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#include "shim-signal.h"
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
static pid_t hakurei_shim_param_ppid = -1;
static int hakurei_shim_fd = -1;
/* see shim.go for handling of the message */
static inline ssize_t hakurei_shim_write(hakurei_shim_msg msg) {
int savedErrno = errno;
unsigned char buf = (unsigned char)msg;
ssize_t ret = write(hakurei_shim_fd, &buf, 1);
if (ret == -1 && errno != EAGAIN)
exit(EXIT_FAILURE);
errno = savedErrno;
return ret;
}
static void hakurei_shim_sigaction(int sig, siginfo_t *si, void *ucontext) {
if (sig != SIGCONT || si == NULL) {
hakurei_shim_write(HAKUREI_SHIM_INVALID);
return;
}
if (si->si_pid == hakurei_shim_param_ppid) {
hakurei_shim_write(HAKUREI_SHIM_EXIT_REQUESTED);
return;
}
hakurei_shim_write(HAKUREI_SHIM_BAD_PID);
if (getppid() != hakurei_shim_param_ppid)
hakurei_shim_write(HAKUREI_SHIM_ORPHAN);
}
void hakurei_shim_setup_cont_signal(pid_t ppid, int fd) {
if (hakurei_shim_param_ppid != -1 || hakurei_shim_fd != -1)
*(volatile int *)NULL = 0; /* unreachable */
struct sigaction new_action = {0}, old_action = {0};
if (sigaction(SIGCONT, NULL, &old_action) != 0)
return;
if (old_action.sa_handler != SIG_DFL) {
errno = ENOTRECOVERABLE;
return;
}
new_action.sa_sigaction = hakurei_shim_sigaction;
if (sigemptyset(&new_action.sa_mask) != 0)
return;
new_action.sa_flags = SA_ONSTACK | SA_SIGINFO;
if (sigaction(SIGCONT, &new_action, NULL) != 0)
return;
errno = 0;
hakurei_shim_param_ppid = ppid;
hakurei_shim_fd = fd;
}
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