usr/src/lib/libtecla/common/errmsg.c

   1 /*
   2  * Copyright (c) 2000, 2001, 2002, 2003, 2004 by Martin C. Shepherd.
   3  *
   4  * All rights reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, and/or sell copies of the Software, and to permit persons
  11  * to whom the Software is furnished to do so, provided that the above
  12  * copyright notice(s) and this permission notice appear in all copies of
  13  * the Software and that both the above copyright notice(s) and this
  14  * permission notice appear in supporting documentation.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  18  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
  19  * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  20  * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
  21  * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
  22  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  23  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  24  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  25  *
  26  * Except as contained in this notice, the name of a copyright holder
  27  * shall not be used in advertising or otherwise to promote the sale, use
  28  * or other dealings in this Software without prior written authorization
  29  * of the copyright holder.
  30  */
  31
  32 #pragma ident   "%Z%%M% %I%     %E% SMI"
  33
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <errno.h>
  37 #include <stdarg.h>
  38
  39 #include "errmsg.h"
  40
  41 /*
  42  * Encapsulate the error reporting buffer in an opaque object.
  43  */
  44 struct ErrMsg {
  45   char msg[ERR_MSG_LEN+1];  /* An error message */
  46 };
  47
  48 /*.......................................................................
  49  * Create a new error-message object.
  50  *
  51  * Output:
  52  *  return  ErrMsg *  The new object, or NULL on error.
  53  */
  54 ErrMsg *_new_ErrMsg(void)
  55 {
  56   ErrMsg *err;  /* The object to be returned */
  57 /*
  58  * Allocate the container.
  59  */
  60   err = malloc(sizeof(ErrMsg));
  61   if(!err) {
  62     errno = ENOMEM;
  63     return NULL;
  64   };
  65 /*
  66  * Before attempting any operation that might fail, initialize the
  67  * container at least up to the point at which it can safely be passed
  68  * to del_ErrMsg().
  69  */
  70   err->msg[0] = '\0';
  71   return err;
  72 }
  73
  74 /*.......................................................................
  75  * Delete an error-message object.
  76  *
  77  * Input:
  78  *  err     ErrMsg *  The object to be deleted.
  79  * Output:
  80  *  return  ErrMsg *  The deleted object (always NULL).
  81  */
  82 ErrMsg *_del_ErrMsg(ErrMsg *err)
  83 {
  84   if(err) {
  85     free(err);
  86   };
  87   return NULL;
  88 }
  89
  90 /*.......................................................................
  91  * Record the concatenation of a list of string arguments in an error
  92  * message object. The last argument must be END_ERR_MSG to terminate
  93  * the argument list.
  94  *
  95  * Input:
  96  *  err      ErrMsg *   The error-message container.
  97  *  ...  const char *   Zero or more strings to be concatenated in buff[].
  98  *  ...  const char *   The last argument must always be END_ERR_MSG to
  99  *                      terminate the argument list.
 100  */
 101 void _err_record_msg(ErrMsg *err, ...)
 102 {
 103   va_list ap;         /* The variable argument list */
 104   const char *s;      /* The string being printed */
 105   size_t msglen = 0;  /* The total length of the message */
 106 /*
 107  * Nowhere to record the result?
 108  */
 109   if(!err) {
 110     errno = EINVAL;
 111     return;
 112   };
 113 /*
 114  * Concatenate the list of argument strings in err->msg[].
 115  */
 116   va_start(ap, err);
 117   while((s = va_arg(ap, const char *)) != END_ERR_MSG) {
 118 /*
 119  * How much room is left in the output buffer (note that the output
 120  * buffer has ERR_MSG_LEN+1 elements).
 121  */
 122     int nleft = ERR_MSG_LEN - msglen;
 123 /*
 124  * How long is the next string to be appended?
 125  */
 126     size_t slen = strlen(s);
 127 /*
 128  * If there is any room left, append as much of the string
 129  * as will fit.
 130  */
 131     if(nleft > 0) {
 132       int nnew = slen < nleft ? slen : nleft;
 133       strncpy(err->msg + msglen, s, nnew);
 134       msglen += nnew;
 135     };
 136   };
 137   va_end(ap);
 138 /*
 139  * Terminate the message.
 140  */
 141   err->msg[msglen] = '\0';
 142   return;
 143 }
 144
 145 /*.......................................................................
 146  * Return a pointer to the error message buffer.
 147  *
 148  * Input:
 149  *  err     ErrMsg *  The container of the error message buffer.
 150  * Output:
 151  *  return    char *  The current error message, or NULL if err==NULL.
 152  */
 153 char *_err_get_msg(ErrMsg *err)
 154 {
 155   return err ? err->msg : NULL;
 156 }
 157
 158 /*.......................................................................
 159  * Replace the current error message with an empty string.
 160  *
 161  * Input:
 162  *  err     ErrMsg *  The container of the error message buffer.
 163  */
 164 void _err_clear_msg(ErrMsg *err)
 165 {
 166   if(err)
 167     err->msg[0] = '\0';
 168 }
 169