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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 | 23 | #include <stdlib.h> |
1968a360 LP |
24 | #include <string.h> |
25 | #include <sys/prctl.h> | |
07630cea | 26 | #include <unistd.h> |
1968a360 | 27 | |
07630cea | 28 | #include "copy.h" |
3ffd4af2 | 29 | #include "fd-util.h" |
8752c575 | 30 | #include "locale-util.h" |
1968a360 | 31 | #include "macro.h" |
3ffd4af2 | 32 | #include "pager.h" |
07630cea | 33 | #include "process-util.h" |
ce30c8dc | 34 | #include "signal-util.h" |
07630cea LP |
35 | #include "string-util.h" |
36 | #include "terminal-util.h" | |
37 | #include "util.h" | |
1968a360 LP |
38 | |
39 | static pid_t pager_pid = 0; | |
40 | ||
919ce0b7 | 41 | noreturn static void pager_fallback(void) { |
6a7c676c | 42 | int r; |
46e65dcc | 43 | |
59f448cf | 44 | r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (uint64_t) -1, false); |
6a7c676c LP |
45 | if (r < 0) { |
46 | log_error_errno(r, "Internal pager failed: %m"); | |
4a8e40eb MS |
47 | _exit(EXIT_FAILURE); |
48 | } | |
46e65dcc | 49 | |
4a8e40eb MS |
50 | _exit(EXIT_SUCCESS); |
51 | } | |
52 | ||
1b12a7b5 | 53 | int pager_open(bool jump_to_end) { |
bcbd61db | 54 | _cleanup_close_pair_ int fd[2] = { -1, -1 }; |
1968a360 LP |
55 | const char *pager; |
56 | pid_t parent_pid; | |
57 | ||
58 | if (pager_pid > 0) | |
f89a3b6f | 59 | return 1; |
1968a360 | 60 | |
8481248b | 61 | if (!on_tty()) |
f89a3b6f | 62 | return 0; |
729e3769 | 63 | |
bcbd61db LP |
64 | pager = getenv("SYSTEMD_PAGER"); |
65 | if (!pager) | |
66 | pager = getenv("PAGER"); | |
67 | ||
68 | /* If the pager is explicitly turned off, honour it */ | |
69 | if (pager && (pager[0] == 0 || streq(pager, "cat"))) | |
70 | return 0; | |
71 | ||
1968a360 LP |
72 | /* Determine and cache number of columns before we spawn the |
73 | * pager so that we get the value from the actual tty */ | |
bcbd61db | 74 | (void) columns(); |
1968a360 | 75 | |
4a62c710 MS |
76 | if (pipe(fd) < 0) |
77 | return log_error_errno(errno, "Failed to create pager pipe: %m"); | |
1968a360 LP |
78 | |
79 | parent_pid = getpid(); | |
80 | ||
81 | pager_pid = fork(); | |
bcbd61db | 82 | if (pager_pid < 0) |
65359589 | 83 | return log_error_errno(errno, "Failed to fork pager: %m"); |
1968a360 LP |
84 | |
85 | /* In the child start the pager */ | |
86 | if (pager_pid == 0) { | |
a1b4e6e9 | 87 | const char* less_opts, *less_charset; |
1968a360 | 88 | |
ce30c8dc LP |
89 | (void) reset_all_signal_handlers(); |
90 | (void) reset_signal_mask(); | |
91 | ||
bcbd61db | 92 | (void) dup2(fd[0], STDIN_FILENO); |
3d94f76c | 93 | safe_close_pair(fd); |
1968a360 | 94 | |
a1b4e6e9 | 95 | /* Initialize a good set of less options */ |
f366d58d JD |
96 | less_opts = getenv("SYSTEMD_LESS"); |
97 | if (!less_opts) | |
98 | less_opts = "FRSXMK"; | |
1b12a7b5 | 99 | if (jump_to_end) |
63c372cb | 100 | less_opts = strjoina(less_opts, " +G"); |
f366d58d | 101 | setenv("LESS", less_opts, 1); |
1968a360 | 102 | |
a1b4e6e9 LP |
103 | /* Initialize a good charset for less. This is |
104 | * particularly important if we output UTF-8 | |
105 | * characters. */ | |
106 | less_charset = getenv("SYSTEMD_LESSCHARSET"); | |
107 | if (!less_charset && is_locale_utf8()) | |
108 | less_charset = "utf-8"; | |
109 | if (less_charset) | |
110 | setenv("LESSCHARSET", less_charset, 1); | |
111 | ||
1968a360 LP |
112 | /* Make sure the pager goes away when the parent dies */ |
