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#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <stdbool.h>
#include <fcntl.h>
#include <stdlib.h>
#include <assert.h>
#include <asm/ioctls.h>
// Testcase for locked async fd bug -- taviso 16-Dec-2009
int main(int argc, char **argv)
{
int fd;
pid_t child;
unsigned flag = ~0;
fd = open("/dev/urandom", O_RDONLY);
// set up exclusive lock, but dont block
flock(fd, LOCK_EX | LOCK_NB);
// set ASYNC flag on descriptor
ioctl(fd, FIOASYNC, &flag);
// close the file descriptor to trigger the bug
close(fd);
// now exec some stuff to populate the AT_RANDOM entries, which will cause
// the released file to be used.
// This assumes /bin/true is an elf executable, and that this kernel
// supports AT_RANDOM.
do switch (child = fork()) {
case 0: execl("/bin/true", "/bin/true", NULL);
abort();
case -1: fprintf(stderr, "fork() failed, %m\n");
break;
default: fprintf(stderr, ".");
break;
} while (waitpid(child, NULL, 0) != -1);
fprintf(stderr, "waitpid() failed, %m\n");
return 1;
}
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