By adding a 'write_ready' interface following the lines of the existing
'read_ready', VFS plugins become able to propagate the (de-)saturation
of I/O buffers to the VFS user. This information is important when using
a non-blocking file descriptor for writing into a TCP socket. Once the
application observes EAGAIN, it expects a subsequent 'select' call to
return as soon as new I/O buffer space becomes available.
Before this patch, the select call would always return under this
condition, causing an unnecessarily busy write loop.
Issue #4697
This patch removes the 'Insufficient_buffer' exception by returning the
WRITE_ERR_WOULD_BLOCK result value instead. It also eliminates the
superfluous WRITE_ERR_AGAIN and WRITE_ERR_INTERRUPT codes.
Issue #4697
This patch facilitates the batching of I/O operations in the VFS library
by replacing the implicit wakeup of remote peer (via the traditional
packet-stream interface like 'submit_packet') by explicit wakeup
signalling.
The wakeup signalling is triggered not before the VFS user settles down.
E.g., for libc-based applications, this is the case if the libc goes
idle, waiting for external I/O.
In the case of a busy writer to a non-blocking file descriptor or socket
(e.g., lighttpd), the remote peers are woken up once a write operation
yields an out-count of 0.
The deferring of wakeup signals is accommodated by the new 'Remote_io'
mechanism (vfs/remote_io.h) that is designated to be used by all VFS
plugins that interact with asynchronous Genode services for I/O.
Issue #4697
* retrieve Genode::Env from plugin, this way no mesa applications need to
be changed.
* add 'vfs_gpu' api
* remove when all required functionality is implemented within the plugin.
issue #4380
When a <gpu> node is present in the VFS, the plugin opens a
Gpu::Connection for each open call to the 'gpu' node and installs a
completion signal handler. A read only to the fd returned only comes
back if a completion signal has been received between two read
transctions to the fd.
For now the Gpu::Connections can be retrieved by calling the
'vfs_gpu_connection(unsigned long id)' function. The id can be obtained
using 'stat' on the 'gpu' device and is located in the inode (st_ino)
field of the stat buffer.
issue #4380
Previously unconditional calls to Genode::log in cbe init and the cbe trust
anchor VFS plugin were made dependent on a verbosity flag that is set to
"false" by default.
Ref #4032
Instead of simply encrypting the private key with AES-256 when storing it to
the 'encrypted_private_key' file, wrap it using the AES-key-wrap algorithm
described in RFC 3394 "Advanced Encryption Standard (AES) Key Wrap Algorithm".
This is more secure and enables us to directly check whether the passphrase
entered by the user was correct or not.
Ref #4032
As the file formerly named 'secured_superblock' actually contains the hash of
the superblock that was secured, it was renamed 'superblock_hash'.
Ref #4032
As the file formerly named 'keyfile' actually contains the encrypted private
key of the Trust Anchor, it was renamed 'encrypted_private_key'.
Ref #4032
By now, the symmetric keys were only XOR'ed with the private key as placeholder
for a real encryption. Now they are encrypted using AES256 with the TA's
private key as key
Ref #4032.
A private key of 256 bits is generated pseudo-randomly using the jitterentropy
VFS plugin on initialization. The private key is stored in the key file
encrypted via AES256 using the SHA256 hash of the users passphrase. When
unlocking the CBE device, the encrypted private key is read from the key file
and decrypted with the hash of the users passphrase.
Ref #4032
Instead of using the user passphrase directly, use its SHA256 hash calculated
using libcrypto. The passphrase hash is still stored in the key file to be
used as base for the very primitive way of generating the private key.
Ref #4032
Closing the keyfile handle after a write operation wasn't synchronised to the
actual end of the write operation.
Issuing a write operation at the back end returns successfull as soon as the
back end has acknowledged that it will execute the operation. However, the
actual writing of the data might still be in progress at this point. But the
plugin used to close the file handle and declare the operation finished at this
point which led to warnings about acks on unknown file handles and leaking
resources. Now, the plugin issues a sync operation directly after the write
operation and waits for the sync to complete. This ensures that the plugin
doesn't declare the operation finished too early.
Ref #4032
The unlocking operation in the trust anchor was broken wich caused bad keys in
the CBE. This rewrites the whole operation to work as desired. Note that this
doesn't make it more safe! The private key is still almost the same as the
passphrase and stored plaintext.
Ref #4032
The plugin used to close file handles via the 'vfs_env.root_dir.close'.
However, this lead to resource leaks and apparently isn't the right way to
do it. Other VFS plugins do it by calling 'close' directly on the handle and
doing it in the trust anchor plugin also, fixes the leaks.
Ref #4032
Closing the hashfile handle after a write operation wasn't synchronised to the
actual end of the write operation.
Issuing a write operation at the back end returns successfull as soon as the
back end has acknowledged that it will execute the operation. However, the
actual writing of the data might still be in progress at this point. But the
plugin used to close the file handle and declare the operation finished at this
point which led to warnings about acks on unknown file handles and leaking
resources. Now, the plugin issues a sync operation directly after the write
operation and waits for the sync to complete. This ensures that the plugin
doesn't declare the operation finished too early.
Ref #4032
There were no means for issuing a Deinitialize request at the CBE using the
CBE VFS plugin. The new control/deinitialize file fixes this. When writing
"true" to the file, a Deinitialize request is submitted at the CBE. When
reading the file, the state of the operation is returned as a string of the
format "[current_state] last-result: [last_result]" where [current_state] can
be "idle" or "in-progress" and [last_result] can be "none", "success", or
"failed".
Ref #4032
When discarding a snapshot, the CBE VFS plugin didn't communicate the ID of
the snapshot to the CBE. Instead it set the ID argument to 0. Therefore the
operation never had any effect.
Ref #4032
The snapshots file system used to return the number of snapshots on
'num_dirent' when called for the root directory although it was expected to
return 1. This confused the tooling ontop of the VFS.
Ref #4032
Despite being readable, the files control/extend and control/rekey proclaimed
that they were not when asked. This caused the fs_query tool to not report the
content of the files although it could have.
Ref #4032
Stat calls on the control/extend and control/rekey files returned a bogus file
size that led to an error in the VFS File_content tool. The tool complained
that the size of the file determined while reading the content differs from the
one reported by the stat operation. Now, the stat call will always determine
the actual size of what would be read. However, it isn't guaranteed that this
size doesn't change in the time after the stat operation and before the read
operation.
Ref #4032
Both, trace_logger and vfs_trace had their own trace_buffer.h. This
commit consolidates the existing implementations and provides the
resulting trace_buffer.h at 'include/trace/'. It thereby becomes part of
the trace api archive.
genodelabs/genode#4244
File size must be the same as the number of bytes that can be read from
the file. Otherwise, this will trigger a `Truncated_during_read`
exception.
Fixesgenodelabs/genode#4240
