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cf851879 | 1 | /* $OpenBSD: buffer.c,v 1.30 2006/08/01 23:22:47 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 | ||
cf851879 | 19 | #include <stdio.h> |
00146caa | 20 | #include <string.h> |
21 | ||
8efc0c15 | 22 | #include "xmalloc.h" |
23 | #include "buffer.h" | |
42f11eb2 | 24 | #include "log.h" |
8efc0c15 | 25 | |
69d9d413 | 26 | #define BUFFER_MAX_CHUNK 0x100000 |
27 | #define BUFFER_MAX_LEN 0xa00000 | |
28 | #define BUFFER_ALLOCSZ 0x008000 | |
29 | ||
8efc0c15 | 30 | /* Initializes the buffer structure. */ |
31 | ||
6ae2364d | 32 | void |
5260325f | 33 | buffer_init(Buffer *buffer) |
8efc0c15 | 34 | { |
20419cc1 | 35 | const u_int len = 4096; |
36 | ||
37 | buffer->alloc = 0; | |
38 | buffer->buf = xmalloc(len); | |
39 | buffer->alloc = len; | |
5260325f | 40 | buffer->offset = 0; |
41 | buffer->end = 0; | |
8efc0c15 | 42 | } |
43 | ||
44 | /* Frees any memory used for the buffer. */ | |
45 | ||
6ae2364d | 46 | void |
5260325f | 47 | buffer_free(Buffer *buffer) |
8efc0c15 | 48 | { |
20419cc1 | 49 | if (buffer->alloc > 0) { |
50 | memset(buffer->buf, 0, buffer->alloc); | |
5bd34316 | 51 | buffer->alloc = 0; |
20419cc1 | 52 | xfree(buffer->buf); |
53 | } | |
8efc0c15 | 54 | } |
55 | ||
aa3378df | 56 | /* |
57 | * Clears any data from the buffer, making it empty. This does not actually | |
58 | * zero the memory. | |
59 | */ | |
8efc0c15 | 60 | |
6ae2364d | 61 | void |
5260325f | 62 | buffer_clear(Buffer *buffer) |
8efc0c15 | 63 | { |
5260325f | 64 | buffer->offset = 0; |
65 | buffer->end = 0; | |
8efc0c15 | 66 | } |
67 | ||
68 | /* Appends data to the buffer, expanding it if necessary. */ | |
69 | ||
6ae2364d | 70 | void |
6c0fa2b1 | 71 | buffer_append(Buffer *buffer, const void *data, u_int len) |
8efc0c15 | 72 | { |
6c0fa2b1 | 73 | void *p; |
74 | p = buffer_append_space(buffer, len); | |
75 | memcpy(p, data, len); | |
8efc0c15 | 76 | } |
77 | ||
69d9d413 | 78 | static int |
79 | buffer_compact(Buffer *buffer) | |
80 | { | |
81 | /* | |
82 | * If the buffer is quite empty, but all data is at the end, move the | |
83 | * data to the beginning. | |
84 | */ | |
85 | if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { | |
86 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
87 | buffer->end - buffer->offset); | |
88 | buffer->end -= buffer->offset; | |
89 | buffer->offset = 0; | |
90 | return (1); | |
91 | } | |
92 | return (0); | |
93 | } | |
94 | ||
aa3378df | 95 | /* |
96 | * Appends space to the buffer, expanding the buffer if necessary. This does | |
97 | * not actually copy the data into the buffer, but instead returns a pointer | |
98 | * to the allocated region. | |
99 | */ | |
8efc0c15 | 100 | |
6c0fa2b1 | 101 | void * |
102 | buffer_append_space(Buffer *buffer, u_int len) | |
8efc0c15 | 103 | { |
49525395 | 104 | u_int newlen; |
6c0fa2b1 | 105 | void *p; |
106 | ||
fa1d7d85 | 107 | if (len > BUFFER_MAX_CHUNK) |
22d62d31 | 108 | fatal("buffer_append_space: len %u not supported", len); |
109 | ||
5260325f | 110 | /* If the buffer is empty, start using it from the beginning. */ |
111 | if (buffer->offset == buffer->end) { | |
112 | buffer->offset = 0; | |
113 | buffer->end = 0; | |
114 | } | |
115 | restart: | |
116 | /* If there is enough space to store all data, store it now. */ | |
117 | if (buffer->end + len < buffer->alloc) { | |
6c0fa2b1 | 118 | p = buffer->buf + buffer->end; |
5260325f | 119 | buffer->end += len; |
6c0fa2b1 | 120 | return p; |
5260325f | 121 | } |
69d9d413 | 122 | |
123 | /* Compact data back to the start of the buffer if necessary */ | |
124 | if (buffer_compact(buffer)) | |
5260325f | 125 | goto restart; |
b6453d99 | 126 | |
69d9d413 | 127 | /* Increase the size of the buffer and retry. */ |
128 | newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ); | |
fa1d7d85 | 129 | if (newlen > BUFFER_MAX_LEN) |
22d62d31 | 130 | fatal("buffer_append_space: alloc %u not supported", |
49525395 | 131 | newlen); |
c5d10563 | 132 | buffer->buf = xrealloc(buffer->buf, 1, newlen); |
