Enhance native stack dumps.
Provides a new mechanism for dumpstate (while running as root)
to request that debuggerd dump the stacks of native processes that
we care about in bug reports. In this mode, the backtrace
is formatted to look similar to a Dalvik backtrace.
Moved the tombstone generating code into a separate file to
make it easier to maintain.
Fixed a bug where sometimes the stack traces would be incomplete
because we were not waiting for each thread to stop after issuing
PTRACE_ATTACH, only the main thread. So sometimes we were missing
traces for some threads.
Refactored the logging code to prevent accidentally writing data
to logcat when explicitly dumping a tombstone or backtrace from the
console.
Only root or system server can request to dump backtraces but
only root can dump tombstones.
Bug: 6615693
Change-Id: Ib3edcc16f9f3a687e414e3f2d250d9500566123b
diff --git a/debuggerd/tombstone.c b/debuggerd/tombstone.c
new file mode 100644
index 0000000..2e92846
--- /dev/null
+++ b/debuggerd/tombstone.c
@@ -0,0 +1,700 @@
+/*
+ * 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>
+
+#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";
+ case SIGSTKFLT: return "SIGSTKFLT";
+ 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_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.
+ */
+ bool found = false;
+ 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) {
+ found = true;
+ next = map->next;
+ break;
+ } else if (addr >= map->end) {
+ /* map would be between "prev" and this entry */
+ next = map;
+ map = NULL;
+ break;
+ }
+
+ prev = map;
+ map = map->next;
+ }
+
+ /*
+ * Show "next" then "match" then "prev" so that the addresses appear in
+ * ascending order (like /proc/pid/maps).
+ */
+ if (next != NULL) {
+ _LOG(log, false, " %08x-%08x %s\n", next->start, next->end, next->name);
+ } else {
+ _LOG(log, false, " (no map below)\n");
+ }
+ if (map != NULL) {
+ _LOG(log, false, " %08x-%08x %s\n", map->start, map->end, map->name);
+ } else {
+ _LOG(log, false, " (no map for address)\n");
+ }
+ if (prev != NULL) {
+ _LOG(log, false, " %08x-%08x %s\n", prev->start, prev->end, prev->name);
+ } else {
+ _LOG(log, false, " (no map above)\n");
+ }
+}
+
+static void dump_thread(const ptrace_context_t* context, log_t* log, pid_t tid, bool at_fault,
+ int* total_sleep_time_usec) {
+ wait_for_stop(tid, total_sleep_time_usec);
+
+ dump_registers(context, log, tid, at_fault);
+ dump_backtrace_and_stack(context, log, tid, at_fault);
+ if (at_fault) {
+ dump_memory_and_code(context, log, tid, at_fault);
+ dump_nearby_maps(context, log, tid);
+ }
+}
+
+/* Return true if some thread is not detached cleanly */
+static bool dump_sibling_thread_report(const ptrace_context_t* context,
+ log_t* log, pid_t pid, pid_t tid, int* total_sleep_time_usec) {
+ char task_path[64];
+ snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
+
+ DIR* d = opendir(task_path);
+ /* Bail early if cannot open the task directory */
+ if (d == NULL) {
+ XLOG("Cannot open /proc/%d/task\n", pid);
+ return false;
+ }
+
+ bool detach_failed = false;
+ struct dirent debuf;
+ struct dirent *de;
+ while (!readdir_r(d, &debuf, &de) && de) {
+ /* Ignore "." and ".." */
+ if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
+ continue;
+ }
+
+ /* The main thread at fault has been handled individually */
+ char* end;
+ pid_t new_tid = strtoul(de->d_name, &end, 10);
+ if (*end || new_tid == tid) {
+ continue;
+ }
+
+ /* Skip this thread if cannot ptrace it */
+ if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0) {
+ continue;
+ }
+
+ _LOG(log, true, "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
+ dump_thread_info(log, pid, new_tid, false);
+ dump_thread(context, log, new_tid, false, total_sleep_time_usec);
+
+ if (ptrace(PTRACE_DETACH, new_tid, 0, 0) != 0) {
+ LOG("ptrace detach from %d failed: %s\n", new_tid, strerror(errno));
+ detach_failed = true;
+ }
+ }
+
+ closedir(d);
+ return detach_failed;
+}
+
+/*
+ * Reads the contents of the specified log device, filters out the entries
+ * that don't match the specified pid, and writes them to the tombstone file.
