xref: /system/core/debuggerd/tombstone.c

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stddef.h>
#include <stdbool.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <dirent.h>
#include <time.h>
#include <sys/ptrace.h>
#include <sys/stat.h>

#include <private/android_filesystem_config.h>

#include <cutils/logger.h>
#include <cutils/properties.h>

#include <corkscrew/demangle.h>
#include <corkscrew/backtrace.h>

#ifdef HAVE_SELINUX
#include <selinux/android.h>
#endif

#include "machine.h"
#include "tombstone.h"
#include "utility.h"

#define STACK_DEPTH 32
#define STACK_WORDS 16

#define MAX_TOMBSTONES  10
#define TOMBSTONE_DIR   "/data/tombstones"

#define typecheck(x,y) {    \
    typeof(x) __dummy1;     \
    typeof(y) __dummy2;     \
    (void)(&__dummy1 == &__dummy2); }


static bool signal_has_address(int sig) {
    switch (sig) {
        case SIGILL:
        case SIGFPE:
        case SIGSEGV:
        case SIGBUS:
            return true;
        default:
            return false;
    }
}

static const char *get_signame(int sig)
{
    switch(sig) {
    case SIGILL:     return "SIGILL";
    case SIGABRT:    return "SIGABRT";
    case SIGBUS:     return "SIGBUS";
    case SIGFPE:     return "SIGFPE";
    case SIGSEGV:    return "SIGSEGV";
    case SIGPIPE:    return "SIGPIPE";
#ifdef SIGSTKFLT
    case SIGSTKFLT:  return "SIGSTKFLT";
#endif
    case SIGSTOP:    return "SIGSTOP";
    default:         return "?";
    }
}

static const char *get_sigcode(int signo, int code)
{
    switch (signo) {
    case SIGILL:
        switch (code) {
        case ILL_ILLOPC: return "ILL_ILLOPC";
        case ILL_ILLOPN: return "ILL_ILLOPN";
        case ILL_ILLADR: return "ILL_ILLADR";
        case ILL_ILLTRP: return "ILL_ILLTRP";
        case ILL_PRVOPC: return "ILL_PRVOPC";
        case ILL_PRVREG: return "ILL_PRVREG";
        case ILL_COPROC: return "ILL_COPROC";
        case ILL_BADSTK: return "ILL_BADSTK";
        }
        break;
    case SIGBUS:
        switch (code) {
        case BUS_ADRALN: return "BUS_ADRALN";
        case BUS_ADRERR: return "BUS_ADRERR";
        case BUS_OBJERR: return "BUS_OBJERR";
        }
        break;
    case SIGFPE:
        switch (code) {
        case FPE_INTDIV: return "FPE_INTDIV";
        case FPE_INTOVF: return "FPE_INTOVF";
        case FPE_FLTDIV: return "FPE_FLTDIV";
        case FPE_FLTOVF: return "FPE_FLTOVF";
        case FPE_FLTUND: return "FPE_FLTUND";
        case FPE_FLTRES: return "FPE_FLTRES";
        case FPE_FLTINV: return "FPE_FLTINV";
        case FPE_FLTSUB: return "FPE_FLTSUB";
        }
        break;
    case SIGSEGV:
        switch (code) {
        case SEGV_MAPERR: return "SEGV_MAPERR";
        case SEGV_ACCERR: return "SEGV_ACCERR";
        }
        break;
    }
    return "?";
}

static void dump_revision_info(log_t* log)
{
    char revision[PROPERTY_VALUE_MAX];

    property_get("ro.revision", revision, "unknown");

    _LOG(log, false, "Revision: '%s'\n", revision);
}

static void dump_build_info(log_t* log)
{
    char fingerprint[PROPERTY_VALUE_MAX];

    property_get("ro.build.fingerprint", fingerprint, "unknown");

