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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 6536 | serge | 1 | /* |
| 2 | * Copyright (c) 1990 The Regents of the University of California. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms are permitted |
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| 6 | * provided that the above copyright notice and this paragraph are |
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| 7 | * duplicated in all such forms and that any documentation, |
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| 8 | * advertising materials, and other materials related to such |
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| 9 | * distribution and use acknowledge that the software was developed |
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| 10 | * by the University of California, Berkeley. The name of the |
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| 11 | * University may not be used to endorse or promote products derived |
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| 12 | * from this software without specific prior written permission. |
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| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 16 | */ |
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| 17 | |||
| 18 | /* |
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| 19 | FUNCTION |
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| 20 | < |
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| 21 | |||
| 22 | INDEX |
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| 23 | gets |
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| 24 | INDEX |
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| 25 | _gets_r |
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| 26 | |||
| 27 | ANSI_SYNOPSIS |
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| 28 | #include |
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| 29 | |||
| 30 | char *gets(char *<[buf]>); |
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| 31 | |||
| 32 | char *_gets_r(struct _reent *<[reent]>, char *<[buf]>); |
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| 33 | |||
| 34 | TRAD_SYNOPSIS |
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| 35 | #include |
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| 36 | |||
| 37 | char *gets(<[buf]>) |
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| 38 | char *<[buf]>; |
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| 39 | |||
| 40 | char *_gets_r(<[reent]>, <[buf]>) |
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| 41 | struct _reent *<[reent]>; |
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| 42 | char *<[buf]>; |
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| 43 | |||
| 44 | DESCRIPTION |
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| 45 | Reads characters from standard input until a newline is found. |
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| 46 | The characters up to the newline are stored in <[buf]>. The |
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| 47 | newline is discarded, and the buffer is terminated with a 0. |
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| 48 | |||
| 49 | This is a @emph{dangerous} function, as it has no way of checking |
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| 50 | the amount of space available in <[buf]>. One of the attacks |
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| 51 | used by the Internet Worm of 1988 used this to overrun a |
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| 52 | buffer allocated on the stack of the finger daemon and |
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| 53 | overwrite the return address, causing the daemon to execute |
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| 54 | code downloaded into it over the connection. |
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| 55 | |||
| 56 | The alternate function <<_gets_r>> is a reentrant version. The extra |
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| 57 | argument <[reent]> is a pointer to a reentrancy structure. |
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| 58 | |||
| 59 | |||
| 60 | RETURNS |
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| 61 | < |
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| 62 | in. If end of file occurs with some data already accumulated, |
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| 63 | the data is returned with no other indication. If end of file |
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| 64 | occurs with no data in the buffer, NULL is returned. |
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| 65 | |||
| 66 | Supporting OS subroutines required: < |
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| 67 | < |
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| 68 | */ |
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| 69 | |||
| 70 | #include <_ansi.h> |
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| 71 | #include |
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| 72 | #include |
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| 73 | #include "local.h" |
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| 74 | |||
| 75 | char * |
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| 76 | _DEFUN(_gets_r, (ptr, buf), |
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| 77 | struct _reent *ptr _AND |
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| 78 | char *buf) |
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| 79 | { |
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| 80 | register int c; |
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| 81 | register char *s = buf; |
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| 82 | FILE *fp; |
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| 83 | |||
| 84 | _REENT_SMALL_CHECK_INIT (ptr); |
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| 85 | fp = _stdin_r (ptr); |
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| 86 | CHECK_INIT (ptr, fp); |
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| 87 | _newlib_flockfile_start (fp); |
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| 88 | while ((c = __sgetc_r (ptr, fp)) != '\n') |
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| 89 | if (c == EOF) |
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| 90 | if (s == buf) |
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| 91 | { |
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| 92 | _newlib_flockfile_exit (fp); |
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| 93 | return NULL; |
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| 94 | } |
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| 95 | else |
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| 96 | break; |
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| 97 | else |
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| 98 | *s++ = c; |
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| 99 | *s = 0; |
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| 100 | _newlib_flockfile_end (fp); |
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| 101 | return buf; |
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| 102 | } |
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| 103 | |||
| 104 | #ifndef _REENT_ONLY |
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| 105 | |||
| 106 | char * |
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| 107 | _DEFUN(gets, (buf), |
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| 108 | char *buf) |
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| 109 | { |
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| 110 | return _gets_r (_REENT, buf); |
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| 111 | } |
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| 112 | |||
| 113 | #endif |