1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/process_util.h"
#include <fcntl.h>
#include <os/availability.h>
#include <spawn.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string>
#include "base/command_line.h"
#include "base/eintr_wrapper.h"
#include "base/logging.h"
#include "mozilla/ipc/FileDescriptorShuffle.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/Result.h"
#include "mozilla/ipc/LaunchError.h"
extern "C" {
// N.B. the syscalls are available back to 10.5, but the C wrappers
// only in 10.12. Fortunately, 10.12 is our current baseline.
int pthread_chdir_np(const char* dir) API_AVAILABLE(macosx(10.12));
int pthread_fchdir_np(int fd) API_AVAILABLE(macosx(10.12));
int responsibility_spawnattrs_setdisclaim(posix_spawnattr_t attrs, int disclaim)
API_AVAILABLE(macosx(10.14));
}
namespace {
static mozilla::EnvironmentLog gProcessLog("MOZ_PROCESS_LOG");
} // namespace
namespace base {
Result<Ok, LaunchError> LaunchApp(const std::vector<std::string>& argv,
const LaunchOptions& options, ProcessHandle* process_handle) {
Result<Ok, LaunchError> retval = Ok();
char* argv_copy[argv.size() + 1];
for (size_t i = 0; i < argv.size(); i++) {
argv_copy[i] = const_cast<char*>(argv[i].c_str());
}
argv_copy[argv.size()] = NULL;
EnvironmentArray env_storage;
const EnvironmentArray& vars =
options.full_env ? options.full_env : (env_storage = BuildEnvironmentArray(options.env_map));
posix_spawn_file_actions_t file_actions;
int err = posix_spawn_file_actions_init(&file_actions);
if (err != 0) {
DLOG(WARNING) << "posix_spawn_file_actions_init failed";
return Err(LaunchError("posix_spawn_file_actions_init", err));
}
auto file_actions_guard =
mozilla::MakeScopeExit([&file_actions] { posix_spawn_file_actions_destroy(&file_actions); });
// Turn fds_to_remap array into a set of dup2 calls.
//
// Init() there will call fcntl(F_DUPFD/F_DUPFD_CLOEXEC) under the hood in
// https://searchfox.org/mozilla-central/rev/55d5c4b9dffe5e59eb6b019c1a930ec9ada47e10/ipc/glue/FileDescriptorShuffle.cpp#72
// so it will set errno.
mozilla::ipc::FileDescriptorShuffle shuffle;
if (!shuffle.Init(options.fds_to_remap)) {
DLOG(WARNING) << "FileDescriptorShuffle::Init failed";
return Err(LaunchError("FileDescriptorShuffle", errno));
}
for (const auto& fd_map : shuffle.Dup2Sequence()) {
int src_fd = fd_map.first;
int dest_fd = fd_map.second;
int rv = posix_spawn_file_actions_adddup2(&file_actions, src_fd, dest_fd);
if (rv != 0) {
DLOG(WARNING) << "posix_spawn_file_actions_adddup2 failed";
return Err(LaunchError("posix_spawn_file_actions_adddup2", rv));
}
}
// macOS 10.15 allows adding a chdir operation to the file actions;
// this ought to be part of the standard but sadly is not. On older
// versions, we can use a different nonstandard extension:
// pthread_{f,}chdir_np, so we can temporarily change the calling
// thread's cwd (which is then inherited by the child) without
// disturbing other threads, and then restore it afterwards.
