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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 | ||
22 | #include <sys/types.h> | |
4a8e40eb | 23 | #include <fcntl.h> |
1968a360 LP |
24 | #include <stdlib.h> |
25 | #include <unistd.h> | |
26 | #include <string.h> | |
27 | #include <sys/prctl.h> | |
28 | ||
29 | #include "pager.h" | |
30 | #include "util.h" | |
31 | #include "macro.h" | |
32 | ||
33 | static pid_t pager_pid = 0; | |
34 | ||
919ce0b7 | 35 | noreturn static void pager_fallback(void) { |
4a8e40eb | 36 | ssize_t n; |
46e65dcc | 37 | |
4a8e40eb MS |
38 | do { |
39 | n = splice(STDIN_FILENO, NULL, STDOUT_FILENO, NULL, 64*1024, 0); | |
40 | } while (n > 0); | |
46e65dcc | 41 | |
4a8e40eb | 42 | if (n < 0) { |
56f64d95 | 43 | log_error_errno(errno, "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 LP |
86 | |
87 | dup2(fd[0], STDIN_FILENO); | |
3d94f76c | 88 | safe_close_pair(fd); |
1968a360 | 89 | |
f366d58d JD |
90 | less_opts = getenv("SYSTEMD_LESS"); |
91 | if (!less_opts) | |
92 | less_opts = "FRSXMK"; | |
1b12a7b5 | 93 | if (jump_to_end) |
f366d58d JD |
94 | less_opts = strappenda(less_opts, " +G"); |
95 | setenv("LESS", less_opts, 1); | |
1968a360 LP |
96 | |
97 | /* Make sure the pager goes away when the parent dies */ | |
98 | if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0) | |
99 | _exit(EXIT_FAILURE); | |
100 | ||
101 | /* Check whether our parent died before we were able | |
102 | * to set the death signal */ | |
103 | if (getppid() != parent_pid) | |
104 | _exit(EXIT_SUCCESS); | |
105 | ||
106 | if (pager) { | |
107 | execlp(pager, pager, NULL); | |
108 | execl("/bin/sh", "sh", "-c", pager, NULL); | |
109 | } | |
110 | ||
111 | /* Debian's alternatives command for pagers is | |
112 | * called 'pager'. Note that we do not call | |
113 | * sensible-pagers here, since that is just a | |
114 | * shell script that implements a logic that | |
115 | * is similar to this one anyway, but is | |
116 | * Debian-specific. */ | |
117 | execlp("pager", "pager", NULL); | |
118 | ||
119 | execlp("less", "less", NULL); | |
120 | execlp("more", "more", NULL); | |
1968a360 | 121 | |
4a8e40eb MS |
122 | pager_fallback(); |
123 | /* not reached */ | |
1968a360 LP |
124 | } |
125 | ||
126 | /* Return in the parent */ | |
4a62c710 MS |
127 | if (dup2(fd[1], STDOUT_FILENO) < 0) |
128 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); | |
1968a360 | 129 | |
3d94f76c | 130 | safe_close_pair(fd); |
f89a3b6f | 131 | return 1; |
1968a360 LP |
132 | } |
133 | ||
134 | void pager_close(void) { | |
135 | ||
136 | if (pager_pid <= 0) | |
137 | return; | |
138 | ||
139 | /* Inform pager that we are done */ | |
140 | fclose(stdout); | |
141 | kill(pager_pid, SIGCONT); | |
c73d180d | 142 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
143 | pager_pid = 0; |
144 | } | |
f89a3b6f LP |
145 | |
146 | bool pager_have(void) { | |
147 | return pager_pid > 0; | |
148 | } | |
78002a67 ZJS |
149 | |
150 | int show_man_page(const char *desc, bool null_stdio) { | |
151 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
152 | char *e = NULL; | |
153 | pid_t pid; | |
154 | size_t k; | |
155 | int r; | |
156 | siginfo_t status; | |
157 | ||
158 | k = strlen(desc); | |
159 | ||
160 | if (desc[k-1] == ')') | |
161 | e = strrchr(desc, '('); | |
162 | ||
163 | if (e) { | |
164 | char *page = NULL, *section = NULL; | |
165 | ||
166 | page = strndupa(desc, e - desc); | |
167 | section = strndupa(e + 1, desc + k - e - 2); | |
168 | ||
169 | args[1] = section; | |
170 | args[2] = page; | |
171 | } else | |
172 | args[1] = desc; | |
173 | ||
174 | pid = fork(); | |
4a62c710 MS |
175 | if (pid < 0) |
176 | return log_error_errno(errno, "Failed to fork: %m"); | |
78002a67 ZJS |
177 | |
178 | if (pid == 0) { | |
179 | /* Child */ | |
180 | if (null_stdio) { | |
181 | r = make_null_stdio(); | |
182 | if (r < 0) { | |
da927ba9 | 183 | log_error_errno(r, "Failed to kill stdio: %m"); |
78002a67 ZJS |
184 | _exit(EXIT_FAILURE); |
185 | } | |
186 | } | |
187 | ||
188 | execvp(args[0], (char**) args); | |
56f64d95 | 189 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
190 | _exit(EXIT_FAILURE); |
191 | } | |
192 | ||
193 | r = wait_for_terminate(pid, &status); | |
194 | if (r < 0) | |
195 | return r; | |
196 | ||
197 | log_debug("Exit code %i status %i", status.si_code, status.si_status); | |
198 | return status.si_status; | |
199 | } |