./move.sh

1 files changed, 223 insertions, 0 deletions

diff --git a/src/libshared/pager.c b/src/libshared/pager.c
new file mode 100644
index 0000000000..05b2b15e40
--- /dev/null
+++ b/src/libshared/pager.c
@@ -0,0 +1,223 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+#include "copy.h"
+#include "fd-util.h"
+#include "locale-util.h"
+#include "log.h"
+#include "macro.h"
+#include "pager.h"
+#include "process-util.h"
+#include "signal-util.h"
+#include "string-util.h"
+#include "terminal-util.h"
+
+static pid_t pager_pid = 0;
+
+noreturn static void pager_fallback(void) {
+        int r;
+
+        r = copy_bytes(STDIN_FILENO, STDOUT_FILENO, (uint64_t) -1, false);
+        if (r < 0) {
+                log_error_errno(r, "Internal pager failed: %m");
+                _exit(EXIT_FAILURE);
+        }
+
+        _exit(EXIT_SUCCESS);
+}
+
+int pager_open(bool jump_to_end) {
+        _cleanup_close_pair_ int fd[2] = { -1, -1 };
+        const char *pager;
+        pid_t parent_pid;
+
+        if (pager_pid > 0)
+                return 1;
+
+        if (!on_tty())
+                return 0;
+
+        pager = getenv("SYSTEMD_PAGER");
+        if (!pager)
+                pager = getenv("PAGER");
+
+        /* If the pager is explicitly turned off, honour it */
+        if (pager && (pager[0] == 0 || streq(pager, "cat")))
+                return 0;
+
+        /* Determine and cache number of columns before we spawn the
+         * pager so that we get the value from the actual tty */
+        (void) columns();
+
+        if (pipe(fd) < 0)
+                return log_error_errno(errno, "Failed to create pager pipe: %m");
+
+        parent_pid = getpid();
+
+        pager_pid = fork();
+        if (pager_pid < 0)
+                return log_error_errno(errno, "Failed to fork pager: %m");
+
+        /* In the child start the pager */
+        if (pager_pid == 0) {
+                const char* less_opts, *less_charset;
+
+                (void) reset_all_signal_handlers();
+                (void) reset_signal_mask();
+
+                (void) dup2(fd[0], STDIN_FILENO);
+                safe_close_pair(fd);
+
+                /* Initialize a good set of less options */
+                less_opts = getenv("SYSTEMD_LESS");
+                if (!less_opts)
+                        less_opts = "FRSXMK";
+                if (jump_to_end)
+                        less_opts = strjoina(less_opts, " +G");
+                setenv("LESS", less_opts, 1);
+
+                /* Initialize a good charset for less. This is
+                 * particularly important if we output UTF-8
+                 * characters. */
+                less_charset = getenv("SYSTEMD_LESSCHARSET");
+                if (!less_charset && is_locale_utf8())
+                        less_charset = "utf-8";
+                if (less_charset)
+                        setenv("LESSCHARSET", less_charset, 1);
+
+                /* Make sure the pager goes away when the parent dies */
+                if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
+                        _exit(EXIT_FAILURE);
+
+                /* Check whether our parent died before we were able
+                 * to set the death signal */
+                if (getppid() != parent_pid)
+                        _exit(EXIT_SUCCESS);
+
+                if (pager) {
+                        execlp(pager, pager, NULL);
+                        execl("/bin/sh", "sh", "-c", pager, NULL);
+                }
+
+                /* Debian's alternatives command for pagers is
+                 * called 'pager'. Note that we do not call
+                 * sensible-pagers here, since that is just a
+                 * shell script that implements a logic that
+                 * is similar to this one anyway, but is
+                 * Debian-specific. */
+                execlp("pager", "pager", NULL);
+
+                execlp("less", "less", NULL);
+                execlp("more", "more", NULL);
+
+                pager_fallback();
+                /* not reached */
+        }
+
+        /* Return in the parent */
+        if (dup2(fd[1], STDOUT_FILENO) < 0)
+                return log_error_errno(errno, "Failed to duplicate pager pipe: %m");
+        if (dup2(fd[1], STDERR_FILENO) < 0)
+                return log_error_errno(errno, "Failed to duplicate pager pipe: %m");
+
+        return 1;
+}
+
+void pager_close(void) {
+
+        if (pager_pid <= 0)
+                return;
+
+        /* Inform pager that we are done */
+        stdout = safe_fclose(stdout);
+        stderr = safe_fclose(stderr);
+
+        (void) kill(pager_pid, SIGCONT);
+        (void) wait_for_terminate(pager_pid, NULL);
+        pager_pid = 0;
+}
+
+bool pager_have(void) {
+        return pager_pid > 0;
+}
+
+int show_man_page(const char *desc, bool null_stdio) {
+        const char *args[4] = { "man", NULL, NULL, NULL };
+        char *e = NULL;
+        pid_t pid;
+        size_t k;
+        int r;
+        siginfo_t status;
+
+        k = strlen(desc);
+
+        if (desc[k-1] == ')')
+                e = strrchr(desc, '(');
+
+        if (e) {
+                char *page = NULL, *section = NULL;
+
+                page = strndupa(desc, e - desc);
+                section = strndupa(e + 1, desc + k - e - 2);
+
+                args[1] = section;
+                args[2] = page;
+        } else
+                args[1] = desc;
+
+        pid = fork();
+        if (pid < 0)
+                return log_error_errno(errno, "Failed to fork: %m");
+
+        if (pid == 0) {
+                /* Child */
+
+                (void) reset_all_signal_handlers();
+                (void) reset_signal_mask();
+
+                if (null_stdio) {
+                        r = make_null_stdio();
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to kill stdio: %m");
+                                _exit(EXIT_FAILURE);
+                        }
+                }
+
+                execvp(args[0], (char**) args);
+                log_error_errno(errno, "Failed to execute man: %m");
+                _exit(EXIT_FAILURE);
+        }
+
+        r = wait_for_terminate(pid, &status);
+        if (r < 0)
+                return r;
+
+        log_debug("Exit code %i status %i", status.si_code, status.si_status);
+        return status.si_status;
+}