Annotation of src/usr.bin/ssh/buffer.c, Revision 1.26
1.26 ! djm 1: /* $OpenBSD$ */
1.1 deraadt 2: /*
1.3 deraadt 3: * Author: Tatu Ylonen <ylo@cs.hut.fi>
4: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5: * All rights reserved
6: * Functions for manipulating fifo buffers (that can grow if needed).
1.6 markus 7: *
1.8 deraadt 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".
1.3 deraadt 13: */
1.1 deraadt 14:
15: #include "includes.h"
16:
17: #include "xmalloc.h"
18: #include "buffer.h"
1.10 markus 19: #include "log.h"
1.1 deraadt 20:
21: /* Initializes the buffer structure. */
22:
1.6 markus 23: void
1.2 markus 24: buffer_init(Buffer *buffer)
1.1 deraadt 25: {
1.18 markus 26: const u_int len = 4096;
27:
28: buffer->alloc = 0;
29: buffer->buf = xmalloc(len);
30: buffer->alloc = len;
1.2 markus 31: buffer->offset = 0;
32: buffer->end = 0;
1.1 deraadt 33: }
34:
35: /* Frees any memory used for the buffer. */
36:
1.6 markus 37: void
1.2 markus 38: buffer_free(Buffer *buffer)
1.1 deraadt 39: {
1.18 markus 40: if (buffer->alloc > 0) {
41: memset(buffer->buf, 0, buffer->alloc);
1.19 markus 42: buffer->alloc = 0;
1.18 markus 43: xfree(buffer->buf);
44: }
1.1 deraadt 45: }
46:
1.4 markus 47: /*
48: * Clears any data from the buffer, making it empty. This does not actually
49: * zero the memory.
50: */
1.1 deraadt 51:
1.6 markus 52: void
1.2 markus 53: buffer_clear(Buffer *buffer)
1.1 deraadt 54: {
1.2 markus 55: buffer->offset = 0;
56: buffer->end = 0;
1.1 deraadt 57: }
58:
59: /* Appends data to the buffer, expanding it if necessary. */
60:
1.6 markus 61: void
1.14 stevesk 62: buffer_append(Buffer *buffer, const void *data, u_int len)
1.1 deraadt 63: {
1.14 stevesk 64: void *p;
65: p = buffer_append_space(buffer, len);
66: memcpy(p, data, len);
1.1 deraadt 67: }
68:
1.4 markus 69: /*
70: * Appends space to the buffer, expanding the buffer if necessary. This does
71: * not actually copy the data into the buffer, but instead returns a pointer
72: * to the allocated region.
73: */
1.1 deraadt 74:
1.14 stevesk 75: void *
76: buffer_append_space(Buffer *buffer, u_int len)
1.1 deraadt 77: {
1.17 deraadt 78: u_int newlen;
1.14 stevesk 79: void *p;
80:
1.23 markus 81: if (len > BUFFER_MAX_CHUNK)
1.16 markus 82: fatal("buffer_append_space: len %u not supported", len);
83:
1.2 markus 84: /* If the buffer is empty, start using it from the beginning. */
85: if (buffer->offset == buffer->end) {
86: buffer->offset = 0;
87: buffer->end = 0;
88: }
89: restart:
90: /* If there is enough space to store all data, store it now. */
91: if (buffer->end + len < buffer->alloc) {
1.14 stevesk 92: p = buffer->buf + buffer->end;
1.2 markus 93: buffer->end += len;
1.14 stevesk 94: return p;
1.2 markus 95: }
1.4 markus 96: /*
97: * If the buffer is quite empty, but all data is at the end, move the
98: * data to the beginning and retry.
