/* * Backtrace debugging * Copyright (c) 2009, Jouni Malinen * * This software may be distributed under the terms of the BSD license. * See README for more details. */ #ifdef WPA_TRACE_BFD #define _GNU_SOURCE #include #endif /* WPA_TRACE_BCD */ #include "includes.h" #include "common.h" #include "trace.h" #ifdef WPA_TRACE static struct dl_list active_references = { &active_references, &active_references }; #ifdef WPA_TRACE_BFD #include #define DMGL_PARAMS (1 << 0) #define DMGL_ANSI (1 << 1) static char *prg_fname = NULL; static bfd *cached_abfd = NULL; static asymbol **syms = NULL; static unsigned long start_offset; static int start_offset_looked_up; static int callback(struct dl_phdr_info *info, size_t size, void *data) { /* * dl_iterate_phdr(3): * "The first object visited by callback is the main program." */ start_offset = info->dlpi_addr; /* * dl_iterate_phdr(3): * "The dl_iterate_phdr() function walks through the list of an * application's shared objects and calls the function callback * once for each object, until either all shared objects have * been processed or callback returns a nonzero value." */ return 1; } 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)) { wpa_printf(MSG_ERROR, "readlink: %s", strerror(errno)); 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; } } struct bfd_data { bfd_vma pc; bfd_boolean found; const char *filename; const char *function; unsigned int line; }; /* * binutils removed the bfd parameter and renamed things but * those were macros so we can detect their absence. * Cf. https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=fd3619828e94a24a92cddec42cbc0ab33352eeb4;hp=5dfda3562a69686c43aad4fb0269cc9d5ec010d5 */ #ifndef bfd_get_section_vma #define bfd_get_section_vma(bfd, section) bfd_section_vma(section) #endif #ifndef bfd_get_section_size #define bfd_get_section_size bfd_section_size #endif 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_hostptr_t) ((u8 *) pc - start_offset); 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); aname = NULL; data.found = bfd_find_inliner_info(abfd, &data.filename, &data.function, &data.line); } while (data.found); } static const char * wpa_trace_bfd_addr2func(void *pc) { bfd *abfd = cached_abfd; struct bfd_data data; if (abfd == NULL) return NULL; data.pc = (bfd_hostptr_t) ((u8 *) pc - start_offset); data.found = FALSE; bfd_map_over_sections(abfd, find_addr_sect, &data); if (!data.found) return NULL; return data.function; } static void wpa_trace_bfd_init(void) { if (!prg_fname) { get_prg_fname(); if (!prg_fname) return; } 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; } if (!start_offset_looked_up) { dl_iterate_phdr(callback, NULL); start_offset_looked_up = 1; } } void wpa_trace_dump_funcname(const char *title, void *pc) { wpa_printf(MSG_INFO, "WPA_TRACE: %s: %p", title, pc); wpa_trace_bfd_init(); wpa_trace_bfd_addr(pc); } size_t wpa_trace_calling_func(const char *buf[], size_t len) { bfd *abfd; void *btrace_res[WPA_TRACE_LEN]; int i, btrace_num; size_t pos = 0; if (len == 0) return 0; if (len > WPA_TRACE_LEN) len = WPA_TRACE_LEN; wpa_trace_bfd_init(); abfd = cached_abfd; if (!abfd) return 0; btrace_num = backtrace(btrace_res, len); if (btrace_num < 1) return 0; for (i = 0; i < btrace_num; i++) { struct bfd_data data; data.pc = (bfd_hostptr_t) ((u8 *) btrace_res[i] - start_offset); data.found = FALSE; bfd_map_over_sections(abfd, find_addr_sect, &data); while (data.found) { if (data.function && (pos > 0 || os_strcmp(data.function, __func__) != 0)) { buf[pos++] = data.function; if (pos == len) return pos; } data.found = bfd_find_inliner_info(abfd, &data.filename, &data.function, &data.line); } } return pos; } #else /* WPA_TRACE_BFD */ #define wpa_trace_bfd_init() do { } while (0) #define wpa_trace_bfd_addr(pc) do { } while (0) #define wpa_trace_bfd_addr2func(pc) NULL #endif /* WPA_TRACE_BFD */ void wpa_trace_dump_func(const char *title, void **btrace, int btrace_num) { char **sym; int i; enum { TRACE_HEAD, TRACE_RELEVANT, TRACE_TAIL } state; wpa_trace_bfd_init(); wpa_printf(MSG_INFO, "WPA_TRACE: %s - START", title); sym = backtrace_symbols(btrace, btrace_num); state = TRACE_HEAD; for (i = 0; i < btrace_num; i++) { const char *func = wpa_trace_bfd_addr2func(btrace[i]); if (state == TRACE_HEAD && func && (os_strcmp(func, "wpa_trace_add_ref_func") == 0 || os_strcmp(func, "wpa_trace_check_ref") == 0 || os_strcmp(func, "wpa_trace_show") == 0)) continue; if (state == TRACE_TAIL && sym && sym[i] && os_strstr(sym[i], "__libc_start_main")) break; if (state == TRACE_HEAD) state = TRACE_RELEVANT; 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]); if (state == TRACE_RELEVANT && func && os_strcmp(func, "main") == 0) state = TRACE_TAIL; } free(sym); wpa_printf(MSG_INFO, "WPA_TRACE: %s - END", title); } void wpa_trace_show(const char *title) { struct info { WPA_TRACE_INFO } info; wpa_trace_record(&info); wpa_trace_dump(title, &info); } void wpa_trace_add_ref_func(struct wpa_trace_ref *ref, const void *addr) { if (addr == NULL) return; ref->addr = addr; wpa_trace_record(ref); dl_list_add(&active_references, &ref->list); } void wpa_trace_check_ref(const void *addr) { struct wpa_trace_ref *ref; dl_list_for_each(ref, &active_references, struct wpa_trace_ref, list) { if (addr != ref->addr) continue; wpa_trace_show("Freeing referenced memory"); wpa_trace_dump("Reference registration", ref); abort(); } } void wpa_trace_deinit(void) { #ifdef WPA_TRACE_BFD free(syms); syms = NULL; #endif /* WPA_TRACE_BFD */ } #endif /* WPA_TRACE */