    _LOG(log, false, "Build fingerprint: '%s'\n", fingerprint);
}

static void dump_fault_addr(log_t* log, pid_t tid, int sig)
{
    siginfo_t si;

    memset(&si, 0, sizeof(si));
    if(ptrace(PTRACE_GETSIGINFO, tid, 0, &si)){
        _LOG(log, false, "cannot get siginfo: %s\n", strerror(errno));
    } else if (signal_has_address(sig)) {
        _LOG(log, false, "signal %d (%s), code %d (%s), fault addr %08x\n",
             sig, get_signame(sig),
             si.si_code, get_sigcode(sig, si.si_code),
             (uintptr_t) si.si_addr);
    } else {
        _LOG(log, false, "signal %d (%s), code %d (%s), fault addr --------\n",
             sig, get_signame(sig), si.si_code, get_sigcode(sig, si.si_code));
    }
}

static void dump_thread_info(log_t* log, pid_t pid, pid_t tid, bool at_fault) {
    char path[64];
    char threadnamebuf[1024];
    char* threadname = NULL;
    FILE *fp;

    snprintf(path, sizeof(path), "/proc/%d/comm", tid);
    if ((fp = fopen(path, "r"))) {
        threadname = fgets(threadnamebuf, sizeof(threadnamebuf), fp);
        fclose(fp);
        if (threadname) {
            size_t len = strlen(threadname);
            if (len && threadname[len - 1] == '\n') {
                threadname[len - 1] = '\0';
            }
        }
    }

    if (at_fault) {
        char procnamebuf[1024];
        char* procname = NULL;

        snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
        if ((fp = fopen(path, "r"))) {
            procname = fgets(procnamebuf, sizeof(procnamebuf), fp);
            fclose(fp);
        }

        _LOG(log, false, "pid: %d, tid: %d, name: %s  >>> %s <<<\n", pid, tid,
                threadname ? threadname : "UNKNOWN",
                procname ? procname : "UNKNOWN");
    } else {
        _LOG(log, true, "pid: %d, tid: %d, name: %s\n", pid, tid,
                threadname ? threadname : "UNKNOWN");
    }
}

static void dump_backtrace(const ptrace_context_t* context __attribute((unused)),
        log_t* log, pid_t tid __attribute((unused)), bool at_fault,
        const backtrace_frame_t* backtrace, size_t frames) {
    _LOG(log, !at_fault, "\nbacktrace:\n");

    backtrace_symbol_t backtrace_symbols[STACK_DEPTH];
    get_backtrace_symbols_ptrace(context, backtrace, frames, backtrace_symbols);
    for (size_t i = 0; i < frames; i++) {
        char line[MAX_BACKTRACE_LINE_LENGTH];
        format_backtrace_line(i, &backtrace[i], &backtrace_symbols[i],
                line, MAX_BACKTRACE_LINE_LENGTH);
        _LOG(log, !at_fault, "    %s\n", line);
    }
    free_backtrace_symbols(backtrace_symbols, frames);
}

static void dump_stack_segment(const ptrace_context_t* context, log_t* log, pid_t tid,
        bool only_in_tombstone, uintptr_t* sp, size_t words, int label) {
    for (size_t i = 0; i < words; i++) {
        uint32_t stack_content;
        if (!try_get_word_ptrace(tid, *sp, &stack_content)) {
            break;
        }

        const map_info_t* mi;
        const symbol_t* symbol;
        find_symbol_ptrace(context, stack_content, &mi, &symbol);

        if (symbol) {
            char* demangled_name = demangle_symbol_name(symbol->name);
            const char* symbol_name = demangled_name ? demangled_name : symbol->name;
            uint32_t offset = stack_content - (mi->start + symbol->start);
            if (!i && label >= 0) {
                if (offset) {
                    _LOG(log, only_in_tombstone, "    #%02d  %08x  %08x  %s (%s+%u)\n",
                            label, *sp, stack_content, mi ? mi->name : "", symbol_name, offset);
                } else {
                    _LOG(log, only_in_tombstone, "    #%02d  %08x  %08x  %s (%s)\n",
                            label, *sp, stack_content, mi ? mi->name : "", symbol_name);
                }
            } else {
                if (offset) {
                    _LOG(log, only_in_tombstone, "         %08x  %08x  %s (%s+%u)\n",
                            *sp, stack_content, mi ? mi->name : "", symbol_name, offset);
                } else {
                    _LOG(log, only_in_tombstone, "         %08x  %08x  %s (%s)\n",
                            *sp, stack_content, mi ? mi->name : "", symbol_name);
                }
            }
            free(demangled_name);
        } else {
            if (!i && label >= 0) {
                _LOG(log, only_in_tombstone, "    #%02d  %08x  %08x  %s\n",
                        label, *sp, stack_content, mi ? mi->name : "");
            } else {
                _LOG(log, only_in_tombstone, "         %08x  %08x  %s\n",
                        *sp, stack_content, mi ? mi->name : "");
            }
        }

