1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
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
11 (at your option) any later version.
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
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
26 #include <sys/prctl.h>
30 #include "process-util.h"
32 #include "terminal-util.h"
33 #include "signal-util.h"
35 static pid_t pager_pid = 0;
37 noreturn static void pager_fallback(void) {
41 n = splice(STDIN_FILENO, NULL, STDOUT_FILENO, NULL, 64*1024, 0);
45 log_error_errno(errno, "Internal pager failed: %m");
52 int pager_open(bool jump_to_end) {
61 if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER")))
62 if (!*pager || streq(pager, "cat"))
68 /* Determine and cache number of columns before we spawn the
69 * pager so that we get the value from the actual tty */
73 return log_error_errno(errno, "Failed to create pager pipe: %m");
75 parent_pid = getpid();
80 log_error_errno(errno, "Failed to fork pager: %m");
85 /* In the child start the pager */
87 const char* less_opts;
89 (void) reset_all_signal_handlers();
90 (void) reset_signal_mask();
92 dup2(fd[0], STDIN_FILENO);
95 less_opts = getenv("SYSTEMD_LESS");
99 less_opts = strjoina(less_opts, " +G");
100 setenv("LESS", less_opts, 1);
102 /* Make sure the pager goes away when the parent dies */
103 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
106 /* Check whether our parent died before we were able
107 * to set the death signal */
108 if (getppid() != parent_pid)
112 execlp(pager, pager, NULL);
113 execl("/bin/sh", "sh", "-c", pager, NULL);
116 /* Debian's alternatives command for pagers is
117 * called 'pager'. Note that we do not call
118 * sensible-pagers here, since that is just a
119 * shell script that implements a logic that
120 * is similar to this one anyway, but is
121 * Debian-specific. */
122 execlp("pager", "pager", NULL);
124 execlp("less", "less", NULL);
125 execlp("more", "more", NULL);
131 /* Return in the parent */
132 if (dup2(fd[1], STDOUT_FILENO) < 0)
133 return log_error_errno(errno, "Failed to duplicate pager pipe: %m");
139 void pager_close(void) {
144 /* Inform pager that we are done */
146 kill(pager_pid, SIGCONT);
147 (void) wait_for_terminate(pager_pid, NULL);
151 bool pager_have(void) {
152 return pager_pid > 0;
155 int show_man_page(const char *desc, bool null_stdio) {
156 const char *args[4] = { "man", NULL, NULL, NULL };
165 if (desc[k-1] == ')')
166 e = strrchr(desc, '(');
169 char *page = NULL, *section = NULL;
171 page = strndupa(desc, e - desc);
172 section = strndupa(e + 1, desc + k - e - 2);
181 return log_error_errno(errno, "Failed to fork: %m");
186 (void) reset_all_signal_handlers();
187 (void) reset_signal_mask();
190 r = make_null_stdio();
192 log_error_errno(r, "Failed to kill stdio: %m");
197 execvp(args[0], (char**) args);
198 log_error_errno(errno, "Failed to execute man: %m");
202 r = wait_for_terminate(pid, &status);
206 log_debug("Exit code %i status %i", status.si_code, status.si_status);
207 return status.si_status;