[src/trunk]: src/sys/lib/libsa * Fix the volume zero recognition bug; it was ...

[ross <ross%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/55f1c4e72fe0
branches:  trunk
changeset: 476232:55f1c4e72fe0
user:      ross <ross%NetBSD.org@localhost>
date:      Fri Sep 10 07:22:03 1999 +0000

description:
* Fix the volume zero recognition bug; it was interacting with a
  feature to avoid rereads (which was added to work around bugs in
  old SRM versions that wouldn't rewind DATs, but would return no
  error on rewind callbacks)
* Initialize the volzero signature in ustarfs_open(), rather than as a
  side effect of the first read.
* Centralize error retry.

diffstat:

 sys/lib/libsa/ustarfs.c |  59 ++++++++++++++++++++++++++++++++++--------------
 1 files changed, 41 insertions(+), 18 deletions(-)

diffs (118 lines):

diff -r 2c0a6a7b53fa -r 55f1c4e72fe0 sys/lib/libsa/ustarfs.c
--- a/sys/lib/libsa/ustarfs.c   Fri Sep 10 06:28:10 1999 +0000
+++ b/sys/lib/libsa/ustarfs.c   Fri Sep 10 07:22:03 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ustarfs.c,v 1.10 1999/09/01 02:32:26 ross Exp $        */
+/*     $NetBSD: ustarfs.c,v 1.11 1999/09/10 07:22:03 ross Exp $        */
 
 /* [Notice revision 2.2]
  * Copyright (c) 1997, 1998 Avalon Computer Systems, Inc.
@@ -126,6 +126,7 @@
        int     uas_init_window;        /* data present in window */
        int     uas_init_fs;            /* ust FS actually found */
        int     uas_volzerosig;         /* ID volume 0 by signature */
+       int     uas_sigdone;            /* did sig already */
        int     uas_offset;             /* amount of cylinder below lba 0 */
 } ust_active_t;
 
@@ -138,9 +139,11 @@
 static int convert __P((const char *, int, int));
 static int get_volume __P((struct open_file *, int));
 static void setwindow(ust_active_t *, ustoffs, ustoffs);
+static int real_fs_cylinder_read __P((struct open_file *, ustoffs, int));
 static int ustarfs_cylinder_read __P((struct open_file *, ustoffs, int));
 static void ustarfs_sscanf __P((const char *, const char *, int *));
 static int read512block __P((struct open_file *, ustoffs, char block[512]));
+static int init_volzero_sig __P((struct open_file *));
 
 static int
 convert(f, base, fw)
@@ -176,6 +179,21 @@
        struct open_file *f;
        ustoffs seek2;
 {
+       int i, e;
+
+       for (i = 0; i < 3; ++i) {
+               e = real_fs_cylinder_read(f, seek2, forcelabel);
+               if (e == 0)
+                       return 0;
+       }
+       return e;
+}
+
+static int
+real_fs_cylinder_read(f, seek2, forcelabel)
+       struct open_file *f;
+       ustoffs seek2;
+{
        int i;
        int e = 0;      /* XXX work around gcc warning */
        ustoffs lda;
@@ -255,9 +273,7 @@
                        needvolume + 1);
                getchar();
                printf("\n");
-               e = ustarfs_cylinder_read(f, 0, 1);
-               if (e)          /* Try again on error, needed on i386 */
-                       e = ustarfs_cylinder_read(f, 0, 1);
+               e = ustarfs_cylinder_read(f, 0, needvolume != 0);
                if (e)
                        return e;
                if(strncmp(formatid, ustf->uas_1cyl, strlen(formatid))) {
@@ -300,20 +316,6 @@
        dienow = 0;
        ustf = f->f_fsdata;
 
-       if (!ustf->uas_init_window
-       &&   ustf->uas_windowbase == 0) {
-               /*
-                * The algorithm doesn't require this, but without it we would
-                * need some trick to get the cylinder zero signature computed.
-                * That signature is used to identify volume zero, which we
-                * don't give a USTARFS label to. (It's platform-dependent.)
-                */
-               e = ustarfs_cylinder_read(f, 0, 0);
-               if (e)
-                       return e;
-               ustf->uas_volzerosig = checksig(ustf);
-               setwindow(ustf, 0, 0);
-       }
        /*
         * if (vda in window)
         *      copy out and return data
@@ -351,6 +353,24 @@
        goto tryagain;
 }
 
+static int
+init_volzero_sig(f)
+       struct open_file *f;
+{
+       int e;
+       ust_active_t *ustf;
+
+       ustf = f->f_fsdata;
+       if (!ustf->uas_sigdone) {
+               e = ustarfs_cylinder_read(f, 0, 0);
+               if (e)
+                       return e;
+               ustf->uas_volzerosig = checksig(ustf);
+               setwindow(ustf, 0, 0);
+       }
+       return 0;
+}
+
 int
 ustarfs_open(path, f)
        char *path;
@@ -373,6 +393,9 @@
        /* default to 2880 sector floppy */
        ustf->uas_volsize = 80 * 2 * 18 * 512 - lda2pda(0);
        ustf->uas_fseek = 0;
+       e = init_volzero_sig(f);
+       if (e)
+               return e;
        for(;;) {
                ustf->uas_filestart = offset;
                e2 = read512block(f, offset, block);