nghttp2/src/shrpx_exec.cc

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/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2016 Tatsuhiro Tsujikawa
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "shrpx_exec.h"
#include <cerrno>
#include "shrpx_signal.h"
#include "shrpx_log.h"
#include "util.h"
#include "template.h"
using namespace nghttp2;
namespace shrpx {
// inspired by h2o_read_command function from h2o project:
// https://github.com/h2o/h2o
int exec_read_command(Process &proc, char *const argv[]) {
int rv;
int pfd[2];
#ifdef O_CLOEXEC
if (pipe2(pfd, O_CLOEXEC) == -1) {
return -1;
}
#else // !O_CLOEXEC
if (pipe(pfd) == -1) {
return -1;
}
util::make_socket_closeonexec(pfd[0]);
util::make_socket_closeonexec(pfd[1]);
#endif // !O_CLOEXEC
auto closer = defer([&pfd]() {
if (pfd[0] != -1) {
close(pfd[0]);
}
if (pfd[1] != -1) {
close(pfd[1]);
}
});
sigset_t oldset;
rv = shrpx_signal_block_all(&oldset);
if (rv != 0) {
auto error = errno;
LOG(ERROR) << "Blocking all signals failed: errno=" << error;
return -1;
}
auto pid = fork();
if (pid == 0) {
// This is multithreaded program, and we are allowed to use only
// async-signal-safe functions here.
// child process
shrpx_signal_unset_worker_proc_ign_handler();
rv = shrpx_signal_unblock_all();
if (rv != 0) {
constexpr char msg[] = "Unblocking all signals failed\n";
while (write(STDERR_FILENO, msg, str_size(msg)) == -1 && errno == EINTR)
;
nghttp2_Exit(EXIT_FAILURE);
}
dup2(pfd[1], 1);
close(pfd[0]);
rv = execv(argv[0], argv);
if (rv == -1) {
constexpr char msg[] = "Could not execute command\n";
while (write(STDERR_FILENO, msg, str_size(msg)) == -1 && errno == EINTR)
;
nghttp2_Exit(EXIT_FAILURE);
}
// unreachable
}
// parent process
if (pid == -1) {
auto error = errno;
LOG(ERROR) << "Could not execute command: " << argv[0]
<< ", fork() failed, errno=" << error;
}
rv = shrpx_signal_set(&oldset);
if (rv != 0) {
auto error = errno;
LOG(FATAL) << "Restoring all signals failed: errno=" << error;
nghttp2_Exit(EXIT_FAILURE);
}
if (pid == -1) {
return -1;
}
close(pfd[1]);
pfd[1] = -1;
util::make_socket_nonblocking(pfd[0]);
proc.pid = pid;
proc.rfd = pfd[0];
pfd[0] = -1;
return 0;
}
} // namespace shrpx