1 /* 2 * Dropbear SSH 3 * 4 * Copyright (c) 2002-2004 Matt Johnston 5 * All rights reserved. 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this software and associated documentation files (the "Software"), to deal 9 * in the Software without restriction, including without limitation the rights 10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11 * copies of the Software, and to permit persons to whom the Software is 12 * furnished to do so, subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 23 * SOFTWARE. */ 24 25 #include "includes.h" 26 #include "dbutil.h" 27 #include "circbuffer.h" 28 29 #define MAX_CBUF_SIZE 100000000 30 31 circbuffer * cbuf_new(unsigned int size) { 32 33 circbuffer *cbuf = NULL; 34 35 if (size > MAX_CBUF_SIZE) { 36 dropbear_exit("bad cbuf size"); 37 } 38 39 cbuf = (circbuffer*)m_malloc(sizeof(circbuffer)); 40 cbuf->data = (unsigned char*)m_malloc(size); 41 cbuf->used = 0; 42 cbuf->readpos = 0; 43 cbuf->writepos = 0; 44 cbuf->size = size; 45 46 return cbuf; 47 } 48 49 void cbuf_free(circbuffer * cbuf) { 50 51 m_free(cbuf->data); 52 m_free(cbuf); 53 } 54 55 unsigned int cbuf_getused(circbuffer * cbuf) { 56 57 return cbuf->used; 58 59 } 60 61 unsigned int cbuf_getavail(circbuffer * cbuf) { 62 63 return cbuf->size - cbuf->used; 64 65 } 66 67 unsigned int cbuf_readlen(circbuffer *cbuf) { 68 69 dropbear_assert(((2*cbuf->size)+cbuf->writepos-cbuf->readpos)%cbuf->size == cbuf->used%cbuf->size); 70 dropbear_assert(((2*cbuf->size)+cbuf->readpos-cbuf->writepos)%cbuf->size == (cbuf->size-cbuf->used)%cbuf->size); 71 72 if (cbuf->used == 0) { 73 TRACE(("cbuf_readlen: unused buffer")) 74 return 0; 75 } 76 77 if (cbuf->readpos < cbuf->writepos) { 78 return cbuf->writepos - cbuf->readpos; 79 } 80 81 return cbuf->size - cbuf->readpos; 82 } 83 84 unsigned int cbuf_writelen(circbuffer *cbuf) { 85 86 dropbear_assert(cbuf->used <= cbuf->size); 87 dropbear_assert(((2*cbuf->size)+cbuf->writepos-cbuf->readpos)%cbuf->size == cbuf->used%cbuf->size); 88 dropbear_assert(((2*cbuf->size)+cbuf->readpos-cbuf->writepos)%cbuf->size == (cbuf->size-cbuf->used)%cbuf->size); 89 90 if (cbuf->used == cbuf->size) { 91 TRACE(("cbuf_writelen: full buffer")) 92 return 0; /* full */ 93 } 94 95 if (cbuf->writepos < cbuf->readpos) { 96 return cbuf->readpos - cbuf->writepos; 97 } 98 99 return cbuf->size - cbuf->writepos; 100 } 101 102 unsigned char* cbuf_readptr(circbuffer *cbuf, unsigned int len) { 103 if (len > cbuf_readlen(cbuf)) { 104 dropbear_exit("bad cbuf read"); 105 } 106 107 return &cbuf->data[cbuf->readpos]; 108 } 109 110 unsigned char* cbuf_writeptr(circbuffer *cbuf, unsigned int len) { 111 112 if (len > cbuf_writelen(cbuf)) { 113 dropbear_exit("bad cbuf write"); 114 } 115 116 return &cbuf->data[cbuf->writepos]; 117 } 118 119 void cbuf_incrwrite(circbuffer *cbuf, unsigned int len) { 120 if (len > cbuf_writelen(cbuf)) { 121 dropbear_exit("bad cbuf write"); 122 } 123 124 cbuf->used += len; 125 dropbear_assert(cbuf->used <= cbuf->size); 126 cbuf->writepos = (cbuf->writepos + len) % cbuf->size; 127 } 128 129 130 void cbuf_incrread(circbuffer *cbuf, unsigned int len) { 131 if (len > cbuf_readlen(cbuf)) { 132 dropbear_exit("bad cbuf read"); 133 } 134 135 dropbear_assert(cbuf->used >= len); 136 cbuf->used -= len; 137 cbuf->readpos = (cbuf->readpos + len) % cbuf->size; 138 } 139
