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/*
* Copyright (c) 2006 Darren Tucker
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define NUM_OPENS 10
int closefrom(int);
void
fail(char *msg)
{
fprintf(stderr, "closefrom: %s\n", msg);
exit(1);
}
int
main(void)
{
int i, max, fds[NUM_OPENS];
char buf[512];
for (i = 0; i < NUM_OPENS; i++)
if ((fds[i] = open("/dev/null", O_RDONLY)) == -1)
exit(0); /* can't test */
max = i - 1;
/* should close last fd only */
closefrom(fds[max]);
if (close(fds[max]) != -1)
fail("failed to close highest fd");
/* make sure we can still use remaining descriptors */
for (i = 0; i < max; i++)
if (read(fds[i], buf, sizeof(buf)) == -1)
fail("closed descriptors it should not have");
/* should close all fds */
closefrom(fds[0]);
for (i = 0; i < NUM_OPENS; i++)
if (close(fds[i]) != -1)
fail("failed to close from lowest fd");
return 0;
}
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