Import sources from 2011-03-30 iso image

1 files changed, 255 insertions, 0 deletions

diff --git a/sys/src/cmd/dossrv/xfile.c b/sys/src/cmd/dossrv/xfile.c
new file mode 100755
index 000000000..6dbfb40d4
--- /dev/null
+++ b/sys/src/cmd/dossrv/xfile.c
@@ -0,0 +1,255 @@
+#include <u.h>
+#include <libc.h>
+#include "iotrack.h"
+#include "dat.h"
+#include "fns.h"
+
+#define	FIDMOD	127	/* prime */
+
+static Xfs	*xhead;
+static Xfile	*xfiles[FIDMOD], *freelist;
+static MLock	xlock, xlocks[FIDMOD], freelock;
+
+static int
+okmode(int omode, int fmode)
+{
+	if(omode == OREAD)
+		return fmode & 4;
+	/* else ORDWR */
+	return (fmode & 6) == 6;
+}
+
+Xfs *
+getxfs(char *user, char *name)
+{
+	Xfs *xf, *fxf;
+	Dir *dir;
+	Qid dqid;
+	char *p, *q;
+	long offset;
+	int fd, omode;
+
+	USED(user);
+	if(name==nil || name[0]==0)
+		name = deffile;
+	if(name == nil){
+		errno = Enofilsys;
+		return 0;
+	}
+
+	/*
+	 * If the name passed is of the form 'name:offset' then
+	 * offset is used to prime xf->offset. This allows accessing
+	 * a FAT-based filesystem anywhere within a partition.
+	 * Typical use would be to mount a filesystem in the presence
+	 * of a boot manager programme at the beginning of the disc.
+	 */
+	offset = 0;
+	if(p = strrchr(name, ':')){
+		*p++ = 0;
+		offset = strtol(p, &q, 0);
+		chat("name %s, offset %ld\n", p, offset);
+		if(offset < 0 || p == q){
+			errno = Enofilsys;
+			return 0;
+		}
+		offset *= Sectorsize;
+	}
+
+	if(readonly)
+		omode = OREAD;
+	else
+		omode = ORDWR;
+	fd = open(name, omode);
+
+	if(fd < 0 && omode==ORDWR){
+		omode = OREAD;
+		fd = open(name, omode);
+	}
+
+	if(fd < 0){
+		chat("can't open %s: %r\n", name);
+		errno = Eerrstr;
+		return 0;
+	}
+	dir = dirfstat(fd);
+	if(dir == nil){
+		errno = Eio;
+		close(fd);
+		return 0;
+	}
+
+	dqid = dir->qid;
+	free(dir);
+	mlock(&xlock);
+	for(fxf=0,xf=xhead; xf; xf=xf->next){
+		if(xf->ref == 0){
+			if(fxf == 0)
+				fxf = xf;
+			continue;
+		}
+		if(!eqqid(xf->qid, dqid))
+			continue;
+		if(strcmp(xf->name, name) != 0 || xf->dev < 0)
+			continue;
+		if(devcheck(xf) < 0) /* look for media change */
+			continue;
+		if(offset && xf->offset != offset)
+			continue;
+		chat("incref \"%s\", dev=%d...", xf->name, xf->dev);
+		++xf->ref;
+		unmlock(&xlock);
+		close(fd);
+		return xf;
+	}
+	if(fxf == nil){
+		fxf = malloc(sizeof(Xfs));
+		if(fxf == nil){
+			unmlock(&xlock);
+			close(fd);
+			errno = Enomem;
+			return nil;
+		}
+		fxf->next = xhead;
+		xhead = fxf;
+	}
+	chat("alloc \"%s\", dev=%d...", name, fd);
+	fxf->name = strdup(name);
+	fxf->ref = 1;
+	fxf->qid = dqid;
+	fxf->dev = fd;
+	fxf->fmt = 0;
+	fxf->offset = offset;
+	fxf->ptr = nil;
+	fxf->isfat32 = 0;
+	fxf->omode = omode;
+	unmlock(&xlock);
+	return fxf;
+}
+
+void
+refxfs(Xfs *xf, int delta)
+{
+	mlock(&xlock);
+	xf->ref += delta;
+	if(xf->ref == 0){
+		chat("free \"%s\", dev=%d...", xf->name, xf->dev);
+		free(xf->name);
+		free(xf->ptr);
+		purgebuf(xf);
+		if(xf->dev >= 0){
+			close(xf->dev);
+			xf->dev = -1;
+		}
+	}
+	unmlock(&xlock);
+}
+
+Xfile *
+xfile(int fid, int flag)
+{
+	Xfile **hp, *f, *pf;
+	int k;
+
+	k = ((ulong)fid) % FIDMOD;
+	hp = &xfiles[k];
+	mlock(&xlocks[k]);
+	pf = nil;
+	for(f=*hp; f; f=f->next){
+		if(f->fid == fid)
+			break;
+		pf = f;
+	}
+	if(f && pf){
+		pf->next = f->next;
+		f->next = *hp;
+		*hp = f;
+	}
+	switch(flag){
+	default:
+		panic("xfile");
+	case Asis:
+		unmlock(&xlocks[k]);
+		return (f && f->xf && f->xf->dev < 0) ? nil : f;
+	case Clean:
+		break;
+	case Clunk:
+		if(f){
+			*hp = f->next;
+			unmlock(&xlocks[k]);
+			clean(f);
+			mlock(&freelock);
+			f->next = freelist;
+			freelist = f;
+			unmlock(&freelock);
+		} else
+			unmlock(&xlocks[k]);
+		return nil;
+	}
+	unmlock(&xlocks[k]);
+	if(f)
+		return clean(f);
+	mlock(&freelock);
+	if(f = freelist){	/* assign = */
+		freelist = f->next;
+		unmlock(&freelock);
+	} else {
+		unmlock(&freelock);
+		f = malloc(sizeof(Xfile));
+		if(f == nil){
+			errno = Enomem;
+			return nil;
+		}
+	}
+	mlock(&xlocks[k]);
+	f->next = *hp;
+	*hp = f;
+	unmlock(&xlocks[k]);
+	f->fid = fid;
+	f->flags = 0;
+	f->qid = (Qid){0,0,0};
+	f->xf = nil;
+	f->ptr = nil;
+	return f;
+}
+
+Xfile *
+clean(Xfile *f)
+{
+	if(f->ptr){
+		free(f->ptr);
+		f->ptr = nil;
+	}
+	if(f->xf){
+		refxfs(f->xf, -1);
+		f->xf = nil;
+	}
+	f->flags = 0;
+	f->qid = (Qid){0,0,0};
+	return f;
+}
+
+/*
+ * the file at <addr, offset> has moved
+ * relocate the dos entries of all fids in the same file
+ */
+void
+dosptrreloc(Xfile *f, Dosptr *dp, ulong addr, ulong offset)
+{
+	int i;
+	Xfile *p;
+	Dosptr *xdp;
+
+	for(i=0; i < FIDMOD; i++){
+		for(p = xfiles[i]; p != nil; p = p->next){
+			xdp = p->ptr;
+			if(p != f && p->xf == f->xf
+			&& xdp != nil && xdp->addr == addr && xdp->offset == offset){
+				memmove(xdp, dp, sizeof(Dosptr));
+				xdp->p = nil;
+				xdp->d = nil;
+				p->qid.path = QIDPATH(xdp);
+			}
+		}
+	}
+}