA_TRACE_BFD
+CFLAGS += -DWPA_TRACE_BFD
+LIBS += -lbfd
+LIBS_c += -lbfd
+endif
 endif
 
 OBJS += ../src/utils/eloop.o
@@ -725,7 +732,7 @@ OBJS_c += ../src/utils/trace.o
 OBJS_c += ../src/utils/wpa_debug.o
 endif
 hostapd_cli: $(OBJS_c)
-	$(CC) $(LDFLAGS) -o hostapd_cli $(OBJS_c)
+	$(CC) $(LDFLAGS) -o hostapd_cli $(OBJS_c) $(LIBS_c)
 
 NOBJS = nt_password_hash.o ../src/crypto/ms_funcs.o $(SHA1OBJS) ../src/crypto/rc4.o ../src/crypto/md5.o
 ifdef CONFIG_INTERNAL_MD5

src/utils/trace.c

@@ -19,16 +19,228 @@
 
 #ifdef WPA_TRACE
 
+#ifdef WPA_TRACE_BFD
+#include <bfd.h>
+#include <demangle.h>
+
+static char *prg_fname = NULL;
+static bfd *cached_abfd = NULL;
+static asymbol **syms = NULL;
+
+static void get_prg_fname(void)
+{
+	char exe[50], fname[512];
+	int len;
+	os_snprintf(exe, sizeof(exe) - 1, "/proc/%u/exe", getpid());
+	len = readlink(exe, fname, sizeof(fname) - 1);
+	if (len < 0 || len >= (int) sizeof(fname)) {
+		perror("readlink");
+		return;
+	}
+	fname[len] = '\0';
+	prg_fname = strdup(fname);
+}
+
+
+static bfd * open_bfd(const char *fname)
+{
+	bfd *abfd;
+	char **matching;
+
+	abfd = bfd_openr(prg_fname, NULL);
+	if (abfd == NULL) {
+		wpa_printf(MSG_INFO, "bfd_openr failed");
+		return NULL;
+	}
+
+	if (bfd_check_format(abfd, bfd_archive)) {
+		wpa_printf(MSG_INFO, "bfd_check_format failed");
+		bfd_close(abfd);
+		return NULL;
+	}
+
+	if (!bfd_check_format_matches(abfd, bfd_object, &matching)) {
+		wpa_printf(MSG_INFO, "bfd_check_format_matches failed");
+		free(matching);
+		bfd_close(abfd);
+		return NULL;
+	}
+
+	return abfd;
+}
+
+
+static void read_syms(bfd *abfd)
+{
+	long storage, symcount;
+	bfd_boolean dynamic = FALSE;
+
+	if (syms)
+		return;
+
+	if (!(bfd_get_file_flags(abfd) & HAS_SYMS)) {
+		wpa_printf(MSG_INFO, "No symbols");
+		return;
+	}
+
+	storage = bfd_get_symtab_upper_bound(abfd);
+	if (storage == 0) {
+		storage = bfd_get_dynamic_symtab_upper_bound(abfd);
+		dynamic = TRUE;
+	}
+	if (storage < 0) {
+		wpa_printf(MSG_INFO, "Unknown symtab upper bound");
+		return;
+	}
+
+	syms = malloc(storage);
+	if (syms == NULL) {
+		wpa_printf(MSG_INFO, "Failed to allocate memory for symtab "
+			   "(%ld bytes)", storage);
+		return;
+	}
+	if (dynamic)
+		symcount = bfd_canonicalize_dynamic_symtab(abfd, syms);
+	else
+		symcount = bfd_canonicalize_symtab(abfd, syms);
+	if (symcount < 0) {
+		wpa_printf(MSG_INFO, "Failed to canonicalize %ssymtab",
+			   dynamic ? "dynamic " : "");
+		free(syms);
+		syms = NULL;
+		return;
+	}
+	wpa_printf(MSG_INFO, "BFD: Read %ld symbols (%ld bytes)",
+		   symcount, storage);
+}
+
+
+struct bfd_data {
+	bfd_vma pc;
+	bfd_boolean found;
+	const char *filename;
+	const char *function;
+	unsigned int line;
+};
+
+
+static void find_addr_sect(bfd *abfd, asection *section, void *obj)
+{
+	struct bfd_data *data = obj;
+	bfd_vma vma;
+	bfd_size_type size;
+
+	if (data->found)
+		return;
+
+	if (!(bfd_get_section_vma(abfd, section)))
+		return;
+
+	vma = bfd_get_section_vma(abfd, section);
+	if (data->pc < vma)
+		return;
+
+	size = bfd_get_section_size(section);
+	if (data->pc >= vma + size)
+		return;
+
+	data->found = bfd_find_nearest_line(abfd, section, syms,
+					    data->pc - vma,
+					    &data->filename,
+					    &data->function,
+					    &data->line);
+}
+
+
+static void wpa_trace_bfd_addr(void *pc)
+{
+	bfd *abfd = cached_abfd;
+	struct bfd_data data;
+	const char *name;
+	char *aname = NULL;
+	const char *filename;
+
+	if (abfd == NULL)
+		return;
+
+	data.pc = (bfd_vma) pc;
+	data.found = FALSE;
+	bfd_map_over_sections(abfd, find_addr_sect, &data);
+
+	if (!data.found)
+		return;
+
+	do {
+		if (data.function)
+			aname = bfd_demangle(abfd, data.function,
+					     DMGL_ANSI | DMGL_PARAMS);
+		name = aname ? aname : data.function;
+		filename = data.filename;
+		if (filename) {
+			char *end = os_strrchr(filename, '/');
+			int i = 0;
+			while (*filename && *filename == prg_fname[i] &&
+			       filename <= end) {
+				filename++;
+				i++;
+			}
+		}
+		wpa_printf(MSG_INFO, "     %s() %s:%u",
+			   name, filename, data.line);
+		free(aname);
+
+		data.found = bfd_find_inliner_info(abfd, &data.filename,
+						   &data.function, &data.line);
+	} while (data.found);
+}
+
+
+static void wpa_trace_bfd_init(void)
+{
+	if (!prg_fname) {
+		get_prg_fname();
+		if (!prg_fname)
+			return;
+		wpa_printf(MSG_INFO, "BFD[%s]", prg_fname);
+	}
+
+	if (!cached_abfd) {
+		cached_abfd = open_bfd(prg_fname);
+		if (!cached_abfd) {
+			wpa_printf(MSG_INFO, "Failed to open bfd");
+			return;
+		}
+	}
+
+	read_syms(cached_abfd);
+	if (!syms) {
+		wpa_printf(MSG_INFO, "Failed to read symbols");
+		return;
+	}
+}
+
+#else /* WPA_TRACE_BFD */
+
+#define wpa_trace_bfd_init() do { } while (0)
+#define wpa_trace_bfd_addr(pc) do { } while (0)
+
+#endif /* WPA_TRACE_BFD */
+
 void wpa_trace_dump_func(const char *title, void **btrace, int btrace_num)
 {
 	char **sym;
 	int i;
 
