Annotation of src/usr.bin/ssh/buffer.c, Revision 1.20
1.1 deraadt 1: /*
1.3 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Functions for manipulating fifo buffers (that can grow if needed).
1.6 markus 6: *
1.8 deraadt 7: * 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".
1.3 deraadt 12: */
1.1 deraadt 13:
14: #include "includes.h"
1.20 ! markus 15: RCSID("$OpenBSD: buffer.c,v 1.19 2003/09/18 07:54:48 markus Exp $");
1.1 deraadt 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:
1.16 markus 81: if (len > 0x100000)
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: */
1.2 markus 100: if (buffer->offset > buffer->alloc / 2) {
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. */
1.17 deraadt 108:
109: newlen = buffer->alloc + len + 32768;
110: if (newlen > 0xa00000)
1.16 markus 111: fatal("buffer_append_space: alloc %u not supported",
1.17 deraadt 112: newlen);
113: buffer->buf = xrealloc(buffer->buf, newlen);
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:
1.6 markus 129: void
1.14 stevesk 130: buffer_get(Buffer *buffer, void *buf, u_int len)
1.1 deraadt 131: {
1.2 markus 132: if (len > buffer->end - buffer->offset)
1.11 markus 133: fatal("buffer_get: trying to get more bytes %d than in buffer %d",
134: len, buffer->end - buffer->offset);
1.2 markus 135: memcpy(buf, buffer->buf + buffer->offset, len);
136: buffer->offset += len;
1.1 deraadt 137: }
138:
139: /* Consumes the given number of bytes from the beginning of the buffer. */
140:
1.6 markus 141: void
1.9 markus 142: buffer_consume(Buffer *buffer, u_int bytes)
1.1 deraadt 143: {
1.2 markus 144: if (bytes > buffer->end - buffer->offset)
1.5 markus 145: fatal("buffer_consume: trying to get more bytes than in buffer");
1.2 markus 146: buffer->offset += bytes;
147: }
1.1 deraadt 148:
149: /* Consumes the given number of bytes from the end of the buffer. */
150:
1.6 markus 151: void
1.9 markus 152: buffer_consume_end(Buffer *buffer, u_int bytes)
1.1 deraadt 153: {
1.2 markus 154: if (bytes > buffer->end - buffer->offset)
1.5 markus 155: fatal("buffer_consume_end: trying to get more bytes than in buffer");
1.2 markus 156: buffer->end -= bytes;
157: }
1.1 deraadt 158:
159: /* Returns a pointer to the first used byte in the buffer. */
160:
1.14 stevesk 161: void *
1.2 markus 162: buffer_ptr(Buffer *buffer)
1.1 deraadt 163: {
1.2 markus 164: return buffer->buf + buffer->offset;
1.1 deraadt 165: }
166:
167: /* Dumps the contents of the buffer to stderr. */
168:
1.6 markus 169: void
1.2 markus 170: buffer_dump(Buffer *buffer)
1.1 deraadt 171: {
1.20 ! markus 172: u_int i;
1.15 stevesk 173: u_char *ucp = buffer->buf;
1.2 markus 174:
1.13 markus 175: for (i = buffer->offset; i < buffer->end; i++) {
176: fprintf(stderr, "%02x", ucp[i]);
177: if ((i-buffer->offset)%16==15)
178: fprintf(stderr, "\r\n");
179: else if ((i-buffer->offset)%2==1)
180: fprintf(stderr, " ");
181: }
1.12 markus 182: fprintf(stderr, "\r\n");
1.1 deraadt 183: }
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