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putty-source/stubs/null-plug.c

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Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
/*
* nullplug.c: provide a null implementation of the Plug vtable which
* ignores all calls. Occasionally useful in cases where we want to
* make a network connection just to see if it works, but not do
* anything with it afterwards except close it again.
*/
#include "putty.h"
Pass the calling Socket to plug_log. This enables plug_log to run query methods on the socket in order to find out useful information to log. I don't expect it's sensible to do anything else with it.
2024-06-26 07:29:39 +00:00
void nullplug_log(Plug *plug, Socket *s, PlugLogType type, SockAddr *addr,
Make all Plugs have a log function, even if no-op. Commit 8f5e9a4f8dc796a introduced a segfault into both Windows Pageant and Windows connection sharing upstreams when they receive an incoming named-pipe connection. This occurs because the PlugVtables for those incoming connections had a null pointer in the 'log' field, because hitherto, only sockets involved with an outgoing connection expected to receive plug_log() notifications. But I added such a notification in make_handle_socket, forgetting that that function is used for both outgoing and incoming named-pipe connections (among other things). So now a Plug implementation that expects to be set up by the plug_accepting() method on a listener may still receive PLUGLOG_CONNECT_SUCCESS. I could fix that by adding a parameter to make_handle_socket telling it whether to send a notification, but that seems like more faff than is really needed. Simpler to make a rule that says _all_ Socket types must implement the log() method, even if only with a no-op function. We already have a no-op implementation of log(), in nullplug.c. So I've exposed that outside its module (in the same style as all the nullseat functions and so on), to make it really easy to add log() methods to PlugVtables that don't need one.
2021-09-15 12:48:30 +00:00
int port, const char *err_msg, int err_code)
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
{
}
New API for plug_closing() with a custom type enum. Passing an operating-system-specific error code to plug_closing(), such as errno or GetLastError(), was always a bit weird, given that it generally had to be handled by cross-platform receiving code in backends. I had the platform.h implementations #define any error values that the cross-platform code would have to handle specially, but that's still not a great system, because it also doesn't leave freedom to invent error representations of my own that don't correspond to any OS code. (For example, the ones I just removed from proxy.h.) So now, the OS error code is gone from the plug_closing API, and in its place is a custom enumeration of closure types: normal, error, and the special case BROKEN_PIPE which is the only OS error code we have so far needed to handle specially. (All others just mean 'abandon the connection and print the textual message'.) Having already centralised the handling of OS error codes in the previous commit, we've now got a convenient place to add any further type codes for errors needing special handling: each of Unix plug_closing_errno(), Windows plug_closing_system_error(), and Windows plug_closing_winsock_error() can easily grow extra special cases if need be, and each one will only have to live in one place.
2021-11-06 13:28:32 +00:00
void nullplug_closing(Plug *plug, PlugCloseType type, const char *error_msg)
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
{
}
Make all Plugs have a log function, even if no-op. Commit 8f5e9a4f8dc796a introduced a segfault into both Windows Pageant and Windows connection sharing upstreams when they receive an incoming named-pipe connection. This occurs because the PlugVtables for those incoming connections had a null pointer in the 'log' field, because hitherto, only sockets involved with an outgoing connection expected to receive plug_log() notifications. But I added such a notification in make_handle_socket, forgetting that that function is used for both outgoing and incoming named-pipe connections (among other things). So now a Plug implementation that expects to be set up by the plug_accepting() method on a listener may still receive PLUGLOG_CONNECT_SUCCESS. I could fix that by adding a parameter to make_handle_socket telling it whether to send a notification, but that seems like more faff than is really needed. Simpler to make a rule that says _all_ Socket types must implement the log() method, even if only with a no-op function. We already have a no-op implementation of log(), in nullplug.c. So I've exposed that outside its module (in the same style as all the nullseat functions and so on), to make it really easy to add log() methods to PlugVtables that don't need one.
