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"
36 static pid_t pager_pid = 0;
38 noreturn static void pager_fallback(void) {
41 r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (off_t) -1, false);
43 log_error_errno(r, "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 (void) reset_all_signal_handlers();
88 (void) reset_signal_mask();
90 dup2(fd[0], STDIN_FILENO);
93 less_opts = getenv("SYSTEMD_LESS");
97 less_opts = strjoina(less_opts, " +G");
98 setenv("LESS", less_opts, 1);
100 /* Make sure the pager goes away when the parent dies */
101 if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
104 /* Check whether our parent died before we were able
105 * to set the death signal */
106 if (getppid() != parent_pid)
110 execlp(pager, pager, NULL);
111 execl("/bin/sh", "sh", "-c", pager, NULL);
114 /* Debian's alternatives command for pagers is
115 * called 'pager'. Note that we do not call
116 * sensible-pagers here, since that is just a
117 * shell script that implements a logic that
118 * is similar to this one anyway, but is
119 * Debian-specific. */
120 execlp("pager", "pager", NULL);
122 execlp("less", "less", NULL);
123 execlp("more", "more", NULL);
129 /* Return in the parent */
130 if (dup2(fd[1], STDOUT_FILENO) < 0)
131 return log_error_errno(errno, "Failed to duplicate pager pipe: %m");
132 if (dup2(fd[1], STDERR_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 #if defined(__GLIBC__)
148 #endif // in musl-libc this is a const
151 #if defined(__GLIBC__)
153 #endif // in musl-libc this is a const
155 kill(pager_pid, SIGCONT);
156 (void) wait_for_terminate(pager_pid, NULL);
160 bool pager_have(void) {
161 return pager_pid > 0;
164 /// UNNEEDED by elogind
166 int show_man_page(const char *desc, bool null_stdio) {
167 const char *args[4] = { "man", NULL, NULL, NULL };
176 if (desc[k-1] == ')')
177 e = strrchr(desc, '(');
180 char *page = NULL, *section = NULL;
182 page = strndupa(desc, e - desc);
183 section = strndupa(e + 1, desc + k - e - 2);
192 return log_error_errno(errno, "Failed to fork: %m");
197 (void) reset_all_signal_handlers();
198 (void) reset_signal_mask();
201 r = make_null_stdio();
203 log_error_errno(r, "Failed to kill stdio: %m");
208 execvp(args[0], (char**) args);
209 log_error_errno(errno, "Failed to execute man: %m");
213 r = wait_for_terminate(pid, &status);
217 log_debug("Exit code %i status %i", status.si_code, status.si_status);
218 return status.si_status;