729e3769c3
This adds a number of new options to systemctl, for presets, reenabling, masking/unmask, and runtime operations.
121 lines
3.7 KiB
C
121 lines
3.7 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2011 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/types.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/prctl.h>
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#include <signal.h>
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#include <fcntl.h>
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#include "log.h"
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#include "util.h"
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#include "spawn-agent.h"
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static pid_t agent_pid = 0;
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void agent_open(void) {
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pid_t parent_pid;
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if (agent_pid > 0)
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return;
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/* We check STDIN here, not STDOUT, since this is about input,
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* not output */
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if (!isatty(STDIN_FILENO))
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return;
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parent_pid = getpid();
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/* Spawns a temporary TTY agent, making sure it goes away when
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* we go away */
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agent_pid = fork();
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if (agent_pid < 0) {
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log_error("Failed to fork agent: %m");
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return;
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}
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if (agent_pid == 0) {
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/* In the child */
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int fd;
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bool stdout_is_tty, stderr_is_tty;
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/* Make sure the agent goes away when the parent dies */
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if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
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_exit(EXIT_FAILURE);
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/* Check whether our parent died before we were able
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* to set the death signal */
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if (getppid() != parent_pid)
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_exit(EXIT_SUCCESS);
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/* Don't leak fds to the agent */
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close_all_fds(NULL, 0);
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stdout_is_tty = isatty(STDOUT_FILENO);
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stderr_is_tty = isatty(STDERR_FILENO);
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if (!stdout_is_tty || !stderr_is_tty) {
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/* Detach from stdout/stderr. and reopen
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* /dev/tty for them. This is important to
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* ensure that when systemctl is started via
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* popen() or a similar call that expects to
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* read EOF we actually do generate EOF and
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* not delay this indefinitely by because we
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* keep an unused copy of stdin around. */
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fd = open("/dev/tty", O_WRONLY);
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if (fd < 0) {
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log_error("Failed to open /dev/tty: %m");
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_exit(EXIT_FAILURE);
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}
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if (!stdout_is_tty)
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dup2(fd, STDOUT_FILENO);
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if (!stderr_is_tty)
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dup2(fd, STDERR_FILENO);
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if (fd > 2)
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close(fd);
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}
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execl(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, "--watch", NULL);
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log_error("Unable to execute agent: %m");
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_exit(EXIT_FAILURE);
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}
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}
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void agent_close(void) {
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if (agent_pid <= 0)
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return;
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/* Inform agent that we are done */
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kill(agent_pid, SIGTERM);
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kill(agent_pid, SIGCONT);
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wait_for_terminate(agent_pid, NULL);
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agent_pid = 0;
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}
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