/***********************************************************************/ /* chmod - exercise CHMOD DOS function call (#43) */ /***********************************************************************/ /* (c) copyright Jerry M. Carlin 8/14/1983 */ /* permission given to use or distribute so long as no money charged. */ /* If questions, call 415-680-7590. */ /***********************************************************************/ /*#define DEBUG 1*/ #include "stdio.h" #define CARRY 1 /* 8086 flags carry bit */ #define FCALL 0x21 /* function call int per DOS 2.0 manual pg D-2 */ #define CHMOD 0x43 /* DOS 2.0 Change File Mode pg D-39 */ #define SETDTA 0x1A /* Set Disk Transfer Address pg D-26 */ #define FFIRST 0x4E /* DOS 2.0 Find First File pg D-49 */ #define FNEXT 0x4F /* DOS 2.0 Find Next File pg D-50 */ /* file attributes from DOS 2.0 manual page C-4 */ #define RO 01 /* read only */ #define HIDE 02 /* hidden file */ #define SYS 04 /* system file */ #define VOLLBL 08 /* special volume label - in first 11 bytes */ #define SUBDIR 0x10 /* defines a subdirectory */ #define ARCHV 0x20 /* archive bit */ char *index(); struct regval { unsigned ax,bx,cx,dx,si,di,ds,es; } iregs, oregs, fileregs; struct segreg { unsigned cs,ss,sds,ses; } sr; main(ac,av) int ac; char *av[]; { char attr[9]; /* file attributes */ int flags; /* 8086 flag register */ char buff[128]; /* disk I/O buffer */ char fullname[128]; /* full file name including drive and dir */ char ddprefix[120]; /* drive and directory info */ int i; bdos(SETDTA,buff); /* Set Data Transfer Address */ iregs.ax = 17152; /* set ah = 43 */ segread(&sr); /* get stack & data seg regs */ iregs.ds = sr.sds; iregs.es = sr.ses; fileregs.ds = iregs.ds; fileregs.es = iregs.es; fileregs.ax = 0x4E00; /* find first */ fileregs.cx = HIDE | SYS | SUBDIR; /* allow any file */ if (strcmp(av[1],"help") == 0 || strcmp(av[1],"?") == 0 || ac == 1) { printf("\nchmod [-[r][h][s][a]] filename.ext "); printf("[filename.ext...]\n"); printf("\nUse the '-' option to set file modes. Omit"); printf(" the '-' option for mode display.\nA dash by "); printf(" itself (chmod - filename) sets normal mode.\n\n"); printf("Settable flags:\n r = read only\n"); printf(" h = hidden\n s = system"); printf("\n a = archive\n\nAny flag not set will be reset."); printf(" This means that if you do not, \nfor example, set"); printf(" read-only the file will be write enabled.\n\n"); printf("DOS global filename chars '*' and '?' may be used.\n"); printf("\nMode display includes 'w' for write ok and "); printf("'d' for a subdirectory.\n\n"); exit(0); } if (av[1][0] == '-') /* set mode */ { iregs.ax |= 1; /* set update bit */ iregs.cx = 0; if (index(av[1],'r') != 0 || index(av[1],'R') != 0) iregs.cx |= RO; if (index(av[1],'h') != 0 || index(av[1],'H') != 0) iregs.cx |= HIDE; if (index(av[1],'s') != 0 || index(av[1],'S') != 0) iregs.cx |= SYS; if (index(av[1],'a') != 0 || index(av[1],'A') != 0) iregs.cx |= ARCHV; #ifdef DEBUG printf("fun code =%x\n",iregs.ax); printf("set mode =%x\n",iregs.cx); #endif ++av; /* skip over set mode word */ --ac; while (--ac > 0) { fileregs.dx = *++av; flags = sysint(FCALL,&fileregs,&oregs); if (oregs.ax) { perror(fileregs.dx,oregs.ax); continue; } buildp(*av,ddprefix); while (oregs.ax == 0) { strcpy(fullname,ddprefix); strcat(fullname,buff+30); iregs.dx = fullname; flags = sysint(FCALL,&iregs,&oregs); if (flags & CARRY) perror(iregs.dx,oregs.ax); oregs.ax = bdos(FNEXT,0) & 0xff; } } exit(0); } /**********************************/ /* else report on current setting */ /**********************************/ while (--ac > 0) { fileregs.dx = *++av; flags = sysint(FCALL,&fileregs,&oregs); /* Find First */ if (oregs.ax) { perror(fileregs.dx,oregs.ax); continue; } i = 0; buildp(*av,ddprefix); while (i == 0) { strcpy(fullname,ddprefix); strcat(fullname,buff+30); /* see pg D-49 */ iregs.dx = fullname; /* next file */ flags = sysint(FCALL,&iregs,&oregs); #ifdef DEBUG printf("file = %s\n",iregs.dx); printf("err code = %x\n",oregs.ax); printf("8086flags= %x\n",flags); printf("mode byte= %d\n",oregs.cx); #endif if (flags & CARRY) { perror(iregs.dx,oregs.ax); break; } if (oregs.cx & RO) attr[0] = 'r'; else attr[0] = 'w'; if (oregs.cx & HIDE) attr[1] = 'h'; else attr[1] = '-'; if (oregs.cx & SYS) attr[2] = 's'; else attr[2] = '-'; if (oregs.cx & SUBDIR) attr[3] = 'd'; else attr[3] = '-'; if (oregs.cx & ARCHV) attr[4] = 'a'; else attr[4] = '-'; attr[5] = '\0'; printf("%s %s\n",attr,iregs.dx); i = bdos(FNEXT,0) & 0xff; /* Find Next */ } } exit(0); } /*****************************************************************/ /* print error - see error return table DOS 2.0 Manual page D-14 */ /*****************************************************************/ perror(s,code) char *s; unsigned code; { printf("chmod: File %s",s); switch(code) { case 2: case 18: /* perror called with 18 if bad filename entered */ printf(" not found.\n"); break; case 3: printf(". Path not found.\n"); break; case 5: printf(". Access denied.\n"); break; default: printf(". DOS error code %u returned.\n",code); } return; } /********************************************************/ /* build prefix str containing drive and directory info */ /* needed since FFIRST DTA does not store this info */ /********************************************************/ buildp(fullname,ddprefix) char *fullname; /* full path name (input) */ char *ddprefix; /* drive and directory info */ { #ifdef DEBUG char *savep; savep = ddprefix; #endif while ((index(fullname,':') != 0) || (index(fullname,'\\') != 0)) *ddprefix++ = *fullname++; *ddprefix = '\0'; #ifdef DEBUG printf("Prefix=%s\n",savep); #endif }