Skip to content

Instantly share code, notes, and snippets.

@jhunt
Created Aug 4, 2015
Embed
What would you like to do?
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <poll.h>
#include <sys/time.h>
#include <sys/resource.h>
int open_files(unsigned long *soft, unsigned long *hard, unsigned long *current);
int main(int argc, char **argv)
{
if (argc == 2) {
unsigned int max;
if (strcmp(argv[1], "max") == 0)
max = 0xffffffff;
else
max = strtoul(argv[1], NULL, 10);
int i;
for (i = 0; i < max; i++)
if (!tmpfile())
break;
}
unsigned long soft, hard, current;
if (open_files(&soft, &hard, &current) != 0) {
perror("open_files");
return 1;
}
printf("%lu fds used (limit %lu/%lu)\n", current, soft, hard);
return 0;
}
int open_files(unsigned long *soft, unsigned long *hard, unsigned long *current)
{
int rc, i;
struct rlimit lim;
errno = EINVAL;
if (!soft || !hard || !current)
return -1;
rc = getrlimit(RLIMIT_NOFILE, &lim);
if (rc != 0)
return rc;
*soft = (unsigned long)lim.rlim_cur;
*hard = (unsigned long)lim.rlim_max;
struct pollfd *fds = calloc(*soft, sizeof(struct pollfd));
if (!fds)
return -1;
for (i = 0; i < *soft; i++)
fds[i].fd = i;
rc = poll(fds, *soft, 0);
if (rc < 0)
return rc;
*current = *soft;
for (i = 0; i < lim.rlim_cur; i++)
if (fds[i].revents & POLLNVAL)
*current--;
return 0;
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment