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-rw-r--r--libcr_ipc/coroutine_chan.h115
-rw-r--r--libcr_ipc/coroutine_rpc.h108
-rw-r--r--libcr_ipc/coroutine_sema.c95
-rw-r--r--libcr_ipc/coroutine_sema.h35
4 files changed, 353 insertions, 0 deletions
diff --git a/libcr_ipc/coroutine_chan.h b/libcr_ipc/coroutine_chan.h
new file mode 100644
index 0000000..a3621a6
--- /dev/null
+++ b/libcr_ipc/coroutine_chan.h
@@ -0,0 +1,115 @@
+/* coroutine_chan.h - Simple channel system for coroutine.{h,c}
+ *
+ * Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+/**
+ * The cr_chan_* macros form a simple Go-like unbuffered channel
+ * mechanism built on top of the cr_pause_and_yeild() and cr_unpause()
+ * primitives.
+ */
+#ifndef _COROUTINE_CHAN_H_
+#define _COROUTINE_CHAN_H_
+
+#include <assert.h>
+
+#include "coroutine.h"
+
+/**
+ * cr_chan_t(val_t) returns the type definition for a channel on
+ * that transports values of type `val_t`.
+ */
+#define cr_chan_t(val_t) struct { \
+ bool ok_to_write; \
+ cid_t reader, *tail_reader; \
+ val_t *reader_val; \
+ \
+ bool ok_to_read; \
+ cid_t writer, *tail_writer; \
+ val_t *writer_val; \
+ }
+
+/* These "functions" are preprocessor macros instead of real C
+ * functions so that the compiler can do type-checking instead of
+ * having these functions take `void*`. */
+
+/**
+ * ch_chan_send(*ch, val) sends `val` over `ch`.
+ */
+#define cr_chan_send(ch, _val) do { \
+ if ((ch)->ok_to_write) { /* non-blocking */ \
+ *((ch)->reader_val) = (_val); \
+ (ch)->ok_to_write = false; \
+ cr_unpause((ch)->reader); \
+ } else { /* blocking */ \
+ cid_t next = 0; \
+ if ((ch)->writer) { \
+ *((ch)->tail_writer) = cr_getcid(); \
+ (ch)->tail_writer = &next; \
+ cr_pause_and_yield(); \
+ } else { \
+ (ch)->writer = cr_getcid(); \
+ (ch)->tail_writer = &next; \
+ } \
+ assert((ch)->writer == cr_getcid()); \
+ (ch)->writer_val = &(_val); \
+ (ch)->ok_to_read = true; \
+ cr_pause_and_yield(); \
+ assert((ch)->ok_to_read == false); \
+ if (next) { \
+ (ch)->writer = next; \
+ cr_unpause(next); \
+ } else { \
+ (ch)->writer = 0; \
+ (ch)->tail_writer = NULL; \
+ } \
+ } \
+ } while (0)
+
+/**
+ * cr_chan_recv(ch, val_p) reads a value from ch into `*val_p`.
+ */
+#define cr_chan_recv(ch, _val_p) do { \
+ if ((ch)->ok_to_read) { /* non-blocking */ \
+ *(_val_p) = *((ch)->writer_val); \
+ (ch)->ok_to_read = false; \
+ cr_unpause((ch)->writer; \
+ } else { /* blocking */ \
+ cid_t next = 0; \
+ if ((ch)->reader) { \
+ *((ch)->tail_reader) = cr_getcid(); \
+ (ch)->tail_reader = &next; \
+ cr_pause_and_yield(); \
+ } else { \
+ (ch)->reader = cr_getcid(); \
+ (ch)->tail_reader = &next; \
+ } \
+ assert((ch)->reader == cr_getcid()); \
+ (ch)->reader_val = (_val_p); \
+ (ch)->ok_to_write = true; \
+ cr_pause_and_yield(); \
+ assert((ch)->ok_to_write == false); \
+ if (next) { \
+ (ch)->reader = next; \
+ cr_unpause(next); \
+ } else { \
+ (ch)->reader = 0; \
+ (ch)->tail_reader = NULL; \
+ } \
+ } \
+ } while (0)
+
+/**
+ * cr_chan_can_send(ch) returns whether cr_chan_send(ch, val) would
+ * run without blocking.
+ */
+#define cr_chan_can_send(ch) ((ch)->ok_to_write)
+
+/**
+ * cr_chan_can_recv(ch) returns whether cr_chan_recv(ch, &val) would
+ * run without blocking.
