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Initial support for cgroups

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Similar to how systemd creates cgroups for all services, for purposes of
tracking, Finit now does the same.  We also mount all available cgroups
in the /sys/fs/cgroup namespace.

This patch adds support for grouping processes in logical cgroups, like
systemd, and an `initctl ps` command to list the hieararchy.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
This commit is contained in:
Joachim Nilsson
2019-02-05 18:35:36 +01:00
parent 85261c9acd
commit f51fde4d46
8 changed files with 267 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/Makefile.am
+2 -1
View File
@@ -10,6 +10,7 @@ endif
bin_PROGRAMS = logit
sbin_PROGRAMS = finit initctl reboot
pkglibexec_SCRIPTS = cgreaper.sh
if WATCHDOGD
pkglibexec_PROGRAMS = watchdogd
endif
@@ -17,7 +18,7 @@ endif
logit_SOURCES = logit.c
logit_CFLAGS = -W -Wall -Wextra -Wno-unused-parameter -std=gnu99
finit_SOURCES = api.c \
finit_SOURCES = api.c cgroup.c cgroup.h \
cond.c cond-w.c cond.h \
telinit.c \
conf.c conf.h \
src/cgreaper.sh
Executable
+11
View File
@@ -0,0 +1,11 @@
#!/bin/sh
# Called by kernel when last child in cgroup exists
BASE=/sys/fs/cgroup/finit
PROC=`basename $1`
DIR="$BASE$1"
logit -p daemon.info -t finit "$PROC stopped, cleaning up control group $DIR"
rmdir $DIR
exit 0
src/cgroup.c
+143
View File
@@ -0,0 +1,143 @@
/* Finit control group support functions
*
* Copyright (c) 2019 Joachim Nilsson <troglobit@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <lite/lite.h>
#include <sys/mount.h>
#include "log.h"
#include "util.h"
static int cg_init = 0;
/*
* Called by Finit at early boot to mount initial cgroups
*/
void cgroup_init(void)
{
FILE *fp;
char buf[80];
int opts = MS_NODEV | MS_NOEXEC | MS_NOSUID;
fp = fopen("/proc/cgroups", "r");
if (!fp) {
_d("No cgroup support");
return;
}
if (mount("none", "/sys/fs/cgroup", "tmpfs", opts, NULL)) {
_d("Failed mounting cgroups");
goto fail;
}
/* Skip first line, header */
fgets(buf, sizeof(buf), fp);
while (fgets(buf, sizeof(buf), fp)) {
char *cgroup;
char rc[80];
cgroup = strtok(buf, "\t ");
if (!cgroup)
continue;
snprintf(rc, sizeof(rc), "/sys/fs/cgroup/%s", cgroup);
mkdir(rc, 0755);
if (mount("cgroup", rc, "cgroup", opts, cgroup))
_d("Failed mounting %s cgroup on %s", cgroup, rc);
}
/* Default cgroups for process monitoring */
mkdir("/sys/fs/cgroup/finit", 0755);
if (mount("none", "/sys/fs/cgroup/finit", "cgroup", opts, "none,name=finit")) {
_pe("Failed mounting Finit cgroup hierarchy");
goto fail;
}
/* Set up reaper and enable callbacks */
echo("/sys/fs/cgroup/finit/release_agent", 0, "/libexec/finit/cgreaper.sh");
echo("/sys/fs/cgroup/finit/notify_on_release", 0, "1");
/* Default groups, PID 1, services, and user/login processes */
mkdir("/sys/fs/cgroup/finit/init", 0755);
mkdir("/sys/fs/cgroup/finit/system", 0755);
mkdir("/sys/fs/cgroup/finit/user", 0755);
/* Move ourselves to init */
echo("/sys/fs/cgroup/finit/init/cgroup.procs", 0, "1");
/* We have signal, main screen turn on! */
cg_init = 1;
fail:
fclose(fp);
}
static int move_pid(char *group, char *name, int pid)
{
char path[256];
snprintf(path, sizeof(path), "/sys/fs/cgroup/%s/%s", group, name);
if (mkdir(path, 0755) && errno != EEXIST)
return 1;
strlcat(path, "/cgroup.procs", sizeof(path));
return echo(path, 0, "%d", pid);
}
int cgroup_user(char *name)
{
if (!cg_init)
return 0;
return move_pid("finit/user", name, getpid());
}
int cgroup_service(char *cmd, int pid)
{
char *nm;
if (!cg_init)
return 0;
if (pid <= 0) {
errno = EINVAL;
return 1;
}
nm = strrchr(cmd, '/');
if (nm)
nm++;
else
nm = cmd;
return move_pid("finit/system", nm, pid);
}
/**
* Local Variables:
* indent-tabs-mode: t
* c-file-style: "linux"
* End:
*/
src/cgroup.h
+32
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@@ -0,0 +1,32 @@
/* Finit control group support functions
*
* Copyright (c) 2019 Joachim Nilsson <troglobit@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef FINIT_CGROUP_H_
#define FINIT_CGROUP_H_
void cgroup_init (void);
int cgroup_user (char *name);
int cgroup_service (char *cmd, int pid);
#endif /* FINIT_CGROUP_H_ */
src/finit.c
+6
View File
@@ -36,6 +36,7 @@
#include <lite/lite.h>
#include "finit.h"
#include "cgroup.h"
#include "cond.h"
#include "conf.h"
#include "helpers.h"
@@ -352,6 +353,11 @@ int main(int argc, char* argv[])
if (fisdir("/proc/bus/usb"))
mount("none", "/proc/bus/usb", "usbfs", 0, NULL);
/*
* Initialize default control groups, if available
*/
cgroup_init();
/*
* Parse kernel command line (debug, rescue, splash, etc.)
