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31652869 | 1 | /* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */ |
8efc0c15 | 2 | /* |
5260325f | 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
5260325f | 4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
5 | * All rights reserved | |
5260325f | 6 | * Functions for manipulating fifo buffers (that can grow if needed). |
6ae2364d | 7 | * |
bcbf86ec | 8 | * As far as I am concerned, the code I have written for this software |
9 | * can be used freely for any purpose. Any derived versions of this | |
10 | * software must be clearly marked as such, and if the derived work is | |
11 | * incompatible with the protocol description in the RFC file, it must be | |
12 | * called by a name other than "ssh" or "Secure Shell". | |
5260325f | 13 | */ |
8efc0c15 | 14 | |
15 | #include "includes.h" | |
8efc0c15 | 16 | |
536c14e8 | 17 | #include <sys/param.h> |
18 | ||
cf851879 | 19 | #include <stdio.h> |
00146caa | 20 | #include <string.h> |
31652869 | 21 | #include <stdarg.h> |
00146caa | 22 | |
8efc0c15 | 23 | #include "xmalloc.h" |
24 | #include "buffer.h" | |
42f11eb2 | 25 | #include "log.h" |
8efc0c15 | 26 | |
69d9d413 | 27 | #define BUFFER_MAX_CHUNK 0x100000 |
28 | #define BUFFER_MAX_LEN 0xa00000 | |
29 | #define BUFFER_ALLOCSZ 0x008000 | |
30 | ||
8efc0c15 | 31 | /* Initializes the buffer structure. */ |
32 | ||
6ae2364d | 33 | void |
5260325f | 34 | buffer_init(Buffer *buffer) |
8efc0c15 | 35 | { |
20419cc1 | 36 | const u_int len = 4096; |
37 | ||
38 | buffer->alloc = 0; | |
39 | buffer->buf = xmalloc(len); | |
40 | buffer->alloc = len; | |
5260325f | 41 | buffer->offset = 0; |
42 | buffer->end = 0; | |
8efc0c15 | 43 | } |
44 | ||
45 | /* Frees any memory used for the buffer. */ | |
46 | ||
6ae2364d | 47 | void |
5260325f | 48 | buffer_free(Buffer *buffer) |
8efc0c15 | 49 | { |
20419cc1 | 50 | if (buffer->alloc > 0) { |
51 | memset(buffer->buf, 0, buffer->alloc); | |
5bd34316 | 52 | buffer->alloc = 0; |
20419cc1 | 53 | xfree(buffer->buf); |
54 | } | |
8efc0c15 | 55 | } |
56 | ||
aa3378df | 57 | /* |
58 | * Clears any data from the buffer, making it empty. This does not actually | |
59 | * zero the memory. | |
60 | */ | |
8efc0c15 | 61 | |
6ae2364d | 62 | void |
5260325f | 63 | buffer_clear(Buffer *buffer) |
8efc0c15 | 64 | { |
5260325f | 65 | buffer->offset = 0; |
66 | buffer->end = 0; | |
8efc0c15 | 67 | } |
68 | ||
69 | /* Appends data to the buffer, expanding it if necessary. */ | |
70 | ||
6ae2364d | 71 | void |
6c0fa2b1 | 72 | buffer_append(Buffer *buffer, const void *data, u_int len) |
8efc0c15 | 73 | { |
6c0fa2b1 | 74 | void *p; |
75 | p = buffer_append_space(buffer, len); | |
76 | memcpy(p, data, len); | |
8efc0c15 | 77 | } |
78 | ||
69d9d413 | 79 | static int |
80 | buffer_compact(Buffer *buffer) | |
81 | { | |
82 | /* | |
83 | * If the buffer is quite empty, but all data is at the end, move the | |
84 | * data to the beginning. | |
85 | */ | |
86 | if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { | |
87 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
88 | buffer->end - buffer->offset); | |
89 | buffer->end -= buffer->offset; | |
90 | buffer->offset = 0; | |
91 | return (1); | |
92 | } | |
93 | return (0); | |
94 | } | |
95 | ||
aa3378df | 96 | /* |
97 | * Appends space to the buffer, expanding the buffer if necessary. This does | |
98 | * not actually copy the data into the buffer, but instead returns a pointer | |
99 | * to the allocated region. | |
100 | */ | |
8efc0c15 | 101 | |
6c0fa2b1 | 102 | void * |
103 | buffer_append_space(Buffer *buffer, u_int len) | |
8efc0c15 | 104 | { |
49525395 | 105 | u_int newlen; |
6c0fa2b1 | 106 | void *p; |
107 | ||
fa1d7d85 | 108 | if (len > BUFFER_MAX_CHUNK) |
22d62d31 | 109 | fatal("buffer_append_space: len %u not supported", len); |
110 | ||
5260325f | 111 | /* If the buffer is empty, start using it from the beginning. */ |
112 | if (buffer->offset == buffer->end) { | |
113 | buffer->offset = 0; | |
114 | buffer->end = 0; | |
115 | } | |
116 | restart: | |
117 | /* If there is enough space to store all data, store it now. */ | |
118 | if (buffer->end + len < buffer->alloc) { | |
6c0fa2b1 | 119 | p = buffer->buf + buffer->end; |
5260325f | 120 | buffer->end += len; |
6c0fa2b1 | 121 | return p; |
5260325f | 122 | } |
69d9d413 | 123 | |
124 | /* Compact data back to the start of the buffer if necessary */ | |
