mirror of https://github.com/python/cpython
38 lines
930 B
C
38 lines
930 B
C
/*
|
|
* Public domain dup2() lookalike
|
|
* by Curtis Jackson @ AT&T Technologies, Burlington, NC
|
|
* electronic address: burl!rcj
|
|
*
|
|
* dup2 performs the following functions:
|
|
*
|
|
* Check to make sure that fd1 is a valid open file descriptor.
|
|
* Check to see if fd2 is already open; if so, close it.
|
|
* Duplicate fd1 onto fd2; checking to make sure fd2 is a valid fd.
|
|
* Return fd2 if all went well; return BADEXIT otherwise.
|
|
*/
|
|
|
|
#include <errno.h> // errno
|
|
#include <fcntl.h> // fcntl()
|
|
#include <unistd.h> // close()
|
|
|
|
#define BADEXIT -1
|
|
|
|
int
|
|
dup2(int fd1, int fd2)
|
|
{
|
|
if (fd1 != fd2) {
|
|
#ifdef F_DUPFD
|
|
if (fcntl(fd1, F_GETFL) < 0)
|
|
return BADEXIT;
|
|
if (fcntl(fd2, F_GETFL) >= 0)
|
|
close(fd2);
|
|
if (fcntl(fd1, F_DUPFD, fd2) < 0)
|
|
return BADEXIT;
|
|
#else
|
|
errno = ENOTSUP;
|
|
return BADEXIT;
|
|
#endif
|
|
}
|
|
return fd2;
|
|
}
|