src/shared/spawn-polkit-agent.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2011 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <poll.h>
  22 #include <signal.h>
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25
  26 #include "fd-util.h"
  27 #include "io-util.h"
  28 #include "log.h"
  29 #include "macro.h"
  30 #include "process-util.h"
  31 #include "spawn-polkit-agent.h"
  32 #include "stdio-util.h"
  33 #include "time-util.h"
  34 #include "util.h"
  35
  36 #if ENABLE_POLKIT
  37 static pid_t agent_pid = 0;
  38
  39 int polkit_agent_open(void) {
  40         int r;
  41         int pipe_fd[2];
  42         char notify_fd[DECIMAL_STR_MAX(int) + 1];
  43
  44         if (agent_pid > 0)
  45                 return 0;
  46
  47         /* Clients that run as root don't need to activate/query polkit */
  48         if (geteuid() == 0)
  49                 return 0;
  50
  51         /* We check STDIN here, not STDOUT, since this is about input,
  52          * not output */
  53         if (!isatty(STDIN_FILENO))
  54                 return 0;
  55
  56         if (pipe2(pipe_fd, 0) < 0)
  57                 return -errno;
  58
  59         xsprintf(notify_fd, "%i", pipe_fd[1]);
  60
  61         r = fork_agent(&agent_pid,
  62                        &pipe_fd[1], 1,
  63                        POLKIT_AGENT_BINARY_PATH,
  64                        POLKIT_AGENT_BINARY_PATH, "--notify-fd", notify_fd, "--fallback", NULL);
  65
  66         /* Close the writing side, because that's the one for the agent */
  67         safe_close(pipe_fd[1]);
  68
  69         if (r < 0)
  70                 log_error_errno(r, "Failed to fork TTY ask password agent: %m");
  71         else
  72                 /* Wait until the agent closes the fd */
  73                 fd_wait_for_event(pipe_fd[0], POLLHUP, USEC_INFINITY);
  74
  75         safe_close(pipe_fd[0]);
  76
  77         return r;
  78 }
  79
  80 void polkit_agent_close(void) {
  81
  82         if (agent_pid <= 0)
  83                 return;
  84
  85         /* Inform agent that we are done */
  86         (void) kill(agent_pid, SIGTERM);
  87         (void) kill(agent_pid, SIGCONT);
  88
  89         (void) wait_for_terminate(agent_pid, NULL);
  90         agent_pid = 0;
  91 }
  92
  93 #else
  94
  95 int polkit_agent_open(void) {
  96         return 0;
  97 }
  98
  99 void polkit_agent_close(void) {
 100 }
 101
 102 #endif