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/*
* Copyright (C) 2022 The University of Notre Dame
* This software is distributed under the GNU General Public License.
* See the file COPYING for details.
*/
#include "debug.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#if defined(OPEN_MAX)
#define FD_MAX OPEN_MAX
#elif defined(_POSIX_OPEN_MAX)
#define FD_MAX _POSIX_OPEN_MAX
#else
#define FD_MAX 256 /* guess */
#endif
int fd_max(void)
{
errno = 0;
int max = (int)sysconf(_SC_OPEN_MAX);
if (max == -1) {
if (errno == 0) {
max = FD_MAX;
} else {
debug(D_DEBUG, "sysconf(_SC_OPEN_MAX) error: %s", strerror(errno));
exit(EXIT_FAILURE);
}
}
return max;
}
int fd_nonstd_close(void)
{
int fd, max = fd_max();
for (fd = STDERR_FILENO + 1; fd < max; fd++) {
if (close(fd) == -1 && errno != EBADF) {
debug(D_DEBUG, "could not close open file descriptor: %s", strerror(errno));
return errno;
}
}
return 0;
}
int fd_null(int fd, int oflag)
{
int rc;
int fdn;
start:
fdn = open("/dev/null", oflag);
if (fdn == -1) {
if (errno == EINTR)
goto start;
else
return -1;
}
if (dup2(fdn, fd) == -1) {
rc = errno;
goto out;
}
rc = 0;
out:
while (close(fdn) == -1 && errno == EINTR)
; /* nothing we can do if this fails any other way */
return rc;
}
/* vim: set noexpandtab tabstop=8: */
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