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https://github.com/topjohnwu/ndk-busybox.git
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53a2299230
start-stop-daemon man page: -b|--background Typically used with programs that don't detach on their own. This option will force start-stop-daemon to fork before starting the process, and force it into the background. WARNING: start-stop-daemon cannot check the exit status if the process fails to execute for any reason. This is a last resort, and is only meant for programs that either make no sense forking on their own, or where it's not feasible to add the code for it to do this itself. This is usefull for applets like watchdog
271 lines
4.5 KiB
C
271 lines
4.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini start-stop-daemon implementation(s) for busybox
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*
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* Written by Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>,
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* public domain.
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* Adapted for busybox David Kimdon <dwhedon@gordian.com>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include <signal.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <unistd.h>
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#include "pwd.h"
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#include "busybox.h"
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static int start = 0;
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static int stop = 0;
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static int fork_before_exec = 0;
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static int signal_nr = 15;
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static int user_id = -1;
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static const char *userspec = NULL;
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static const char *cmdname = NULL;
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static char *execname = NULL;
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static char *startas = NULL;
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typedef struct pid_list {
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struct pid_list *next;
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int pid;
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} pid_list;
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static pid_list *found = NULL;
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static inline void
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push(int pid)
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{
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pid_list *p;
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p = xmalloc(sizeof(*p));
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p->next = found;
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p->pid = pid;
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found = p;
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}
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static void
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parse_options(int argc, char * const *argv)
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{
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int c;
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for (;;) {
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c = getopt (argc, argv, "a:n:s:u:x:KSb");
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if (c == EOF)
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break;
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switch (c) {
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case 'K':
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stop = 1;
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break;
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case 'S':
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start = 1;
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break;
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case 'a':
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startas = optarg;
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break;
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case 'n':
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cmdname = optarg;
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break;
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case 's':
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if (sscanf(optarg, "%d", &signal_nr) != 1)
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error_msg_and_die ("-s takes a numeric argument");
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break;
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case 'u':
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userspec = optarg;
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break;
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case 'x':
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execname = optarg;
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break;
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case 'b':
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fork_before_exec = 1;
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break;
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default:
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show_usage();
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}
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}
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if (start == stop)
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error_msg_and_die ("need one of -S or -K");
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if (!execname && !userspec)
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error_msg_and_die ("need at least one of -x or -u");
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if (!startas)
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startas = execname;
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if (start && !startas)
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error_msg_and_die ("-S needs -x or -a");
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}
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static int
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pid_is_exec(int pid, const char *exec)
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{
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char buf[PATH_MAX];
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FILE *fp;
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sprintf(buf, "/proc/%d/cmdline", pid);
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fp = fopen(buf, "r");
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if (fp && fgets (buf, sizeof (buf), fp) ) {
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if (strncmp (buf, exec, strlen(exec)) == 0)
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return 1;
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}
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return 0;
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}
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static int
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pid_is_user(int pid, int uid)
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{
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struct stat sb;
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char buf[32];
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sprintf(buf, "/proc/%d", pid);
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if (stat(buf, &sb) != 0)
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return 0;
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return (sb.st_uid == uid);
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}
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static int
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pid_is_cmd(int pid, const char *name)
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{
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char buf[32];
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FILE *f;
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int c;
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sprintf(buf, "/proc/%d/stat", pid);
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f = fopen(buf, "r");
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if (!f)
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return 0;
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while ((c = getc(f)) != EOF && c != '(')
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;
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if (c != '(') {
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fclose(f);
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return 0;
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}
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/* this hopefully handles command names containing ')' */
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while ((c = getc(f)) != EOF && c == *name)
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name++;
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fclose(f);
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return (c == ')' && *name == '\0');
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}
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static void
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check(int pid)
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{
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if (execname && !pid_is_exec(pid, execname)) {
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return;
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}
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if (userspec && !pid_is_user(pid, user_id)) {
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return;
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}
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if (cmdname && !pid_is_cmd(pid, cmdname)) {
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return;
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}
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push(pid);
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}
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static void
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do_procfs(void)
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{
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DIR *procdir;
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struct dirent *entry;
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int foundany, pid;
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procdir = opendir("/proc");
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if (!procdir)
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perror_msg_and_die ("opendir /proc");
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foundany = 0;
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while ((entry = readdir(procdir)) != NULL) {
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if (sscanf(entry->d_name, "%d", &pid) != 1)
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continue;
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foundany++;
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check(pid);
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}
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closedir(procdir);
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if (!foundany)
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error_msg_and_die ("nothing in /proc - not mounted?");
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}
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static void
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do_stop(void)
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{
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char what[1024];
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pid_list *p;
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int killed = 0;
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if (cmdname)
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strcpy(what, cmdname);
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else if (execname)
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strcpy(what, execname);
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else if (userspec)
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sprintf(what, "process(es) owned by `%s'", userspec);
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else
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error_msg_and_die ("internal error, please report");
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if (!found) {
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printf("no %s found; none killed.\n", what);
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return;
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}
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for (p = found; p; p = p->next) {
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if (kill(p->pid, signal_nr) == 0) {
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p->pid = -p->pid;
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killed++;
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} else {
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perror_msg("warning: failed to kill %d:", p->pid);
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}
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}
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if (killed) {
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printf("stopped %s (pid", what);
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for (p = found; p; p = p->next)
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if(p->pid < 0)
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printf(" %d", -p->pid);
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printf(").\n");
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}
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}
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int
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start_stop_daemon_main(int argc, char **argv)
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{
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parse_options(argc, argv);
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argc -= optind;
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argv += optind;
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if (userspec && sscanf(userspec, "%d", &user_id) != 1)
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user_id = my_getpwnam(userspec);
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do_procfs();
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if (stop) {
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do_stop();
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return EXIT_SUCCESS;
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}
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if (found) {
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printf("%s already running.\n%d\n", execname ,found->pid);
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return EXIT_SUCCESS;
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}
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*--argv = startas;
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if (fork_before_exec) {
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if (daemon(0, 0) == -1)
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perror_msg_and_die ("unable to fork");
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}
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setsid();
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execv(startas, argv);
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perror_msg_and_die ("unable to start %s", startas);
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}
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