1 files changed, 100 insertions, 0 deletions
diff --git a/sys/src/cmd/pkg/unpkg.c b/sys/src/cmd/pkg/unpkg.c
new file mode 100644
index 000000000..2c749e3b3
--- /dev/null
+++ b/sys/src/cmd/pkg/unpkg.c
@@ -0,0 +1,100 @@
+#include <u.h>
+#include <libc.h>
+#include <mp.h>
+#include <libsec.h>
+
+struct th {
+  char *name;
+  ulong perm;
+  ulong size;
+  char type;
+  char *user, *group;
+};
+
+static char *sndup(char* s, ulong n) {
+	char *d, *p;
+	p = memchr(s, 0, n);
+	if(p)
+		n = p-s;
+	d = malloc(n+1);
+	memcpy(d,s,n);
+	d[n] = 0;
+	return d;
+}
+
+
+int readheader(int fd, struct th* th) {
+  int i;
+  char b[512];
+  if(readn(fd, b, 512) != 512) return -1;
+  
+  // Check for end of archive
+  for(i=0; i<512; i++) {
+	if(b[i]!=0) goto rhok;
+  }
+  if(readn(fd, b, 512) != 512) return -1;
+  for(i=0; i<512; i++) {
+	if(b[i]!=0) return -1;
+  }
+  return 0;
+
+ rhok:
+  th->name = sndup(b, 100);
+  th->perm = strtoul(b+100, nil, 8);
+  th->size = strtoul(b+124, nil, 8);
+  th->type = b[156];
+  th->user = sndup(b+265, 32);
+  th->group= sndup(b+297, 32);
+  return 1;
+}
+
+int main(void) {
+  while(1) {
+	struct th th;
+	ulong off;
+	uchar b[512];
+	DigestState *s;
+	int wfd;
+	int r = readheader(0, &th);
+	if(r <= 0) return r;
+
+	switch(th.type) {
+	case '5':
+		create(th.name, OREAD, DMDIR|th.perm);
+		break;
+	case '0': case 0:
+		print("A %s\n", th.name);
+		r = access(th.name, 0);
+		if(r == 0) {
+			print("File already exists: %s\n", th.name);
+			return -1;
+		}
+		if((wfd = create(th.name, OWRITE, th.perm)) < 0) {
+			print("Create failed: %s\n", th.name);
+			return -1;
+		}
+		s = nil;
+		for(off=0; off<th.size; off+=512) {
+			int n = th.size-off;
+			n = n<512 ? n : 512;
+			if(readn(0, b, 512) != 512) return -1;
+			if(write(wfd, b, n) != n) return -1;
+			s = sha1(b, n, nil, s);
+		}
+
+		uchar digest[20], hdigest[41];
+		sha1(nil, 0, digest, s);
+		enc16((char*)hdigest, 41, digest, 20);
+		fprint(2, "%s\t%s\n", th.name, hdigest);
+		close(wfd);
+		break;
+	default:
+		print("Unknown file type '%c'\n", th.type);
+		return -1;
+	}
+
+	free(th.name);
+	free(th.user);
+	free(th.group);
+  }
+}