        *sp += sizeof(uint32_t);
    }
}

static void dump_stack(const ptrace_context_t* context, log_t* log, pid_t tid, bool at_fault,
        const backtrace_frame_t* backtrace, size_t frames) {
    bool have_first = false;
    size_t first, last;
    for (size_t i = 0; i < frames; i++) {
        if (backtrace[i].stack_top) {
            if (!have_first) {
                have_first = true;
                first = i;
            }
            last = i;
        }
    }
    if (!have_first) {
        return;
    }

    _LOG(log, !at_fault, "\nstack:\n");

    // Dump a few words before the first frame.
    bool only_in_tombstone = !at_fault;
    uintptr_t sp = backtrace[first].stack_top - STACK_WORDS * sizeof(uint32_t);
    dump_stack_segment(context, log, tid, only_in_tombstone, &sp, STACK_WORDS, -1);

    // Dump a few words from all successive frames.
    // Only log the first 3 frames, put the rest in the tombstone.
    for (size_t i = first; i <= last; i++) {
        const backtrace_frame_t* frame = &backtrace[i];
        if (sp != frame->stack_top) {
            _LOG(log, only_in_tombstone, "         ........  ........\n");
            sp = frame->stack_top;
        }
        if (i - first == 3) {
            only_in_tombstone = true;
        }
        if (i == last) {
            dump_stack_segment(context, log, tid, only_in_tombstone, &sp, STACK_WORDS, i);
            if (sp < frame->stack_top + frame->stack_size) {
                _LOG(log, only_in_tombstone, "         ........  ........\n");
            }
        } else {
            size_t words = frame->stack_size / sizeof(uint32_t);
            if (words == 0) {
                words = 1;
            } else if (words > STACK_WORDS) {
                words = STACK_WORDS;
            }
            dump_stack_segment(context, log, tid, only_in_tombstone, &sp, words, i);
        }
    }
}

static void dump_backtrace_and_stack(const ptrace_context_t* context, log_t* log, pid_t tid,
        bool at_fault) {
    backtrace_frame_t backtrace[STACK_DEPTH];
    ssize_t frames = unwind_backtrace_ptrace(tid, context, backtrace, 0, STACK_DEPTH);
    if (frames > 0) {
        dump_backtrace(context, log, tid, at_fault, backtrace, frames);
        dump_stack(context, log, tid, at_fault, backtrace, frames);
    }
}

static void dump_nearby_maps(const ptrace_context_t* context, log_t* log, pid_t tid) {
    siginfo_t si;
    memset(&si, 0, sizeof(si));
    if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si)) {
        _LOG(log, false, "cannot get siginfo for %d: %s\n",
                tid, strerror(errno));
        return;
    }
    if (!signal_has_address(si.si_signo)) {
        return;
    }

    uintptr_t addr = (uintptr_t) si.si_addr;
    addr &= ~0xfff;     /* round to 4K page boundary */
    if (addr == 0) {    /* null-pointer deref */
        return;
    }

    _LOG(log, false, "\nmemory map around fault addr %08x:\n", (int)si.si_addr);

    /*
     * Search for a match, or for a hole where the match would be.  The list
     * is backward from the file content, so it starts at high addresses.
     */
    map_info_t* map = context->map_info_list;
    map_info_t *next = NULL;
    map_info_t *prev = NULL;
    while (map != NULL) {
        if (addr >= map->start && addr < map->end) {
            next = map->next;
            break;
        } else if (addr >= map->end) {
            /* map would be between "prev" and this entry */
            next = map;
            map = NULL;