Commit a13bb7a0 authored by Philip Chimento's avatar Philip Chimento Committed by Philip Chimento

overrides: Allow DBus methods with file descriptor lists

For DBus proxies, we now allow calling methods with an extra
Gio.UnixFDList argument. This does not break existing code because we
already allowed a bunch of arguments in any order. Gio.DBusProxy.call()
is the same under the hood as Gio.DBusProxy.call_with_unix_fd_list(),
only with a null FD list parameter, so we can replace the former with
the latter.

Previously, synchronously called DBus proxy methods would return an
unpacked GVariant. Now, if called with a Gio.UnixFDList they will return
[unpacked GVariant, FDList]. This also does not break existing code
because it was not possible to call a method with an FDList before, and
the return value is unchanged if not calling with an FDList. This does
mean, unfortunately, that if you have a method with an 'h' in its return
signature but not in its argument signatures, you will have to call it
with an empty FDList in order to receive an FDList with the return
value, if calling synchronously.

On the DBus service side, when receiving a method call, we now pass the
FDList received from DBus to the called method. Previously, sync methods
were passed the parameters, and async methods were passed the parameters
plus the Gio.DBusInvocation object. Appending the Gio.UnixFDList to
those parameters also should not break existing code, although it could
if the method examines the number of arguments. (That is unlikely, since
DBus doesn't have methods with variable arguments.)

TODO: Check whether this works on non-Unix platforms.

Closes #204.
parent 7b9d03de
const Gio = imports.gi.Gio;
const GLib = imports.gi.GLib;
const ByteArray = imports.byteArray;
const {Gio, GjsPrivate, GLib} = imports.gi;
/* The methods list with their signatures.
*
* *** NOTE: If you add stuff here, you need to update testIntrospectReal
* *** NOTE: If you add stuff here, you need to update the Test class below.
*/
var TestIface = '<node> \
<interface name="org.gnome.gjs.Test"> \
......@@ -72,6 +72,22 @@ var TestIface = '<node> \
<method name="structArray"> \
<arg type="a(ii)" direction="out"/> \
</method> \
<method name="fdIn"> \
<arg type="h" direction="in"/> \
<arg type="ay" direction="out"/> \
</method> \
<method name="fdIn2"> \
<arg type="h" direction="in"/> \
<arg type="ay" direction="out"/> \
</method> \
<method name="fdOut"> \
<arg type="ay" direction="in"/> \
<arg type="h" direction="out"/> \
</method> \
<method name="fdOut2"> \
<arg type="ay" direction="in"/> \
<arg type="h" direction="out"/> \
</method> \
<signal name="signalFoo"> \
<arg type="s" direction="out"/> \
</signal> \
......@@ -201,6 +217,39 @@ class Test {
structArray() {
return [[128, 123456], [42, 654321]];
}
fdIn(fdIndex, fdList) {
const fd = fdList.get(fdIndex);
const stream = new Gio.UnixInputStream({fd, closeFd: true});
const bytes = stream.read_bytes(4096, null);
return bytes;
}
// Same as fdIn(), but implemented asynchronously
fdIn2Async([fdIndex], invocation, fdList) {
const fd = fdList.get(fdIndex);
const stream = new Gio.UnixInputStream({fd, closeFd: true});
stream.read_bytes_async(4096, GLib.PRIORITY_DEFAULT, null, (obj, res) => {
const bytes = obj.read_bytes_finish(res);
invocation.return_value(new GLib.Variant('(ay)', [bytes]));
});
}
fdOut(bytes) {
const fd = GjsPrivate.open_bytes(bytes);
const fdList = Gio.UnixFDList.new_from_array([fd]);
return [0, fdList];
}
fdOut2Async([bytes], invocation) {
GLib.idle_add(GLib.PRIORITY_DEFAULT, function() {
