]>
Commit | Line | Data |
---|---|---|
729e3769 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2011 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <sys/types.h> | |
23 | #include <stdlib.h> | |
24 | #include <unistd.h> | |
25 | #include <string.h> | |
26 | #include <sys/prctl.h> | |
27 | #include <signal.h> | |
28 | #include <fcntl.h> | |
29 | ||
30 | #include "log.h" | |
31 | #include "util.h" | |
32 | #include "spawn-agent.h" | |
33 | ||
34 | static pid_t agent_pid = 0; | |
35 | ||
36 | void agent_open(void) { | |
37 | pid_t parent_pid; | |
38 | ||
39 | if (agent_pid > 0) | |
40 | return; | |
41 | ||
42 | /* We check STDIN here, not STDOUT, since this is about input, | |
43 | * not output */ | |
44 | if (!isatty(STDIN_FILENO)) | |
45 | return; | |
46 | ||
47 | parent_pid = getpid(); | |
48 | ||
49 | /* Spawns a temporary TTY agent, making sure it goes away when | |
50 | * we go away */ | |
51 | ||
52 | agent_pid = fork(); | |
53 | if (agent_pid < 0) { | |
54 | log_error("Failed to fork agent: %m"); | |
55 | return; | |
56 | } | |
57 | ||
58 | if (agent_pid == 0) { | |
59 | /* In the child */ | |
60 | ||
61 | int fd; | |
62 | bool stdout_is_tty, stderr_is_tty; | |
63 | ||
64 | /* Make sure the agent goes away when the parent dies */ | |
65 | if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) | |
66 | _exit(EXIT_FAILURE); | |
67 | ||
68 | /* Check whether our parent died before we were able | |
69 | * to set the death signal */ | |
70 | if (getppid() != parent_pid) | |
71 | _exit(EXIT_SUCCESS); | |
72 | ||
73 | /* Don't leak fds to the agent */ | |
74 | close_all_fds(NULL, 0); | |
75 | ||
76 | stdout_is_tty = isatty(STDOUT_FILENO); | |
77 | stderr_is_tty = isatty(STDERR_FILENO); | |
78 | ||
79 | if (!stdout_is_tty || !stderr_is_tty) { | |
80 | /* Detach from stdout/stderr. and reopen | |
81 | * /dev/tty for them. This is important to | |
82 | * ensure that when systemctl is started via | |
83 | * popen() or a similar call that expects to | |
84 | * read EOF we actually do generate EOF and | |
85 | * not delay this indefinitely by because we | |
86 | * keep an unused copy of stdin around. */ | |
87 | fd = open("/dev/tty", O_WRONLY); | |
88 | if (fd < 0) { | |
89 | log_error("Failed to open /dev/tty: %m"); | |
90 | _exit(EXIT_FAILURE); | |
91 | } | |
92 | ||
93 | if (!stdout_is_tty) | |
94 | dup2(fd, STDOUT_FILENO); | |
95 | ||
96 | if (!stderr_is_tty) | |
97 | dup2(fd, STDERR_FILENO); | |
98 | ||
99 | if (fd > 2) | |
100 | close(fd); | |
101 | } | |
102 | ||
103 | execl(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, "--watch", NULL); | |
104 | ||
105 | log_error("Unable to execute agent: %m"); | |
106 | _exit(EXIT_FAILURE); | |
107 | } | |
108 | } | |
109 | ||
110 | void agent_close(void) { | |
111 | ||
112 | if (agent_pid <= 0) | |
113 | return; | |
114 | ||
115 | /* Inform agent that we are done */ | |
116 | kill(agent_pid, SIGTERM); | |
117 | kill(agent_pid, SIGCONT); | |
118 | wait_for_terminate(agent_pid, NULL); | |
119 | agent_pid = 0; | |
120 | } |