X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=src%2Fguestfs.pod;h=d005257a9279fb6a58a2e471b435a14f170ae335;hb=b369fa6f91185efd4503aba4565671b8a0380d23;hp=7f810f34e99ede58942969cb7009256dde4ce349;hpb=f93cbe5756cf052cce8049087afdcf714a3fc70c;p=libguestfs.git

diff --git a/src/guestfs.pod b/src/guestfs.pod
index 7f810f3..d005257 100644
--- a/src/guestfs.pod
+++ b/src/guestfs.pod
@@ -33,7 +33,8 @@ schemes, qcow, qcow2, vmdk.
 
 Libguestfs provides ways to enumerate guest storage (eg. partitions,
 LVs, what filesystem is in each LV, etc.).  It can also run commands
-in the context of the guest.  Also you can access filesystems over FTP.
+in the context of the guest.  Also you can access filesystems over
+FUSE.
 
 Libguestfs is a library that can be linked with C and C++ management
 programs (or management programs written in OCaml, Perl, Python, Ruby,
@@ -449,10 +450,10 @@ Where we can help is in resolving the case insensitivity of paths.
 For this, call C<guestfs_case_sensitive_path>.
 
 Libguestfs also provides some help for decoding Windows Registry
-"hive" files, through the library C<libhivex> which is part of
-libguestfs.  You have to locate and download the hive file(s)
-yourself, and then pass them to C<libhivex> functions.  See also the
-programs L<hivexml(1)>, L<hivexget(1)> and L<virt-win-reg(1)> for more
+"hive" files, through the library C<hivex> which is part of the
+libguestfs project.  You have to locate and download the hive file(s)
+yourself, and then pass them to C<hivex> functions.  See also the
+programs L<hivexml(1)>, L<hivexsh(1)> and L<virt-win-reg(1)> for more
 help on this issue.
 
 =head2 USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES
@@ -588,6 +589,29 @@ C<guestfish -c command> to run commands.
 
 =back
 
+=head2 PROTOCOL LIMITS
+
+Internally libguestfs uses a message-based protocol to pass API calls
+and their responses to and from a small "appliance" (see L</INTERNALS>
+for plenty more detail about this).  The maximum message size used by
+the protocol is slightly less than 4 MB.  For some API calls you may
+need to be aware of this limit.  The API calls which may be affected
+are individually documented, with a link back to this section of the
+documentation.
+
+A simple call such as C<guestfs_cat> returns its result (the file
+data) in a simple string.  Because this string is at some point
+internally encoded as a message, the maximum size that it can return
+is slightly under 4 MB.  If the requested file is larger than this
+then you will get an error.
+
+In order to transfer large files into and out of the guest filesystem,
+you need to use particular calls that support this.  The sections
+L</UPLOADING> and L</DOWNLOADING> document how to do this.
+
+You might also consider mounting the disk image using our FUSE
+filesystem support (L<guestmount(1)>).
+
 =head1 CONNECTION MANAGEMENT
 
 =head2 guestfs_h *
@@ -783,7 +807,7 @@ need the compile time check as well):
    dl = dlopen (NULL, RTLD_LAZY);
    if (!dl) {
      fprintf (stderr, "dlopen: %s\n", dlerror ());
-     exit (1);
+     exit (EXIT_FAILURE);
    }
    has_function = dlsym (dl, "guestfs_dd") != NULL;
    dlclose (dl);