1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Buffer manipulation routines. These routines can be used to format 28 * data within a data buffer without worrying about overrunning the 29 * buffer. 30 * 31 * A ctxbuf_t structure is used to track the current location within 32 * the buffer. The ctxbuf_init() must be called first to initialize the 33 * context structure. ctxbuf_printf() can then be called to fill the buffer. 34 * ctxbuf_printf will discard any data that would overrun the buffer and 35 * the buffer will always be null terminated. 36 */ 37 38 #pragma ident "%Z%%M% %I% %E% SMI" 39 40 #include <stdio.h> 41 #include <stdarg.h> 42 #include <smbsrv/libsmb.h> 43 44 /* 45 * smb_ctxbuf_init 46 * 47 * Initialize the buffer context structure. 48 * This must be called before any of the other 49 * buffer routines can be used. 50 * 51 * Returns -1 if invalid parameters, 0 otherwise 52 */ 53 int smb_ctxbuf_init(smb_ctxbuf_t * ctx,unsigned char * buf,size_t buflen)54 smb_ctxbuf_init(smb_ctxbuf_t *ctx, unsigned char *buf, size_t buflen) 55 { 56 if (ctx == 0 || buf == 0 || buflen == 0) 57 return (-1); 58 59 buf[0] = '\0'; 60 61 ctx->basep = buf; 62 ctx->curp = buf; 63 ctx->endp = &buf[buflen]; 64 65 return (0); 66 } 67 68 /* 69 * smb_ctxbuf_len 70 * 71 * Return the amount of data stored in the buffer, 72 * excluding the terminating null character. Similar 73 * to strlen() 74 * 75 * Returns 0 if the ctx is invalid. 76 */ 77 int smb_ctxbuf_len(smb_ctxbuf_t * ctx)78 smb_ctxbuf_len(smb_ctxbuf_t *ctx) 79 { 80 if (ctx == 0 || ctx->basep == 0 || 81 ctx->curp == 0 || ctx->endp == 0) 82 return (0); 83 else 84 /*LINTED E_PTRDIFF_OVERFLOW*/ 85 return (ctx->curp - ctx->basep); 86 } 87 88 /* 89 * smb_ctxbuf_printf 90 * 91 * Move formatted output (based on fmt string) to the buffer 92 * identified in ctxbuf. Any output characters beyond the buffer 93 * are discarded and a null character is written at the end of the 94 * characters actually written. 95 * 96 * Returns 97 * Always return the number of bytes actually written (excluding the 98 * terminating null). 99 */ 100 int smb_ctxbuf_printf(smb_ctxbuf_t * ctx,const char * fmt,...)101 smb_ctxbuf_printf(smb_ctxbuf_t *ctx, const char *fmt, ...) 102 { 103 int n; 104 va_list args; 105 106 if (ctx == 0 || ctx->basep == 0 || 107 ctx->curp == 0 || ctx->endp == 0) 108 return (-1); 109 110 va_start(args, fmt); 111 /*LINTED E_PTRDIFF_OVERFLOW*/ 112 n = vsnprintf((char *)ctx->curp, ctx->endp-ctx->curp, fmt, args); 113 ctx->curp += n; 114 va_end(args); 115 116 /* 117 * return the number of bytes moved into the buffer. 118 */ 119 return (n); 120 } 121