* Also calls log_init() to set correct log level
src/getty.c
+2
View File
@@ -32,6 +32,7 @@
#include <termios.h>
#include "finit.h"
#include "cgroup.h"
#include "helpers.h"
#include "sig.h"
#include "utmp-api.h"
@@ -192,6 +193,7 @@ static int do_login(char *name)
{
struct stat st;
cgroup_user(name);
execl(_PATH_LOGIN, _PATH_LOGIN, name, NULL);
/*
src/initctl.c
+68
View File
@@ -509,6 +509,70 @@ static int show_status(char *arg)
return 0;
}
static int dump_cgroup(const char *fpath, const struct stat *sb, int tflag, struct FTW *ftwbuf)
{
FILE *fp;
char *group;
char path[256];
char buf[256];
int user = 0;
int num = 0;
if (tflag == FTW_F)
return 0;
snprintf(path, sizeof(path), "%s/cgroup.procs", fpath);
fp = fopen(path, "r");
if (!fp)
return 0;
if (strstr(fpath, "finit/user"))
user = 1;
group = strrchr(fpath, '/');
if (!group)
return 0;
group++;
while (fgets(buf, sizeof(buf), fp)) {
FILE *cfp;
int pid;
if (num == 0)
printf("%c :- %s/", user ? ' ' : '|', group);
num++;
pid = atoi(chomp(buf));
snprintf(path, sizeof(path), "/proc/%d/cmdline", pid);
cfp = fopen(path, "r");
if (!cfp)
continue;
fgets(buf, sizeof(buf), cfp);
fclose(cfp);
printf("\n%c :- %d %s", user ? ' ' : '|', pid, buf);
}
fclose(fp);
if (num)
printf("\r%c\n", user ? ' ' : '|');
return 0;
}
static int show_cgroup(char *arg)
{
puts("finit/");
puts("|- init/");
nftw("/sys/fs/cgroup/finit/init", dump_cgroup, 20, 0);
puts("|- system/");
nftw("/sys/fs/cgroup/finit/system", dump_cgroup, 20, 0);
puts("`- user/");
nftw("/sys/fs/cgroup/finit/user", dump_cgroup, 20, 0);
return 0;
}
static int usage(int rc)
{
fprintf(stderr,
@@ -543,6 +607,8 @@ static int usage(int rc)
" status <JOB|NAME>[:ID] Show service status, by job# or name\n"
" status | show Show status of services, default command\n"
"\n"
" ps List processes based on cgroups\n"
"\n"
" runlevel [0-9] Show or set runlevel: 0 halt, 6 reboot\n"
" reboot Reboot system\n"
" halt Halt system\n"
@@ -583,6 +649,8 @@ int main(int argc, char *argv[])
{ "status", show_status },
{ "show", show_status }, /* Convenience alias */
{ "ps", show_cgroup },
{ "runlevel", do_runlevel },
{ "reboot", do_reboot },
{ "halt", do_halt },
src/service.c
+3
View File
@@ -32,6 +32,7 @@
#include <net/if.h>
#include <lite/lite.h>
#include "cgroup.h"
#include "conf.h"
#include "cond.h"
#include "finit.h"
@@ -185,6 +186,8 @@ static int service_start(svc_t *svc)
sigprocmask(SIG_BLOCK, &nmask, &omask);
pid = fork();
cgroup_service(svc->cmd, pid);
if (pid == 0) {
int status;
char *home = NULL;