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WEGA/src/cmd/doscopy/dosdev.c

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+/**************************************************************************
+***************************************************************************
+ 
+	W E G A - Quelle	(C) TU KMSt / ZFT/KEAW  Abt. WAE - 1988
+	Programm: dosdev.c
+ 
+	Bearbeiter	: P. Hoge
+	Datum		: 24.11.89
+	Version		: 1.3
+ 
+***************************************************************************
+**************************************************************************/
+
+/* Bereitstellen von DCP-Disk Informationen */
+
+#include "dos.h"
+#include <signal.h>
+
+/* dosdev() oeffnet DCP-Geraetefiles und
+ * belegt Struktur dosdisc mit gueltigen Werten
+ */
+dosdev(fn,mode,dp)
+char *fn;
+int mode;
+register struct dosdisc *dp;
+{
+ register int i, bps, fat=0;
+ unsigned long off=0;
+ unsigned char b[17];	/* Boot-Record-Informationen */
+
+ if ((dp->fd=open(fn,mode)) < 0)
+	return(-1);
+
+ if (mode) {	/* nicht read only */
+	signal(SIGALRM, SIG_IGN);
+	signal(SIGHUP, SIG_IGN);
+	signal(SIGINT, SIG_IGN);
+	signal(SIGQUIT, SIG_IGN);
+	signal(SIGTERM, SIG_IGN);
+ }
+
+ /* Ermitteln ob Floppy oder Harddisk */
+
+ lseek(dp->fd,(long)0,0);
+ if (read(dp->fd,b,1) != 1)
+	return(-1);
+ if (b[0] != 0xeb) { /* Harddisk */
+	lseek(dp->fd,(long)0x1be,0);
+	i = 4;
+	while (i--) {
+		if (read(dp->fd,b,16) != 16)
+			return(-1);
+		if (b[4] == 1) { /* DCP-Partion */
+			fat = 12;
+			break;
+		}
+		if (b[4] == 4) {
+			fat = 16;
+			break;
+		}
+	}
+	if (fat == 0)
+		return(-1);
+	off = ((b[9]*256) + b[8]) * 512;
+ }
+
+ lseek(dp->fd,off+11,0);
+ if (read(dp->fd,b,17) != 17)
+	return(-1);
+ bps = b[1]*256+b[0];
+ dp->fat1 = (b[4]*256+b[3])*bps + off;
+ dp->fatnum = b[5];
+ dp->maindir = off + ((b[4]*256+b[3]) + (b[12]*256+b[11]) * dp->fatnum) * bps;
+ dp->dirnum = b[7]*256+b[6];
+ dp->data = dp->maindir+(dp->dirnum * 32);
+ dp->clustsiz = b[2] * bps;
+ dp->vol = b[9]*256 + b[8];
+ dp->nclust = ((long)dp->vol*bps - dp->data + off) / dp->clustsiz;
+
+ if (fat == 0) {
+	if (dp->nclust > 4095)
+		fat = 16;
+	else
+		fat = 12;
+ }
+ dp->fatlen = fat;
+ return(0);
+}