Annotation of src/usr.bin/ssh/buffer.c, Revision 1.17
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"
1.17 ! deraadt 15: RCSID("$OpenBSD: buffer.c,v 1.16 2002/06/26 08:54:18 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: {
1.2 markus 26: buffer->alloc = 4096;
27: buffer->buf = xmalloc(buffer->alloc);
28: buffer->offset = 0;
29: buffer->end = 0;
1.1 deraadt 30: }
31:
32: /* Frees any memory used for the buffer. */
33:
1.6 markus 34: void
1.2 markus 35: buffer_free(Buffer *buffer)
1.1 deraadt 36: {
1.2 markus 37: memset(buffer->buf, 0, buffer->alloc);
38: xfree(buffer->buf);
1.1 deraadt 39: }
40:
1.4 markus 41: /*
42: * Clears any data from the buffer, making it empty. This does not actually
43: * zero the memory.
44: */
1.1 deraadt 45:
1.6 markus 46: void
1.2 markus 47: buffer_clear(Buffer *buffer)
1.1 deraadt 48: {
1.2 markus 49: buffer->offset = 0;
50: buffer->end = 0;
1.1 deraadt 51: }
52:
53: /* Appends data to the buffer, expanding it if necessary. */
54:
1.6 markus 55: void
1.14 stevesk 56: buffer_append(Buffer *buffer, const void *data, u_int len)
1.1 deraadt 57: {
1.14 stevesk 58: void *p;
59: p = buffer_append_space(buffer, len);
60: memcpy(p, data, len);
1.1 deraadt 61: }
62:
1.4 markus 63: /*
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: */
1.1 deraadt 68:
1.14 stevesk 69: void *
70: buffer_append_space(Buffer *buffer, u_int len)
1.1 deraadt 71: {
1.17 ! deraadt 72: u_int newlen;
1.14 stevesk 73: void *p;
74:
1.16 markus 75: if (len > 0x100000)
76: fatal("buffer_append_space: len %u not supported", len);
77:
1.2 markus 78: /* If the buffer is empty, start using it from the beginning. */
79: if (buffer->offset == buffer->end) {
80: buffer->offset = 0;
81: buffer->end = 0;
82: }
83: restart:
84: /* If there is enough space to store all data, store it now. */
85: if (buffer->end + len < buffer->alloc) {
1.14 stevesk 86: p = buffer->buf + buffer->end;
1.2 markus 87: buffer->end += len;
1.14 stevesk 88: return p;
1.2 markus 89: }
1.4 markus 90: /*
91: * If the buffer is quite empty, but all data is at the end, move the
92: * data to the beginning and retry.
93: */
1.2 markus 94: if (buffer->offset > buffer->alloc / 2) {
95: memmove(buffer->buf, buffer->buf + buffer->offset,
96: buffer->end - buffer->offset);
97: buffer->end -= buffer->offset;
98: buffer->offset = 0;
99: goto restart;
100: }
101: /* Increase the size of the buffer and retry. */
1.17 ! deraadt 102:
! 103: newlen = buffer->alloc + len + 32768;
! 104: if (newlen > 0xa00000)
1.16 markus 105: fatal("buffer_append_space: alloc %u not supported",
1.17 ! deraadt 106: newlen);
! 107: buffer->buf = xrealloc(buffer->buf, newlen);
! 108: buffer->alloc = newlen;
1.2 markus 109: goto restart;
1.14 stevesk 110: /* NOTREACHED */
1.1 deraadt 111: }
112:
113: /* Returns the number of bytes of data in the buffer. */
114:
1.9 markus 115: u_int
1.2 markus 116: buffer_len(Buffer *buffer)
1.1 deraadt 117: {
1.2 markus 118: return buffer->end - buffer->offset;
1.1 deraadt 119: }
120:
121: /* Gets data from the beginning of the buffer. */
122:
1.6 markus 123: void
1.14 stevesk 124: buffer_get(Buffer *buffer, void *buf, u_int len)
1.1 deraadt 125: {
1.2 markus 126: if (len > buffer->end - buffer->offset)
1.11 markus 127: fatal("buffer_get: trying to get more bytes %d than in buffer %d",
128: len, buffer->end - buffer->offset);
1.2 markus 129: memcpy(buf, buffer->buf + buffer->offset, len);
130: buffer->offset += len;
1.1 deraadt 131: }
132:
133: /* Consumes the given number of bytes from the beginning of the buffer. */
134:
1.6 markus 135: void
1.9 markus 136: buffer_consume(Buffer *buffer, u_int bytes)
1.1 deraadt 137: {
1.2 markus 138: if (bytes > buffer->end - buffer->offset)
1.5 markus 139: fatal("buffer_consume: trying to get more bytes than in buffer");
1.2 markus 140: buffer->offset += bytes;
141: }
1.1 deraadt 142:
143: /* Consumes the given number of bytes from the end of the buffer. */
144:
1.6 markus 145: void
1.9 markus 146: buffer_consume_end(Buffer *buffer, u_int bytes)
1.1 deraadt 147: {
1.2 markus 148: if (bytes > buffer->end - buffer->offset)
1.5 markus 149: fatal("buffer_consume_end: trying to get more bytes than in buffer");
1.2 markus 150: buffer->end -= bytes;
151: }
1.1 deraadt 152:
153: /* Returns a pointer to the first used byte in the buffer. */
154:
1.14 stevesk 155: void *
1.2 markus 156: buffer_ptr(Buffer *buffer)
1.1 deraadt 157: {
1.2 markus 158: return buffer->buf + buffer->offset;
1.1 deraadt 159: }
160:
161: /* Dumps the contents of the buffer to stderr. */
162:
1.6 markus 163: void
1.2 markus 164: buffer_dump(Buffer *buffer)
1.1 deraadt 165: {
1.2 markus 166: int i;
1.15 stevesk 167: u_char *ucp = buffer->buf;
1.2 markus 168:
1.13 markus 169: for (i = buffer->offset; i < buffer->end; i++) {
170: fprintf(stderr, "%02x", ucp[i]);
171: if ((i-buffer->offset)%16==15)
172: fprintf(stderr, "\r\n");
173: else if ((i-buffer->offset)%2==1)
174: fprintf(stderr, " ");
175: }
1.12 markus 176: fprintf(stderr, "\r\n");
1.1 deraadt 177: }
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