Do not set a default value to struct fileystem.xfer_align and related

variables when we could not get a filesystem alignment because of a lack
of statfs/statvfs family of functions to know what we can trust the alignment.

SVN-Revision: 2921

diff --git a/libarchive/archive_read_disk_posix.c b/libarchive/archive_read_disk_posix.c
index 34f94f020468b093c9a0c5be4328af13bec6bfab..3fe5cabb119a0f2470c1ab2cf5544dbb7f37f053 100644 (file)
--- a/libarchive/archive_read_disk_posix.c
+++ b/libarchive/archive_read_disk_posix.c
@@ -577,8 +577,13 @@ setup_suitable_read_buffer(struct archive_read_disk *a)
        size_t s;
 
        if (cf->allocation_ptr == NULL) {
+               /* If we couldn't get a filesystem alignment,
+                * we use 4096 as default value but we won't use
+                * O_DIRECT to open() and openat() operations. */
+               long xfer_align = (cf->xfer_align == -1)?4096:cf->xfer_align;
+
                if (cf->max_xfer_size != -1)
-                       asize = cf->max_xfer_size + cf->xfer_align;
+                       asize = cf->max_xfer_size + xfer_align;
                else {
                        long incr = cf->incr_xfer_size;
                        /* Some platform does not set a proper value to
@@ -586,13 +591,18 @@ setup_suitable_read_buffer(struct archive_read_disk *a)
                        if (incr < 0)
                                incr = cf->min_xfer_size;
                        if (cf->min_xfer_size < 0) {
-                               incr = cf->xfer_align;
-                               asize = cf->xfer_align;
+                               incr = xfer_align;
+                               asize = xfer_align;
                        } else
                                asize = cf->min_xfer_size;
+
+                       /* Increase a buffer size up to 64K bytes in
+                        * a proper incremant size. */
                        while (asize < 1024*64)
                                asize += incr;
-                       asize += cf->xfer_align;
+                       /* Take a margin to adjust to the filesystem
+                        * alignment. */
+                       asize += xfer_align;
                }
                cf->allocation_ptr = malloc(asize);
                if (cf->allocation_ptr == NULL) {
@@ -606,16 +616,16 @@ setup_suitable_read_buffer(struct archive_read_disk *a)
                 * Calculate proper address for the filesystem.
                 */
                s = (uintptr_t)cf->allocation_ptr;
-               s %= cf->xfer_align;
+               s %= xfer_align;
                if (s > 0)
-                       s = cf->xfer_align - s;
+                       s = xfer_align - s;
 
                /*
                 * Set a read buffer pointer in the proper alignment of
                 * the current filesystem.
                 */
                cf->buff = cf->allocation_ptr + s;
-               cf->buff_size = asize - cf->xfer_align;
+               cf->buff_size = asize - xfer_align;
        }
        return (ARCHIVE_OK);
 }
@@ -1460,10 +1470,10 @@ setup_current_filesystem(struct archive_read_disk *a)
 #endif
        t->current_filesystem->synthetic = -1;/* Not supported */
        t->current_filesystem->remote = -1;/* Not supported */
-       t->current_filesystem->xfer_align = 4096;
+       t->current_filesystem->xfer_align = -1;/* Unknown */
        t->current_filesystem->max_xfer_size = -1;
-       t->current_filesystem->min_xfer_size = 4096;
-       t->current_filesystem->incr_xfer_size = 4096;
+       t->current_filesystem->min_xfer_size = -1;
+       t->current_filesystem->incr_xfer_size = -1;
 
 #if defined(HAVE_READDIR_R)
        /* Set maximum filename length. */