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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
1968a360 | 2 | |
a8fbdf54 TA |
3 | #include <errno.h> |
4 | #include <signal.h> | |
5 | #include <stddef.h> | |
6 | #include <stdint.h> | |
7 | #include <stdio.h> | |
1968a360 | 8 | #include <stdlib.h> |
1968a360 LP |
9 | #include <string.h> |
10 | #include <sys/prctl.h> | |
07630cea | 11 | #include <unistd.h> |
1968a360 | 12 | |
07630cea | 13 | #include "copy.h" |
3ffd4af2 | 14 | #include "fd-util.h" |
6432da6a ZJS |
15 | #include "fileio.h" |
16 | #include "io-util.h" | |
8752c575 | 17 | #include "locale-util.h" |
a8fbdf54 | 18 | #include "log.h" |
1968a360 | 19 | #include "macro.h" |
3ffd4af2 | 20 | #include "pager.h" |
07630cea | 21 | #include "process-util.h" |
ce30c8dc | 22 | #include "signal-util.h" |
07630cea | 23 | #include "string-util.h" |
57c9e047 | 24 | #include "strv.h" |
07630cea | 25 | #include "terminal-util.h" |
1968a360 LP |
26 | |
27 | static pid_t pager_pid = 0; | |
28 | ||
3f603952 LP |
29 | static int stored_stdout = -1; |
30 | static int stored_stderr = -1; | |
31 | static bool stdout_redirected = false; | |
32 | static bool stderr_redirected = false; | |
33 | ||
848e863a | 34 | _noreturn_ static void pager_fallback(void) { |
6a7c676c | 35 | int r; |
46e65dcc | 36 | |
1c876927 | 37 | r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (uint64_t) -1, 0); |
6a7c676c LP |
38 | if (r < 0) { |
39 | log_error_errno(r, "Internal pager failed: %m"); | |
4a8e40eb MS |
40 | _exit(EXIT_FAILURE); |
41 | } | |
46e65dcc | 42 | |
4a8e40eb MS |
43 | _exit(EXIT_SUCCESS); |
44 | } | |
45 | ||
6432da6a ZJS |
46 | static int no_quit_on_interrupt(int exe_name_fd, const char *less_opts) { |
47 | _cleanup_fclose_ FILE *file = NULL; | |
48 | _cleanup_free_ char *line = NULL; | |
49 | int r; | |
50 | ||
51 | assert(exe_name_fd >= 0); | |
52 | assert(less_opts); | |
53 | ||
54 | /* This takes ownership of exe_name_fd */ | |
55 | file = fdopen(exe_name_fd, "r"); | |
56 | if (!file) { | |
57 | safe_close(exe_name_fd); | |
58 | return log_debug_errno(errno, "Failed to create FILE object: %m"); | |
59 | } | |
60 | ||
61 | /* Find the last line */ | |
62 | for (;;) { | |
63 | _cleanup_free_ char *t = NULL; | |
64 | ||
65 | r = read_line(file, LONG_LINE_MAX, &t); | |
66 | if (r < 0) | |
67 | return r; | |
68 | if (r == 0) | |
69 | break; | |
70 | ||
71 | free_and_replace(line, t); | |
72 | } | |
73 | ||
74 | /* We only treat "less" specially. | |
75 | * Return true whenever option K is *not* set. */ | |
76 | r = streq_ptr(line, "less") && !strchr(less_opts, 'K'); | |
77 | ||
78 | log_debug("Pager executable is \"%s\", options \"%s\", quit_on_interrupt: %s", | |
79 | strnull(line), less_opts, yes_no(!r)); | |
80 | return r; | |
81 | } | |
82 | ||
0221d68a | 83 | int pager_open(PagerFlags flags) { |
6432da6a | 84 | _cleanup_close_pair_ int fd[2] = { -1, -1 }, exe_name_pipe[2] = { -1, -1 }; |
43942e80 | 85 | _cleanup_strv_free_ char **pager_args = NULL; |
6432da6a | 86 | const char *pager, *less_opts; |
4c253ed1 | 87 | int r; |
1968a360 | 88 | |
0221d68a | 89 | if (flags & PAGER_DISABLE) |
ea4b98e6 AK |
90 | return 0; |
91 | ||
1968a360 | 92 | if (pager_pid > 0) |
f89a3b6f | 93 | return 1; |
1968a360 | 94 | |
ac96418b | 95 | if (terminal_is_dumb()) |
f89a3b6f | 96 | return 0; |
729e3769 | 97 | |