49525395 | 133 | buffer->alloc = newlen; |
5260325f | 134 | goto restart; |
6c0fa2b1 | 135 | /* NOTREACHED */ |
8efc0c15 | 136 | } |
137 | ||
69d9d413 | 138 | /* |
139 | * Check whether an allocation of 'len' will fit in the buffer | |
140 | * This must follow the same math as buffer_append_space | |
141 | */ | |
142 | int | |
143 | buffer_check_alloc(Buffer *buffer, u_int len) | |
144 | { | |
145 | if (buffer->offset == buffer->end) { | |
146 | buffer->offset = 0; | |
147 | buffer->end = 0; | |
148 | } | |
149 | restart: | |
150 | if (buffer->end + len < buffer->alloc) | |
151 | return (1); | |
152 | if (buffer_compact(buffer)) | |
153 | goto restart; | |
154 | if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) | |
155 | return (1); | |
156 | return (0); | |
157 | } | |
158 | ||
8efc0c15 | 159 | /* Returns the number of bytes of data in the buffer. */ |
160 | ||
1e3b8b07 | 161 | u_int |
5260325f | 162 | buffer_len(Buffer *buffer) |
8efc0c15 | 163 | { |
5260325f | 164 | return buffer->end - buffer->offset; |
8efc0c15 | 165 | } |
166 | ||
167 | /* Gets data from the beginning of the buffer. */ | |
168 | ||
b82a59f2 | 169 | int |
170 | buffer_get_ret(Buffer *buffer, void *buf, u_int len) | |
8efc0c15 | 171 | { |
b82a59f2 | 172 | if (len > buffer->end - buffer->offset) { |
173 | error("buffer_get_ret: trying to get more bytes %d than in buffer %d", | |
b37caf1a | 174 | len, buffer->end - buffer->offset); |
b82a59f2 | 175 | return (-1); |
176 | } | |
5260325f | 177 | memcpy(buf, buffer->buf + buffer->offset, len); |
178 | buffer->offset += len; | |
b82a59f2 | 179 | return (0); |
180 | } | |
181 | ||
182 | void | |
183 | buffer_get(Buffer *buffer, void *buf, u_int len) | |
184 | { | |
185 | if (buffer_get_ret(buffer, buf, len) == -1) | |
186 | fatal("buffer_get: buffer error"); | |
8efc0c15 | 187 | } |
188 | ||
189 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
190 | ||
b82a59f2 | 191 | int |
192 | buffer_consume_ret(Buffer *buffer, u_int bytes) | |
193 | { | |
194 | if (bytes > buffer->end - buffer->offset) { | |
195 | error("buffer_consume_ret: trying to get more bytes than in buffer"); | |
196 | return (-1); | |
197 | } | |
198 | buffer->offset += bytes; | |
199 | return (0); | |
200 | } | |
201 | ||
6ae2364d | 202 | void |
1e3b8b07 | 203 | buffer_consume(Buffer *buffer, u_int bytes) |
8efc0c15 | 204 | { |
b82a59f2 | 205 | if (buffer_consume_ret(buffer, bytes) == -1) |
206 | fatal("buffer_consume: buffer error"); | |
5260325f | 207 | } |
8efc0c15 | 208 | |
209 | /* Consumes the given number of bytes from the end of the buffer. */ | |
210 | ||
b82a59f2 | 211 | int |
212 | buffer_consume_end_ret(Buffer *buffer, u_int bytes) | |
213 | { | |
214 | if (bytes > buffer->end - buffer->offset) | |
215 | return (-1); | |
216 | buffer->end -= bytes; | |
217 | return (0); | |
218 | } | |
219 | ||
6ae2364d | 220 | void |
1e3b8b07 | 221 | buffer_consume_end(Buffer *buffer, u_int bytes) |
8efc0c15 | 222 | { |
b82a59f2 | 223 | if (buffer_consume_end_ret(buffer, bytes) == -1) |
f54651ce | 224 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); |
5260325f | 225 | } |
8efc0c15 | 226 | |
227 | /* Returns a pointer to the first used byte in the buffer. */ | |
228 | ||
6c0fa2b1 | 229 | void * |
5260325f | 230 | buffer_ptr(Buffer *buffer) |
8efc0c15 | 231 | { |
5260325f | 232 | return buffer->buf + buffer->offset; |
8efc0c15 | 233 | } |
234 | ||
235 | /* Dumps the contents of the buffer to stderr. */ | |
236 | ||
6ae2364d | 237 | void |
5260325f | 238 | buffer_dump(Buffer *buffer) |
8efc0c15 | 239 | { |
f04181fe | 240 | u_int i; |
e6207598 | 241 | u_char *ucp = buffer->buf; |
5260325f | 242 | |
8002af61 | 243 | for (i = buffer->offset; i < buffer->end; i++) { |
244 | fprintf(stderr, "%02x", ucp[i]); | |
245 | if ((i-buffer->offset)%16==15) | |
246 | fprintf(stderr, "\r\n"); | |
247 | else if ((i-buffer->offset)%2==1) | |
248 | fprintf(stderr, " "); | |
249 | } | |
0490e609 | 250 | fprintf(stderr, "\r\n"); |
8efc0c15 | 251 | } |