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#include "first.h"
/**
* angel process for lighttpd
*
* the purpose is the run as root all the time and handle:
* - restart on crash
* - spawn on HUP to allow graceful restart
* - ...
*
* it has to stay safe and small to be trustable
*/
#include <sys/wait.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h> /* _exit() execvp() fork() */
#define BINPATH SBIN_DIR"/lighttpd"
static volatile sig_atomic_t restart = 0;
static pid_t pid = -1;
__attribute_cold__
static void signal_handler (int sig)
{
if (pid <= 0) return;
if (sig == SIGHUP) {
/* trigger graceful shutdown of lighttpd, then restart lighttpd */
sig = SIGINT;
restart = -1;
}
/* forward signal to the child */
kill(pid, sig);
}
__attribute_cold__
static void signal_setup (void)
{
signal(SIGCHLD, SIG_DFL);
signal(SIGALRM, SIG_DFL);
signal(SIGPIPE, SIG_IGN);
signal(SIGINT, signal_handler);
signal(SIGTERM, signal_handler);
signal(SIGUSR1, signal_handler);
signal(SIGHUP, signal_handler);
}
__attribute_cold__
int main (int argc, char **argv)
{
UNUSED(argc);
*(const char **)&argv[0] = BINPATH;
#ifdef __COVERITY__
__coverity_tainted_data_sanitize__(argv);
#endif
signal_setup();
do {
if (-1 == pid) {
pid = fork();
if (-1 == pid) return -1;
if (0 == pid) {
/* intentionally pass argv params */
/* coverity[tainted_string : FALSE] */
execvp(argv[0], argv);
_exit(1);
}
}
int exitcode = 0;
if ((pid_t)-1 == waitpid(pid, &exitcode, 0)) {
if (errno == ECHILD) break; /* child exists; should not happen */
continue;
}
const char *msg = NULL;
int code = 0;
if (WIFEXITED(exitcode)) {
code = WEXITSTATUS(exitcode);
msg = "%s.%d: child (pid=%d) exited normally with exitcode: %d\n";
}
else if (WIFSIGNALED(exitcode)) {
code = WTERMSIG(exitcode);
msg = "%s.%d: child (pid=%d) exited unexpectedly with signal %d, "
"restarting\n";
restart = -1;
}
if (msg)
fprintf(stderr, msg, __FILE__, __LINE__, pid, code);
pid = restart; /* -1 for restart, 0 to exit */
restart = 0;
} while (pid != 0);
return 0;
}
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