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#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <stdlib.h>
static void do_exec(const char *path, const char *arg, const sigset_t *mask)
{
pid_t pid;
int status;
pid = fork();
if (pid == -1) {
perror("fork");
exit(1);
}
if (pid == 0) {
sigprocmask(SIG_SETMASK, mask, NULL);
execl(path, path, arg, (char *) NULL);
fprintf(stderr, "FAILED: execl failed with %s\n",
strerror(errno));
} else {
int ret;
do
ret = waitpid(pid, &status, 0);
while(ret == -1 && errno == EINTR);
if (ret != pid) {
perror("waitpid");
exit(1);
}
if (status != 0) {
fprintf(stderr, "child exec failed\n");
exit(1);
}
}
}
int main(int argc, char **argv)
{
if (argc == 1) {
sigset_t mask;
sigfillset(&mask);
do_exec(argv[0], "full", &mask);
sigemptyset(&mask);
do_exec(argv[0], "empty", &mask);
} else {
sigset_t mask;
int i;
int empty;
if (strcmp(argv[1], "full") == 0)
empty = 0;
else if (strcmp(argv[1], "empty") == 0)
empty = 1;
else {
fprintf(stderr, "empty or full?\n");
exit(1);
}
sigprocmask(SIG_SETMASK, NULL, &mask);
for(i = 1; i < NSIG; i++) {
if (i == SIGKILL || i == SIGSTOP)
continue;
if (empty) {
if (sigismember(&mask, i))
printf("empty: signal %d added to mask\n", i);
} else {
if (!sigismember(&mask, i))
printf("full: signal %d missing from mask\n", i);
}
}
}
return 0;
}
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