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536c14e8 | 1 | /* $OpenBSD: buffer.c,v 1.29 2006/07/26 02:35:17 stevesk 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 | ||
00146caa | 19 | #include <string.h> |
20 | ||
8efc0c15 | 21 | #include "xmalloc.h" |
22 | #include "buffer.h" | |
42f11eb2 | 23 | #include "log.h" |
8efc0c15 | 24 | |
69d9d413 | 25 | #define BUFFER_MAX_CHUNK 0x100000 |
26 | #define BUFFER_MAX_LEN 0xa00000 | |
27 | #define BUFFER_ALLOCSZ 0x008000 | |
28 | ||
8efc0c15 | 29 | /* Initializes the buffer structure. */ |
30 | ||
6ae2364d | 31 | void |
5260325f | 32 | buffer_init(Buffer *buffer) |
8efc0c15 | 33 | { |
20419cc1 | 34 | const u_int len = 4096; |
35 | ||
36 | buffer->alloc = 0; | |
37 | buffer->buf = xmalloc(len); | |
38 | buffer->alloc = len; | |
5260325f | 39 | buffer->offset = 0; |
40 | buffer->end = 0; | |
8efc0c15 | 41 | } |
42 | ||
43 | /* Frees any memory used for the buffer. */ | |
44 | ||
6ae2364d | 45 | void |
5260325f | 46 | buffer_free(Buffer *buffer) |
8efc0c15 | 47 | { |
20419cc1 | 48 | if (buffer->alloc > 0) { |
49 | memset(buffer->buf, 0, buffer->alloc); | |
5bd34316 | 50 | buffer->alloc = 0; |
20419cc1 | 51 | xfree(buffer->buf); |
52 | } | |
8efc0c15 | 53 | } |
54 | ||
aa3378df | 55 | /* |
56 | * Clears any data from the buffer, making it empty. This does not actually | |
57 | * zero the memory. | |
58 | */ | |
8efc0c15 | 59 | |
6ae2364d | 60 | void |
5260325f | 61 | buffer_clear(Buffer *buffer) |
8efc0c15 | 62 | { |
5260325f | 63 | buffer->offset = 0; |
64 | buffer->end = 0; | |
8efc0c15 | 65 | } |
66 | ||
67 | /* Appends data to the buffer, expanding it if necessary. */ | |
68 | ||
6ae2364d | 69 | void |
6c0fa2b1 | 70 | buffer_append(Buffer *buffer, const void *data, u_int len) |
8efc0c15 | 71 | { |
6c0fa2b1 | 72 | void *p; |
73 | p = buffer_append_space(buffer, len); | |
74 | memcpy(p, data, len); | |
8efc0c15 | 75 | } |
76 | ||
69d9d413 | 77 | static int |
78 | buffer_compact(Buffer *buffer) | |
79 | { | |
80 | /* | |
81 | * If the buffer is quite empty, but all data is at the end, move the | |
82 | * data to the beginning. | |
83 | */ | |
84 | if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { | |
85 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
86 | buffer->end - buffer->offset); | |
87 | buffer->end -= buffer->offset; | |
88 | buffer->offset = 0; | |
89 | return (1); | |
90 | } | |
91 | return (0); | |
92 | } | |
93 | ||
aa3378df | 94 | /* |
95 | * Appends space to the buffer, expanding the buffer if necessary. This does | |
96 | * not actually copy the data into the buffer, but instead returns a pointer | |
97 | * to the allocated region. | |
98 | */ | |
8efc0c15 | 99 | |
6c0fa2b1 | 100 | void * |
101 | buffer_append_space(Buffer *buffer, u_int len) | |
8efc0c15 | 102 | { |
49525395 | 103 | u_int newlen; |
6c0fa2b1 | 104 | void *p; |
105 | ||
fa1d7d85 | 106 | if (len > BUFFER_MAX_CHUNK) |
22d62d31 | 107 | fatal("buffer_append_space: len %u not supported", len); |
108 | ||
5260325f | 109 | /* If the buffer is empty, start using it from the beginning. */ |
110 | if (buffer->offset == buffer->end) { | |
111 | buffer->offset = 0; | |
112 | buffer->end = 0; | |
113 | } | |
114 | restart: | |
115 | /* If there is enough space to store all data, store it now. */ | |
116 | if (buffer->end + len < buffer->alloc) { | |
6c0fa2b1 | 117 | p = buffer->buf + buffer->end; |
5260325f | 118 | buffer->end += len; |
6c0fa2b1 | 119 | return p; |
5260325f | 120 | } |
69d9d413 | 121 | |
122 | /* Compact data back to the start of the buffer if necessary */ | |
123 | if (buffer_compact(buffer)) | |
5260325f | 124 | goto restart; |
b6453d99 | 125 | |
69d9d413 | 126 | /* Increase the size of the buffer and retry. */ |
127 | newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ); | |
fa1d7d85 | 128 | if (newlen > BUFFER_MAX_LEN) |
22d62d31 | 129 | fatal("buffer_append_space: alloc %u not supported", |
49525395 | 130 | newlen); |
c5d10563 | 131 | buffer->buf = xrealloc(buffer->buf, 1, newlen); |
