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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Functions for manipulating fifo buffers (that can grow if needed).
Damien Miller4af51302000-04-16 11:18:38 +10006 *
Damien Millere4340be2000-09-16 13:29:08 +11007 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
Damien Miller95def091999-11-25 00:26:21 +110012 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100013
14#include "includes.h"
Damien Miller4a8ed542002-01-22 23:33:31 +110015RCSID("$OpenBSD: buffer.c,v 1.15 2002/01/18 18:14:17 stevesk Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100016
17#include "xmalloc.h"
18#include "buffer.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000019#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100020
21/* Initializes the buffer structure. */
22
Damien Miller4af51302000-04-16 11:18:38 +100023void
Damien Miller95def091999-11-25 00:26:21 +110024buffer_init(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100025{
Damien Miller95def091999-11-25 00:26:21 +110026 buffer->alloc = 4096;
27 buffer->buf = xmalloc(buffer->alloc);
28 buffer->offset = 0;
29 buffer->end = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100030}
31
32/* Frees any memory used for the buffer. */
33
Damien Miller4af51302000-04-16 11:18:38 +100034void
Damien Miller95def091999-11-25 00:26:21 +110035buffer_free(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100036{
Damien Miller95def091999-11-25 00:26:21 +110037 memset(buffer->buf, 0, buffer->alloc);
38 xfree(buffer->buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100039}
40
Damien Miller5428f641999-11-25 11:54:57 +110041/*
42 * Clears any data from the buffer, making it empty. This does not actually
43 * zero the memory.
44 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100045
Damien Miller4af51302000-04-16 11:18:38 +100046void
Damien Miller95def091999-11-25 00:26:21 +110047buffer_clear(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100048{
Damien Miller95def091999-11-25 00:26:21 +110049 buffer->offset = 0;
50 buffer->end = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051}
52
53/* Appends data to the buffer, expanding it if necessary. */
54
Damien Miller4af51302000-04-16 11:18:38 +100055void
Damien Miller5a6b4fe2001-12-21 14:56:54 +110056buffer_append(Buffer *buffer, const void *data, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100057{
Damien Miller5a6b4fe2001-12-21 14:56:54 +110058 void *p;
59 p = buffer_append_space(buffer, len);
60 memcpy(p, data, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100061}
62
Damien Miller5428f641999-11-25 11:54:57 +110063/*
64 * Appends space to the buffer, expanding the buffer if necessary. This does
65 * not actually copy the data into the buffer, but instead returns a pointer
66 * to the allocated region.
67 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100068
Damien Miller5a6b4fe2001-12-21 14:56:54 +110069void *
70buffer_append_space(Buffer *buffer, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100071{
Damien Miller5a6b4fe2001-12-21 14:56:54 +110072 void *p;
73
Damien Miller95def091999-11-25 00:26:21 +110074 /* If the buffer is empty, start using it from the beginning. */
75 if (buffer->offset == buffer->end) {
76 buffer->offset = 0;
77 buffer->end = 0;
78 }
79restart:
80 /* If there is enough space to store all data, store it now. */
81 if (buffer->end + len < buffer->alloc) {
Damien Miller5a6b4fe2001-12-21 14:56:54 +110082 p = buffer->buf + buffer->end;
Damien Miller95def091999-11-25 00:26:21 +110083 buffer->end += len;
Damien Miller5a6b4fe2001-12-21 14:56:54 +110084 return p;
Damien Miller95def091999-11-25 00:26:21 +110085 }
Damien Miller5428f641999-11-25 11:54:57 +110086 /*
87 * If the buffer is quite empty, but all data is at the end, move the
88 * data to the beginning and retry.