113 | if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) | |
114 | _exit(EXIT_FAILURE); | |
115 | ||
116 | /* Check whether our parent died before we were able | |
117 | * to set the death signal */ | |
118 | if (getppid() != parent_pid) | |
119 | _exit(EXIT_SUCCESS); | |
120 | ||
121 | if (pager) { | |
122 | execlp(pager, pager, NULL); | |
123 | execl("/bin/sh", "sh", "-c", pager, NULL); | |
124 | } | |
125 | ||
126 | /* Debian's alternatives command for pagers is | |
127 | * called 'pager'. Note that we do not call | |
128 | * sensible-pagers here, since that is just a | |
129 | * shell script that implements a logic that | |
130 | * is similar to this one anyway, but is | |
131 | * Debian-specific. */ | |
132 | execlp("pager", "pager", NULL); | |
133 | ||
134 | execlp("less", "less", NULL); | |
135 | execlp("more", "more", NULL); | |
1968a360 | 136 | |
4a8e40eb MS |
137 | pager_fallback(); |
138 | /* not reached */ | |
1968a360 LP |
139 | } |
140 | ||
141 | /* Return in the parent */ | |
4a62c710 MS |
142 | if (dup2(fd[1], STDOUT_FILENO) < 0) |
143 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
8b5264aa LP |
144 | if (dup2(fd[1], STDERR_FILENO) < 0) |
145 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
1968a360 | 146 | |
f89a3b6f | 147 | return 1; |
1968a360 LP |
148 | } |
149 | ||
150 | void pager_close(void) { | |
151 | ||
152 | if (pager_pid <= 0) | |
153 | return; | |
154 | ||
155 | /* Inform pager that we are done */ | |
74ca738f LP |
156 | stdout = safe_fclose(stdout); |
157 | stderr = safe_fclose(stderr); | |
8b5264aa | 158 | |
74ca738f | 159 | (void) kill(pager_pid, SIGCONT); |
c73d180d | 160 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
161 | pager_pid = 0; |
162 | } | |
f89a3b6f LP |
163 | |
164 | bool pager_have(void) { | |
165 | return pager_pid > 0; | |
166 | } | |
78002a67 ZJS |
167 | |
168 | int show_man_page(const char *desc, bool null_stdio) { | |
169 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
170 | char *e = NULL; | |
171 | pid_t pid; | |
172 | size_t k; | |
173 | int r; | |
174 | siginfo_t status; | |
175 | ||
176 | k = strlen(desc); | |
177 | ||
178 | if (desc[k-1] == ')') | |
179 | e = strrchr(desc, '('); | |
180 | ||
181 | if (e) { | |
182 | char *page = NULL, *section = NULL; | |
183 | ||
184 | page = strndupa(desc, e - desc); | |
185 | section = strndupa(e + 1, desc + k - e - 2); | |
186 | ||
187 | args[1] = section; | |
188 | args[2] = page; | |
189 | } else | |
190 | args[1] = desc; | |
191 | ||
192 | pid = fork(); | |
4a62c710 MS |
193 | if (pid < 0) |
194 | return log_error_errno(errno, "Failed to fork: %m"); | |
78002a67 ZJS |
195 | |
196 | if (pid == 0) { | |
197 | /* Child */ | |
ce30c8dc LP |
198 | |
199 | (void) reset_all_signal_handlers(); | |
200 | (void) reset_signal_mask(); | |
201 | ||
78002a67 ZJS |
202 | if (null_stdio) { |
203 | r = make_null_stdio(); | |
204 | if (r < 0) { | |
da927ba9 | 205 | log_error_errno(r, "Failed to kill stdio: %m"); |
78002a67 ZJS |
206 | _exit(EXIT_FAILURE); |
207 | } | |
208 | } | |
209 | ||
210 | execvp(args[0], (char**) args); | |
56f64d95 | 211 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
212 | _exit(EXIT_FAILURE); |
213 | } | |
214 | ||
215 | r = wait_for_terminate(pid, &status); | |
216 | if (r < 0) | |
217 | return r; | |
218 | ||
219 | log_debug("Exit code %i status %i", status.si_code, status.si_status); | |
220 | return status.si_status; | |
221 | } |