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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" |
8752c575 | 15 | #include "locale-util.h" |
a8fbdf54 | 16 | #include "log.h" |
1968a360 | 17 | #include "macro.h" |
3ffd4af2 | 18 | #include "pager.h" |
07630cea | 19 | #include "process-util.h" |
ce30c8dc | 20 | #include "signal-util.h" |
07630cea | 21 | #include "string-util.h" |
57c9e047 | 22 | #include "strv.h" |
07630cea | 23 | #include "terminal-util.h" |
1968a360 LP |
24 | |
25 | static pid_t pager_pid = 0; | |
26 | ||
3f603952 LP |
27 | static int stored_stdout = -1; |
28 | static int stored_stderr = -1; | |
29 | static bool stdout_redirected = false; | |
30 | static bool stderr_redirected = false; | |
31 | ||
848e863a | 32 | _noreturn_ static void pager_fallback(void) { |
6a7c676c | 33 | int r; |
46e65dcc | 34 | |
1c876927 | 35 | r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (uint64_t) -1, 0); |
6a7c676c LP |
36 | if (r < 0) { |
37 | log_error_errno(r, "Internal pager failed: %m"); | |
4a8e40eb MS |
38 | _exit(EXIT_FAILURE); |
39 | } | |
46e65dcc | 40 | |
4a8e40eb MS |
41 | _exit(EXIT_SUCCESS); |
42 | } | |
43 | ||
ea4b98e6 | 44 | int pager_open(bool no_pager, bool jump_to_end) { |
bcbd61db | 45 | _cleanup_close_pair_ int fd[2] = { -1, -1 }; |
43942e80 | 46 | _cleanup_strv_free_ char **pager_args = NULL; |
1968a360 | 47 | const char *pager; |
4c253ed1 | 48 | int r; |
1968a360 | 49 | |
ea4b98e6 AK |
50 | if (no_pager) |
51 | return 0; | |
52 | ||
1968a360 | 53 | if (pager_pid > 0) |
f89a3b6f | 54 | return 1; |
1968a360 | 55 | |
ac96418b | 56 | if (terminal_is_dumb()) |
f89a3b6f | 57 | return 0; |
729e3769 | 58 | |
85afeae8 LP |
59 | if (!is_main_thread()) |
60 | return -EPERM; | |
61 | ||
bcbd61db LP |
62 | pager = getenv("SYSTEMD_PAGER"); |
63 | if (!pager) | |
64 | pager = getenv("PAGER"); | |
65 | ||
43942e80 YW |
66 | if (pager) { |
67 | pager_args = strv_split(pager, WHITESPACE); | |
68 | if (!pager_args) | |
69 | return -ENOMEM; | |
70 | ||
71 | /* If the pager is explicitly turned off, honour it */ | |
72 | if (strv_isempty(pager_args) || strv_equal(pager_args, STRV_MAKE("cat"))) | |
73 | return 0; | |
74 | } | |
bcbd61db | 75 | |
d13b5227 LP |
76 | /* Determine and cache number of columns/lines before we spawn the pager so that we get the value from the |
77 | * actual tty */ | |
bcbd61db | 78 | (void) columns(); |
d13b5227 | 79 | (void) lines(); |
1968a360 | 80 | |
d262e99e | 81 | if (pipe2(fd, O_CLOEXEC) < 0) |
4a62c710 | 82 | return log_error_errno(errno, "Failed to create pager pipe: %m"); |
1968a360 | 83 | |
b6e1fff1 | 84 | r = safe_fork("(pager)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pager_pid); |
4c253ed1 | 85 | if (r < 0) |
b6e1fff1 | 86 | return r; |
4c253ed1 | 87 | if (r == 0) { |
a1b4e6e9 | 88 | const char* less_opts, *less_charset; |
1968a360 | 89 | |
4c253ed1 | 90 | /* In the child start the pager */ |
ce30c8dc | 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"); |
0357fa0d ZJS |
101 | if (setenv("LESS", less_opts, 1) < 0) |
102 | _exit(EXIT_FAILURE); | |
1968a360 | 103 | |
a1b4e6e9 LP |
104 | /* Initialize a good charset for less. This is |
105 | * particularly important if we output UTF-8 | |
106 | * characters. */ | |
107 | less_charset = getenv("SYSTEMD_LESSCHARSET"); | |
108 | if (!less_charset && is_locale_utf8()) | |
109 | less_charset = "utf-8"; | |
0357fa0d ZJS |
110 | if (less_charset && |
111 | setenv("LESSCHARSET", less_charset, 1) < 0) | |
112 | _exit(EXIT_FAILURE); | |
