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5f554ff10e
TEST=util_test ProcessUtil.ProcessArgumentsForPID R=rsesek@chromium.org Review URL: https://codereview.chromium.org/461253002
103 lines
3.2 KiB
C++
103 lines
3.2 KiB
C++
// Copyright 2014 The Crashpad Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "util/posix/process_util.h"
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#include <string.h>
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#include <sys/sysctl.h>
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#include <sys/types.h>
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#include "base/basictypes.h"
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namespace crashpad {
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bool ProcessArgumentsForPID(pid_t pid, std::vector<std::string>* argv) {
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// The format of KERN_PROCARGS2 is explained in 10.9.2 adv_cmds-153/ps/print.c
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// getproclline(). It is an int (argc) followed by the executable’s string
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// area. The string area consists of NUL-terminated strings, beginning with
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// the executable path, and then starting on an aligned boundary, all of the
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// elements of argv, envp, and applev.
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// It is possible for a process to exec() in between the two sysctl() calls
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// below. If that happens, and the string area of the new program is larger
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// than that of the old one, args_size_estimate will be too small. To detect
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// this situation, the second sysctl() attempts to fetch args_size_estimate +
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// 1 bytes, expecting to only receive args_size_estimate. If it gets the extra
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// byte, it indicates that the string area has grown, and the sysctl() pair
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// will be retried a limited number of times.
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size_t args_size_estimate;
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size_t args_size;
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std::string args;
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int tries = 3;
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do {
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int mib[] = {CTL_KERN, KERN_PROCARGS2, pid};
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int rv = sysctl(mib, arraysize(mib), NULL, &args_size_estimate, NULL, 0);
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if (rv != 0) {
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return false;
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}
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args_size = args_size_estimate + 1;
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args.resize(args_size);
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rv = sysctl(mib, arraysize(mib), &args[0], &args_size, NULL, 0);
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if (rv != 0) {
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return false;
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}
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} while (args_size == args_size_estimate + 1 && tries--);
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if (args_size == args_size_estimate + 1) {
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return false;
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}
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// KERN_PROCARGS2 needs to at least contain argc.
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if (args_size < sizeof(int)) {
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return false;
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}
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args.resize(args_size);
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// Get argc.
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int argc;
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memcpy(&argc, &args[0], sizeof(argc));
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// Find the end of the executable path.
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size_t start_pos = sizeof(argc);
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size_t nul_pos = args.find('\0', start_pos);
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if (nul_pos == std::string::npos) {
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return false;
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}
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// Find the beginning of the string area.
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start_pos = args.find_first_not_of('\0', nul_pos);
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if (start_pos == std::string::npos) {
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return false;
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}
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std::vector<std::string> local_argv;
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while (argc-- && nul_pos != std::string::npos) {
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nul_pos = args.find('\0', start_pos);
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local_argv.push_back(args.substr(start_pos, nul_pos - start_pos));
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start_pos = nul_pos + 1;
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}
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if (argc >= 0) {
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// Not every argument was recovered.
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return false;
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}
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argv->swap(local_argv);
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return true;
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}
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} // namespace crashpad
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