libtf: initial commit

libtf is to be user-space cooperative threading library similar
to State Threads (http://state-threads.sourceforge.net/), but
with additional support for multiple cores, using better
algorithms and taking advantage of new Linux kernel syscalls
such as eventfd, signalfd and epoll (edge-triggered mode).

Initial implementation has setjmp based user-space context
switching and trivial testcase. Works on Linux/x86.

TFbuild uses ideas from different build systems, namely Kbuild,
but it's inner workings are quite different. All build files are
included (using macro trickery) instead of recursive making. Thus
the build dependency graph is complete and should yield good make
performance. Also parallel stuff should work.

16 files changed, 937 insertions, 0 deletions

diff --git a/DESIGN b/DESIGN
new file mode 100644
index 0000000..2ffc535
--- /dev/null
+++ b/DESIGN
@@ -0,0 +1,19 @@
+SCHEDULER
+- 4-heap (or 2-heap) with linked nodes
+- epoll
+- edge-triggered monitoring for file i/o (no syscalls to modify fdset)
+- signalfd for signal handling
+- eventfd for thread pool wakeup
+
+FIBERS
+- timer node on fiber control data (for delayed heapify; and reuse on timeouts)
+- fd, signal, pid wait struct on stack of wait function
+- fiber_kill can interrupt wait
+
+SCHEDULER <-> THREAD POOL
+- scheduler queues to thread pool array fifo queue,
+    - semaphore protects threads so no underqueueing happens
+    - eventfd notifies scheduler when queue has free space again
+    - head/tail updated atomically and item position recovered
+- thread pool atomically pushes to resume atomic stack and sets eventfd
+    - scheduler thread atomically pops all and updates fiber states
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..33859f9
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,8 @@
+##
+# Package definitions
+
+PACKAGE := libtf
+VERSION := 0.1
+TFBUILD := build/
+
+include $(TFBUILD)TFbuild.main
diff --git a/TFbuild b/TFbuild
new file mode 100644
index 0000000..7bfde59
--- /dev/null
+++ b/TFbuild
@@ -0,0 +1,7 @@
+subdirs-y		+= src
+subdirs-$(TEST)		+= test
+CFLAGS			+= -I$(srctree)include
+
+install:
+	$(INSTALLDIR) $(DESTDIR)$(DOCDIR)
+	$(INSTALL) README $(DESTDIR)$(DOCDIR)
diff --git a/build/TFbuild.epilogue b/build/TFbuild.epilogue
new file mode 100644
index 0000000..af0baad
--- /dev/null
+++ b/build/TFbuild.epilogue
@@ -0,0 +1,20 @@
+# Store per-directory variables
+#$(call MemoizeVariables, CFLAGS LDFLAGS LIBS)
+
+file-vars := $(filter $(foreach m,$(local-vars),$(m)_%),$(.VARIABLES))
+file-vars := $(filter-out $(foreach m,$(local-vars),$(m)_ALL),$(file-vars))
+$(foreach m,$(file-vars),$(eval $(call MemoizeVariable,$(m))))
+
+# Handle this directory's rules
+$(foreach m,$(libs-y),$(eval $(call CreateLibrary,$(m))))
+$(foreach m,$(progs-y),$(eval $(call CreateProgram,$(m))))
+
+# Handle subdir of this subdir
+subdirs--$(recursion-level)	:= $(addsuffix /,$(subdirs-y))
+include $(subdirs-y:%=$(build-prologue) $(current-dir)%/TFbuild $(build-epilogue))
+
+# And restore parent context
+$(foreach m,$(local-vars),$(eval $(call MemoizeAndPopVariable,$(m))))
