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cgls: add pager support to systemd-cgls

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This commit is contained in:
Lennart Poettering 2011-07-07 02:34:35 +02:00
parent 8092a428d4
commit 1968a36040
6 changed files with 190 additions and 103 deletions
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6
Makefile.am
View File

@ -1118,7 +1118,8 @@ systemctl_SOURCES = \
src/cgroup-show.c \
src/cgroup-util.c \
src/exit-status.c \
src/unit-name.c
src/unit-name.c \
src/pager.c
systemctl_CFLAGS = \
$(AM_CFLAGS) \
@ -1177,7 +1178,8 @@ systemd_readahead_replay_LDADD = \
systemd_cgls_SOURCES = \
src/cgls.c \
src/cgroup-show.c \
src/cgroup-util.c
src/cgroup-util.c \
src/pager.c
systemd_cgls_CFLAGS = \
$(AM_CFLAGS)

23
src/cgls.c
View File

@ -30,20 +30,29 @@
#include "cgroup-util.h"
#include "log.h"
#include "util.h"
#include "pager.h"
static bool arg_no_pager = false;
static void help(void) {
printf("%s [OPTIONS...] [CGROUP...]\n\n"
"Recursively show control group contents.\n\n"
" -h --help Show this help\n",
" -h --help Show this help\n"
" --no-pager Do not pipe output into a pager.\n",
program_invocation_short_name);
}
static int parse_argv(int argc, char *argv[]) {
enum {
ARG_NO_PAGER = 0x100
};
static const struct option options[] = {
{ "help", no_argument, NULL, 'h' },
{ NULL, 0, NULL, 0 }
{ "help", no_argument, NULL, 'h' },
{ "no-pager", no_argument, NULL, ARG_NO_PAGER },
{ NULL, 0, NULL, 0 }
};
int c;
@ -59,6 +68,10 @@ static int parse_argv(int argc, char *argv[]) {
help();
return 0;
case ARG_NO_PAGER:
arg_no_pager = true;
break;
case '?':
return -EINVAL;
@ -84,6 +97,9 @@ int main(int argc, char *argv[]) {
goto finish;
}
if (!arg_no_pager)
pager_open();
if (optind < argc) {
unsigned i;
@ -132,6 +148,7 @@ int main(int argc, char *argv[]) {
retval = EXIT_SUCCESS;
finish:
pager_close();
return retval;
}

122
src/pager.c Normal file
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@ -0,0 +1,122 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
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 General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/types.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/prctl.h>
#include "pager.h"
#include "util.h"
#include "macro.h"
static pid_t pager_pid = 0;
void pager_open(void) {
int fd[2];
const char *pager;
pid_t parent_pid;
if (pager_pid > 0)
return;
if (isatty(STDOUT_FILENO) <= 0)
return;
if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER")))
if (!*pager || streq(pager, "cat"))
return;
/* Determine and cache number of columns before we spawn the
* pager so that we get the value from the actual tty */
columns();
if (pipe(fd) < 0) {
log_error("Failed to create pager pipe: %m");
return;
}
parent_pid = getpid();
pager_pid = fork();
if (pager_pid < 0) {
log_error("Failed to fork pager: %m");
close_pipe(fd);
return;
}
/* In the child start the pager */
if (pager_pid == 0) {
dup2(fd[0], STDIN_FILENO);
close_pipe(fd);
setenv("LESS", "FRSX", 0);
/* 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);
execlp("cat", "cat", NULL);
log_error("Unable to execute pager: %m");
_exit(EXIT_FAILURE);
}
/* Return in the parent */
if (dup2(fd[1], STDOUT_FILENO) < 0)
log_error("Failed to duplicate pager pipe: %m");
close_pipe(fd);
}
void pager_close(void) {
if (pager_pid <= 0)
return;
/* Inform pager that we are done */
fclose(stdout);
kill(pager_pid, SIGCONT);
wait_for_terminate(pager_pid, NULL);
pager_pid = 0;
}

28
src/pager.h Normal file
View File

@ -0,0 +1,28 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#ifndef foopagerhfoo
#define foopagerhfoo
/***
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 General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
void pager_open(void);
void pager_close(void);
#endif

