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1968a360 LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
9 | under the terms of the GNU Lesser General Public License as published by |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
1968a360 LP |
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 | |
5430f7f2 | 16 | Lesser General Public License for more details. |
1968a360 | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
1968a360 LP |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
20 | ***/ | |
21 | ||
4a8e40eb | 22 | #include <fcntl.h> |
1968a360 LP |
23 | #include <stdlib.h> |
24 | #include <unistd.h> | |
25 | #include <string.h> | |
26 | #include <sys/prctl.h> | |
27 | ||
28 | #include "pager.h" | |
29 | #include "util.h" | |
0b452006 | 30 | #include "process-util.h" |
1968a360 | 31 | #include "macro.h" |
288a74cc | 32 | #include "terminal-util.h" |
ce30c8dc | 33 | #include "signal-util.h" |
6a7c676c | 34 | #include "copy.h" |
1968a360 LP |
35 | |
36 | static pid_t pager_pid = 0; | |
37 | ||
919ce0b7 | 38 | noreturn static void pager_fallback(void) { |
6a7c676c | 39 | int r; |
46e65dcc | 40 | |
6a7c676c LP |
41 | r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (off_t) -1, false); |
42 | if (r < 0) { | |
43 | log_error_errno(r, "Internal pager failed: %m"); | |
4a8e40eb MS |
44 | _exit(EXIT_FAILURE); |
45 | } | |
46e65dcc | 46 | |
4a8e40eb MS |
47 | _exit(EXIT_SUCCESS); |
48 | } | |
49 | ||
1b12a7b5 | 50 | int pager_open(bool jump_to_end) { |
1968a360 LP |
51 | int fd[2]; |
52 | const char *pager; | |
53 | pid_t parent_pid; | |
f89a3b6f | 54 | int r; |
1968a360 LP |
55 | |
56 | if (pager_pid > 0) | |
f89a3b6f | 57 | return 1; |
1968a360 | 58 | |
1968a360 LP |
59 | if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER"))) |
60 | if (!*pager || streq(pager, "cat")) | |
f89a3b6f | 61 | return 0; |
1968a360 | 62 | |
8481248b | 63 | if (!on_tty()) |
f89a3b6f | 64 | return 0; |
729e3769 | 65 | |
1968a360 LP |
66 | /* Determine and cache number of columns before we spawn the |
67 | * pager so that we get the value from the actual tty */ | |
68 | columns(); | |
69 | ||
4a62c710 MS |
70 | if (pipe(fd) < 0) |
71 | return log_error_errno(errno, "Failed to create pager pipe: %m"); | |
1968a360 LP |
72 | |
73 | parent_pid = getpid(); | |
74 | ||
75 | pager_pid = fork(); | |
76 | if (pager_pid < 0) { | |
f89a3b6f | 77 | r = -errno; |
56f64d95 | 78 | log_error_errno(errno, "Failed to fork pager: %m"); |
3d94f76c | 79 | safe_close_pair(fd); |
f89a3b6f | 80 | return r; |
1968a360 LP |
81 | } |
82 | ||
83 | /* In the child start the pager */ | |
84 | if (pager_pid == 0) { | |
f366d58d | 85 | const char* less_opts; |
1968a360 | 86 | |
ce30c8dc LP |
87 | (void) reset_all_signal_handlers(); |
88 | (void) reset_signal_mask(); | |
89 | ||
1968a360 | 90 | dup2(fd[0], STDIN_FILENO); |
3d94f76c | 91 | safe_close_pair(fd); |
1968a360 | 92 | |
f366d58d JD |
93 | less_opts = getenv("SYSTEMD_LESS"); |
94 | if (!less_opts) | |
95 | less_opts = "FRSXMK"; | |
1b12a7b5 | 96 | if (jump_to_end) |
63c372cb | 97 | less_opts = strjoina(less_opts, " +G"); |
f366d58d | 98 | setenv("LESS", less_opts, 1); |
1968a360 LP |
99 | |
100 | /* Make sure the pager goes away when the parent dies */ | |
101 | if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) | |
102 | _exit(EXIT_FAILURE); | |
103 | ||