a1b4e6e9 | 113 | |
43942e80 YW |
114 | if (pager_args) |
115 | execvp(pager_args[0], pager_args); | |
1968a360 LP |
116 | |
117 | /* Debian's alternatives command for pagers is | |
118 | * called 'pager'. Note that we do not call | |
119 | * sensible-pagers here, since that is just a | |
120 | * shell script that implements a logic that | |
121 | * is similar to this one anyway, but is | |
122 | * Debian-specific. */ | |
123 | execlp("pager", "pager", NULL); | |
124 | ||
125 | execlp("less", "less", NULL); | |
126 | execlp("more", "more", NULL); | |
1968a360 | 127 | |
4a8e40eb MS |
128 | pager_fallback(); |
129 | /* not reached */ | |
1968a360 LP |
130 | } |
131 | ||
132 | /* Return in the parent */ | |
a45e7bb4 MS |
133 | stored_stdout = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, 3); |
134 | if (dup2(fd[1], STDOUT_FILENO) < 0) { | |
135 | stored_stdout = safe_close(stored_stdout); | |
4a62c710 | 136 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); |
a45e7bb4 MS |
137 | } |
138 | stdout_redirected = true; | |
139 | ||
140 | stored_stderr = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, 3); | |
141 | if (dup2(fd[1], STDERR_FILENO) < 0) { | |
142 | stored_stderr = safe_close(stored_stderr); | |
8b5264aa | 143 | return log_error_errno(errno, "Failed to duplicate pager pipe: %m"); |
a45e7bb4 MS |
144 | } |
145 | stderr_redirected = true; | |
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 */ | |
a45e7bb4 | 156 | (void) fflush(stdout); |
77018a8c MS |
157 | if (stdout_redirected) |
158 | if (stored_stdout < 0 || dup2(stored_stdout, STDOUT_FILENO) < 0) | |
159 | (void) close(STDOUT_FILENO); | |
a45e7bb4 MS |
160 | stored_stdout = safe_close(stored_stdout); |
161 | (void) fflush(stderr); | |
77018a8c MS |
162 | if (stderr_redirected) |
163 | if (stored_stderr < 0 || dup2(stored_stderr, STDERR_FILENO) < 0) | |
164 | (void) close(STDERR_FILENO); | |
a45e7bb4 MS |
165 | stored_stderr = safe_close(stored_stderr); |
166 | stdout_redirected = stderr_redirected = false; | |
8b5264aa | 167 | |
74ca738f | 168 | (void) kill(pager_pid, SIGCONT); |
c73d180d | 169 | (void) wait_for_terminate(pager_pid, NULL); |
1968a360 LP |
170 | pager_pid = 0; |
171 | } | |
f89a3b6f LP |
172 | |
173 | bool pager_have(void) { | |
174 | return pager_pid > 0; | |
175 | } | |
78002a67 ZJS |
176 | |
177 | int show_man_page(const char *desc, bool null_stdio) { | |
178 | const char *args[4] = { "man", NULL, NULL, NULL }; | |
179 | char *e = NULL; | |
180 | pid_t pid; | |
181 | size_t k; | |
182 | int r; | |
78002a67 ZJS |
183 | |
184 | k = strlen(desc); | |
185 | ||
186 | if (desc[k-1] == ')') | |
187 | e = strrchr(desc, '('); | |
188 | ||
189 | if (e) { | |
190 | char *page = NULL, *section = NULL; | |
191 | ||
192 | page = strndupa(desc, e - desc); | |
193 | section = strndupa(e + 1, desc + k - e - 2); | |
194 | ||
195 | args[1] = section; | |
196 | args[2] = page; | |
197 | } else | |
198 | args[1] = desc; | |
199 | ||
b6e1fff1 | 200 | r = safe_fork("(man)", FORK_RESET_SIGNALS|FORK_DEATHSIG|(null_stdio ? FORK_NULL_STDIO : 0)|FORK_LOG, &pid); |
4c253ed1 | 201 | if (r < 0) |
b6e1fff1 | 202 | return r; |
4c253ed1 | 203 | if (r == 0) { |
78002a67 | 204 | /* Child */ |
78002a67 | 205 | execvp(args[0], (char**) args); |
56f64d95 | 206 | log_error_errno(errno, "Failed to execute man: %m"); |
78002a67 ZJS |
207 | _exit(EXIT_FAILURE); |
208 | } | |
209 | ||
2e87a1fd | 210 | return wait_for_terminate_and_check(NULL, pid, 0); |
78002a67 | 211 | } |