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/*
* Copyright (C) 2022 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 <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include "PidUtils.h"
namespace unwindstack {
static bool Exited(pid_t pid) {
int status;
pid_t wait_pid = waitpid(pid, &status, WNOHANG);
if (wait_pid != pid) {
return false;
}
if (WIFEXITED(status)) {
fprintf(stderr, "%d died: Process exited with code %d\n", pid, WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
fprintf(stderr, "%d died: Process exited due to signal %d\n", pid, WTERMSIG(status));
} else {
fprintf(stderr, "%d died: Process finished for unknown reason\n", pid);
}
return true;
}
bool Quiesce(pid_t pid) {
siginfo_t si;
// Wait for up to 10 seconds.
for (time_t start_time = time(nullptr); time(nullptr) - start_time < 10;) {
if (ptrace(PTRACE_GETSIGINFO, pid, 0, &si) == 0) {
return true;
}
if (errno != ESRCH) {
if (errno == EINVAL) {
// The process is in group-stop state, so try and kick the
// process out of that state.
if (ptrace(PTRACE_LISTEN, pid, 0, 0) == -1) {
// Cannot recover from this, so just pretend it worked and see
// if we can unwind.
return true;
}
} else {
perror("ptrace getsiginfo failed");
return false;
}
}
usleep(5000);
}
fprintf(stderr, "Did not quiesce in 10 seconds\n");
return false;
}
bool Attach(pid_t pid) {
// Wait up to 45 seconds to attach.
for (time_t start_time = time(nullptr); time(nullptr) - start_time < 45;) {
if (ptrace(PTRACE_ATTACH, pid, 0, 0) == 0) {
break;
}
if (errno != ESRCH) {
perror("Failed to attach");
return false;
}
usleep(5000);
}
if (Quiesce(pid)) {
return true;
}
if (ptrace(PTRACE_DETACH, pid, 0, 0) == -1) {
perror("Failed to detach");
}
return false;
}
bool Detach(pid_t pid) {
if (ptrace(PTRACE_DETACH, pid, 0, 0) == -1) {
perror("ptrace detach failed");
return false;
}
return true;
}
bool RunWhenQuiesced(pid_t pid, bool leave_attached, std::function<PidRunEnum()> fn) {
// Wait up to 120 seconds to run the fn.
PidRunEnum status = PID_RUN_KEEP_GOING;
for (time_t start_time = time(nullptr);
time(nullptr) - start_time < 120 && status == PID_RUN_KEEP_GOING;) {
if (Attach(pid)) {
status = fn();
if (status == PID_RUN_PASS && leave_attached) {
return true;
}
if (!Detach(pid)) {
return false;
}
} else if (Exited(pid)) {
return false;
}
usleep(5000);
}
if (status == PID_RUN_KEEP_GOING) {
fprintf(stderr, "Timed out waiting for pid %d to be ready\n", pid);
}
return status == PID_RUN_PASS;
}
} // namespace unwindstack
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