commit ff649ea5ab6a83910e414841fd02997cf9d54e60
author Christopher Ferris <cferris@google.com> Sat Sep 13 13:53:08 2014 -0700
committer Christopher Ferris <cferris@google.com> Mon Sep 15 18:29:47 2014 -0700
tree 7b01798b0d48374934da78ddd2433751846a7133
parent 6e9798f2e44c82b0cd8257f96b7d23285a7edc67

Use the correct fuse_init_out structure size.

Kernel 2.6.16 is the first stable kernel with struct fuse_init_out
defined (fuse version 7.6). The structure is the same from 7.6 through
7.22. Beginning with 7.23, the structure increased in size and added
new parameters.

If the kernel only works on minor revs older than or equal to 22,
then use the older structure size since this code only uses the 7.22
version of the structure.

Change-Id: If2507a02ad674fcf02869a325221339ae1ace64d

sdcard/sdcard.c

diff --git a/sdcard/sdcard.c b/sdcard/sdcard.c
index 9b55b33..f55a98a 100644
--- a/sdcard/sdcard.c
+++ b/sdcard/sdcard.c
@@ -29,6 +29,7 @@
 #include <string.h>
 #include <sys/inotify.h>
 #include <sys/mount.h>
+#include <sys/param.h>
 #include <sys/resource.h>
 #include <sys/stat.h>
 #include <sys/statfs.h>
@@ -1420,17 +1421,42 @@
         const struct fuse_in_header* hdr, const struct fuse_init_in* req)
 {
     struct fuse_init_out out;
+    size_t fuse_struct_size;
 
     TRACE("[%d] INIT ver=%d.%d maxread=%d flags=%x\n",
             handler->token, req->major, req->minor, req->max_readahead, req->flags);
+
+    /* Kernel 2.6.16 is the first stable kernel with struct fuse_init_out
+     * defined (fuse version 7.6). The structure is the same from 7.6 through
+     * 7.22. Beginning with 7.23, the structure increased in size and added
+     * new parameters.
+     */
+    if (req->major != FUSE_KERNEL_VERSION || req->minor < 6) {
+        ERROR("Fuse kernel version mismatch: Kernel version %d.%d, Expected at least %d.6",
+              req->major, req->minor, FUSE_KERNEL_VERSION);
+        return -1;
+    }
+
+    out.minor = MIN(req->minor, FUSE_KERNEL_MINOR_VERSION);
+    fuse_struct_size = sizeof(out);
+#if defined(FUSE_COMPAT_22_INIT_OUT_SIZE)
+    /* FUSE_KERNEL_VERSION >= 23. */
+
+    /* If the kernel only works on minor revs older than or equal to 22,
+     * then use the older structure size since this code only uses the 7.22
+     * version of the structure. */
+    if (req->minor <= 22) {
+        fuse_struct_size = FUSE_COMPAT_22_INIT_OUT_SIZE;
+    }
+#endif
+
     out.major = FUSE_KERNEL_VERSION;
-    out.minor = FUSE_KERNEL_MINOR_VERSION;
     out.max_readahead = req->max_readahead;
     out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES;
     out.max_background = 32;
     out.congestion_threshold = 32;
     out.max_write = MAX_WRITE;
-    fuse_reply(fuse, hdr->unique, &out, sizeof(out));
+    fuse_reply(fuse, hdr->unique, &out, fuse_struct_size);
     return NO_STATUS;
 }