const fd = GjsPrivate.open_bytes(bytes);
const fdList = Gio.UnixFDList.new_from_array([fd]);
invocation.return_value_with_unix_fd_list(new GLib.Variant('(h)', [0]),
fdList);
return GLib.SOURCE_REMOVE;
});
}
}
const ProxyClass = Gio.DBusProxy.makeProxyWrapper(TestIface);
......@@ -484,4 +533,63 @@ describe('Exported DBus object', function () {
});
loop.run();
});
it('can call a remote method with a Unix FD', function (done) {
const expectedBytes = ByteArray.fromString('some bytes');
const fd = GjsPrivate.open_bytes(expectedBytes);
const fdList = Gio.UnixFDList.new_from_array([fd]);
proxy.fdInRemote(0, fdList, ([bytes], exc, outFdList) => {
expect(exc).toBeNull();
expect(outFdList).toBeNull();
expect(bytes).toEqual(expectedBytes);
done();
});
});
it('can call an asynchronously implemented remote method with a Unix FD', function (done) {
const expectedBytes = ByteArray.fromString('some bytes');
const fd = GjsPrivate.open_bytes(expectedBytes);
const fdList = Gio.UnixFDList.new_from_array([fd]);
proxy.fdIn2Remote(0, fdList, ([bytes], exc, outFdList) => {
expect(exc).toBeNull();
expect(outFdList).toBeNull();
expect(bytes).toEqual(expectedBytes);
done();
});
});
function readBytesFromFdSync(fd) {
const stream = new Gio.UnixInputStream({fd, closeFd: true});
const bytes = stream.read_bytes(4096, null);
return ByteArray.fromGBytes(bytes);
}
it('can call a remote method that returns a Unix FD', function (done) {
const expectedBytes = ByteArray.fromString('some bytes');
proxy.fdOutRemote(expectedBytes, ([fdIndex], exc, outFdList) => {
expect(exc).toBeNull();
const bytes = readBytesFromFdSync(outFdList.get(fdIndex));
expect(bytes).toEqual(expectedBytes);
done();
});
});
it('can call an asynchronously implemented remote method that returns a Unix FD', function (done) {
const expectedBytes = ByteArray.fromString('some bytes');
proxy.fdOut2Remote(expectedBytes, ([fdIndex], exc, outFdList) => {
expect(exc).toBeNull();
const bytes = readBytesFromFdSync(outFdList.get(fdIndex));
expect(bytes).toEqual(expectedBytes);
done();
});
});
it('throws an exception when not passing a Gio.UnixFDList to a method that requires one', function () {
expect(() => proxy.fdInRemote(0, () => {})).toThrow();
});
it('throws an exception when passing a handle out of range of a Gio.UnixFDList', function () {
const fdList = new Gio.UnixFDList();
expect(() => proxy.fdInRemote(0, fdList, () => {})).toThrow();
});
});
......@@ -21,8 +21,13 @@
*/
#include <config.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <gio/gio.h>
#include <glib-unix.h>
#include <glib.h>
#include <glib/gi18n.h>
......@@ -108,3 +113,77 @@ gjs_param_spec_get_owner_type(GParamSpec *pspec)
{
return pspec->owner_type;
}
// Adapted from glnx_throw_errno_prefix()
G_GNUC_PRINTF(2, 3)
static gboolean throw_errno_prefix(GError** error, const char* fmt, ...) {
int errsv = errno;
char* old_msg;
GString* buf;
va_list args;
if (!error)
return FALSE;
va_start(args, fmt);
g_set_error_literal(error, G_IO_ERROR, g_io_error_from_errno(errsv),
g_strerror(errsv));
old_msg = g_steal_pointer(&(*error)->message);
buf = g_string_new("");
g_string_append_vprintf(buf, fmt, args);
g_string_append(buf, ": ");
g_string_append(buf, old_msg);
g_free(old_msg);
(*error)->message = g_string_free(g_steal_pointer(&buf), FALSE);
va_end(args);
errno = errsv;
return FALSE;
}
/**
* gjs_open_bytes:
* @bytes: bytes to send to the pipe
* @error: Return location for a #GError, or %NULL
*
* Creates a pipe and sends @bytes to it, such that it is suitable for passing
* to g_subprocess_launcher_take_fd().