+ *
+ * If "tailOnly" is set, we only print the last few lines.
+ */
+static void dump_log_file(log_t* log, pid_t pid, const char* filename,
+ bool tailOnly)
+{
+ bool first = true;
+
+ /* circular buffer, for "tailOnly" mode */
+ const int kShortLogMaxLines = 5;
+ const int kShortLogLineLen = 256;
+ char shortLog[kShortLogMaxLines][kShortLogLineLen];
+ int shortLogCount = 0;
+ int shortLogNext = 0;
+
+ int logfd = open(filename, O_RDONLY | O_NONBLOCK);
+ if (logfd < 0) {
+ XLOG("Unable to open %s: %s\n", filename, strerror(errno));
+ return;
+ }
+
+ union {
+ unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1];
+ struct logger_entry entry;
+ } log_entry;
+
+ while (true) {
+ ssize_t actual = read(logfd, log_entry.buf, LOGGER_ENTRY_MAX_LEN);
+ if (actual < 0) {
+ if (errno == EINTR) {
+ /* interrupted by signal, retry */
+ continue;
+ } else if (errno == EAGAIN) {
+ /* non-blocking EOF; we're done */
+ break;
+ } else {
+ _LOG(log, true, "Error while reading log: %s\n",
+ strerror(errno));
+ break;
+ }
+ } else if (actual == 0) {
+ _LOG(log, true, "Got zero bytes while reading log: %s\n",
+ strerror(errno));
+ break;
+ }
+
+ /*
+ * NOTE: if you XLOG something here, this will spin forever,
+ * because you will be writing as fast as you're reading. Any
+ * high-frequency debug diagnostics should just be written to
+ * the tombstone file.
+ */
+
+ struct logger_entry* entry = &log_entry.entry;
+
+ if (entry->pid != (int32_t) pid) {
+ /* wrong pid, ignore */
+ continue;
+ }
+
+ if (first) {
+ _LOG(log, true, "--------- %slog %s\n",
+ tailOnly ? "tail end of " : "", filename);
+ first = false;
+ }
+
+ /*
+ * Msg format is: <priority:1><tag:N>\0<message:N>\0
+ *
+ * We want to display it in the same format as "logcat -v threadtime"
+ * (although in this case the pid is redundant).
+ *
+ * TODO: scan for line breaks ('\n') and display each text line
+ * on a separate line, prefixed with the header, like logcat does.
+ */
+ static const char* kPrioChars = "!.VDIWEFS";
+ unsigned char prio = entry->msg[0];
+ char* tag = entry->msg + 1;
+ char* msg = tag + strlen(tag) + 1;
+
+ /* consume any trailing newlines */
+ char* eatnl = msg + strlen(msg) - 1;
+ while (eatnl >= msg && *eatnl == '\n') {
+ *eatnl-- = '\0';
+ }
+
+ char prioChar = (prio < strlen(kPrioChars) ? kPrioChars[prio] : '?');
+
+ char timeBuf[32];
+ time_t sec = (time_t) entry->sec;
+ struct tm tmBuf;
+ struct tm* ptm;
+ ptm = localtime_r(&sec, &tmBuf);
+ strftime(timeBuf, sizeof(timeBuf), "%m-%d %H:%M:%S", ptm);
+
+ if (tailOnly) {
+ snprintf(shortLog[shortLogNext], kShortLogLineLen,
+ "%s.%03d %5d %5d %c %-8s: %s",
+ timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
+ prioChar, tag, msg);
+ shortLogNext = (shortLogNext + 1) % kShortLogMaxLines;
+ shortLogCount++;
+ } else {
+ _LOG(log, true, "%s.%03d %5d %5d %c %-8s: %s\n",
+ timeBuf, entry->nsec / 1000000, entry->pid, entry->tid,
+ prioChar, tag, msg);
+ }
+ }
+
+ if (tailOnly) {
+ int i;
+
+ /*
+ * If we filled the buffer, we want to start at "next", which has
+ * the oldest entry. If we didn't, we want to start at zero.