+ */
+#define cr_chan_can_recv(ch) ((ch)->ok_to_read)
+
+#endif /* _COROUTINE_CHAN_H_ */
diff --git a/libcr_ipc/coroutine_rpc.h b/libcr_ipc/coroutine_rpc.h
new file mode 100644
index 0000000..11d40d7
--- /dev/null
+++ b/libcr_ipc/coroutine_rpc.h
@@ -0,0 +1,108 @@
+/* coroutine_rpc.h - Simple request/response system for coroutine.{h,c}
+ *
+ * Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+/**
+ * The cr_rpc_* macros form a simple request/response mechanism built
+ * on top of the cr_pause_and_yeild() and cr_unpause() primitives.
+ */
+#ifndef _COROUTINE_RPC_H_
+#define _COROUTINE_RPC_H_
+
+#include <assert.h>
+
+#include "coroutine.h"
+
+/**
+ * cr_rpc_t(req_t, resp_t) returns the type definition for a
+ * rcp-channel on which the requester submits a value of type `req_t`
+ * and the responder responds with a value of type `resp_t`.
+ *
+ * There may be multiple concurrent requesters, but only one
+ * concurrent responder. If you need multiple concurrent responders,
+ * set up a system of coroutine_chan.h channels.
+ */
+#define cr_rpc_t(req_t, resp_t) struct { \
+ cid_t requester, *tail_requester; \
+ cid_t responder; \
+ req_t *req_p; \
+ resp_t *resp_p; \
+ }
+
+/* These "functions" are preprocessor macros instead of real C
+ * functions so that the compiler can do type-checking instead of
+ * having these functions take `void*`. */
+
+/**
+ * ch_rpc_req(cr_rpc_t(req_t, resp_t) *ch, resp_t *resp, req_t req)
+ * submits the `req` request to `ch` puts the response in `*resp_p`.
+ *
+ * Blocking: Always; until the responder has called both
+ * cr_rpc_recv_req() and cr_rpc_send_resp().
+ */
+#define cr_rpc_req(ch, _resp_p, _req) do { \
+ cid_t next = 0; \
+ if ((ch)->requester) { \
+ *((ch)->tail_requester = cr_getcid(); \
+ (ch)->tail_requester = &next; \
+ cr_pause_and_yield(); \
+ } else { \
+ (ch)->requester = cr_getcid(); \
+ (ch)->tail_requester = &next; \
+ } \
+ assert((ch)->requester == cr_getcid()); \
+ (ch)->req_p = &(_req); \
+ (ch)->resp_p = (_resp_p; \
+ if ((ch)->responder != 0) \
+ cr_unpause((ch)->responder); \
+ cr_pause_and_yield(); \
+ if (next) { \
+ (ch)->requester = next; \
+ cr_unpause(next); \
+ } else { \
+ (ch)->requester = 0; \
+ (ch)->tail_requester = NULL; \
+ }
+ } while (0)
+
+/**
+ * cr_rpc_have_req(cr_rpc_t(req_t, resp_t) *ch) allows a responder
+ * to check whether or not there is a request waiting to be received
+ * (with cr_rpc_recv_req()) without blocking if there is not.
+ *
+ * Blocking: Never.
+ */
+#define cr_rpc_have_req(ch) ((ch)->req_p != NULL)
+
+/**
+ * cr_rpc_recv_req(cr_rpc_t(req_t, resp_t) *ch, req_t *req_p) reads
+ * a request from ch into `*req_p`.
+ *
+ * If there is not a pending request on `ch`, blocks until there is.
+ *
+ * Blocking: Maybe.
+ */
+#define cr_rpc_recv_req(ch, _req_p) do { \
+ (ch)->responder = cr_getcid(); \
+ if ((ch)->requester == 0) \
+ cr_pause_and_yield(); \
+ *(_req_p) = *((ch)->req_p); \
+ (ch)->req_p = NULL; \
+ } while (0)
+
+/**
+ * cr_rpc_send_resp(cr_rpc_t(req_t, resp_t) *ch, resp_t resp) sends
+ * the reply to the most-recently-read request.
+ *
+ * Blocking: Never.
