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1 /* GETS.C |
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2 * |
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3 * Portions Copyright (c) 1990-2005 Nokia Corporation and/or its subsidiary(-ies). |
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4 * All rights reserved. |
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5 */ |
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6 |
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7 /* |
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8 * Copyright (c) 1990 The Regents of the University of California. |
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9 * All rights reserved. |
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10 * |
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11 * Redistribution and use in source and binary forms are permitted |
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12 * provided that the above copyright notice and this paragraph are |
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13 * duplicated in all such forms and that any documentation, |
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14 * advertising materials, and other materials related to such |
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15 * distribution and use acknowledge that the software was developed |
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16 * by the University of California, Berkeley. The name of the |
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17 * University may not be used to endorse or promote products derived |
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18 * from this software without specific prior written permission. |
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19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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20 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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22 */ |
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23 |
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24 |
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25 /* |
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26 |
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27 FUNCTION |
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28 <<gets>>---get character string (obsolete, use <<fgets>> instead) |
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29 INDEX |
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30 gets |
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31 INDEX |
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32 _gets_r |
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33 |
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34 ANSI_SYNOPSIS |
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35 #include <stdio.h> |
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36 |
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37 char *gets(char *<[buf]>); |
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38 |
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39 char *_gets_r(void *<[reent]>, char *<[buf]>); |
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40 |
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41 TRAD_SYNOPSIS |
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42 #include <stdio.h> |
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43 |
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44 char *gets(<[buf]>) |
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45 char *<[buf]>; |
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46 |
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47 char *_gets_r(<[reent]>, <[buf]>) |
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48 char *<[reent]>; |
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49 char *<[buf]>; |
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50 |
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51 DESCRIPTION |
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52 Reads characters from standard input until a newline is found. |
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53 The characters up to the newline are stored in <[buf]>. The |
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54 newline is discarded, and the buffer is terminated with a 0. |
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55 |
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56 This is a @emph{dangerous} function, as it has no way of checking |
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57 the amount of space available in <[buf]>. One of the attacks |
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58 used by the Internet Worm of 1988 used this to overrun a |
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59 buffer allocated on the stack of the finger daemon and |
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60 overwrite the return address, causing the daemon to execute |
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61 code downloaded into it over the connection. |
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62 |
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63 The alternate function <<_gets_r>> is a reentrant version. The extra |
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64 argument <[reent]> is a pointer to a reentrancy structure. |
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65 |
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66 |
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67 RETURNS |
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68 <<gets>> returns the buffer passed to it, with the data filled |
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69 in. If end of file occurs with some data already accumulated, |
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70 the data is returned with no other indication. If end of file |
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71 occurs with no data in the buffer, NULL is returned. |
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72 |
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73 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>, |
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74 <<lseek>>, <<read>>, <<sbrk>>, <<write>>. |
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75 */ |
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76 |
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77 #include <stdio_r.h> |
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78 #include "LOCAL.H" |
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79 |
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80 /** |
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81 A reentrant version of gets(). |
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82 */ |
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83 EXPORT_C char * |
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84 _gets_r (struct _reent *ptr, char *buf) |
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85 { |
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86 register int c; |
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87 register char *s = buf; |
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88 |
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89 while ((c = _getchar_r (ptr)) != '\n') |
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90 if (c == EOF) |
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91 if (s == buf) |
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92 return NULL; |
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93 else |
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94 break; |
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95 else |
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96 *s++ = (char)c; |
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97 *s = 0; |
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98 return buf; |
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99 } |
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100 |
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101 #ifndef _REENT_ONLY |
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102 |
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103 /** |
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104 Get a string from stdin. |
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105 Reads characters from stdin and stores them into buffer |
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106 until a newline (\n) or EOF character is encountered. |
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107 @return On success, the buffer parameter is returned. |
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108 On end-of-file or error, a null pointer is returned. |
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109 @param pointer to a buffer where to receive the resulting string. |
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110 */ |
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111 EXPORT_C char * |
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112 gets (char *buf) |
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113 { |
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114 return _gets_r (_REENT, buf); |
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115 } |
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116 |
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117 #endif |