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/>.
22 #include <sys/types.h>
27 #include <sys/prctl.h>
33 static pid_t pager_pid = 0;
35 noreturn static void pager_fallback(void) {
39 n = splice(STDIN_FILENO, NULL, STDOUT_FILENO, NULL, 64*1024, 0);
43 log_error("Internal pager failed: %m");
50 int pager_open(bool jump_to_end) {
59 if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER")))
60 if (!*pager || streq(pager, "cat"))
66 /* Determine and cache number of columns before we spawn the
67 * pager so that we get the value from the actual tty */
71 log_error("Failed to create pager pipe: %m");
75 parent_pid = getpid();
80 log_error("Failed to fork pager: %m");
85 /* In the child start the pager */
87 const char* less_opts;
89 dup2(fd[0], STDIN_FILENO);
92 less_opts = getenv("SYSTEMD_LESS");
96 less_opts = strappenda(less_opts, " +G");
97 setenv("LESS", less_opts, 1);
99 /* Make sure the pager goes away when the parent dies */
100 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
103 /* Check whether our parent died before we were able
104 * to set the death signal */
105 if (getppid() != parent_pid)
109 execlp(pager, pager, NULL);
110 execl("/bin/sh", "sh", "-c", pager, NULL);
113 /* Debian's alternatives command for pagers is
114 * called 'pager'. Note that we do not call
115 * sensible-pagers here, since that is just a
116 * shell script that implements a logic that
117 * is similar to this one anyway, but is
118 * Debian-specific. */
119 execlp("pager", "pager", NULL);
121 execlp("less", "less", NULL);
122 execlp("more", "more", NULL);
128 /* Return in the parent */
129 if (dup2(fd[1], STDOUT_FILENO) < 0) {
130 log_error("Failed to duplicate pager pipe: %m");
138 void pager_close(void) {
143 /* Inform pager that we are done */
145 kill(pager_pid, SIGCONT);
146 (void) wait_for_terminate(pager_pid, NULL);
150 bool pager_have(void) {
151 return pager_pid > 0;
154 int show_man_page(const char *desc, bool null_stdio) {
155 const char *args[4] = { "man", NULL, NULL, NULL };
164 if (desc[k-1] == ')')
165 e = strrchr(desc, '(');
168 char *page = NULL, *section = NULL;
170 page = strndupa(desc, e - desc);
171 section = strndupa(e + 1, desc + k - e - 2);
180 log_error("Failed to fork: %m");
187 r = make_null_stdio();
189 log_error_errno(r, "Failed to kill stdio: %m");
194 execvp(args[0], (char**) args);
195 log_error("Failed to execute man: %m");
199 r = wait_for_terminate(pid, &status);
203 log_debug("Exit code %i status %i", status.si_code, status.si_status);
204 return status.si_status;