+ */
+#define cr_rpc_send_resp(ch, _resp) do { \
+ (ch)->responder = 0; \
+ *((ch)->resp_p) = (_resp); \
+ (ch)->resp_p = NULL; \
+ cr_unpause((ch)->requester); \
+ } while (0)
+
+#endif /* _COROUTINE_RPC_H_ */
diff --git a/libcr_ipc/coroutine_sema.c b/libcr_ipc/coroutine_sema.c
new file mode 100644
index 0000000..a8b5ec4
--- /dev/null
+++ b/libcr_ipc/coroutine_sema.c
@@ -0,0 +1,95 @@
+/* coroutine_sema.h - Simple semaphores for coroutine.{h,c}
+ *
+ * Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+#include <assert.h>
+
+#include "coroutine_sema.h"
+
+struct cid_list {
+ cid_t val;
+ struct cid_list *next;
+};
+
+/* head->next->next->tail */
+
+struct _cr_sema {
+ int cnt;
+
+ struct cid_list *head, **tail;
+ /* locked indicates that a call from within a coroutine is is
+ * messing with ->{head,tail}, so a signal handler can't read
+ * it. */
+ bool locked;
+};
+
+/** Drain the sema->{head,tail} list. Returns true if cr_getcid() was drained. */
+static inline bool drain(volatile cr_sema_t *sema) {
+ assert(!sema->locked);
+ cid_t self = cr_getcid();
+
+ enum drain_result {
+ DRAINING,
+ DRAINED_SELF, /* stopped because drained `self` */
+ DRAINED_ALL, /* stopped because sema->head == NULL */
+ DRAINED_SOME, /* stopped because sema->cnt == 0 */
+ } state = DRAINING;
+ do {
+ sema->locked = true;
+ while (state == DRAINING) {
+ if (!sema->head) {
+ state = DRAINED_ALL;
+ } else if (!sema->cnt) {
+ state = DRAINED_SOME;
+ } else {
+ sema->cnt--;
+ cid_t cid = sema->head->val;
+ if (cid == self)
+ state = DRAINED_SELF;
+ else
+ cr_unpause(sema->head->val);
+ sema->head = sema->head->next;
+ if (!sema->head)
+ sema->tail = &sema->head;
+ }
+ }
+ sema->locked = false;
+ /* If there are still coroutines in sema->head, check
+ * that sema->cnt wasn't incremented between `if
+ * (!sema->cnt)` and `sema->locked = false`. */
+ } while (state == DRAINED_SOME && cnt);
+ /* If state == DRAINED_SELF, then we better have been the last
+ * item in the list! */
+ assert(state != DRAINED_SELF || !sema->head);
+ return state == DRAINED_SELF;
+}
+
+void cr_sema_signal(volatile cr_sema_t *sema) {
+ sema->cnt++;
+ if (!sema->locked)
+ drain();
+}
+
+void cr_sema_wait(volatile cr_sema_t *sema) {
+ struct cid_list self = {
+ .val = cr_getcid(),
+ .next = NULL,
+ };
+
+ sema->locked = true;
+ if (!sema->tail)
+ sema->head = &self;
+ else
+ *(sema->tail) = &self;
+ sema->tail = &(self.next);
+ sema->locked = false;
+
+ if (drain())
+ /* DRAINED_SELF: (1) No need to pause+yield, (2) we
+ * better have been the last item in the list! */
+ assert(!self.next);
+ else
+ cr_pause_and_yield();
+}
diff --git a/libcr_ipc/coroutine_sema.h b/libcr_ipc/coroutine_sema.h
new file mode 100644
index 0000000..57d5855
--- /dev/null
+++ b/libcr_ipc/coroutine_sema.h
@@ -0,0 +1,35 @@
+/* coroutine_sema.h - Simple semaphores for coroutine.{h,c}
+ *
+ * Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _COROUTINE_SEMA_H_
+#define _COROUTINE_SEMA_H_
+
+/**
+ * A cr_sema_t is a fair unbounded[1] counting semaphore.
+ *
+ * [1]: Well, INT_MAX
+ */
+typedef struct sema_t cr_sema_t;
+
+/**
+ * Increment the semaphore,
+ *
+ * @blocks never
+ * @yields never
+ * @run_in anywhere (coroutine, sighandler)
+ */
+void cr_sema_signal(cr_sema_t *sema);
+
+/**
+ * Wait until the semaphore is >0, then decrement it.
+ *
+ * @blocks maybe
+ * @yields maybe
+ * @may_run_in coroutine
+ */
+void cr_sema_wait(cr_sema_t *sema);
+
+#endif /* _COROUTINE_SEMA_H_ */
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