+	wpa_trace_bfd_init();
 	wpa_printf(MSG_INFO, "WPA_TRACE: %s - START", title);
 	sym = backtrace_symbols(btrace, btrace_num);
-	for (i = 0; i < btrace_num; i++)
-		wpa_printf(MSG_INFO, "[%d]: %p: %s",
-			   i, btrace[i], sym ? sym[i] : "");
+	for (i = 0; i < btrace_num; i++) {
+		if (sym)
+			wpa_printf(MSG_INFO, "[%d]: %s", i, sym[i]);
+		else
+			wpa_printf(MSG_INFO, "[%d]: ?? [%p]", i, btrace[i]);
+		wpa_trace_bfd_addr(btrace[i]);
+	}
 	free(sym);
 	wpa_printf(MSG_INFO, "WPA_TRACE: %s - END", title);
 }

wpa_supplicant/Makefile

@@ -74,6 +74,14 @@ OBJS += ../src/utils/trace.o
 OBJS_p += ../src/utils/trace.o
 OBJS_c += ../src/utils/trace.o
 OBJS_c += ../src/utils/wpa_debug.o
+LDFLAGS += -rdynamic
+CFLAGS += -funwind-tables
+ifdef CONFIG_WPA_TRACE_BFD
+CFLAGS += -DWPA_TRACE_BFD
+LIBS += -lbfd
+LIBS_p += -lbfd
+LIBS_c += -lbfd
+endif
 endif
 
 ifndef CONFIG_ELOOP