int old_cwd_fd = -1;
if (!options.workdir.empty()) {
if (@available(macOS 10.15, *)) {
int rv = posix_spawn_file_actions_addchdir_np(&file_actions, options.workdir.c_str());
if (rv != 0) {
DLOG(WARNING) << "posix_spawn_file_actions_addchdir_np failed";
return Err(LaunchError("posix_spawn_file_actions_addchdir", rv));
}
} else {
old_cwd_fd = open(".", O_RDONLY | O_CLOEXEC | O_DIRECTORY);
if (old_cwd_fd < 0) {
DLOG(WARNING) << "open(\".\") failed";
return Err(LaunchError("open", errno));
}
if (pthread_chdir_np(options.workdir.c_str()) != 0) {
DLOG(WARNING) << "pthread_chdir_np failed";
return Err(LaunchError("pthread_chdir_np", errno));
}
}
}
auto thread_cwd_guard = mozilla::MakeScopeExit([old_cwd_fd] {
if (old_cwd_fd >= 0) {
if (pthread_fchdir_np(old_cwd_fd) != 0) {
DLOG(ERROR) << "pthread_fchdir_np failed; thread is in the wrong directory!";
}
close(old_cwd_fd);
}
});
// Initialize spawn attributes.
posix_spawnattr_t spawnattr;
err = posix_spawnattr_init(&spawnattr);
if (err != 0) {
DLOG(WARNING) << "posix_spawnattr_init failed";
return Err(LaunchError("posix_spawnattr_init", err));
}
auto spawnattr_guard =
mozilla::MakeScopeExit([&spawnattr] { posix_spawnattr_destroy(&spawnattr); });
#if defined(XP_MACOSX) && defined(__aarch64__)
if (options.arch == PROCESS_ARCH_X86_64) {
cpu_type_t cpu_pref = CPU_TYPE_X86_64;
size_t count = 1;
size_t ocount = 0;
int rv = posix_spawnattr_setbinpref_np(&spawnattr, count, &cpu_pref, &ocount);
if ((rv != 0) || (ocount != count)) {
DLOG(WARNING) << "posix_spawnattr_setbinpref_np failed";
return Err(LaunchError("posix_spawnattr_setbinpref_np", rv));
}
}
#endif
if (options.disclaim) {
if (@available(macOS 10.14, *)) {
int err = responsibility_spawnattrs_setdisclaim(&spawnattr, 1);
if (err != 0) {
DLOG(WARNING) << "responsibility_spawnattrs_setdisclaim failed";
return Err(LaunchError("responsibility_spawnattrs_setdisclaim", err));
}
}
}
// Prevent the child process from inheriting any file descriptors
// that aren't named in `file_actions`. (This is an Apple-specific
// extension to posix_spawn.)
err = posix_spawnattr_setflags(&spawnattr, POSIX_SPAWN_CLOEXEC_DEFAULT);
if (err != 0) {
DLOG(WARNING) << "posix_spawnattr_setflags failed";
return Err(LaunchError("posix_spawnattr_setflags", err));
}
// Exempt std{in,out,err} from being closed by POSIX_SPAWN_CLOEXEC_DEFAULT.
for (int fd = 0; fd <= STDERR_FILENO; ++fd) {
err = posix_spawn_file_actions_addinherit_np(&file_actions, fd);
if (err != 0) {
DLOG(WARNING) << "posix_spawn_file_actions_addinherit_np failed";
return Err(LaunchError("posix_spawn_file_actions_addinherit_np", err));
}
}
int pid = 0;
int spawn_succeeded =
(posix_spawnp(&pid, argv_copy[0], &file_actions, &spawnattr, argv_copy, vars.get()) == 0);
bool process_handle_valid = pid > 0;
if (!spawn_succeeded || !process_handle_valid) {
DLOG(WARNING) << "posix_spawnp failed";
retval = Err(LaunchError("posix_spawnp", spawn_succeeded));
} else {
gProcessLog.print("==> process %d launched child process %d\n", GetCurrentProcId(), pid);
if (options.wait) HANDLE_EINTR(waitpid(pid, 0, 0));
if (process_handle) *process_handle = pid;
}
return retval;
}
Result<Ok, LaunchError> LaunchApp(const CommandLine& cl, const LaunchOptions& options,
ProcessHandle* process_handle) {
return LaunchApp(cl.argv(), options, process_handle);
}
} // namespace base
|
