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_errno(errno, "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 return log_error_errno(errno, "Failed to create pager pipe: %m");
73 parent_pid = getpid();
78 log_error_errno(errno, "Failed to fork pager: %m");
83 /* In the child start the pager */
85 const char* less_opts;
87 dup2(fd[0], STDIN_FILENO);
90 less_opts = getenv("SYSTEMD_LESS");
94 less_opts = strjoina(less_opts, " +G");
95 setenv("LESS", less_opts, 1);
97 /* Make sure the pager goes away when the parent dies */
98 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
101 /* Check whether our parent died before we were able
102 * to set the death signal */
103 if (getppid() != parent_pid)
107 execlp(pager, pager, NULL);
108 execl("/bin/sh", "sh", "-c", pager, NULL);
111 /* Debian's alternatives command for pagers is
112 * called 'pager'. Note that we do not call
113 * sensible-pagers here, since that is just a
114 * shell script that implements a logic that
115 * is similar to this one anyway, but is
116 * Debian-specific. */
117 execlp("pager", "pager", NULL);
119 execlp("less", "less", NULL);
120 execlp("more", "more", NULL);
126 /* Return in the parent */
127 if (dup2(fd[1], STDOUT_FILENO) < 0)
128 return log_error_errno(errno, "Failed to duplicate pager pipe: %m");
134 void pager_close(void) {
139 /* Inform pager that we are done */
141 kill(pager_pid, SIGCONT);
142 (void) wait_for_terminate(pager_pid, NULL);
146 bool pager_have(void) {
147 return pager_pid > 0;
150 int show_man_page(const char *desc, bool null_stdio) {
151 const char *args[4] = { "man", NULL, NULL, NULL };
160 if (desc[k-1] == ')')
161 e = strrchr(desc, '(');
164 char *page = NULL, *section = NULL;
166 page = strndupa(desc, e - desc);
167 section = strndupa(e + 1, desc + k - e - 2);
176 return log_error_errno(errno, "Failed to fork: %m");
181 r = make_null_stdio();
183 log_error_errno(r, "Failed to kill stdio: %m");
188 execvp(args[0], (char**) args);
189 log_error_errno(errno, "Failed to execute man: %m");
193 r = wait_for_terminate(pid, &status);
197 log_debug("Exit code %i status %i", status.si_code, status.si_status);
198 return status.si_status;