+
+current-dir  := $(parent-dir--$(recursion-level))
+current-dirc := $(parent-dirc--$(recursion-level))
diff --git a/build/TFbuild.main b/build/TFbuild.main
new file mode 100644
index 0000000..23ca461
--- /dev/null
+++ b/build/TFbuild.main
@@ -0,0 +1,233 @@
+# call once recursively so we get rid of default rules and variables
+ifndef RECURSIVE
+
+all:
+
+Makefile: ;
+
+%:
+	@$(MAKE) -rR --no-print-directory RECURSIVE=1 $(MAKECMDGOALS)
+
+else
+
+# default target
+all: libs progs
+	@:
+
+.SECONDEXPANSION:
+
+# default directories
+DESTDIR		?=
+SBINDIR		?= /usr/sbin
+CONFDIR		?= /etc/$(PACKAGE)
+MANDIR		?= /usr/share/man
+DOCDIR		?= /usr/share/doc/$(PACKAGE)
+STATEDIR	?= /var/run
+
+# utilities and default flags for them.
+CROSS_COMPILE	?=
+CC		:= $(CROSS_COMPILE)gcc
+AR		:= $(CROSS_COMPILE)ar
+RANLIB		:= $(CROSS_COMPILE)ranlib
+LD		:= $(CROSS_COMPILE)ld
+INSTALL		:= install
+INSTALLDIR	:= $(INSTALL) -d
+
+CFLAGS		:= -Wall -Wstrict-prototypes -D_GNU_SOURCE -std=gnu99
+CFLAGS_ALL	?= -g -O2
+LDFLAGS		:= $(LDFLAGS)
+LDFLAGS_ALL	?= -g
+
+# some helpers
+PHONY:=all libs progs allobjdirs arguments-changed
+build-prologue:=$(TFBUILD)TFbuild.prologue
+build-epilogue:=$(TFBUILD)TFbuild.epilogue
+comma:=,
+squote:='
+empty:=
+space:=$(empty) $(empty)
+separator:=--
+
+ifdef V
+  ifeq ("$(origin V)", "command line")
+    VERBOSE = $(V)
+  endif
+endif
+ifndef VERBOSE
+  VERBOSE = 0
+endif
+ifeq ($(VERBOSE),1)
+  quiet =
+  Q =
+else
+  quiet=quiet_
+  Q = @
+endif
+ifneq ($(findstring s,$(MAKEFLAGS)),)
+  quiet=silent_
+endif
+
+# recursion related stuff
+srctree			:=
+objtree			:= obj/
+current-dir		:=
+current-dirc		:=
+recursion-level		= $(words $(current-dirc))
+next-recursion-level	= $(words $(current-dirc) dummy)
+objdir			= $(objtree)$(current-dir)
+
+# globals
+all-progs		:=
+all-libs		:=
+local-vars		:= CFLAGS LDFLAGS LIBS
+
+# helper macros for targets
+escsq = $(subst $(squote),'\$(squote)',$1)
+printable-target = $(patsubst $(objtree)%,%,$@)
+depfile = $(subst $(comma),_,$(@).d)
+#arg-check-prereq = $(if $(arg-check),arguments-changed \
+	#$(warning arg-check $(arg-check))\
+	#$(warning old $@ - $(cmd_$(@)))\
+	#$(warning new $1 - $(cmd_$(1)))\
+	#)
+arg-check-prereq = $(if $(arg-check),arguments-changed)
+arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$(@))) \
+                    $(filter-out $(cmd_$(@)), $(cmd_$(1))) )
+echo-cmd = $(if $($(quiet)cmd_$(1)),\
+	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
+cmd = @$(echo-cmd) $(cmd_$(1))
+primary_source = $(firstword $^)
+
+#target-objects2=$(addprefix $(objdir),$(if $(filter-out $(origin $(1)-objs-y),undefined),$($(1)-objs-y),$(1).o))
+#target-objects=$(warning target-objects $(1)=$(target-objects2))$(target-objects2)
+target-objects=$(addprefix $(objdir),$(if $(filter-out $(origin $(1)-objs-y),undefined),$($(1)-objs-y),$(1).o))
+
+# why - tell all prerequisites that have changed
+ifeq ($(VERBOSE),2)
+why = - due to $(filter-out $(PHONY),$?) $(filter $(PHONY),$^)
+echo-why = $(call escsq, $(strip $(why)))
+endif
+
+# rules for targets
+define CreateDirectory
+ifeq ($(filter createdir-$(1),$(PHONY)),)
