| // Copyright (c) 2011 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 "chrome/common/multi_process_lock.h" |
| |
| #include <stddef.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <sys/socket.h> |
| #include <sys/un.h> |
| #include <unistd.h> |
| |
| #include "base/compiler_specific.h" |
| #include "base/logging.h" |
| #include "base/macros.h" |
| #include "base/posix/eintr_wrapper.h" |
| |
| class MultiProcessLockLinux : public MultiProcessLock { |
| public: |
| explicit MultiProcessLockLinux(const std::string& name) |
| : name_(name), fd_(-1) { } |
| |
| ~MultiProcessLockLinux() override { |
| if (fd_ != -1) { |
| Unlock(); |
| } |
| } |
| |
| bool TryLock() override { |
| struct sockaddr_un address; |
| |
| // +1 for terminator, +1 for 0 in position 0 that makes it an |
| // abstract named socket. |
| const size_t max_len = sizeof(address.sun_path) - 2; |
| |
| if (fd_ != -1) { |
| DLOG(ERROR) << "MultiProcessLock is already locked - " << name_; |
| return true; |
| } |
| |
| if (name_.length() > max_len) { |
| LOG(ERROR) << "Socket name too long (" << name_.length() |
| << " > " << max_len << ") - " << name_; |
| return false; |
| } |
| |
| memset(&address, 0, sizeof(address)); |
| int print_length = snprintf(&address.sun_path[1], |
| max_len + 1, |
| "%s", name_.c_str()); |
| |
| if (print_length < 0 || |
| print_length > static_cast<int>(max_len)) { |
| PLOG(ERROR) << "Couldn't create sun_path - " << name_; |
| return false; |
| } |
| |
| // Must set the first character of the path to something non-zero |
| // before we call SUN_LEN which depends on strcpy working. |
| address.sun_path[0] = '@'; |
| size_t length = SUN_LEN(&address); |
| |
| // Reset the first character of the path back to zero so that |
| // bind returns an abstract name socket. |
| address.sun_path[0] = 0; |
| address.sun_family = AF_LOCAL; |
| |
| int socket_fd = socket(AF_LOCAL, SOCK_STREAM, 0); |
| if (socket_fd < 0) { |
| PLOG(ERROR) << "Couldn't create socket - " << name_; |
| return false; |
| } |
| |
| if (bind(socket_fd, |
| reinterpret_cast<sockaddr *>(&address), |
| length) == 0) { |
| fd_ = socket_fd; |
| return true; |
| } else { |
| DVLOG(1) << "Couldn't bind socket - " |
| << &(address.sun_path[1]) |
| << " Length: " << length; |
| if (IGNORE_EINTR(close(socket_fd)) < 0) { |
| PLOG(ERROR) << "close"; |
| } |
| return false; |
| } |
| } |
| |
| void Unlock() override { |
| if (fd_ == -1) { |
| DLOG(ERROR) << "Over-unlocked MultiProcessLock - " << name_; |
| return; |
| } |
| if (IGNORE_EINTR(close(fd_)) < 0) { |
| DPLOG(ERROR) << "close"; |
| } |
| fd_ = -1; |
| } |
| |
| private: |
| std::string name_; |
| int fd_; |
| DISALLOW_COPY_AND_ASSIGN(MultiProcessLockLinux); |
| }; |
| |
| MultiProcessLock* MultiProcessLock::Create(const std::string &name) { |
| return new MultiProcessLockLinux(name); |
| } |