return of venti

src/cmd/venti/srv/rdarena.c

@@ -0,0 +1,91 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	verbose;
+
+void
+usage(void)
+{
+	fprint(2, "usage: rdarena [-v] arenapart arena\n");
+	threadexitsall(0);
+}
+
+static void
+rdarena(Arena *arena)
+{
+	ZBlock *b;
+	u64int a, e;
+	u32int bs;
+
+	fprint(2, "copying %s to standard output\n", arena->name);
+	printarena(2, arena);
+
+	bs = MaxIoSize;
+	if(bs < arena->blocksize)
+		bs = arena->blocksize;
+
+	b = alloczblock(bs, 0, arena->blocksize);
+	e = arena->base + arena->size + arena->blocksize;
+	for(a = arena->base - arena->blocksize; a + arena->blocksize <= e; a += bs){
+		if(a + bs > e)
+			bs = arena->blocksize;
+		if(readpart(arena->part, a, b->data, bs) < 0)
+			fprint(2, "can't copy %s, read at %lld failed: %r\n", arena->name, a);	
+		if(write(1, b->data, bs) != bs)
+			sysfatal("can't copy %s, write at %lld failed: %r", arena->name, a);
+	}
+
+	freezblock(b);
+}
+
+void
+threadmain(int argc, char *argv[])
+{
+	ArenaPart *ap;
+	Part *part;
+	char *file, *aname;
+	int i;
+
+	ventifmtinstall();
+	statsinit();
+
+	ARGBEGIN{
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	readonly = 1;
+
+	if(argc != 2)
+		usage();
+
+	file = argv[0];
+	aname = argv[1];
+
+	part = initpart(file, OREAD|ODIRECT);
+	if(part == nil)
+		sysfatal("can't open partition %s: %r", file);
+
+	ap = initarenapart(part);
+	if(ap == nil)
+		sysfatal("can't initialize arena partition in %s: %r", file);
+
+	if(verbose)
+		printarenapart(2, ap);
+
+	initdcache(8 * MaxDiskBlock);
+
+	for(i = 0; i < ap->narenas; i++){
+		if(strcmp(ap->arenas[i]->name, aname) == 0){
+			rdarena(ap->arenas[i]);
+			threadexitsall(0);
+		}
+	}
+
+	sysfatal("couldn't find arena %s\n", aname);
+}