99: */
1.23 markus 100: if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) {
1.2 markus 101: memmove(buffer->buf, buffer->buf + buffer->offset,
102: buffer->end - buffer->offset);
103: buffer->end -= buffer->offset;
104: buffer->offset = 0;
105: goto restart;
106: }
107: /* Increase the size of the buffer and retry. */
1.21 djm 108:
1.17 deraadt 109: newlen = buffer->alloc + len + 32768;
1.23 markus 110: if (newlen > BUFFER_MAX_LEN)
1.16 markus 111: fatal("buffer_append_space: alloc %u not supported",
1.17 deraadt 112: newlen);
1.25 djm 113: buffer->buf = xrealloc(buffer->buf, 1, newlen);
1.17 deraadt 114: buffer->alloc = newlen;
1.2 markus 115: goto restart;
1.14 stevesk 116: /* NOTREACHED */
1.1 deraadt 117: }
118:
119: /* Returns the number of bytes of data in the buffer. */
120:
1.9 markus 121: u_int
1.2 markus 122: buffer_len(Buffer *buffer)
1.1 deraadt 123: {
1.2 markus 124: return buffer->end - buffer->offset;
1.1 deraadt 125: }
126:
127: /* Gets data from the beginning of the buffer. */
128:
1.22 djm 129: int
130: buffer_get_ret(Buffer *buffer, void *buf, u_int len)
1.1 deraadt 131: {
1.22 djm 132: if (len > buffer->end - buffer->offset) {
133: error("buffer_get_ret: trying to get more bytes %d than in buffer %d",
1.11 markus 134: len, buffer->end - buffer->offset);
1.22 djm 135: return (-1);
136: }
1.2 markus 137: memcpy(buf, buffer->buf + buffer->offset, len);
138: buffer->offset += len;
1.22 djm 139: return (0);
140: }
141:
142: void
143: buffer_get(Buffer *buffer, void *buf, u_int len)
144: {
145: if (buffer_get_ret(buffer, buf, len) == -1)
146: fatal("buffer_get: buffer error");
1.1 deraadt 147: }
148:
149: /* Consumes the given number of bytes from the beginning of the buffer. */
150:
1.22 djm 151: int
152: buffer_consume_ret(Buffer *buffer, u_int bytes)
153: {
154: if (bytes > buffer->end - buffer->offset) {
155: error("buffer_consume_ret: trying to get more bytes than in buffer");
156: return (-1);
157: }
158: buffer->offset += bytes;
159: return (0);
160: }
161:
1.6 markus 162: void
1.9 markus 163: buffer_consume(Buffer *buffer, u_int bytes)
1.1 deraadt 164: {
1.22 djm 165: if (buffer_consume_ret(buffer, bytes) == -1)
166: fatal("buffer_consume: buffer error");
1.2 markus 167: }
1.1 deraadt 168:
169: /* Consumes the given number of bytes from the end of the buffer. */
170:
1.22 djm 171: int
172: buffer_consume_end_ret(Buffer *buffer, u_int bytes)
173: {
174: if (bytes > buffer->end - buffer->offset)
175: return (-1);
176: buffer->end -= bytes;
177: return (0);
178: }
179:
1.6 markus 180: void
1.9 markus 181: buffer_consume_end(Buffer *buffer, u_int bytes)
1.1 deraadt 182: {
1.22 djm 183: if (buffer_consume_end_ret(buffer, bytes) == -1)
1.5 markus 184: fatal("buffer_consume_end: trying to get more bytes than in buffer");
1.2 markus 185: }
1.1 deraadt 186:
187: /* Returns a pointer to the first used byte in the buffer. */
188:
1.14 stevesk 189: void *
1.2 markus 190: buffer_ptr(Buffer *buffer)
1.1 deraadt 191: {
1.2 markus 192: return buffer->buf + buffer->offset;
1.1 deraadt 193: }
194:
195: /* Dumps the contents of the buffer to stderr. */
196:
1.6 markus 197: void
1.2 markus 198: buffer_dump(Buffer *buffer)
1.1 deraadt 199: {
1.20 markus 200: u_int i;
1.15 stevesk 201: u_char *ucp = buffer->buf;
1.2 markus 202:
1.13 markus 203: for (i = buffer->offset; i < buffer->end; i++) {
204: fprintf(stderr, "%02x", ucp[i]);
205: if ((i-buffer->offset)%16==15)
206: fprintf(stderr, "\r\n");
207: else if ((i-buffer->offset)%2==1)
208: fprintf(stderr, " ");
209: }
1.12 markus 210: fprintf(stderr, "\r\n");
1.1 deraadt 211: }
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