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/*
* Copyright 2016, 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 <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits>
#include <thread>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/unique_fd.h>
#include <debuggerd/client.h>
#include <procinfo/process.h>
#include "util.h"
using android::base::unique_fd;
static void usage(int exit_code) {
fprintf(stderr, "usage: debuggerd [-b] PID\n");
fprintf(stderr, "\n");
fprintf(stderr, "-b, --backtrace just a backtrace rather than a full tombstone\n");
_exit(exit_code);
}
static std::thread spawn_redirect_thread(unique_fd fd) {
return std::thread([fd{ std::move(fd) }]() {
while (true) {
char buf[BUFSIZ];
ssize_t rc = TEMP_FAILURE_RETRY(read(fd.get(), buf, sizeof(buf)));
if (rc <= 0) {
return;
}
if (!android::base::WriteFully(STDOUT_FILENO, buf, rc)) {
return;
}
}
});
}
int main(int argc, char* argv[]) {
if (argc <= 1) usage(0);
if (argc > 3) usage(1);
if (argc == 3 && strcmp(argv[1], "-b") != 0 && strcmp(argv[1], "--backtrace") != 0) usage(1);
bool backtrace_only = argc == 3;
pid_t pid;
if (!android::base::ParseInt(argv[argc - 1], &pid, 1, std::numeric_limits<pid_t>::max())) {
usage(1);
}
if (getuid() != 0) {
errx(1, "root is required");
}
// Check to see if the process exists and that we can actually send a signal to it.
android::procinfo::ProcessInfo proc_info;
if (!android::procinfo::GetProcessInfo(pid, &proc_info)) {
err(1, "failed to fetch info for process %d", pid);
}
if (proc_info.state == android::procinfo::kProcessStateZombie) {
errx(1, "process %d is a zombie", pid);
}
if (kill(pid, 0) != 0) {
err(1, "cannot send signal to process %d", pid);
}
unique_fd piperead, pipewrite;
if (!Pipe(&piperead, &pipewrite)) {
err(1, "failed to create pipe");
}
std::thread redirect_thread = spawn_redirect_thread(std::move(piperead));
if (!debuggerd_trigger_dump(pid, backtrace_only ? kDebuggerdNativeBacktrace : kDebuggerdTombstone,
0, std::move(pipewrite))) {
redirect_thread.join();
errx(1, "failed to dump process %d", pid);
}
redirect_thread.join();
return 0;
}
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