libpatch_is_devnull.c


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/* See LICENSE file for copyright and license details. */
#include "common.h"
#include <sys/sysmacros.h>


int
libpatch_is_devnull(int fd)
{
	struct stat fd_st;
#ifndef __linux__
	struct stat null_st;
#endif
	if (fstat(fd, &fd_st))
		return -1;
	if (!S_ISCHR(fd_st.st_mode))
		return 0;
#ifdef __linux__
	return fd_st.st_rdev == makedev(1, 3);
#else
	if (stat("/dev/null", &null_st))
		return -1;
	return fd_st.st_rdev == null_st.st_rdev;
#endif
}