Annotation of src/usr.bin/ssh/buffer.c, Revision 1.18
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"
1.18 ! markus 15: RCSID("$OpenBSD: buffer.c,v 1.17 2003/09/16 03:03:47 deraadt 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);
! 42: xfree(buffer->buf);
! 43: }
1.1 deraadt 44: }
45:
1.4 markus 46: /*
47: * Clears any data from the buffer, making it empty. This does not actually
48: * zero the memory.
49: */
1.1 deraadt 50:
1.6 markus 51: void
1.2 markus 52: buffer_clear(Buffer *buffer)
1.1 deraadt 53: {
1.2 markus 54: buffer->offset = 0;
55: buffer->end = 0;
1.1 deraadt 56: }
57:
58: /* Appends data to the buffer, expanding it if necessary. */
59:
1.6 markus 60: void
1.14 stevesk 61: buffer_append(Buffer *buffer, const void *data, u_int len)
1.1 deraadt 62: {
1.14 stevesk 63: void *p;
64: p = buffer_append_space(buffer, len);
65: memcpy(p, data, len);
1.1 deraadt 66: }
67:
1.4 markus 68: /*
69: * Appends space to the buffer, expanding the buffer if necessary. This does
70: * not actually copy the data into the buffer, but instead returns a pointer
71: * to the allocated region.
72: */
1.1 deraadt 73:
1.14 stevesk 74: void *
75: buffer_append_space(Buffer *buffer, u_int len)
1.1 deraadt 76: {
1.17 deraadt 77: u_int newlen;
1.14 stevesk 78: void *p;
79:
1.16 markus 80: if (len > 0x100000)
81: fatal("buffer_append_space: len %u not supported", len);
82:
1.2 markus 83: /* If the buffer is empty, start using it from the beginning. */
84: if (buffer->offset == buffer->end) {
85: buffer->offset = 0;
86: buffer->end = 0;
87: }
88: restart:
89: /* If there is enough space to store all data, store it now. */
90: if (buffer->end + len < buffer->alloc) {
1.14 stevesk 91: p = buffer->buf + buffer->end;
1.2 markus 92: buffer->end += len;
1.14 stevesk 93: return p;
1.2 markus 94: }
1.4 markus 95: /*
96: * If the buffer is quite empty, but all data is at the end, move the
97: * data to the beginning and retry.
98: */
1.2 markus 99: if (buffer->offset > buffer->alloc / 2) {
100: memmove(buffer->buf, buffer->buf + buffer->offset,
101: buffer->end - buffer->offset);
102: buffer->end -= buffer->offset;
103: buffer->offset = 0;
104: goto restart;
105: }
106: /* Increase the size of the buffer and retry. */
1.17 deraadt 107:
108: newlen = buffer->alloc + len + 32768;
109: if (newlen > 0xa00000)
1.16 markus 110: fatal("buffer_append_space: alloc %u not supported",
1.17 deraadt 111: newlen);
112: buffer->buf = xrealloc(buffer->buf, newlen);
113: buffer->alloc = newlen;
1.2 markus 114: goto restart;
1.14 stevesk 115: /* NOTREACHED */
1.1 deraadt 116: }
117:
118: /* Returns the number of bytes of data in the buffer. */
119:
1.9 markus 120: u_int
1.2 markus 121: buffer_len(Buffer *buffer)
1.1 deraadt 122: {
1.2 markus 123: return buffer->end - buffer->offset;
1.1 deraadt 124: }
125:
126: /* Gets data from the beginning of the buffer. */
127:
1.6 markus 128: void
1.14 stevesk 129: buffer_get(Buffer *buffer, void *buf, u_int len)
1.1 deraadt 130: {
1.2 markus 131: if (len > buffer->end - buffer->offset)
1.11 markus 132: fatal("buffer_get: trying to get more bytes %d than in buffer %d",
133: len, buffer->end - buffer->offset);
1.2 markus 134: memcpy(buf, buffer->buf + buffer->offset, len);
135: buffer->offset += len;
1.1 deraadt 136: }
137:
138: /* Consumes the given number of bytes from the beginning of the buffer. */
139:
1.6 markus 140: void
1.9 markus 141: buffer_consume(Buffer *buffer, u_int bytes)
1.1 deraadt 142: {
1.2 markus 143: if (bytes > buffer->end - buffer->offset)
1.5 markus 144: fatal("buffer_consume: trying to get more bytes than in buffer");
1.2 markus 145: buffer->offset += bytes;
146: }
1.1 deraadt 147:
148: /* Consumes the given number of bytes from the end of the buffer. */
149:
1.6 markus 150: void
1.9 markus 151: buffer_consume_end(Buffer *buffer, u_int bytes)
1.1 deraadt 152: {
1.2 markus 153: if (bytes > buffer->end - buffer->offset)
1.5 markus 154: fatal("buffer_consume_end: trying to get more bytes than in buffer");
1.2 markus 155: buffer->end -= bytes;
156: }
1.1 deraadt 157:
158: /* Returns a pointer to the first used byte in the buffer. */
159:
1.14 stevesk 160: void *
1.2 markus 161: buffer_ptr(Buffer *buffer)
1.1 deraadt 162: {
1.2 markus 163: return buffer->buf + buffer->offset;
1.1 deraadt 164: }
165:
166: /* Dumps the contents of the buffer to stderr. */
167:
1.6 markus 168: void
1.2 markus 169: buffer_dump(Buffer *buffer)
1.1 deraadt 170: {
1.2 markus 171: int i;
1.15 stevesk 172: u_char *ucp = buffer->buf;
1.2 markus 173:
1.13 markus 174: for (i = buffer->offset; i < buffer->end; i++) {
175: fprintf(stderr, "%02x", ucp[i]);
176: if ((i-buffer->offset)%16==15)
177: fprintf(stderr, "\r\n");
178: else if ((i-buffer->offset)%2==1)
179: fprintf(stderr, " ");
180: }
1.12 markus 181: fprintf(stderr, "\r\n");
1.1 deraadt 182: }
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