This patch consolidates the repetitive error handling across the RPC
functions, which take node handles or directory handles as arguments.
During this change, I noticed that directory handles - which are values
provided by the client - were not checked for their type before being
used. A misbehaving client may open a file, manually construct a
directory handle using the number of the file handle, and invoke a
directory operation at lx_fs, which would then wrongly access a file
node as directory node.
This patch solves this issue by introducing two distinct methods
_with_open_node and _with_open_dir_node, which perform the respective
safety checks.
Fixes#4608
This patch splits the querying of the number of directory entries from
the directory's 'status' information. Subsuming the number of directory
entries as part of the status makes 'stat' calls too costly for some
file systems that need to read a directory for determining the number of
entries. So when stat'ing the entries of one directory that contains sub
directories, all entries of each sub directory are visited.
Thanks to Cedric Degea for pointing out this performance bottleneck!
With this change, the 'status' function returns a 'Status::size' value
of 0 when called for a directory handle.
Fixes#4603
As accommodating the session component object is already taken care of
be the root component implementation, remove the remaining redundant
checks.
Fixes#4521.
Enable watching files via the inotify interface of the Linux Kernel.
Delivery of watches to components is staggered in order to prevent an
overflow of the ACK queue in cases when a lot of changes are made to the
file system from the Linux side.
Fixes#4070
Some application code is dereferencing the pointer returned by
'packet_content' at packet streams without checking that it is valid.
Throw an exception rather than return a null pointer, except for
zero-length packets, which have somewhat implicit invalid content and
that we believe to be properly handled in all current cases.
The client-side of a packet stream cannot take corrective action if the
server-side is sending packets with invalid content, but the servers
that provide packet streams should catch this exception to detect
misbehaving clients.
Ref #3059
This patch removes the notion of partial writes from the file-system
servers. Since write operations are asynchronously submitted, they are
expected to succeed completely, except for I/O errors. I/O errors are
propagated with the write acknowledgement but those are usually handled
out of band at the client side. Partial writes must never occur because
they would go undetected by clients, which usually don't wait for the
completion of each single write operation.
Until now, most file-system servers returned the number of written bytes
in the acknowledgement packet. If a server managed to write a part of
the request only, it issued the acknowledgement immediately where it
should have cared about writing the remaining part first.
The patch detects such misbehaving server-side code. If partial writes
unexpectedly occur, it prints a message and leaves the corresponding
request unacknowdleged.
Issue #2672
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:
* A class with virtual functions can no longer publicly inherit base
classed without a vtable. The inherited object may either be moved
to a member variable, or inherited privately. The latter would be
used for classes that inherit 'List::Element' or 'Avl_node'. In order
to enable the 'List' and 'Avl_tree' to access the meta data, the
'List' must become a friend.
* Instead of adding a virtual destructor to abstract base classes,
we inherit the new 'Interface' class, which contains a virtual
destructor. This way, single-line abstract base classes can stay
as compact as they are now. The 'Interface' utility resides in
base/include/util/interface.h.
* With the new warnings enabled, all member variables must be explicitly
initialized. Basic types may be initialized with '='. All other types
are initialized with braces '{ ... }' or as class initializers. If
basic types and non-basic types appear in a row, it is nice to only
use the brace syntax (also for basic types) and align the braces.
* If a class contains pointers as members, it must now also provide a
copy constructor and assignment operator. In the most cases, one
would make them private, effectively disallowing the objects to be
copied. Unfortunately, this warning cannot be fixed be inheriting
our existing 'Noncopyable' class (the compiler fails to detect that
the inheriting class cannot be copied and still gives the error).
For now, we have to manually add declarations for both the copy
constructor and assignment operator as private class members. Those
declarations should be prepended with a comment like this:
/*
* Noncopyable
*/
Thread(Thread const &);
Thread &operator = (Thread const &);
In the future, we should revisit these places and try to replace
the pointers with references. In the presence of at least one
reference member, the compiler would no longer implicitly generate
a copy constructor. So we could remove the manual declaration.
Issue #465
The VFS library can be used in single-threaded or multi-threaded
environments and depending on that, signals are handled by the same thread
which uses the VFS library or possibly by a different thread. If a VFS
plugin needs to block to wait for a signal, there is currently no way
which works reliably in both environments.
