blob: 0a8a4aa35995f146dfcc8e648225248fd1629909 [file] [log] [blame]
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"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000015RCSID("$OpenBSD: buffer.c,v 1.10 2001/01/21 19:05:45 markus 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
Ben Lindstrom46c16222000-12-22 01:43:59 +000056buffer_append(Buffer *buffer, const char *data, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100057{
Damien Miller95def091999-11-25 00:26:21 +110058 char *cp;
59 buffer_append_space(buffer, &cp, len);
60 memcpy(cp, 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 Miller4af51302000-04-16 11:18:38 +100069void
Ben Lindstrom46c16222000-12-22 01:43:59 +000070buffer_append_space(Buffer *buffer, char **datap, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100071{
Damien Miller95def091999-11-25 00:26:21 +110072 /* If the buffer is empty, start using it from the beginning. */
73 if (buffer->offset == buffer->end) {
74 buffer->offset = 0;
75 buffer->end = 0;
76 }
77restart:
78 /* If there is enough space to store all data, store it now. */
79 if (buffer->end + len < buffer->alloc) {
80 *datap = buffer->buf + buffer->end;
81 buffer->end += len;
82 return;
83 }
Damien Miller5428f641999-11-25 11:54:57 +110084 /*
85 * If the buffer is quite empty, but all data is at the end, move the
86 * data to the beginning and retry.
87 */
Damien Miller95def091999-11-25 00:26:21 +110088 if (buffer->offset > buffer->alloc / 2) {
89 memmove(buffer->buf, buffer->buf + buffer->offset,
90 buffer->end - buffer->offset);
91 buffer->end -= buffer->offset;
92 buffer->offset = 0;
93 goto restart;
94 }
95 /* Increase the size of the buffer and retry. */
96 buffer->alloc += len + 32768;
97 buffer->buf = xrealloc(buffer->buf, buffer->alloc);
98 goto restart;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100099}
100
101/* Returns the number of bytes of data in the buffer. */
102
Ben Lindstrom46c16222000-12-22 01:43:59 +0000103u_int
Damien Miller95def091999-11-25 00:26:21 +1100104buffer_len(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000105{
Damien Miller95def091999-11-25 00:26:21 +1100106 return buffer->end - buffer->offset;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000107}
108
109/* Gets data from the beginning of the buffer. */
110
Damien Miller4af51302000-04-16 11:18:38 +1000111void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000112buffer_get(Buffer *buffer, char *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000113{
Damien Miller95def091999-11-25 00:26:21 +1100114 if (len > buffer->end - buffer->offset)
Damien Miller22c77262000-04-13 12:26:34 +1000115 fatal("buffer_get: trying to get more bytes than in buffer");
Damien Miller95def091999-11-25 00:26:21 +1100116 memcpy(buf, buffer->buf + buffer->offset, len);
117 buffer->offset += len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000118}
119
120/* Consumes the given number of bytes from the beginning of the buffer. */
121
Damien Miller4af51302000-04-16 11:18:38 +1000122void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000123buffer_consume(Buffer *buffer, u_int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000124{
Damien Miller95def091999-11-25 00:26:21 +1100125 if (bytes > buffer->end - buffer->offset)
Damien Miller22c77262000-04-13 12:26:34 +1000126 fatal("buffer_consume: trying to get more bytes than in buffer");
Damien Miller95def091999-11-25 00:26:21 +1100127 buffer->offset += bytes;
128}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000129
130/* Consumes the given number of bytes from the end of the buffer. */
131
Damien Miller4af51302000-04-16 11:18:38 +1000132void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000133buffer_consume_end(Buffer *buffer, u_int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000134{
Damien Miller95def091999-11-25 00:26:21 +1100135 if (bytes > buffer->end - buffer->offset)
Damien Miller22c77262000-04-13 12:26:34 +1000136 fatal("buffer_consume_end: trying to get more bytes than in buffer");
Damien Miller95def091999-11-25 00:26:21 +1100137 buffer->end -= bytes;
138}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000139
140/* Returns a pointer to the first used byte in the buffer. */
141
Damien Miller95def091999-11-25 00:26:21 +1100142char *
143buffer_ptr(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000144{
Damien Miller95def091999-11-25 00:26:21 +1100145 return buffer->buf + buffer->offset;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000146}
147
148/* Dumps the contents of the buffer to stderr. */
149
Damien Miller4af51302000-04-16 11:18:38 +1000150void
Damien Miller95def091999-11-25 00:26:21 +1100151buffer_dump(Buffer *buffer)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000152{
Damien Miller95def091999-11-25 00:26:21 +1100153 int i;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000154 u_char *ucp = (u_char *) buffer->buf;
Damien Miller95def091999-11-25 00:26:21 +1100155
156 for (i = buffer->offset; i < buffer->end; i++)
157 fprintf(stderr, " %02x", ucp[i]);
158 fprintf(stderr, "\n");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000159}