89 */
Damien Miller95def091999-11-25 00:26:21 +110090 if (buffer->offset > buffer->alloc / 2) {
91 memmove(buffer->buf, buffer->buf + buffer->offset,
92 buffer->end - buffer->offset);
93 buffer->end -= buffer->offset;
94 buffer->offset = 0;
95 goto restart;
96 }
97 /* Increase the size of the buffer and retry. */
98 buffer->alloc += len + 32768;
99 buffer->buf = xrealloc(buffer->buf, buffer->alloc);
100 goto restart;
Damien Miller5a6b4fe2001-12-21 14:56:54 +1100101 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000102}
103
104/* Returns the number of bytes of data in the buffer. */
105
Ben Lindstrom46c16222000-12-22 01:43:59 +0000106u_int
Damien Miller95def091999-11-25 00:26:21 +1100107buffer_len(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108{
Damien Miller95def091999-11-25 00:26:21 +1100109 return buffer->end - buffer->offset;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000110}
111
112/* Gets data from the beginning of the buffer. */
113
Damien Miller4af51302000-04-16 11:18:38 +1000114void
Damien Miller5a6b4fe2001-12-21 14:56:54 +1100115buffer_get(Buffer *buffer, void *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000116{
Damien Miller95def091999-11-25 00:26:21 +1100117 if (len > buffer->end - buffer->offset)
Ben Lindstromd7dd23f2001-04-05 23:36:01 +0000118 fatal("buffer_get: trying to get more bytes %d than in buffer %d",
119 len, buffer->end - buffer->offset);
Damien Miller95def091999-11-25 00:26:21 +1100120 memcpy(buf, buffer->buf + buffer->offset, len);
121 buffer->offset += len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000122}
123
124/* Consumes the given number of bytes from the beginning of the buffer. */
125
Damien Miller4af51302000-04-16 11:18:38 +1000126void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000127buffer_consume(Buffer *buffer, u_int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000128{
Damien Miller95def091999-11-25 00:26:21 +1100129 if (bytes > buffer->end - buffer->offset)
Damien Miller22c77262000-04-13 12:26:34 +1000130 fatal("buffer_consume: trying to get more bytes than in buffer");
Damien Miller95def091999-11-25 00:26:21 +1100131 buffer->offset += bytes;
132}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000133
134/* Consumes the given number of bytes from the end of the buffer. */
135
Damien Miller4af51302000-04-16 11:18:38 +1000136void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000137buffer_consume_end(Buffer *buffer, u_int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000138{
Damien Miller95def091999-11-25 00:26:21 +1100139 if (bytes > buffer->end - buffer->offset)
Damien Miller22c77262000-04-13 12:26:34 +1000140 fatal("buffer_consume_end: trying to get more bytes than in buffer");
Damien Miller95def091999-11-25 00:26:21 +1100141 buffer->end -= bytes;
142}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000143
144/* Returns a pointer to the first used byte in the buffer. */
145
Damien Miller5a6b4fe2001-12-21 14:56:54 +1100146void *
Damien Miller95def091999-11-25 00:26:21 +1100147buffer_ptr(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000148{
Damien Miller95def091999-11-25 00:26:21 +1100149 return buffer->buf + buffer->offset;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000150}
151
152/* Dumps the contents of the buffer to stderr. */
153
Damien Miller4af51302000-04-16 11:18:38 +1000154void
Damien Miller95def091999-11-25 00:26:21 +1100155buffer_dump(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000156{
Damien Miller95def091999-11-25 00:26:21 +1100157 int i;
Damien Miller4a8ed542002-01-22 23:33:31 +1100158 u_char *ucp = buffer->buf;
Damien Miller95def091999-11-25 00:26:21 +1100159
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000160 for (i = buffer->offset; i < buffer->end; i++) {
161 fprintf(stderr, "%02x", ucp[i]);
162 if ((i-buffer->offset)%16==15)
163 fprintf(stderr, "\r\n");
164 else if ((i-buffer->offset)%2==1)
165 fprintf(stderr, " ");
166 }
Ben Lindstrom3bb4f9d2001-04-08 18:30:26 +0000167 fprintf(stderr, "\r\n");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000168}