31 lines
		
	
	
		
			561 B
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			31 lines
		
	
	
		
			561 B
		
	
	
	
		
			C
		
	
	
		
			Executable File
		
	
	
	
	
| #include <lib.h>
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| #define close	_close
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| #define dup2	_dup2
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| #define fcntl	_fcntl
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| #include <fcntl.h>
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| #include <unistd.h>
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| 
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| PUBLIC int dup2(fd, fd2)
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| int fd, fd2;
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| {
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| /* The behavior of dup2 is defined by POSIX in 6.2.1.2 as almost, but not
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|  * quite the same as fcntl.
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|  */
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| 
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|   if (fd2 < 0 || fd2 > OPEN_MAX) {
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| 	errno = EBADF;
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| 	return(-1);
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|   }
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| 
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|   /* Check to see if fildes is valid. */
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|   if (fcntl(fd, F_GETFL) < 0) {
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| 	/* 'fd' is not valid. */
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| 	return(-1);
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|   } else {
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| 	/* 'fd' is valid. */
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| 	if (fd == fd2) return(fd2);
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| 	close(fd2);
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| 	return(fcntl(fd, F_DUPFD, fd2));
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|   }
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| }
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