1 files changed, 130 insertions, 0 deletions
diff --git a/src/cmd/venti/part.c b/src/cmd/venti/part.c
new file mode 100644
index 00000000..dbf7b860
--- /dev/null
+++ b/src/cmd/venti/part.c
@@ -0,0 +1,130 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+u32int	maxblocksize;
+int	readonly;
+
+Part*
+initpart(char *name, int writable)
+{
+	Part *part;
+	Dir *dir;
+	int how;
+
+	part = MK(Part);
+	part->name = estrdup(name);
+	if(!writable && readonly)
+		how = OREAD;
+	else
+		how = ORDWR;
+	part->fd = open(name, how);
+	if(part->fd < 0){
+		if(how == ORDWR)
+			part->fd = open(name, OREAD);
+		if(part->fd < 0){
+			freepart(part);
+			seterr(EOk, "can't open partition='%s': %r", name);
+			return nil;
+		}
+		fprint(2, "warning: %s opened for reading only\n", name);
+	}
+	dir = dirfstat(part->fd);
+	if(dir == nil){
+		freepart(part);
+		seterr(EOk, "can't stat partition='%s': %r", name);
+		return nil;
+	}
+	part->size = dir->length;
+	part->blocksize = 0;
+	free(dir);
+	return part;
+}
+
+void
+freepart(Part *part)
+{
+	if(part == nil)
+		return;
+	close(part->fd);
+	free(part->name);
+	free(part);
+}
+
+void
+partblocksize(Part *part, u32int blocksize)
+{
+	if(part->blocksize)
+		sysfatal("resetting partition=%s's block size", part->name);
+	part->blocksize = blocksize;
+	if(blocksize > maxblocksize)
+		maxblocksize = blocksize;
+}
+
+int
+writepart(Part *part, u64int addr, u8int *buf, u32int n)
+{
+	long m, mm, nn;
+
+	qlock(&stats.lock);
+	stats.diskwrites++;
+	stats.diskbwrites += n;
+	qunlock(&stats.lock);
+
+	if(addr > part->size || addr + n > part->size){
+		seterr(ECorrupt, "out of bounds write to partition='%s'", part->name);
+		return -1;
+	}
+	print("write %s %lud at %llud\n", part->name, n, addr);
+	for(nn = 0; nn < n; nn += m){
+		mm = n - nn;
+		if(mm > MaxIo)
+			mm = MaxIo;
+		m = pwrite(part->fd, &buf[nn], mm, addr + nn);
+		if(m != mm){
+			if(m < 0){
+				seterr(EOk, "can't write partition='%s': %r", part->name);
+				return -1;
+			}
+			logerr(EOk, "truncated write to partition='%s' n=%ld wrote=%ld", part->name, mm, m);
+		}
+	}
+	return 0;
+}
+
+int
+readpart(Part *part, u64int addr, u8int *buf, u32int n)
+{
+	long m, mm, nn;
+	int i;
+
+	qlock(&stats.lock);
+	stats.diskreads++;
+	stats.diskbreads += n;
+	qunlock(&stats.lock);
+
+	if(addr > part->size || addr + n > part->size){
+		seterr(ECorrupt, "out of bounds read from partition='%s': addr=%lld n=%d size=%lld", part->name, addr, n, part->size);
+		return -1;
+	}
+	print("read %s %lud at %llud\n", part->name, n, addr);
+	for(nn = 0; nn < n; nn += m){
+		mm = n - nn;
+		if(mm > MaxIo)
+			mm = MaxIo;
+		m = -1;
+		for(i=0; i<4; i++) {
+			m = pread(part->fd, &buf[nn], mm, addr + nn);
+			if(m == mm)
+				break;
+		}
+		if(m != mm){
+			if(m < 0){
+				seterr(EOk, "can't read partition='%s': %r", part->name);
+				return -1;
+			}
+			logerr(EOk, "warning: truncated read from partition='%s' n=%ld read=%ld", part->name, mm, m);
+		}
+	}
+	return 0;
+}