src/shared/spawn-polkit-agent.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2011 Lennart Poettering
   4 ***/
   5
   6 #include <errno.h>
   7 #include <poll.h>
   8 #include <signal.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11
  12 #include "fd-util.h"
  13 #include "io-util.h"
  14 #include "log.h"
  15 #include "macro.h"
  16 #include "process-util.h"
  17 #include "spawn-polkit-agent.h"
  18 #include "stdio-util.h"
  19 #include "time-util.h"
  20 #include "util.h"
  21
  22 #if ENABLE_POLKIT
  23 static pid_t agent_pid = 0;
  24
  25 int polkit_agent_open(void) {
  26         char notify_fd[DECIMAL_STR_MAX(int) + 1];
  27         int pipe_fd[2], r;
  28
  29         if (agent_pid > 0)
  30                 return 0;
  31
  32         /* Clients that run as root don't need to activate/query polkit */
  33         if (geteuid() == 0)
  34                 return 0;
  35
  36         /* We check STDIN here, not STDOUT, since this is about input, not output */
  37         if (!isatty(STDIN_FILENO))
  38                 return 0;
  39
  40         if (!is_main_thread())
  41                 return -EPERM;
  42
  43         if (pipe2(pipe_fd, 0) < 0)
  44                 return -errno;
  45
  46         xsprintf(notify_fd, "%i", pipe_fd[1]);
  47
  48         r = fork_agent("(polkit-agent)",
  49                        &pipe_fd[1], 1,
  50                        &agent_pid,
  51                        POLKIT_AGENT_BINARY_PATH,
  52                        POLKIT_AGENT_BINARY_PATH, "--notify-fd", notify_fd, "--fallback", NULL);
  53
  54         /* Close the writing side, because that's the one for the agent */
  55         safe_close(pipe_fd[1]);
  56
  57         if (r < 0)
  58                 log_error_errno(r, "Failed to fork TTY ask password agent: %m");
  59         else
  60                 /* Wait until the agent closes the fd */
  61                 fd_wait_for_event(pipe_fd[0], POLLHUP, USEC_INFINITY);
  62
  63         safe_close(pipe_fd[0]);
  64
  65         return r;
  66 }
  67
  68 void polkit_agent_close(void) {
  69
  70         if (agent_pid <= 0)
  71                 return;
  72
  73         /* Inform agent that we are done */
  74         (void) kill_and_sigcont(agent_pid, SIGTERM);
  75         (void) wait_for_terminate(agent_pid, NULL);
  76         agent_pid = 0;
  77 }
  78
  79 #else
  80
  81 int polkit_agent_open(void) {
  82         return 0;
  83 }
  84
  85 void polkit_agent_close(void) {
  86 }
  87
  88 #endif