112 lines
2.8 KiB
C
112 lines
2.8 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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/*
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FUNCTION
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<<gets>>---get character string (obsolete, use <<fgets>> instead)
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INDEX
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gets
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INDEX
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_gets_r
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ANSI_SYNOPSIS
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#include <stdio.h>
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char *gets(char *<[buf]>);
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char *_gets_r(struct _reent *<[reent]>, char *<[buf]>);
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TRAD_SYNOPSIS
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#include <stdio.h>
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char *gets(<[buf]>)
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char *<[buf]>;
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char *_gets_r(<[reent]>, <[buf]>)
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struct _reent *<[reent]>;
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char *<[buf]>;
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DESCRIPTION
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Reads characters from standard input until a newline is found.
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The characters up to the newline are stored in <[buf]>. The
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newline is discarded, and the buffer is terminated with a 0.
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This is a @emph{dangerous} function, as it has no way of checking
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the amount of space available in <[buf]>. One of the attacks
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used by the Internet Worm of 1988 used this to overrun a
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buffer allocated on the stack of the finger daemon and
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overwrite the return address, causing the daemon to execute
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code downloaded into it over the connection.
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The alternate function <<_gets_r>> is a reentrant version. The extra
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argument <[reent]> is a pointer to a reentrancy structure.
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RETURNS
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<<gets>> returns the buffer passed to it, with the data filled
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in. If end of file occurs with some data already accumulated,
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the data is returned with no other indication. If end of file
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occurs with no data in the buffer, NULL is returned.
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Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
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<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
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*/
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#include <_ansi.h>
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#include <reent.h>
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#include <stdio.h>
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char *
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_DEFUN(_gets_r, (ptr, buf),
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struct _reent *ptr _AND
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char *buf)
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{
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register int c;
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register char *s = buf;
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__sfp_lock_acquire ();
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_flockfile (stdin);
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while ((c = __sgetc_r (ptr, stdin)) != '\n')
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if (c == EOF)
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if (s == buf)
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{
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_funlockfile (stdin);
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__sfp_lock_release ();
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return NULL;
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}
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else
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break;
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else
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*s++ = c;
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*s = 0;
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_funlockfile (stdin);
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__sfp_lock_release ();
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return buf;
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}
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#ifndef _REENT_ONLY
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char *
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_DEFUN(gets, (buf),
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char *buf)
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{
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return _gets_r (_REENT, buf);
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}
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#endif
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