108
src/systemctl.c
View File

@ -56,6 +56,7 @@
#include "bus-errors.h"
#include "build.h"
#include "unit-name.h"
#include "pager.h"
static const char *arg_type = NULL;
static char **arg_property = NULL;
@ -118,11 +119,14 @@ static const char *arg_host = NULL;
static bool private_bus = false;
static pid_t pager_pid = 0;
static pid_t agent_pid = 0;
static int daemon_reload(DBusConnection *bus, char **args, unsigned n);
static void pager_open(void);
static void pager_open_if_enabled(void) {
if (!arg_no_pager)
pager_open();
}
static bool on_tty(void) {
static int t = -1;
@ -475,7 +479,7 @@ static int list_units(DBusConnection *bus, char **args, unsigned n) {
assert(bus);
pager_open();
pager_open_if_enabled();
if (!(m = dbus_message_new_method_call(
"org.freedesktop.systemd1",
@ -825,7 +829,7 @@ static int list_jobs(DBusConnection *bus, char **args, unsigned n) {
assert(bus);
pager_open();
pager_open_if_enabled();
if (!(m = dbus_message_new_method_call(
"org.freedesktop.systemd1",
@ -2652,7 +2656,7 @@ static int show(DBusConnection *bus, char **args, unsigned n) {
show_properties = !streq(args[0], "status");
if (show_properties)
pager_open();
pager_open_if_enabled();
if (show_properties && n <= 1) {
/* If not argument is specified inspect the manager
@ -3048,7 +3052,7 @@ static int dump(DBusConnection *bus, char **args, unsigned n) {
dbus_error_init(&error);
pager_open();
pager_open_if_enabled();
if (!(m = dbus_message_new_method_call(
"org.freedesktop.systemd1",
@ -3419,7 +3423,7 @@ static int show_enviroment(DBusConnection *bus, char **args, unsigned n) {
dbus_error_init(&error);
pager_open();
pager_open_if_enabled();
if (!(m = dbus_message_new_method_call(
"org.freedesktop.systemd1",
@ -5602,96 +5606,6 @@ static int runlevel_main(void) {
return 0;
}
static void pager_open(void) {
int fd[2];
const char *pager;
pid_t parent_pid;
if (pager_pid > 0)
return;
if (!on_tty() || arg_no_pager)
return;
if ((pager = getenv("SYSTEMD_PAGER")) || (pager = getenv("PAGER")))
if (!*pager || streq(pager, "cat"))
return;
/* Determine and cache number of columns before we spawn the
* pager so that we get the value from the actual tty */
columns();
if (pipe(fd) < 0) {
log_error("Failed to create pager pipe: %m");
return;
}
parent_pid = getpid();
pager_pid = fork();
if (pager_pid < 0) {
log_error("Failed to fork pager: %m");
close_pipe(fd);
return;
}
/* In the child start the pager */
if (pager_pid == 0) {
dup2(fd[0], STDIN_FILENO);
close_pipe(fd);
setenv("LESS", "FRSX", 0);
/* 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);
} else {
/* 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);
}
log_error("Unable to execute pager: %m");
_exit(EXIT_FAILURE);
}
/* Return in the parent */
if (dup2(fd[1], STDOUT_FILENO) < 0)
log_error("Failed to duplicate pager pipe: %m");
close_pipe(fd);
}
static void pager_close(void) {
siginfo_t dummy;
if (pager_pid <= 0)
return;
/* Inform pager that we are done */
fclose(stdout);
kill(pager_pid, SIGCONT);
wait_for_terminate(pager_pid, &dummy);
pager_pid = 0;
}
static void agent_close(void) {
siginfo_t dummy;

6
src/util.c
View File

@ -3866,8 +3866,12 @@ char *normalize_env_assignment(const char *s) {
}
int wait_for_terminate(pid_t pid, siginfo_t *status) {
siginfo_t dummy;
assert(pid >= 1);
assert(status);
if (!status)
status = &dummy;
for (;;) {
zero(*status);