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 #include <stdio.h> 39 #include <stdarg.h> 40 #include <smbsrv/libsmb.h> 41 42 /* 43 * smb_ctxbuf_init 44 * 45 * Initialize the buffer context structure. 46 * This must be called before any of the other 47 * buffer routines can be used. 48 * 49 * Returns -1 if invalid parameters, 0 otherwise 50 */ 51 int 52 smb_ctxbuf_init(smb_ctxbuf_t *ctx, unsigned char *buf, size_t buflen) 53 { 54 if (ctx == 0 || buf == 0 || buflen == 0) 55 return (-1); 56 57 buf[0] = '\0'; 58 59 ctx->basep = buf; 60 ctx->curp = buf; 61 ctx->endp = &buf[buflen]; 62 63 return (0); 64 } 65 66 /* 67 * smb_ctxbuf_len 68 * 69 * Return the amount of data stored in the buffer, 70 * excluding the terminating null character. Similar 71 * to strlen() 72 * 73 * Returns 0 if the ctx is invalid. 74 */ 75 int 76 smb_ctxbuf_len(smb_ctxbuf_t *ctx) 77 { 78 if (ctx == 0 || ctx->basep == 0 || 79 ctx->curp == 0 || ctx->endp == 0) 80 return (0); 81 else 82 /*LINTED E_PTRDIFF_OVERFLOW*/ 83 return (ctx->curp - ctx->basep); 84 } 85 86 /* 87 * smb_ctxbuf_printf 88 * 89 * Move formatted output (based on fmt string) to the buffer 90 * identified in ctxbuf. Any output characters beyond the buffer 91 * are discarded and a null character is written at the end of the 92 * characters actually written. 93 * 94 * Returns 95 * Always return the number of bytes actually written (excluding the 96 * terminating null). 97 */ 98 int 99 smb_ctxbuf_printf(smb_ctxbuf_t *ctx, const char *fmt, ...) 100 { 101 int n; 102 va_list args; 103 104 if (ctx == 0 || ctx->basep == 0 || 105 ctx->curp == 0 || ctx->endp == 0) 106 return (-1); 107 108 va_start(args, fmt); 109 /*LINTED E_PTRDIFF_OVERFLOW*/ 110 n = vsnprintf((char *)ctx->curp, ctx->endp-ctx->curp, fmt, args); 111 ctx->curp += n; 112 va_end(args); 113 114 /* 115 * return the number of bytes moved into the buffer. 116 */ 117 return (n); 118 } 119