1 #include <sys/cdefs.h> 2 #include "namespace.h" 3 #include <lib.h> 4 5 #include <fcntl.h> 6 #include <unistd.h> 7 8 int dup2(fd, fd2) 9 int fd, fd2; 10 { 11 /* The behavior of dup2 is defined by POSIX in 6.2.1.2 as almost, but not 12 * quite the same as fcntl. 13 */ 14 15 if (fd2 < 0 || fd2 > OPEN_MAX) { 16 errno = EBADF; 17 return(-1); 18 } 19 20 /* Check to see if fildes is valid. */ 21 if (fcntl(fd, F_GETFL) < 0) { 22 /* 'fd' is not valid. */ 23 return(-1); 24 } else { 25 /* 'fd' is valid. */ 26 if (fd == fd2) return(fd2); 27 close(fd2); 28 return(fcntl(fd, F_DUPFD, fd2)); 29 } 30 } 31