2021-09-15 12:48:30 +00:00
void nullplug_receive(Plug *plug, int urgent, const char *data, size_t len)
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
{
}
Make all Plugs have a log function, even if no-op. Commit 8f5e9a4f8dc796a introduced a segfault into both Windows Pageant and Windows connection sharing upstreams when they receive an incoming named-pipe connection. This occurs because the PlugVtables for those incoming connections had a null pointer in the 'log' field, because hitherto, only sockets involved with an outgoing connection expected to receive plug_log() notifications. But I added such a notification in make_handle_socket, forgetting that that function is used for both outgoing and incoming named-pipe connections (among other things). So now a Plug implementation that expects to be set up by the plug_accepting() method on a listener may still receive PLUGLOG_CONNECT_SUCCESS. I could fix that by adding a parameter to make_handle_socket telling it whether to send a notification, but that seems like more faff than is really needed. Simpler to make a rule that says _all_ Socket types must implement the log() method, even if only with a no-op function. We already have a no-op implementation of log(), in nullplug.c. So I've exposed that outside its module (in the same style as all the nullseat functions and so on), to make it really easy to add log() methods to PlugVtables that don't need one.
2021-09-15 12:48:30 +00:00
void nullplug_sent(Plug *plug, size_t bufsize)
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
{
}
Name vtable structure types more consistently. Now they're all called FooVtable, instead of a mixture of that and Foo_vtable.
2018-10-05 06:03:46 +00:00
static const PlugVtable nullplug_plugvt = {
Make all Plugs have a log function, even if no-op. Commit 8f5e9a4f8dc796a introduced a segfault into both Windows Pageant and Windows connection sharing upstreams when they receive an incoming named-pipe connection. This occurs because the PlugVtables for those incoming connections had a null pointer in the 'log' field, because hitherto, only sockets involved with an outgoing connection expected to receive plug_log() notifications. But I added such a notification in make_handle_socket, forgetting that that function is used for both outgoing and incoming named-pipe connections (among other things). So now a Plug implementation that expects to be set up by the plug_accepting() method on a listener may still receive PLUGLOG_CONNECT_SUCCESS. I could fix that by adding a parameter to make_handle_socket telling it whether to send a notification, but that seems like more faff than is really needed. Simpler to make a rule that says _all_ Socket types must implement the log() method, even if only with a no-op function. We already have a no-op implementation of log(), in nullplug.c. So I've exposed that outside its module (in the same style as all the nullseat functions and so on), to make it really easy to add log() methods to PlugVtables that don't need one.
2021-09-15 12:48:30 +00:00
.log = nullplug_log,
Change vtable defs to use C99 designated initialisers. This is a sweeping change applied across the whole code base by a spot of Emacs Lisp. Now, everywhere I declare a vtable filled with function pointers (and the occasional const data member), all the members of the vtable structure are initialised by name using the '.fieldname = value' syntax introduced in C99. We were already using this syntax for a handful of things in the new key-generation progress report system, so it's not new to the code base as a whole. The advantage is that now, when a vtable only declares a subset of the available fields, I can initialise the rest to NULL or zero just by leaving them out. This is most dramatic in a couple of the outlying vtables in things like psocks (which has a ConnectionLayerVtable containing only one non-NULL method), but less dramatically, it means that the new 'flags' field in BackendVtable can be completely left out of every backend definition except for the SUPDUP one which defines it to a nonzero value. Similarly, the test_for_upstream method only used by SSH doesn't have to be mentioned in the rest of the backends; network Plugs for listening sockets don't have to explicitly null out 'receive' and 'sent', and vice versa for 'accepting', and so on. While I'm at it, I've normalised the declarations so they don't use the unnecessarily verbose 'struct' keyword. Also a handful of them weren't const; now they are.
2020-03-10 21:06:29 +00:00
.closing = nullplug_closing,
.receive = nullplug_receive,
.sent = nullplug_sent,
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
};
Make Socket and Plug into structs. I think that means that _every_ one of my traitoids is now a struct containing a vtable pointer as one of its fields (albeit sometimes the only field), and never just a bare pointer.
2018-10-05 06:24:16 +00:00
static Plug nullplug_plug = { &nullplug_plugvt };
Merge duplicate implementations of the trivial Plug. In the course of reworking the socket vtable system, I noticed that both sshshare.c and x11fwd.c independently invented the idea of a Plug none of whose methods do anything. We don't need more than one of those, so let's centralise the idea to somewhere it can be easily reused.
2018-05-27 14:41:12 +00:00
/*
* There's a singleton instance of nullplug, because it's not
* interesting enough to worry about making more than one of them.
*/
Make Socket and Plug into structs. I think that means that _every_ one of my traitoids is now a struct containing a vtable pointer as one of its fields (albeit sometimes the only field), and never just a bare pointer.
2018-10-05 06:24:16 +00:00
Plug *const nullplug = &nullplug_plug;
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