85afeae8 LP |
98 | if (!is_main_thread()) |
99 | return -EPERM; | |
100 | ||
bcbd61db LP |
101 | pager = getenv("SYSTEMD_PAGER"); |
102 | if (!pager) | |
103 | pager = getenv("PAGER"); | |
104 | ||
43942e80 YW |
105 | if (pager) { |
106 | pager_args = strv_split(pager, WHITESPACE); | |
107 | if (!pager_args) | |
108 | return -ENOMEM; | |
109 | ||
110 | /* If the pager is explicitly turned off, honour it */ | |
111 | if (strv_isempty(pager_args) || strv_equal(pager_args, STRV_MAKE("cat"))) | |
112 | return 0; | |
113 | } | |
bcbd61db | 114 | |
d13b5227 LP |
115 | /* Determine and cache number of columns/lines before we spawn the pager so that we get the value from the |
116 | * actual tty */ | |
bcbd61db | 117 | (void) columns(); |
d13b5227 | 118 | (void) lines(); |
1968a360 | 119 | |
d262e99e | 120 | if (pipe2(fd, O_CLOEXEC) < 0) |
4a62c710 | 121 | return log_error_errno(errno, "Failed to create pager pipe: %m"); |
1968a360 | 122 | |
6432da6a ZJS |
123 | /* This is a pipe to feed the name of the executed pager binary into the parent */ |
124 | if (pipe2(exe_name_pipe, O_CLOEXEC) < 0) | |
125 | return log_error_errno(errno, "Failed to create exe_name pipe: %m"); | |
126 | ||
127 | /* Initialize a good set of less options */ | |
128 | less_opts = getenv("SYSTEMD_LESS"); | |
129 | if (!less_opts) | |
130 | less_opts = "FRSXMK"; | |
131 | if (flags & PAGER_JUMP_TO_END) | |
132 | less_opts = strjoina(less_opts, " +G"); | |
133 | ||
b6e1fff1 | 134 | r = safe_fork("(pager)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pager_pid); |
4c253ed1 | 135 | if (r < 0) |
b6e1fff1 | 136 | return r; |
4c253ed1 | 137 | if (r == 0) { |
6432da6a | 138 | const char *less_charset, *exe; |
1968a360 | 139 | |
4c253ed1 | 140 | /* In the child start the pager */ |
ce30c8dc | 141 | |
bcbd61db | 142 | (void) dup2(fd[0], STDIN_FILENO); |
3d94f76c | 143 | safe_close_pair(fd); |
1968a360 | 144 | |
0357fa0d ZJS |
145 | if (setenv("LESS", less_opts, 1) < 0) |
146 | _exit(EXIT_FAILURE); | |
1968a360 | 147 | |
a1b4e6e9 LP |
148 | /* Initialize a good charset for less. This is |
149 | * particularly important if we output UTF-8 | |
150 | * characters. */ | |
151 | less_charset = getenv("SYSTEMD_LESSCHARSET"); | |
152 | if (!less_charset && is_locale_utf8()) | |
153 | less_charset = "utf-8"; | |
0357fa0d ZJS |
154 | if (less_charset && |
155 | setenv("LESSCHARSET", less_charset, 1) < 0) | |
156 | _exit(EXIT_FAILURE); | |
a1b4e6e9 | 157 | |
6432da6a ZJS |
158 | if (pager_args) { |
159 | if (loop_write(exe_name_pipe[1], pager_args[0], strlen(pager_args[0]) + 1, false) < 0) | |
160 | _exit(EXIT_FAILURE); | |
161 | ||
43942e80 | 162 | execvp(pager_args[0], pager_args); |
6432da6a | 163 | } |
1968a360 LP |
164 | |
165 | /* Debian's alternatives command for pagers is | |
166 | * called 'pager'. Note that we do not call | |
167 | * sensible-pagers here, since that is just a | |
168 | * shell script that implements a logic that | |
169 | * is similar to this one anyway, but is | |
170 | * Debian-specific. */ | |
6432da6a ZJS |
171 | FOREACH_STRING(exe, "pager", "less", "more") { |
172 | if (loop_write(exe_name_pipe[1], exe, strlen(exe) + 1, false) < 0) | |
173 | _exit(EXIT_FAILURE); | |
174 | execlp(exe, exe, NULL); | |
175 | } | |
1968a360 | 176 | |
6432da6a ZJS |
177 | if (loop_write(exe_name_pipe[1], "(built-in)", strlen("(built-in") + 1, false) < 0) |
