open_flags.c

cygwin, 著名的在win32下模拟unix操作系统的东东

/*
 * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 * 
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 * 
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 * 
 * http://www.sgi.com 
 * 
 * For further information regarding this notice, see: 
 * 
 * http://oss.sgi.com/projects/GenInfo/NoticeExplan/
 */
/**************************************************************
 *
 *    OS Testing - Silicon Graphics, Inc.
 *
 *    FUNCTION NAME     : parse_open_flags
 *			  openflags2symbols
 *
 *    FUNCTION TITLE    : converts open flag symbols into bitmask
 *			  converts open flag bitmask into symbols
 *
 *    SYNOPSIS:
 *      int parse_open_flags(symbols, badname)
 *	char *symbols;
 *	char **badname;
 *
 *      char *openflags2symbols(openflags, sep, mode)
 *	int openflags;
 *	char *sep;
 *	int mode;
 *
 *    AUTHOR            : Richard Logan
 *
 *    CO-PILOT(s)       : Dean Roehrich
 *
 *    INITIAL RELEASE   : UNICOS 8.0
 *
 *    DESIGN DESCRIPTION
 *	The parse_open_flags function can be used to convert
 *	a list of comma separated open(2) flag symbols (i.e. O_TRUNC)
 *	into the bitmask that can be used by open(2).
 *	If a symbol is unknown and <badname> is not NULL, <badname>
 *	will updated to point that symbol in <string>.
 *	Parse_open_flags will return -1 on this error.
 *      Otherwise parse_open_flags will return the open flag bitmask.
 *	If parse_open_flags returns, <string> will left unchanged.
 *
 * 	The openflags2symbols function attempts to convert open flag
 *	bits into human readable  symbols (i.e. O_TRUNC).  If there 
 *	are more than one symbol, the <sep> string will be placed as
 *	a separator between symbols.  Commonly used separators would
 *	be a comma "," or pipe "|".  If <mode> is one and not all 
 *	<openflags> bits can be converted to symbols, the "UNKNOWN"
 *	symbol will be added to return string.
 * 	Openflags2symbols will return the indentified symbols.
 * 	If no symbols are recognized the return value will be a empty
 * 	string or the "UNKNOWN" symbol.
 *
 *    SPECIAL REQUIREMENTS
 *	None.
 *
 *    UPDATE HISTORY
 *      This should contain the description, author, and date of any
 *      "interesting" modifications (i.e. info should helpful in
 *      maintaining/enhancing this module).
 *      username     description
 *      ----------------------------------------------------------------
 *	rrl    This code was first created during the beginning
 *		of the SFS testing days.  I think that was in 1993.
 *	       This code was updated in 05/96.
 *		(05/96)  openflags2symbols was written.
 *
 *    BUGS/LIMITATIONS
 * 	Currently (05/96) all known symbols are coded into openflags2symbols.
 * 	If new open flags are added this code will have to updated
 * 	to know about them or they will not be recognized.
 *
 **************************************************************/

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/param.h>
#include <string.h> /* strcat */
#include "open_flags.h"

#define UNKNOWN_SYMBOL	"UNKNOWN"

static char Open_symbols[512];	  /* space for openflags2symbols return value */

struct open_flag_t {
    const char *symbol;
    int  flag;
};

static struct open_flag_t Open_flags[] = {
    { "O_RDONLY",	O_RDONLY },
    { "O_WRONLY",	O_WRONLY },
    { "O_RDWR",		O_RDWR },
    { "O_SYNC",		O_SYNC },
    { "O_CREAT",	O_CREAT },
    { "O_TRUNC",	O_TRUNC },
    { "O_EXCL",		O_EXCL },
    { "O_APPEND",	O_APPEND },
    { "O_NONBLOCK",	O_NONBLOCK },
#if O_NOCTTY
    { "O_NOCTTY",	O_NOCTTY },
#endif
#if O_DSYNC
    { "O_DSYNC",	O_DSYNC },
#endif
#if O_RSYNC
    { "O_RSYNC",	O_RSYNC },
#endif
#if O_ASYNC
    { "O_ASYNC",	O_ASYNC },
#endif
#if O_PTYIGN
    { "O_PTYIGN",	O_PTYIGN },
#endif
#if O_NDELAY
    { "O_NDELAY",	O_NDELAY },
#endif
#if O_RAW
    { "O_RAW",		O_RAW },
#endif
#ifdef O_SSD
    { "O_SSD",		O_SSD },
#endif
#if O_BIG
    { "O_BIG",		O_BIG },
#endif
#if O_PLACE
    { "O_PLACE",	O_PLACE },
#endif
#if O_RESTART
    { "O_RESTART",	O_RESTART },
#endif
#if O_SFSXOP
    { "O_SFSXOP",	O_SFSXOP },
#endif
#if O_SFS_DEFER_TM
    { "O_SFS_DEFER_TM",	O_SFS_DEFER_TM },
#endif
#if O_WELLFORMED
    { "O_WELLFORMED",	O_WELLFORMED },
#endif
#if O_LDRAW
    { "O_LDRAW",	O_LDRAW },
#endif
#if O_T3D
    { "O_T3D",	O_T3D },
#endif /* O_T3D */
#if O_PARALLEL
    { "O_PARALLEL",	O_PARALLEL },
    { "O_FSA",	O_PARALLEL|O_WELLFORMED|O_RAW },	/* short cut */
#endif /* O_PARALLEL */
#ifdef O_LARGEFILE
    { "O_LARGEFILE",	O_LARGEFILE },
#endif
#ifdef O_DIRECT
    { "O_DIRECT",	O_DIRECT },
#endif
#ifdef O_PRIV
    { "O_PRIV",		O_PRIV },
#endif