+ */
+ if (shortLogCount < kShortLogMaxLines) {
+ shortLogNext = 0;
+ } else {
+ shortLogCount = kShortLogMaxLines; /* cap at window size */
+ }
+
+ for (i = 0; i < shortLogCount; i++) {
+ _LOG(log, true, "%s\n", shortLog[shortLogNext]);
+ shortLogNext = (shortLogNext + 1) % kShortLogMaxLines;
+ }
+ }
+
+ close(logfd);
+}
+
+/*
+ * Dumps the logs generated by the specified pid to the tombstone, from both
+ * "system" and "main" log devices. Ideally we'd interleave the output.
+ */
+static void dump_logs(log_t* log, pid_t pid, bool tailOnly)
+{
+ dump_log_file(log, pid, "/dev/log/system", tailOnly);
+ dump_log_file(log, pid, "/dev/log/main", tailOnly);
+}
+
+/*
+ * Dumps all information about the specified pid to the tombstone.
+ */
+static bool dump_crash(log_t* log, pid_t pid, pid_t tid, int signal,
+ bool dump_sibling_threads, int* total_sleep_time_usec)
+{
+ /* don't copy log messages to tombstone unless this is a dev device */
+ char value[PROPERTY_VALUE_MAX];
+ property_get("ro.debuggable", value, "0");
+ bool want_logs = (value[0] == '1');
+
+ _LOG(log, false,
+ "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
+ dump_build_info(log);
+ dump_thread_info(log, pid, tid, true);
+ if(signal) {
+ dump_fault_addr(log, tid, signal);
+ }
+
+ ptrace_context_t* context = load_ptrace_context(tid);
+ dump_thread(context, log, tid, true, total_sleep_time_usec);
+
+ if (want_logs) {
+ dump_logs(log, pid, true);
+ }
+
+ bool detach_failed = false;
+ if (dump_sibling_threads) {
+ detach_failed = dump_sibling_thread_report(context, log, pid, tid, total_sleep_time_usec);
+ }
+
+ free_ptrace_context(context);
+
+ if (want_logs) {
+ dump_logs(log, pid, false);
+ }
+ return detach_failed;
+}
+
+/*
+ * find_and_open_tombstone - find an available tombstone slot, if any, of the
+ * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no
+ * file is available, we reuse the least-recently-modified file.
+ *
+ * Returns the path of the tombstone file, allocated using malloc(). Caller must free() it.
+ */
+static char* find_and_open_tombstone(int* fd)
+{
+ unsigned long mtime = ULONG_MAX;
+ struct stat sb;
+
+ /*
+ * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought
+ * to, our logic breaks. This check will generate a warning if that happens.
+ */
+ typecheck(mtime, sb.st_mtime);
+
+ /*
+ * In a single wolf-like pass, find an available slot and, in case none
+ * exist, find and record the least-recently-modified file.
+ */
+ char path[128];
+ int oldest = 0;
+ for (int i = 0; i < MAX_TOMBSTONES; i++) {
+ snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i);
+
+ if (!stat(path, &sb)) {
+ if (sb.st_mtime < mtime) {
+ oldest = i;
+ mtime = sb.st_mtime;
+ }
+ continue;
+ }
+ if (errno != ENOENT)
+ continue;
+
+ *fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600);
+ if (*fd < 0)
+ continue; /* raced ? */
+
+ fchown(*fd, AID_SYSTEM, AID_SYSTEM);
+ return strdup(path);
+ }
+
+ /* we didn't find an available file, so we clobber the oldest one */
+ snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest);
+ *fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+ if (*fd < 0) {
+ LOG("failed to open tombstone file '%s': %s\n", path, strerror(errno));
+ return NULL;
+ }
+ fchown(*fd, AID_SYSTEM, AID_SYSTEM);
+ return strdup(path);
+}
+
+char* engrave_tombstone(pid_t pid, pid_t tid, int signal,
+ bool dump_sibling_threads, bool quiet, bool* detach_failed,
+ int* total_sleep_time_usec) {
+ mkdir(TOMBSTONE_DIR, 0755);
+ chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM);
+
+ int fd;
+ char* path = find_and_open_tombstone(&fd);
+ if (!path) {
+ *detach_failed = false;
+ return NULL;
+ }
+
+ log_t log;
+ log.tfd = fd;
+ log.quiet = quiet;
+ *detach_failed = dump_crash(&log, pid, tid, signal, dump_sibling_threads,
+ total_sleep_time_usec);
+
+ close(fd);
+ return path;
+}