For this reason, this commit makes the interface of the VFS library
nonblocking, similar to the File_system session interface.
The most important changes are:
- Directories are created and opened with the 'opendir()' function and the
directory entries are read with the recently introduced 'queue_read()'
and 'complete_read()' functions.
- Symbolic links are created and opened with the 'openlink()' function and
the link target is read with the 'queue_read()' and 'complete_read()'
functions and written with the 'write()' function.
- The 'write()' function does not wait for signals anymore. This can have
the effect that data written by a VFS library user has not been
processed by a file system server yet when the library user asks for the
size of the file or closes it (both done with RPC functions at the file
system server). For this reason, a user of the VFS library should
request synchronization before calling 'stat()' or 'close()'. To make
sure that a file system server has processed all write request packets
which a client submitted before the synchronization request,
synchronization is now requested at the file system server with a
synchronization packet instead of an RPC function. Because of this
change, the synchronization interface of the VFS library is now split
into 'queue_sync()' and 'complete_sync()' functions.
Fixes#2399
This patch reduces the number of exception types by facilitating
globally defined exceptions for common usage patterns shared by most
services. In particular, RPC functions that demand a session-resource
upgrade not longer reflect this condition via a session-specific
exception but via the 'Out_of_ram' or 'Out_of_caps' types.
Furthermore, the 'Parent::Service_denied', 'Parent::Unavailable',
'Root::Invalid_args', 'Root::Unavailable', 'Service::Invalid_args',
'Service::Unavailable', and 'Local_service::Factory::Denied' types have
been replaced by the single 'Service_denied' exception type defined in
'session/session.h'.
This consolidation eases the error handling (there are fewer exceptions
to handle), alleviates the need to convert exceptions along the
session-creation call chain, and avoids possible aliasing problems
(catching the wrong type with the same name but living in a different
scope).
This patch replaces the 'Parent::Quota_exceeded',
'Service::Quota_exceeded', and 'Root::Quota_exceeded' exceptions
by the single 'Insufficient_ram_quota' exception type.
Furthermore, the 'Parent' interface distinguished now between
'Out_of_ram' (the child's RAM is exhausted) from
'Insufficient_ram_quota' (the child's RAM donation does not suffice to
establish the session).
This eliminates ambiguities and removes the need to convert exception
types along the path of the session creation.
Issue #2398
The read-ready packet informs the server that the client wants to be
notified if a handle becomes readable. When becoming readable, the
server acknowledges packet and the client may queue a read requests
accordingly.
Besides adapting the components to the use of base/log.h, the patch
cleans up a few base headers, i.e., it removes unused includes from
root/component.h, specifically base/heap.h and
ram_session/ram_session.h. Hence, components that relied on the implicit
inclusion of those headers have to manually include those headers now.
While adjusting the log messages, I repeatedly stumbled over the problem
that printing char * arguments is ambiguous. It is unclear whether to
print the argument as pointer or null-terminated string. To overcome
this problem, the patch introduces a new type 'Cstring' that allows the
caller to express that the argument should be handled as null-terminated
string. As a nice side effect, with this type in place, the optional len
argument of the 'String' class could be removed. Instead of supplying a
pair of (char const *, size_t), the constructor accepts a 'Cstring'.
This, in turn, clears the way let the 'String' constructor use the new
output mechanism to assemble a string from multiple arguments (and
thereby getting rid of snprintf within Genode in the near future).
To enforce the explicit resolution of the char * ambiguity, the 'char *'
overload of the 'print' function is marked as deleted.
Issue #1987
Session_label constructor now takes a bare string rather than a
serialized argument buffer.
Replace all instances of previous constructor with 'label_from_args'
function.
Issue #1787
Replace 'attribute(...).has_value("yes")`
with 'attribute_value(..., false)'.
This allows for boolean configuration to be set with values such as
"true", "false", "yes", "no", or "1", "0".
Fixes#2002
Replace the Out_of_node_handles exception with Out_of_metadata.
Clients need to know when the server is out of internal resources,
but not why.
Cleanup and sort the errors at file_system_session.h.
Remove 'Size_limit_reached exception' from File_system, which was
internal to ram_fs.
Issue #1751Fixes#1909
- correctly catch and report non-existing root directories
- remove *all* leading slashes from root-directory attributes and
sanitize empty declarations to current working directory
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