};

int 
parse_open_flags(char *string, char **badname)
{
   int  bits = 0;
   char *name;
   char *cc;
   char savecc;
   int  found;
   int  ind;

   name=string;
   cc=name;

   while ( 1 ) {

      for(; ((*cc != ',') && (*cc != '\0')); cc++);
      savecc = *cc;
      *cc = '\0';

      found = 0;

      for(ind=0; ind < sizeof(Open_flags)/sizeof(struct open_flag_t); ind++) {
          if ( strcmp(name, Open_flags[ind].symbol) == 0 ) {
              bits |= Open_flags[ind].flag;
	      found=1;
	      break;
	  }
      }

      *cc = savecc;	/* restore string */

      if ( found == 0 ) {	/* invalid name */
         if ( badname != NULL )
           *badname = name;
         return -1;
      }

      if ( savecc == '\0' )
	break;

      name = ++cc;

   }	/* end while */

   return bits;

}	/* end of parse_open_flags */


char *
openflags2symbols(int openflags, char *sep, int mode)
{
    int ind;
    int size;
    int bits = openflags;
    int havesome=0;

    Open_symbols[0]='\0';

    size=sizeof(Open_flags)/sizeof(struct open_flag_t);

    /*
     * Deal with special case of O_RDONLY.  If O_WRONLY nor O_RDWR
     * bits are not set, assume O_RDONLY.
     */

    if ( (bits & (O_WRONLY | O_RDWR)) == 0 ) {
	strcat(Open_symbols, "O_RDONLY");
	havesome=1;
    }

    /*
     *  Loop through all but O_RDONLY elments of Open_flags
     */
    for(ind=1; ind < size; ind++) {
	  
	if ( (bits & Open_flags[ind].flag) == Open_flags[ind].flag ) {
	    if ( havesome ) 
		strcat(Open_symbols, sep);

	    strcat(Open_symbols, Open_flags[ind].symbol);
	    havesome++;

	    /* remove flag bits from bits */
	    bits = bits & (~Open_flags[ind].flag);
	}
    }

    /*
     * If not all bits were identified and mode was equal to 1,
     * added UNKNOWN_SYMBOL to return string
     */
    if ( bits && mode == 1 )  {    /* not all bits were identified */
        if ( havesome )
            strcat(Open_symbols, sep);
	strcat(Open_symbols,  UNKNOWN_SYMBOL);
    }

    return Open_symbols;

}   /* end of openflags2symbols */


#ifdef UNIT_TEST

/*
 * The following code provides a UNIT test main for
 * parse_open_flags and openflags2symbols functions.
 */

int
main(argc, argv)
int argc;
char **argv;
{
    int bits;
    int ret;
    char *err;

    if (argc == 1 ) {
	printf("Usage: %s openflagsbits\n\t%s symbols\n", argv[0], argv[0]);
	exit(1);
    }

    if ( sscanf(argv[1], "%i", &bits) == 1 ) {
	printf("openflags2symbols(%#o, \",\", 1) returned %s\n",
	    bits, openflags2symbols(bits, ",", 1));
	
    } else {
	ret=parse_open_flags(argv[1], &err);
	if ( ret == -1 )
	    printf("parse_open_flags(%s, &err) returned -1, err = %s\n", 
	        argv[0], err);
        else
	    printf("parse_open_flags(%s, &err) returned %#o\n", argv[0], ret);
    }

    exit(0);
}

#endif /* end of UNIT_TEST */