*
* Returns: file descriptor, or -1 on error
*/
int gjs_open_bytes(GBytes* bytes, GError** error) {
int pipefd[2], result;
size_t count;
const void* buf;
ssize_t bytes_written;
g_return_val_if_fail(bytes, -1);
g_return_val_if_fail(error == NULL || *error == NULL, -1);
if (!g_unix_open_pipe(pipefd, FD_CLOEXEC, error))
return -1;
buf = g_bytes_get_data(bytes, &count);
bytes_written = write(pipefd[1], buf, count);
if (bytes_written < 0) {
throw_errno_prefix(error, "write");
return -1;
}
if ((size_t)bytes_written != count)
g_warning("%s: %zd bytes sent, only %zu bytes written", __func__, count,
bytes_written);
result = close(pipefd[1]);
if (result == -1) {
throw_errno_prefix(error, "close");
return -1;
}
return pipefd[0];
}
......@@ -59,6 +59,9 @@ GParamFlags gjs_param_spec_get_flags (GParamSpec *pspec);
GType gjs_param_spec_get_value_type (GParamSpec *pspec);
GType gjs_param_spec_get_owner_type (GParamSpec *pspec);
/* For tests */
int gjs_open_bytes(GBytes* bytes, GError** error);
G_END_DECLS
#endif
......@@ -24,10 +24,59 @@ var Lang = imports.lang;
var Signals = imports.signals;
var Gio;
// Ensures that a Gio.UnixFDList being passed into or out of a DBus method with
// a parameter type that includes 'h' somewhere, actually has entries in it for
// each of the indices being passed as an 'h' parameter.
function _validateFDVariant(variant, fdList) {
switch (String.fromCharCode(variant.classify())) {
case 'b':
case 'y':
case 'n':
case 'q':
case 'i':
case 'u':
case 'x':
case 't':
case 'd':
case 'o':
case 'g':
case 's':
return;
case 'h': {
const val = variant.get_handle();
const numFds = fdList.get_length();
if (val >= numFds)
throw new Error(`handle ${val} is out of range of Gio.UnixFDList ` +
`containing ${numFds} FDs`);
return;
}
case 'v':
_validateFDVariant(variant.get_variant(), fdList);
return;
case 'm': {
let val = variant.get_maybe();
if (val)
_validateFDVariant(val, fdList);
return;
}
case 'a':
case '(':
case '{': {
let nElements = variant.n_children();
for (let ix = 0; ix < nElements; ix++)
_validateFDVariant(variant.get_child_value(ix), fdList);
return;
}
}
throw new Error('Assertion failure: this code should not be reached');
}
function _proxyInvoker(methodName, sync, inSignature, arg_array) {
var replyFunc;
var flags = 0;
var cancellable = null;
let fdList = null;
/* Convert arg_array to a *real* array */
arg_array = Array.prototype.slice.call(arg_array);
......@@ -37,7 +86,7 @@ function _proxyInvoker(methodName, sync, inSignature, arg_array) {
var signatureLength = inSignature.length;
var minNumberArgs = signatureLength;
var maxNumberArgs = signatureLength + 3;
var maxNumberArgs = signatureLength + 4;
if (arg_array.length < minNumberArgs) {
throw new Error("Not enough arguments passed for method: " + methodName +
......@@ -45,7 +94,7 @@ function _proxyInvoker(methodName, sync, inSignature, arg_array) {
} else if (arg_array.length > maxNumberArgs) {
throw new Error(`Too many arguments passed for method ${methodName}. ` +
`Maximum is ${maxNumberArgs} including one callback, ` +
'cancellable, and/or flags');
'Gio.Cancellable, Gio.UnixFDList, and/or flags');
}
while (arg_array.length > signatureLength) {
......@@ -57,41 +106,44 @@ function _proxyInvoker(methodName, sync, inSignature, arg_array) {
flags = arg;
} else if (arg instanceof Gio.Cancellable) {
cancellable = arg;
} else if (arg instanceof Gio.UnixFDList) {
fdList = arg;
} else {
throw new Error("Argument " + argNum + " of method " + methodName +
