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/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/signalfd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "util.h"
typedef union {
const void *v;
} Arg;
typedef struct {
const char *name;
void (*func)(const Arg *arg);
const Arg arg;
} Command;
volatile sig_atomic_t signum;
typedef struct {
int sig;
void (*func)(void);
} Sigmap;
static void dispatchcmd(int);
static void sigfifo(void);
static void sigreap(void);
static void sigreboot(void);
static void spawn(const Arg *);
static Sigmap dispatchsig[] = {
{ SIGHUP, sigfifo },
{ SIGCHLD, sigreap },
{ SIGINT, sigreboot },
};
static int sigfd = -1;
static int fifofd = -1;
#include "config.h"
int
main(void)
{
struct signalfd_siginfo siginfo;
sigset_t sigset;
int maxfd, i, ret;
ssize_t n;
fd_set rfds;
if (getpid() != 1)
return EXIT_FAILURE;
setsid();
sigemptyset(&sigset);
for (i = 0; i < LEN(dispatchsig); i++)
sigaddset(&sigset, dispatchsig[i].sig);
sigprocmask(SIG_BLOCK, &sigset, NULL);
sigfd = signalfd(-1, &sigset, 0);
if (sigfd < 0)
eprintf("sinit: signalfd:");
spawn(&(Arg){ .v = rcinitcmd });
while (1) {
FD_ZERO(&rfds);
FD_SET(sigfd, &rfds);
maxfd = sigfd;
if (fifofd != -1) {
FD_SET(fifofd, &rfds);
if (fifofd > maxfd)
maxfd = fifofd;
}
ret = select(maxfd + 1, &rfds, NULL, NULL, NULL);
if (ret < 0)
eprintf("sinit: select:");
if (ret > 0) {
if (FD_ISSET(sigfd, &rfds)) {
n = read(sigfd, &siginfo, sizeof(siginfo));
if (n <= 0)
continue;
for (i = 0; i < LEN(dispatchsig); i++)
if (dispatchsig[i].sig == siginfo.ssi_signo)
dispatchsig[i].func();
}
if (fifofd != -1)
if (FD_ISSET(fifofd, &rfds))
dispatchcmd(fifofd);
}
}
return EXIT_SUCCESS;
}
static void
dispatchcmd(int fd)
{
int i;
char buf[BUFSIZ], *p;
ssize_t n;
n = read(fd, buf, sizeof(buf) - 1);
if (n < 0)
weprintf("sinit: read:");
buf[n] = '\0';
p = strchr(buf, '\n');
if (p)
*p = '\0';
for (i = 0; i < LEN(commands); i++) {
if (strcmp(commands[i].name, buf) == 0) {
commands[i].func(&commands[i].arg);
break;
}
}
}
static void
sigfifo(void)
{
if (!fifopath)
return;
if (fifofd != -1)
close(fifofd);
unlink(fifopath);
umask(0);
if (mkfifo(fifopath, 0600) < 0)
weprintf("sinit: mkfifo %s:", fifopath);
fifofd = open(fifopath, O_RDWR | O_NONBLOCK);
if (fifofd < 0)
weprintf("sinit: open %s:", fifopath);
}
static void
sigreap(void)
{
while (waitpid(-1, NULL, WNOHANG) > 0)
;
}
static void
sigreboot(void)
{
spawn(&(Arg){ .v = rcrebootcmd });
}
static void
spawn(const Arg *arg)
{
int status;
pid_t pid;
char *const *p = arg->v;
pid = fork();
if (pid < 0) {
weprintf("sinit: fork:");
} else if (pid == 0) {
pid = fork();
if (pid < 0)
weprintf("sinit: fork:");
else if (pid > 0)
exit(0);
setsid();
setpgid(0, 0);
execvp(*p, p);
weprintf("sinit: execvp %s:", p);
_exit(errno == ENOENT ? 127 : 126);
}
waitpid(pid, &status, 0);
}
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