49525395 | 132 | buffer->alloc = newlen; |
5260325f | 133 | goto restart; |
6c0fa2b1 | 134 | /* NOTREACHED */ |
8efc0c15 | 135 | } |
136 | ||
69d9d413 | 137 | /* |
138 | * Check whether an allocation of 'len' will fit in the buffer | |
139 | * This must follow the same math as buffer_append_space | |
140 | */ | |
141 | int | |
142 | buffer_check_alloc(Buffer *buffer, u_int len) | |
143 | { | |
144 | if (buffer->offset == buffer->end) { | |
145 | buffer->offset = 0; | |
146 | buffer->end = 0; | |
147 | } | |
148 | restart: | |
149 | if (buffer->end + len < buffer->alloc) | |
150 | return (1); | |
151 | if (buffer_compact(buffer)) | |
152 | goto restart; | |
153 | if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) | |
154 | return (1); | |
155 | return (0); | |
156 | } | |
157 | ||
8efc0c15 | 158 | /* Returns the number of bytes of data in the buffer. */ |
159 | ||
1e3b8b07 | 160 | u_int |
5260325f | 161 | buffer_len(Buffer *buffer) |
8efc0c15 | 162 | { |
5260325f | 163 | return buffer->end - buffer->offset; |
8efc0c15 | 164 | } |
165 | ||
166 | /* Gets data from the beginning of the buffer. */ | |
167 | ||
b82a59f2 | 168 | int |
169 | buffer_get_ret(Buffer *buffer, void *buf, u_int len) | |
8efc0c15 | 170 | { |
b82a59f2 | 171 | if (len > buffer->end - buffer->offset) { |
172 | error("buffer_get_ret: trying to get more bytes %d than in buffer %d", | |
b37caf1a | 173 | len, buffer->end - buffer->offset); |
b82a59f2 | 174 | return (-1); |
175 | } | |
5260325f | 176 | memcpy(buf, buffer->buf + buffer->offset, len); |
177 | buffer->offset += len; | |
b82a59f2 | 178 | return (0); |
179 | } | |
180 | ||
181 | void | |
182 | buffer_get(Buffer *buffer, void *buf, u_int len) | |
183 | { | |
184 | if (buffer_get_ret(buffer, buf, len) == -1) | |
185 | fatal("buffer_get: buffer error"); | |
8efc0c15 | 186 | } |
187 | ||
188 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
189 | ||
b82a59f2 | 190 | int |
191 | buffer_consume_ret(Buffer *buffer, u_int bytes) | |
192 | { | |
193 | if (bytes > buffer->end - buffer->offset) { | |
194 | error("buffer_consume_ret: trying to get more bytes than in buffer"); | |
195 | return (-1); | |
196 | } | |
197 | buffer->offset += bytes; | |
198 | return (0); | |
199 | } | |
200 | ||
6ae2364d | 201 | void |
1e3b8b07 | 202 | buffer_consume(Buffer *buffer, u_int bytes) |
8efc0c15 | 203 | { |
b82a59f2 | 204 | if (buffer_consume_ret(buffer, bytes) == -1) |
205 | fatal("buffer_consume: buffer error"); | |
5260325f | 206 | } |
8efc0c15 | 207 | |
208 | /* Consumes the given number of bytes from the end of the buffer. */ | |
209 | ||
b82a59f2 | 210 | int |
211 | buffer_consume_end_ret(Buffer *buffer, u_int bytes) | |
212 | { | |
213 | if (bytes > buffer->end - buffer->offset) | |
214 | return (-1); | |
215 | buffer->end -= bytes; | |
216 | return (0); | |
217 | } | |
218 | ||
6ae2364d | 219 | void |
1e3b8b07 | 220 | buffer_consume_end(Buffer *buffer, u_int bytes) |
8efc0c15 | 221 | { |
b82a59f2 | 222 | if (buffer_consume_end_ret(buffer, bytes) == -1) |
f54651ce | 223 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); |
5260325f | 224 | } |
8efc0c15 | 225 | |
226 | /* Returns a pointer to the first used byte in the buffer. */ | |
227 | ||
6c0fa2b1 | 228 | void * |
5260325f | 229 | buffer_ptr(Buffer *buffer) |
8efc0c15 | 230 | { |
5260325f | 231 | return buffer->buf + buffer->offset; |
8efc0c15 | 232 | } |
233 | ||
234 | /* Dumps the contents of the buffer to stderr. */ | |
235 | ||
6ae2364d | 236 | void |
5260325f | 237 | buffer_dump(Buffer *buffer) |
8efc0c15 | 238 | { |
f04181fe | 239 | u_int i; |
e6207598 | 240 | u_char *ucp = buffer->buf; |
5260325f | 241 | |
8002af61 | 242 | for (i = buffer->offset; i < buffer->end; i++) { |
243 | fprintf(stderr, "%02x", ucp[i]); | |
244 | if ((i-buffer->offset)%16==15) | |
245 | fprintf(stderr, "\r\n"); | |
246 | else if ((i-buffer->offset)%2==1) | |
247 | fprintf(stderr, " "); | |
248 | } | |
0490e609 | 249 | fprintf(stderr, "\r\n"); |
8efc0c15 | 250 | } |