" is " + typeof(arg) + ". It should be a callback, flags or a Gio.Cancellable");
throw new Error(`Argument ${argNum} of method ${methodName} is ` +
`${typeof arg}. It should be a callback, flags, ` +
'Gio.UnixFDList, or a Gio.Cancellable');
}
}
var inVariant = new GLib.Variant('(' + inSignature.join('') + ')', arg_array);
const inTypeString = `(${inSignature.join('')})`;
const inVariant = new GLib.Variant(inTypeString, arg_array);
if (inTypeString.includes('h')) {
if (!fdList)
throw new Error(`Method ${methodName} with input type containing ` +
'"h" must have a Gio.UnixFDList as an argument');
_validateFDVariant(inVariant, fdList);
}
var asyncCallback = function (proxy, result) {
var outVariant = null, succeeded = false;
try {
outVariant = proxy.call_finish(result);
succeeded = true;
const [outVariant, outFdList] =
proxy.call_with_unix_fd_list_finish(result);
replyFunc(outVariant.deep_unpack(), null, outFdList);
} catch (e) {
replyFunc([], e);
replyFunc([], e, null);
}
if (succeeded)
replyFunc(outVariant.deep_unpack(), null);
};
if (sync) {
return this.call_sync(methodName,
inVariant,
flags,
-1,
cancellable).deep_unpack();
} else {
return this.call(methodName,
inVariant,
flags,
-1,
cancellable,
asyncCallback);
const [outVariant, outFdList] = this.call_with_unix_fd_list_sync(
methodName, inVariant, flags, -1, fdList, cancellable);
if (fdList)
return [outVariant.deep_unpack(), outFdList];
return outVariant.deep_unpack();
}
return this.call_with_unix_fd_list(methodName, inVariant, flags, -1, fdList,
cancellable, asyncCallback);
}
function _logReply(result, exc) {
......@@ -253,7 +305,8 @@ function _handleMethodCall(info, impl, method_name, parameters, invocation) {
if (this[method_name]) {
let retval;
try {
retval = this[method_name].apply(this, parameters.deep_unpack());
const fdList = invocation.get_message().get_unix_fd_list();
retval = this[method_name](...parameters.deep_unpack(), fdList);
} catch (e) {
if (e instanceof GLib.Error) {
invocation.return_gerror(e);
......@@ -273,26 +326,31 @@ function _handleMethodCall(info, impl, method_name, parameters, invocation) {
retval = new GLib.Variant('()', []);
}
try {
let outFdList = null;
if (!(retval instanceof GLib.Variant)) {
// attempt packing according to out signature
let methodInfo = info.lookup_method(method_name);
let outArgs = methodInfo.out_args;
let outSignature = _makeOutSignature(outArgs);
if (outArgs.length == 1) {
if (outSignature.includes('h') &&
retval[retval.length - 1] instanceof Gio.UnixFDList) {
outFdList = retval.pop();
} else if (outArgs.length == 1) {
// if one arg, we don't require the handler wrapping it
// into an Array
retval = [retval];
}
retval = new GLib.Variant(outSignature, retval);
}
invocation.return_value(retval);
invocation.return_value_with_unix_fd_list(retval, outFdList);
} catch(e) {
// if we don't do this, the other side will never see a reply
invocation.return_dbus_error('org.gnome.gjs.JSError.ValueError',
"Service implementation returned an incorrect value type");
}
} else if (this[method_name + 'Async']) {
this[method_name + 'Async'](parameters.deep_unpack(), invocation);
const fdList = invocation.get_message().get_unix_fd_list();
this[`${method_name}Async`](parameters.deep_unpack(), invocation, fdList);
} else {
log('Missing handler for DBus method ' + method_name);
invocation.return_gerror(new Gio.DBusError({ code: Gio.DBusError.UNKNOWN_METHOD,
......
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