178 | _exit(EXIT_FAILURE); | |
4a8e40eb MS |
179 | pager_fallback(); |
180 | /* not reached */ | |
1968a360 LP |
181 | } |
182 | ||
183 | /* Return in the parent */ | |
a45e7bb4 MS |
184 | stored_stdout = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, 3); |
185 | if (dup2(fd[1], STDOUT_FILENO) < 0) { | |
186 | stored_stdout = safe_close(stored_stdout); | |
4a62c710 | 187 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); |
a45e7bb4 MS |
188 | } |
189 | stdout_redirected = true; | |
190 | ||
191 | stored_stderr = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, 3); | |
192 | if (dup2(fd[1], STDERR_FILENO) < 0) { | |
193 | stored_stderr = safe_close(stored_stderr); | |
8b5264aa | 194 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); |
a45e7bb4 MS |
195 | } |
196 | stderr_redirected = true; | |
1968a360 | 197 | |
6432da6a ZJS |
198 | exe_name_pipe[1] = safe_close(exe_name_pipe[1]); |
199 | ||
200 | r = no_quit_on_interrupt(TAKE_FD(exe_name_pipe[0]), less_opts); | |
201 | if (r < 0) | |
202 | return r; | |
203 | if (r > 0) | |
204 | (void) ignore_signals(SIGINT, -1); | |
205 | ||
f89a3b6f | 206 | return 1; |
1968a360 LP |
207 | } |
208 | ||
209 | void pager_close(void) { | |
210 | ||
211 | if (pager_pid <= 0) | |
212 | return; | |
213 | ||
214 | /* Inform pager that we are done */ | |
a45e7bb4 | 215 | (void) fflush(stdout); |
77018a8c MS |
216 | if (stdout_redirected) |
217 | if (stored_stdout < 0 || dup2(stored_stdout, STDOUT_FILENO) < 0) | |
218 | (void) close(STDOUT_FILENO); | |
a45e7bb4 MS |
219 | stored_stdout = safe_close(stored_stdout); |
220 | (void) fflush(stderr); | |
77018a8c MS |
221 | if (stderr_redirected) |
222 | if (stored_stderr < 0 || dup2(stored_stderr, STDERR_FILENO) < 0) | |
223 | (void) close(STDERR_FILENO); | |
a45e7bb4 MS |
224 | stored_stderr = safe_close(stored_stderr); |
225 | stdout_redirected = stderr_redirected = false; | |
8b5264aa | 226 | |
74ca738f | 227 | (void) kill(pager_pid, SIGCONT); |
c73d180d | 228 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
229 | pager_pid = 0; |
230 | } | |
f89a3b6f LP |
231 | |
232 | bool pager_have(void) { | |
233 | return pager_pid > 0; | |
234 | } | |
78002a67 ZJS |
235 | |
236 | int show_man_page(const char *desc, bool null_stdio) { | |
237 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
238 | char *e = NULL; | |
239 | pid_t pid; | |
240 | size_t k; | |
241 | int r; | |
78002a67 ZJS |
242 | |
243 | k = strlen(desc); | |
244 | ||
245 | if (desc[k-1] == ')') | |
246 | e = strrchr(desc, '('); | |
247 | ||
248 | if (e) { | |
249 | char *page = NULL, *section = NULL; | |
250 | ||
251 | page = strndupa(desc, e - desc); | |
252 | section = strndupa(e + 1, desc + k - e - 2); | |
253 | ||
254 | args[1] = section; | |
255 | args[2] = page; | |
256 | } else | |
257 | args[1] = desc; | |
258 | ||
b6e1fff1 | 259 | r = safe_fork("(man)", FORK_RESET_SIGNALS|FORK_DEATHSIG|(null_stdio ? FORK_NULL_STDIO : 0)|FORK_LOG, &pid); |
4c253ed1 | 260 | if (r < 0) |
b6e1fff1 | 261 | return r; |
4c253ed1 | 262 | if (r == 0) { |
78002a67 | 263 | /* Child */ |
78002a67 | 264 | execvp(args[0], (char**) args); |
56f64d95 | 265 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
266 | _exit(EXIT_FAILURE); |
267 | } | |
268 | ||
2e87a1fd | 269 | return wait_for_terminate_and_check(NULL, pid, 0); |
78002a67 | 270 | } |