125 | if (buffer_compact(buffer)) | |
5260325f | 126 | goto restart; |
b6453d99 | 127 | |
69d9d413 | 128 | /* Increase the size of the buffer and retry. */ |
129 | newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ); | |
fa1d7d85 | 130 | if (newlen > BUFFER_MAX_LEN) |
22d62d31 | 131 | fatal("buffer_append_space: alloc %u not supported", |
49525395 | 132 | newlen); |
c5d10563 | 133 | buffer->buf = xrealloc(buffer->buf, 1, newlen); |
49525395 | 134 | buffer->alloc = newlen; |
5260325f | 135 | goto restart; |
6c0fa2b1 | 136 | /* NOTREACHED */ |
8efc0c15 | 137 | } |
138 | ||
69d9d413 | 139 | /* |
140 | * Check whether an allocation of 'len' will fit in the buffer | |
141 | * This must follow the same math as buffer_append_space | |
142 | */ | |
143 | int | |
144 | buffer_check_alloc(Buffer *buffer, u_int len) | |
145 | { | |
146 | if (buffer->offset == buffer->end) { | |
147 | buffer->offset = 0; | |
148 | buffer->end = 0; | |
149 | } | |
150 | restart: | |
151 | if (buffer->end + len < buffer->alloc) | |
152 | return (1); | |
153 | if (buffer_compact(buffer)) | |
154 | goto restart; | |
155 | if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) | |
156 | return (1); | |
157 | return (0); | |
158 | } | |
159 | ||
8efc0c15 | 160 | /* Returns the number of bytes of data in the buffer. */ |
161 | ||
1e3b8b07 | 162 | u_int |
5260325f | 163 | buffer_len(Buffer *buffer) |
8efc0c15 | 164 | { |
5260325f | 165 | return buffer->end - buffer->offset; |
8efc0c15 | 166 | } |
167 | ||
168 | /* Gets data from the beginning of the buffer. */ | |
169 | ||
b82a59f2 | 170 | int |
171 | buffer_get_ret(Buffer *buffer, void *buf, u_int len) | |
8efc0c15 | 172 | { |
b82a59f2 | 173 | if (len > buffer->end - buffer->offset) { |
174 | error("buffer_get_ret: trying to get more bytes %d than in buffer %d", | |
b37caf1a | 175 | len, buffer->end - buffer->offset); |
b82a59f2 | 176 | return (-1); |
177 | } | |
5260325f | 178 | memcpy(buf, buffer->buf + buffer->offset, len); |
179 | buffer->offset += len; | |
b82a59f2 | 180 | return (0); |
181 | } | |
182 | ||
183 | void | |
184 | buffer_get(Buffer *buffer, void *buf, u_int len) | |
185 | { | |
186 | if (buffer_get_ret(buffer, buf, len) == -1) | |
187 | fatal("buffer_get: buffer error"); | |
8efc0c15 | 188 | } |
189 | ||
190 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
191 | ||
b82a59f2 | 192 | int |
193 | buffer_consume_ret(Buffer *buffer, u_int bytes) | |
194 | { | |
195 | if (bytes > buffer->end - buffer->offset) { | |
196 | error("buffer_consume_ret: trying to get more bytes than in buffer"); | |
197 | return (-1); | |
198 | } | |
199 | buffer->offset += bytes; | |
200 | return (0); | |
201 | } | |
202 | ||
6ae2364d | 203 | void |
1e3b8b07 | 204 | buffer_consume(Buffer *buffer, u_int bytes) |
8efc0c15 | 205 | { |
b82a59f2 | 206 | if (buffer_consume_ret(buffer, bytes) == -1) |
207 | fatal("buffer_consume: buffer error"); | |
5260325f | 208 | } |
8efc0c15 | 209 | |
210 | /* Consumes the given number of bytes from the end of the buffer. */ | |
211 | ||
b82a59f2 | 212 | int |
213 | buffer_consume_end_ret(Buffer *buffer, u_int bytes) | |
214 | { | |
215 | if (bytes > buffer->end - buffer->offset) | |
216 | return (-1); | |
217 | buffer->end -= bytes; | |
218 | return (0); | |
219 | } | |
220 | ||
6ae2364d | 221 | void |
1e3b8b07 | 222 | buffer_consume_end(Buffer *buffer, u_int bytes) |
8efc0c15 | 223 | { |
b82a59f2 | 224 | if (buffer_consume_end_ret(buffer, bytes) == -1) |
f54651ce | 225 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); |
5260325f | 226 | } |
8efc0c15 | 227 | |
228 | /* Returns a pointer to the first used byte in the buffer. */ | |
229 | ||
6c0fa2b1 | 230 | void * |
5260325f | 231 | buffer_ptr(Buffer *buffer) |
8efc0c15 | 232 | { |
5260325f | 233 | return buffer->buf + buffer->offset; |
8efc0c15 | 234 | } |
235 | ||
236 | /* Dumps the contents of the buffer to stderr. */ | |
237 | ||
6ae2364d | 238 | void |
5260325f | 239 | buffer_dump(Buffer *buffer) |
8efc0c15 | 240 | { |
f04181fe | 241 | u_int i; |
e6207598 | 242 | u_char *ucp = buffer->buf; |
5260325f | 243 | |
8002af61 | 244 | for (i = buffer->offset; i < buffer->end; i++) { |
245 | fprintf(stderr, "%02x", ucp[i]); | |
246 | if ((i-buffer->offset)%16==15) | |
247 | fprintf(stderr, "\r\n"); | |
248 | else if ((i-buffer->offset)%2==1) | |
249 | fprintf(stderr, " "); | |
250 | } | |
0490e609 | 251 | fprintf(stderr, "\r\n"); |
8efc0c15 | 252 | } |