/* $NetBSD: detach.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */
/*-
* Copyright (c) 2015
* Cryptonector LLC. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Cryptonector LLC may not be used to endorse or promote products
* derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include <errno.h>
#include <fcntl.h>
#ifdef WIN32
#include <io.h>
#include <stdlib.h>
#else
#include <unistd.h>
#endif
#include <krb5/roken.h>
#ifdef WIN32
#define dup2 _dup2
#endif
static int pipefds[2] = {-1, -1};
ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
roken_detach_prep(int argc, char **argv, char *special_arg)
{
pid_t child;
char buf[1];
ssize_t bytes;
int status;
pipefds[0] = -1;
pipefds[1] = -1;
#ifdef WIN32
if (_pipe(pipefds, 4, O_BINARY) == -1)
err(1, "failed to setup to detach daemon (_pipe failed)");
#else
if (pipe(pipefds) == -1)
err(1, "failed to setup to detach daemon (pipe failed)");
#endif
#ifndef WIN32
fflush(stdout);
child = fork();
#else
{
intptr_t child_handle;
int write_side;
size_t i;
char *fildes;
char **new_argv;
new_argv = calloc(argc + 2, sizeof(*new_argv));
if (new_argv == NULL)
err(1, "Out of memory");
write_side = _dup(pipefds[1]); /* The new fd will be inherited */
if (write_side == -1)
err(1, "Out of memory");
if (asprintf(&fildes, "%d", write_side) == -1 ||
fildes == NULL)
err(1, "failed to setup to detach daemon (_dup failed)");
new_argv[0] = argv[0];
new_argv[1] = special_arg;
new_argv[2] = fildes;
for (i = 1; argv[i] != NULL; i++)
new_argv[i + 1] = argv[i];
new_argv[argc + 2] = NULL;
_flushall();
child_handle = spawnvp(_P_NOWAIT, argv[0], new_argv);
if (child_handle == -1)
child = (pid_t)-1;
else
child = GetProcessId((HANDLE)child_handle);
}
#endif
if (child == (pid_t)-1)
err(1, "failed to setup to fork daemon (fork failed)");
#ifndef WIN32
if (child == 0) {
int fd;
(void) close(pipefds[0]);
pipefds[0] = -1;
/*
* Keep stdout/stderr for now so output and errors prior to
* detach_finish() can be seen by the user.
*/
fd = open(_PATH_DEVNULL, O_RDWR, 0);
if (fd == -1)
err(1, "failed to open /dev/null");
(void) dup2(fd, STDIN_FILENO);
if (fd > STDERR_FILENO)
(void) close(fd);
return;
}
#endif
(void) close(pipefds[1]);
pipefds[1] = -1;
do {
bytes = read(pipefds[0], buf, sizeof(buf));
} while (bytes == -1 && errno == EINTR);
(void) close(pipefds[0]);
pipefds[0] = -1;
if (bytes == -1) {
/*
* No need to wait for the process. We've killed it. If it
* doesn't want to exit, we'd have to wait potentially forever,
* but we want to indicate failure to the user as soon as
* possible. A wait with timeout would end the same way
* (attempting to kill the process).
*/
err(1, "failed to setup daemon child (read from child pipe)");
}
if (bytes == 0) {
warnx("daemon child preparation failed, waiting for child");
status = wait_for_process(child);
if (SE_IS_ERROR(status) || SE_PROCSTATUS(status) != 0)
errx(SE_PROCSTATUS(status),
"daemon child preparation failed (child exited)");
}
_exit(0);
}
#ifdef WIN32
#ifdef dup2
#undef dup2
#endif
#define dup2 _dup2
#endif
ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
roken_detach_finish(const char *dir, int daemon_child_fd)
{
char buf[1] = "";
ssize_t bytes;
int fd;
rk_pidfile(NULL);
if (pipefds[1] == -1 && daemon_child_fd != -1)
pipefds[1] = daemon_child_fd;
if (pipefds[0] != -1)
(void) close(pipefds[0]);
if (pipefds[1] == -1)
return;
#ifdef HAVE_SETSID
if (setsid() == -1)
err(1, "failed to detach from tty");
#endif
#ifndef WIN32
/*
* Hopefully we've written any pidfiles by now, if they had to be in
* the current directory...
*
* The daemons do re-open logs and so on, therefore this chdir()
* call needs to be optional for testing.
*/
if (dir != NULL && chdir(dir) == -1)
err(1, "failed to chdir to /");
#endif
do {
bytes = write(pipefds[1], buf, sizeof(buf));
} while (bytes == -1 && errno == EINTR);
if (bytes == -1)
err(1, "failed to signal parent while detaching");
(void) close(pipefds[1]);
if (bytes != sizeof(buf))
errx(1, "failed to signal parent while detaching");
fd = open(_PATH_DEVNULL, O_RDWR, 0);
if (fd == -1)
err(1, "failed to open /dev/null");
/*
* Maybe we should check that our output got written, if redirected
* to a file. File utils normally do this.
*/
(void) dup2(fd, STDOUT_FILENO);
(void) dup2(fd, STDERR_FILENO);
if (fd > 2)
(void) close(fd);
}