busybox/debianutils/start_stop_daemon.c

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/* vi: set sw=4 ts=4: */
/*
* Mini start-stop-daemon implementation(s) for busybox
*
* Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
* public domain.
* Adapted for busybox David Kimdon <dwhedon@gordian.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <signal.h>
#include <errno.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <getopt.h> /* struct option */
#include "busybox.h"
#include "pwd_.h"
static int signal_nr = 15;
static int user_id = -1;
static int quiet = 0;
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static char *userspec = NULL;
static char *cmdname = NULL;
static char *execname = NULL;
static char *pidfile = NULL;
struct pid_list {
struct pid_list *next;
pid_t pid;
};
static struct pid_list *found = NULL;
static inline void
push(pid_t pid)
{
struct pid_list *p;
p = xmalloc(sizeof(*p));
p->next = found;
p->pid = pid;
found = p;
}
static int
pid_is_exec(pid_t pid, const char *name)
{
char buf[32];
struct stat sb, exec_stat;
if (name && stat(name, &exec_stat))
bb_perror_msg_and_die("stat %s", name);
sprintf(buf, "/proc/%d/exe", pid);
if (stat(buf, &sb) != 0)
return 0;
return (sb.st_dev == exec_stat.st_dev && sb.st_ino == exec_stat.st_ino);
}
static int
pid_is_user(int pid, int uid)
{
struct stat sb;
char buf[32];
sprintf(buf, "/proc/%d", pid);
if (stat(buf, &sb) != 0)
return 0;
return (sb.st_uid == uid);
}
static int
pid_is_cmd(pid_t pid, const char *name)
{
char buf[32];
FILE *f;
int c;
sprintf(buf, "/proc/%d/stat", pid);
f = fopen(buf, "r");
if (!f)
return 0;
while ((c = getc(f)) != EOF && c != '(')
;
if (c != '(') {
fclose(f);
return 0;
}
/* this hopefully handles command names containing ')' */
while ((c = getc(f)) != EOF && c == *name)
name++;
fclose(f);
return (c == ')' && *name == '\0');
}
static void
check(int pid)
{
if (execname && !pid_is_exec(pid, execname)) {
return;
}
if (userspec && !pid_is_user(pid, user_id)) {
return;
}
if (cmdname && !pid_is_cmd(pid, cmdname)) {
return;
}
push(pid);
}
static void
do_pidfile(void)
{
FILE *f;
pid_t pid;
f = fopen(pidfile, "r");
if (f) {
if (fscanf(f, "%d", &pid) == 1)
check(pid);
fclose(f);
} else if (errno != ENOENT)
bb_perror_msg_and_die("open pidfile %s", pidfile);
}
static void
do_procinit(void)
{
DIR *procdir;
struct dirent *entry;
int foundany, pid;
if (pidfile) {
do_pidfile();
return;
}
procdir = opendir("/proc");
if (!procdir)
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bb_perror_msg_and_die ("opendir /proc");
foundany = 0;
while ((entry = readdir(procdir)) != NULL) {
if (sscanf(entry->d_name, "%d", &pid) != 1)
continue;
foundany++;
check(pid);
}
closedir(procdir);
if (!foundany)
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bb_error_msg_and_die ("nothing in /proc - not mounted?");
}
static void
do_stop(void)
{
char what[1024];
struct pid_list *p;
int killed = 0;
do_procinit();
if (cmdname)
strcpy(what, cmdname);
else if (execname)
strcpy(what, execname);
else if (pidfile)
sprintf(what, "process in pidfile `%.200s'", pidfile);
else if (userspec)
sprintf(what, "process(es) owned by `%s'", userspec);
else
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bb_error_msg_and_die ("internal error, please report");
if (!found) {
if (!quiet)
printf("no %s found; none killed.\n", what);
return;
}
for (p = found; p; p = p->next) {
if (kill(p->pid, signal_nr) == 0) {
p->pid = -p->pid;
killed++;
} else {
bb_perror_msg("warning: failed to kill %d", p->pid);
}
}
if (!quiet && killed) {
printf("stopped %s (pid", what);
for (p = found; p; p = p->next)
if(p->pid < 0)
printf(" %d", -p->pid);
printf(").\n");
}
}
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static const struct option ssd_long_options[] = {
{ "stop", 0, NULL, 'K' },
{ "start", 0, NULL, 'S' },
{ "background", 0, NULL, 'b' },
{ "quiet", 0, NULL, 'q' },
{ "make-pidfile", 0, NULL, 'm' },
{ "startas", 1, NULL, 'a' },
{ "name", 1, NULL, 'n' },
{ "signal", 1, NULL, 's' },
{ "user", 1, NULL, 'u' },
{ "exec", 1, NULL, 'x' },
{ "pidfile", 1, NULL, 'p' },
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{ 0, 0, 0, 0 }
};
#define SSD_CTX_STOP 1
#define SSD_CTX_START 2
#define SSD_OPT_BACKGROUND 4
#define SSD_OPT_QUIET 8
#define SSD_OPT_MAKEPID 16
int
start_stop_daemon_main(int argc, char **argv)
{
unsigned long opt;
char *signame = NULL;
char *startas = NULL;
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bb_applet_long_options = ssd_long_options;
bb_opt_complementally = "!K~S:S~K";
opt = bb_getopt_ulflags(argc, argv, "KSbqma:n:s:u:x:p:",
&startas, &cmdname, &signame, &userspec, &execname, &pidfile);
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/* Check required one context option was given */
if ((opt & (SSD_CTX_STOP | SSD_CTX_START)) == 0) {
bb_show_usage();
}
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if (opt & SSD_OPT_QUIET)
quiet = 1;
if (signame) {
signal_nr = bb_xgetlarg(signame, 10, 0, NSIG);
}
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if (!execname && !pidfile && !userspec && !cmdname)
bb_error_msg_and_die ("need at least one of -x, -p, -u, or -n");
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if (!startas)
startas = execname;
if ((opt & SSD_CTX_START) && !startas)
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bb_error_msg_and_die ("-S needs -x or -a");
if ((opt & SSD_OPT_MAKEPID) && pidfile == NULL)
bb_error_msg_and_die ("-m needs -p");
argc -= optind;
argv += optind;
if (userspec && sscanf(userspec, "%d", &user_id) != 1)
user_id = bb_xgetpwnam(userspec);
if (opt & SSD_CTX_STOP) {
do_stop();
return EXIT_SUCCESS;
}
do_procinit();
if (found) {
if (!quiet)
printf("%s already running.\n%d\n", execname ,found->pid);
return EXIT_SUCCESS;
}
*--argv = startas;
if (opt & SSD_OPT_BACKGROUND) {
if (daemon(0, 0) == -1)
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bb_perror_msg_and_die ("unable to fork");
setsid();
}
if (opt & SSD_OPT_MAKEPID) {
/* user wants _us_ to make the pidfile */
FILE *pidf = fopen(pidfile, "w");
pid_t pidt = getpid();
if (pidf == NULL)
bb_perror_msg_and_die("Unable to write pidfile '%s'", pidfile);
fprintf(pidf, "%d\n", pidt);
fclose(pidf);
}
execv(startas, argv);
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bb_perror_msg_and_die ("unable to start %s", startas);
}