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git.ipfire.org Git - thirdparty/systemd.git/blob - src/shared/pager.c
2501a53c1998fac408b9db9b83b7e2018ba4a39e
2 This file is part of systemd.
4 Copyright 2010 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
27 #include <sys/prctl.h>
32 #include "locale-util.h"
36 #include "process-util.h"
37 #include "signal-util.h"
38 #include "string-util.h"
40 #include "terminal-util.h"
42 static pid_t pager_pid
= 0;
44 noreturn
static void pager_fallback(void) {
47 r
= copy_bytes(STDIN_FILENO
, STDOUT_FILENO
, (uint64_t) -1, 0);
49 log_error_errno(r
, "Internal pager failed: %m");
56 static int stored_stdout
= -1;
57 static int stored_stderr
= -1;
58 static bool stdout_redirected
= false;
59 static bool stderr_redirected
= false;
61 int pager_open(bool no_pager
, bool jump_to_end
) {
62 _cleanup_close_pair_
int fd
[2] = { -1, -1 };
72 if (terminal_is_dumb())
75 pager
= getenv("SYSTEMD_PAGER");
77 pager
= getenv("PAGER");
79 /* If the pager is explicitly turned off, honour it */
80 if (pager
&& STR_IN_SET(pager
, "", "cat"))
83 /* Determine and cache number of columns before we spawn the
84 * pager so that we get the value from the actual tty */
88 return log_error_errno(errno
, "Failed to create pager pipe: %m");
90 parent_pid
= getpid();
94 return log_error_errno(errno
, "Failed to fork pager: %m");
96 /* In the child start the pager */
98 const char* less_opts
, *less_charset
;
100 (void) reset_all_signal_handlers();
101 (void) reset_signal_mask();
103 (void) dup2(fd
[0], STDIN_FILENO
);
106 /* Initialize a good set of less options */
107 less_opts
= getenv("SYSTEMD_LESS");
109 less_opts
= "FRSXMK";
111 less_opts
= strjoina(less_opts
, " +G");
112 if (setenv("LESS", less_opts
, 1) < 0)
115 /* Initialize a good charset for less. This is
116 * particularly important if we output UTF-8
118 less_charset
= getenv("SYSTEMD_LESSCHARSET");
119 if (!less_charset
&& is_locale_utf8())
120 less_charset
= "utf-8";
122 setenv("LESSCHARSET", less_charset
, 1) < 0)
125 /* Make sure the pager goes away when the parent dies */
126 if (prctl(PR_SET_PDEATHSIG
, SIGTERM
) < 0)
129 /* Check whether our parent died before we were able
130 * to set the death signal */
131 if (getppid() != parent_pid
)
135 execlp(pager
, pager
, NULL
);
136 execl("/bin/sh", "sh", "-c", pager
, NULL
);
139 /* Debian's alternatives command for pagers is
140 * called 'pager'. Note that we do not call
141 * sensible-pagers here, since that is just a
142 * shell script that implements a logic that
143 * is similar to this one anyway, but is
144 * Debian-specific. */
145 execlp("pager", "pager", NULL
);
147 execlp("less", "less", NULL
);
148 execlp("more", "more", NULL
);
154 /* Return in the parent */
155 stored_stdout
= fcntl(STDOUT_FILENO
, F_DUPFD_CLOEXEC
, 3);
156 if (dup2(fd
[1], STDOUT_FILENO
) < 0) {
157 stored_stdout
= safe_close(stored_stdout
);
158 return log_error_errno(errno
, "Failed to duplicate pager pipe: %m");
160 stdout_redirected
= true;
162 stored_stderr
= fcntl(STDERR_FILENO
, F_DUPFD_CLOEXEC
, 3);
163 if (dup2(fd
[1], STDERR_FILENO
) < 0) {
164 stored_stderr
= safe_close(stored_stderr
);
165 return log_error_errno(errno
, "Failed to duplicate pager pipe: %m");
167 stderr_redirected
= true;
172 void pager_close(void) {
177 /* Inform pager that we are done */
178 (void) fflush(stdout
);
179 if (stdout_redirected
&& (stored_stdout
< 0 || dup2(stored_stdout
, STDOUT_FILENO
)) < 0)
180 (void) close(STDOUT_FILENO
);
181 stored_stdout
= safe_close(stored_stdout
);
182 (void) fflush(stderr
);
183 if (stderr_redirected
&& (stored_stderr
< 0 || dup2(stored_stderr
, STDERR_FILENO
)) < 0)
184 (void) close(STDERR_FILENO
);
185 stored_stderr
= safe_close(stored_stderr
);
186 stdout_redirected
= stderr_redirected
= false;
188 (void) kill(pager_pid
, SIGCONT
);
189 (void) wait_for_terminate(pager_pid
, NULL
);
193 bool pager_have(void) {
194 return pager_pid
> 0;
197 int show_man_page(const char *desc
, bool null_stdio
) {
198 const char *args
[4] = { "man", NULL
, NULL
, NULL
};
207 if (desc
[k
-1] == ')')
208 e
= strrchr(desc
, '(');
211 char *page
= NULL
, *section
= NULL
;
213 page
= strndupa(desc
, e
- desc
);
214 section
= strndupa(e
+ 1, desc
+ k
- e
- 2);
223 return log_error_errno(errno
, "Failed to fork: %m");
228 (void) reset_all_signal_handlers();
229 (void) reset_signal_mask();
232 r
= make_null_stdio();
234 log_error_errno(r
, "Failed to kill stdio: %m");
239 execvp(args
[0], (char**) args
);
240 log_error_errno(errno
, "Failed to execute man: %m");
244 r
= wait_for_terminate(pid
, &status
);
248 log_debug("Exit code %i status %i", status
.si_code
, status
.si_status
);
249 return status
.si_status
;