[src/trunk]: src/sys/compat/common It is wishful thinking that vn_readdir wil...

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

details:   https://anonhg.NetBSD.org/src/rev/98070d18f0e6
branches:  trunk
changeset: 326289:98070d18f0e6
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Jan 24 22:11:46 2014 +0000

description:
It is wishful thinking that vn_readdir will return dirent12 structures.

diffstat:

 sys/compat/common/vfs_syscalls_12.c |  137 ++++++++++++++++++++++++++++++++---
 1 files changed, 125 insertions(+), 12 deletions(-)

diffs (177 lines):

diff -r 90cf3dcde095 -r 98070d18f0e6 sys/compat/common/vfs_syscalls_12.c
--- a/sys/compat/common/vfs_syscalls_12.c       Fri Jan 24 22:10:47 2014 +0000
+++ b/sys/compat/common/vfs_syscalls_12.c       Fri Jan 24 22:11:46 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_syscalls_12.c,v 1.29 2011/01/19 10:21:16 tsutsui Exp $     */
+/*     $NetBSD: vfs_syscalls_12.c,v 1.30 2014/01/24 22:11:46 christos Exp $    */
 
 /*
  * Copyright (c) 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls_12.c,v 1.29 2011/01/19 10:21:16 tsutsui Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls_12.c,v 1.30 2014/01/24 22:11:46 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -56,6 +56,7 @@
 #include <sys/syscallargs.h>
 
 #include <compat/sys/stat.h>
+#include <compat/sys/dirent.h>
 
 /*
  * Convert from a new to an old stat structure.
@@ -96,28 +97,140 @@
                syscallarg(u_int) count;
                syscallarg(long *) basep;
        } */
+       struct dirent *bdp;
+       struct vnode *vp;
+       char *inp, *tbuf;               /* Current-format */
+       int len, reclen;                /* Current-format */
+       char *outp;                     /* Dirent12-format */
+       int resid, old_reclen = 0;      /* Dirent12-format */
        struct file *fp;
-       int error, done;
+       struct uio auio;
+       struct iovec aiov;
+       struct dirent12 idb;
+       off_t off;              /* true file offset */
+       int buflen, error, eofflag, nbytes;
+       struct vattr va;
+       off_t *cookiebuf = NULL, *cookie;
+       int ncookies;
        long loff;
-
+                
        /* fd_getvnode() will use the descriptor for us */
        if ((error = fd_getvnode(SCARG(uap, fd), &fp)) != 0)
-               return error;
+               return (error);
+
        if ((fp->f_flag & FREAD) == 0) {
                error = EBADF;
-               goto out;
+               goto out1;
        }
 
+       vp = (struct vnode *)fp->f_data;
+       if (vp->v_type != VDIR) {
+               error = ENOTDIR;
+               goto out1;
+       }
+
+       vn_lock(vp, LK_SHARED | LK_RETRY);
+       error = VOP_GETATTR(vp, &va, l->l_cred);
+       VOP_UNLOCK(vp);
+       if (error)
+               goto out1;
+
        loff = fp->f_offset;
+       nbytes = SCARG(uap, count);
+       buflen = min(MAXBSIZE, nbytes);
+       if (buflen < va.va_blocksize)
+               buflen = va.va_blocksize;
+       tbuf = malloc(buflen, M_TEMP, M_WAITOK);
 
-       error = vn_readdir(fp, SCARG(uap, buf), UIO_USERSPACE,
-                       SCARG(uap, count), &done, l, 0, 0);
+       vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+       off = fp->f_offset;
+again:
+       aiov.iov_base = tbuf;
+       aiov.iov_len = buflen;
+       auio.uio_iov = &aiov;
+       auio.uio_iovcnt = 1;
+       auio.uio_rw = UIO_READ;
+       auio.uio_resid = buflen;
+       auio.uio_offset = off;
+       UIO_SETUP_SYSSPACE(&auio);
+       /*
+         * First we read into the malloc'ed buffer, then
+         * we massage it into user space, one record at a time.
+         */
+       error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag, &cookiebuf,
+           &ncookies);
+       if (error)
+               goto out;
+
+       inp = tbuf;
+       outp = SCARG(uap, buf);
+       resid = nbytes;
+       if ((len = buflen - auio.uio_resid) == 0)
+               goto eof;
 
-       error = copyout(&loff, SCARG(uap, basep), sizeof(long));
-       *retval = done;
- out:
+       for (cookie = cookiebuf; len > 0; len -= reclen) {
+               bdp = (struct dirent *)inp;
+               reclen = bdp->d_reclen;
+               if (reclen & 3)
+                       panic(__func__);
+               if (bdp->d_fileno == 0) {
+                       inp += reclen;  /* it is a hole; squish it out */
+                       if (cookie)
+                               off = *cookie++;
+                       else
+                               off += reclen;
+                       continue;
+               }
+               old_reclen = _DIRENT_RECLEN(&idb, bdp->d_namlen);
+               if (reclen > len || resid < old_reclen) {
+                       /* entry too big for buffer, so just stop */
+                       outp++;
+                       break;
+               }
+               /*
+                * Massage in place to make a Dirent12-shaped dirent (otherwise
+                * we have to worry about touching user memory outside of
+                * the copyout() call).
+                */
+               idb.d_fileno = (uint32_t)bdp->d_fileno;
+               idb.d_reclen = (uint16_t)old_reclen;
+               idb.d_type = (uint8_t)bdp->d_type;
+               idb.d_namlen = (uint8_t)bdp->d_namlen;
+               strcpy(idb.d_name, bdp->d_name);
+               if ((error = copyout(&idb, outp, old_reclen)))
+                       goto out;
+               /* advance past this real entry */
+               inp += reclen;
+               if (cookie)
+                       off = *cookie++; /* each entry points to itself */
+               else
+                       off += reclen;
+               /* advance output past Dirent12-shaped entry */
+               outp += old_reclen;
+               resid -= old_reclen;
+       }
+
+       /* if we squished out the whole block, try again */
+       if (outp == SCARG(uap, buf)) {
+               if (cookiebuf)
+                       free(cookiebuf, M_TEMP);
+               cookiebuf = NULL;
+               goto again;
+       }
+       fp->f_offset = off;     /* update the vnode offset */
+
+eof:
+       *retval = nbytes - resid;
+out:
+       VOP_UNLOCK(vp);
+       if (cookiebuf)
+               free(cookiebuf, M_TEMP);
+       free(tbuf, M_TEMP);
+out1:
        fd_putfile(SCARG(uap, fd));
-       return error;
+       if (error)
+               return error;
+       return copyout(&loff, SCARG(uap, basep), sizeof(long));
 }
 
 /*