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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 | |
59f448cf | 41 | r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (uint64_t) -1, false); |
6a7c676c LP |
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) { |
bcbd61db | 51 | _cleanup_close_pair_ int fd[2] = { -1, -1 }; |
1968a360 LP |
52 | const char *pager; |
53 | pid_t parent_pid; | |
54 | ||
55 | if (pager_pid > 0) | |
f89a3b6f | 56 | return 1; |
1968a360 | 57 | |
8481248b | 58 | if (!on_tty()) |
f89a3b6f | 59 | return 0; |
729e3769 | 60 | |
bcbd61db LP |
61 | pager = getenv("SYSTEMD_PAGER"); |
62 | if (!pager) | |
63 | pager = getenv("PAGER"); | |
64 | ||
65 | /* If the pager is explicitly turned off, honour it */ | |
66 | if (pager && (pager[0] == 0 || streq(pager, "cat"))) | |
67 | return 0; | |
68 | ||
1968a360 LP |
69 | /* Determine and cache number of columns before we spawn the |
70 | * pager so that we get the value from the actual tty */ | |
bcbd61db | 71 | (void) columns(); |
1968a360 | 72 | |
4a62c710 MS |
73 | if (pipe(fd) < 0) |
74 | return log_error_errno(errno, "Failed to create pager pipe: %m"); | |
1968a360 LP |
75 | |
76 | parent_pid = getpid(); | |
77 | ||
78 | pager_pid = fork(); | |
bcbd61db | 79 | if (pager_pid < 0) |
65359589 | 80 | return log_error_errno(errno, "Failed to fork pager: %m"); |
1968a360 LP |
81 | |
82 | /* In the child start the pager */ | |
83 | if (pager_pid == 0) { | |
a1b4e6e9 | 84 | const char* less_opts, *less_charset; |
1968a360 | 85 | |
ce30c8dc LP |
86 | (void) reset_all_signal_handlers(); |
87 | (void) reset_signal_mask(); | |
88 | ||
bcbd61db | 89 | (void) dup2(fd[0], STDIN_FILENO); |
3d94f76c | 90 | safe_close_pair(fd); |
1968a360 | 91 | |
a1b4e6e9 | 92 | /* Initialize a good set of less options */ |
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 | 99 | |
a1b4e6e9 LP |
100 | /* Initialize a good charset for less. This is |
101 | * particularly important if we output UTF-8 | |
102 | * characters. */ | |
103 | less_charset = getenv("SYSTEMD_LESSCHARSET"); | |
104 | if (!less_charset && is_locale_utf8()) | |
105 | less_charset = "utf-8"; | |
106 | if (less_charset) | |
107 | setenv("LESSCHARSET", less_charset, 1); | |
108 | ||
1968a360 LP |
109 | /* Make sure the pager goes away when the parent dies */ |
110 | if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) | |
111 | _exit(EXIT_FAILURE); | |
112 | ||
113 | /* Check whether our parent died before we were able | |
114 | * to set the death signal */ | |
115 | if (getppid() != parent_pid) | |
116 | _exit(EXIT_SUCCESS); | |
117 | ||
118 | if (pager) { | |
119 | execlp(pager, pager, NULL); | |
120 | execl("/bin/sh", "sh", "-c", pager, NULL); | |
121 | } | |
122 | ||
123 | /* Debian's alternatives command for pagers is | |
124 | * called 'pager'. Note that we do not call | |
125 | * sensible-pagers here, since that is just a | |
126 | * shell script that implements a logic that | |
127 | * is similar to this one anyway, but is | |
128 | * Debian-specific. */ | |
129 | execlp("pager", "pager", NULL); | |
130 | ||
131 | execlp("less", "less", NULL); | |
132 | execlp("more", "more", NULL); | |
1968a360 | 133 | |
4a8e40eb MS |
134 | pager_fallback(); |
135 | /* not reached */ | |
1968a360 LP |
136 | } |
137 | ||
138 | /* Return in the parent */ | |
4a62c710 MS |
139 | if (dup2(fd[1], STDOUT_FILENO) < 0) |
140 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
8b5264aa LP |
141 | if (dup2(fd[1], STDERR_FILENO) < 0) |
142 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
1968a360 | 143 | |
f89a3b6f | 144 | return 1; |
1968a360 LP |
145 | } |
146 | ||
147 | void pager_close(void) { | |
148 | ||
149 | if (pager_pid <= 0) | |
150 | return; | |
151 | ||
152 | /* Inform pager that we are done */ | |
74ca738f LP |
153 | stdout = safe_fclose(stdout); |
154 | stderr = safe_fclose(stderr); | |
8b5264aa | 155 | |
74ca738f | 156 | (void) kill(pager_pid, SIGCONT); |
c73d180d | 157 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
158 | pager_pid = 0; |
159 | } | |
f89a3b6f LP |
160 | |
161 | bool pager_have(void) { | |
162 | return pager_pid > 0; | |
163 | } | |
78002a67 ZJS |
164 | |
165 | int show_man_page(const char *desc, bool null_stdio) { | |
166 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
167 | char *e = NULL; | |
168 | pid_t pid; | |
169 | size_t k; | |
170 | int r; | |
171 | siginfo_t status; | |
172 | ||
173 | k = strlen(desc); | |
174 | ||
175 | if (desc[k-1] == ')') | |
176 | e = strrchr(desc, '('); | |
177 | ||
178 | if (e) { | |
179 | char *page = NULL, *section = NULL; | |
180 | ||
181 | page = strndupa(desc, e - desc); | |
182 | section = strndupa(e + 1, desc + k - e - 2); | |
183 | ||
184 | args[1] = section; | |
185 | args[2] = page; | |
186 | } else | |
187 | args[1] = desc; | |
188 | ||
189 | pid = fork(); | |
4a62c710 MS |
190 | if (pid < 0) |
191 | return log_error_errno(errno, "Failed to fork: %m"); | |
78002a67 ZJS |
192 | |
193 | if (pid == 0) { | |
194 | /* Child */ | |
ce30c8dc LP |
195 | |
196 | (void) reset_all_signal_handlers(); | |
197 | (void) reset_signal_mask(); | |
198 | ||
78002a67 ZJS |
199 | if (null_stdio) { |
200 | r = make_null_stdio(); | |
201 | if (r < 0) { | |
da927ba9 | 202 | log_error_errno(r, "Failed to kill stdio: %m"); |
78002a67 ZJS |
203 | _exit(EXIT_FAILURE); |
204 | } | |
205 | } | |
206 | ||
207 | execvp(args[0], (char**) args); | |
56f64d95 | 208 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
209 | _exit(EXIT_FAILURE); |
210 | } | |
211 | ||
212 | r = wait_for_terminate(pid, &status); | |
213 | if (r < 0) | |
214 | return r; | |
215 | ||
216 | log_debug("Exit code %i status %i", status.si_code, status.si_status); | |
217 | return status.si_status; | |
218 | } |