104 | /* Check whether our parent died before we were able | |
105 | * to set the death signal */ | |
106 | if (getppid() != parent_pid) | |
107 | _exit(EXIT_SUCCESS); | |
108 | ||
109 | if (pager) { | |
110 | execlp(pager, pager, NULL); | |
111 | execl("/bin/sh", "sh", "-c", pager, NULL); | |
112 | } | |
113 | ||
114 | /* Debian's alternatives command for pagers is | |
115 | * called 'pager'. Note that we do not call | |
116 | * sensible-pagers here, since that is just a | |
117 | * shell script that implements a logic that | |
118 | * is similar to this one anyway, but is | |
119 | * Debian-specific. */ | |
120 | execlp("pager", "pager", NULL); | |
121 | ||
122 | execlp("less", "less", NULL); | |
123 | execlp("more", "more", NULL); | |
1968a360 | 124 | |
4a8e40eb MS |
125 | pager_fallback(); |
126 | /* not reached */ | |
1968a360 LP |
127 | } |
128 | ||
129 | /* Return in the parent */ | |
4a62c710 MS |
130 | if (dup2(fd[1], STDOUT_FILENO) < 0) |
131 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
8b5264aa LP |
132 | if (dup2(fd[1], STDERR_FILENO) < 0) |
133 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
1968a360 | 134 | |
3d94f76c | 135 | safe_close_pair(fd); |
f89a3b6f | 136 | return 1; |
1968a360 LP |
137 | } |
138 | ||
139 | void pager_close(void) { | |
140 | ||
141 | if (pager_pid <= 0) | |
142 | return; | |
143 | ||
144 | /* Inform pager that we are done */ | |
145 | fclose(stdout); | |
8b5264aa LP |
146 | stdout = NULL; |
147 | ||
148 | fclose(stderr); | |
149 | stderr = NULL; | |
150 | ||
1968a360 | 151 | kill(pager_pid, SIGCONT); |
c73d180d | 152 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
153 | pager_pid = 0; |
154 | } | |
f89a3b6f LP |
155 | |
156 | bool pager_have(void) { | |
157 | return pager_pid > 0; | |
158 | } | |
78002a67 ZJS |
159 | |
160 | int show_man_page(const char *desc, bool null_stdio) { | |
161 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
162 | char *e = NULL; | |
163 | pid_t pid; | |
164 | size_t k; | |
165 | int r; | |
166 | siginfo_t status; | |
167 | ||
168 | k = strlen(desc); | |
169 | ||
170 | if (desc[k-1] == ')') | |
171 | e = strrchr(desc, '('); | |
172 | ||
173 | if (e) { | |
174 | char *page = NULL, *section = NULL; | |
175 | ||
176 | page = strndupa(desc, e - desc); | |
177 | section = strndupa(e + 1, desc + k - e - 2); | |
178 | ||
179 | args[1] = section; | |
180 | args[2] = page; | |
181 | } else | |
182 | args[1] = desc; | |
183 | ||
184 | pid = fork(); | |
4a62c710 MS |
185 | if (pid < 0) |
186 | return log_error_errno(errno, "Failed to fork: %m"); | |
78002a67 ZJS |
187 | |
188 | if (pid == 0) { | |
189 | /* Child */ | |
ce30c8dc LP |
190 | |
191 | (void) reset_all_signal_handlers(); | |
192 | (void) reset_signal_mask(); | |
193 | ||
78002a67 ZJS |
194 | if (null_stdio) { |
195 | r = make_null_stdio(); | |
196 | if (r < 0) { | |
da927ba9 | 197 | log_error_errno(r, "Failed to kill stdio: %m"); |
78002a67 ZJS |
198 | _exit(EXIT_FAILURE); |
199 | } | |
200 | } | |
201 | ||
202 | execvp(args[0], (char**) args); | |
56f64d95 | 203 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
204 | _exit(EXIT_FAILURE); |
205 | } | |
206 | ||
207 | r = wait_for_terminate(pid, &status); | |
208 | if (r < 0) | |
209 | return r; | |
210 | ||
211 | log_debug("Exit code %i status %i", status.si_code, status.si_status); | |
212 | return status.si_status; | |
213 | } |