+PHONY+=createdir-$(1)
+ifneq ($(shell [ -d $(1) ] && echo yes), yes)
+createdir-$(1):
+	$(Q)mkdir -p $(1)
+allobjdirs: createdir-$(1)
+endif
+endif
+endef
+
+define CallRule
+	@set -e;							\
+	$(rule_$(1))
+endef
+
+define ExecuteCommand
+	@set -e;							\
+	$(echo-cmd) $(cmd_$(1));					\
+	echo 'cmd_$@ := $(make-cmd)' > $(@).cmd
+endef
+
+define MemoizeVariable
+ifneq ($($(1)),)
+$(current-dir)--$(1):=$($(1))
+$(1):=
+endif
+endef
+
+define PushVariable
+inherit-$(1)-$(recursion-level):=$($(1))
+endef
+
+define PopVariable
+$(current-dir)--$(1):=$($(1))
+$(1):=$(inherit-$(1)-$(recursion-level))
+endef
+
+define MemoizeAndPopVariable
+$(current-dir)--$(1):=$($(1))
+$(1):=$(inherit-$(1)-$(recursion-level))
+endef
+
+# GCC C-compiler
+c_flags		= -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS_ALL) \
+	$($(dir $(printable-target))--CFLAGS) \
+	$($(dir $(printable-target))--CFLAGS_$(notdir $(primary_source)))
+
+quiet_cmd_cc_o_c = CC      $(printable-target)
+      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $(primary_source)
+
+define rule_cc_o_c
+	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);		\
+	(echo 'cmd_$@ := $(call make-cmd,cc_o_c)'; echo; cat $(depfile)) \
+		> $@.cmd ; \
+	rm $(depfile)
+endef
+
+$(objtree)%.o: $(srctree)%.c $$(call arg-check-prereq,cc_o_c) |allobjdirs
+	$(call CallRule,cc_o_c)
+
+# AR static library archiver
+quiet_cmd_ar	= AR      $(printable-target)
+      cmd_ar	= $(AR) -r $@ $? 2> /dev/null && \
+		  $(RANLIB) $@
+
+define CreateLibrary
+all-libs += $(objdir)$(1).a
+
+$(objdir)$(1).a: $(target-objects) $(LIBS) | createdir-$(objdir)
+
+-include $(addsuffix .cmd,$(target-objects))
+
+$(call CreateDirectory,$(objdir))
+endef
+
+# Linker
+ld_flags	= $(LDFLAGS_ALL) \
+	$($(dir $(printable-target))--LDFLAGS) \
+	$($(dir $(printable-target))--LDFLAGS_$(notdir $(primary_source)))
+
+quiet_cmd_ld	= LD      $(printable-target)
+      cmd_ld	= $(CC) $(ld_flags) -o $@ $(filter-out $(PHONY),$^) $($(@D)--LIBS) $($@--LIBS)
+
+define CreateProgram
+all-progs += $(objdir)$(1)
+
+$(objdir)$(1): $(target-objects) $(LIBS) | createdir-$(objdir)
+
+-include $(addsuffix .cmd,$(objdir)$(1) $(target-objects))
+
+$(call CreateDirectory,$(objdir))
+endef
+
+# version string
+GIT_REV := $(shell test -d .git && git describe 2> /dev/null || echo exported)
+ifneq ($(GIT_REV), exported)
+FULL_VERSION	:= $(patsubst v%,%,$(GIT_REV))
+else
+FULL_VERSION	:= $(VERSION)
+endif
+
+# include the main directory's TFbuild
+include $(build-prologue) TFbuild $(build-epilogue)
+
+# debug dump all variables
+#$(foreach VAR,$(sort $(.VARIABLES)),$(warning $(VAR)=$($(VAR))))
+
+progs: $(all-progs)
+libs: $(all-libs)
+
+$(all-libs): %:
+	$(call ExecuteCommand,ar)
+
+$(all-progs): %: $$(call arg-check-prereq,ld)
+	$(call ExecuteCommand,ld)
+
+.PHONY: $(PHONY)
+$(PHONY):
+
+endif
diff --git a/build/TFbuild.prologue b/build/TFbuild.prologue
new file mode 100644
index 0000000..2878ca0
--- /dev/null
+++ b/build/TFbuild.prologue
@@ -0,0 +1,18 @@
+# Reset all per-directory variables
+subdirs-y			:=
+libs-y				:=
+progs-y				:=
+
+# Remove this directory as being handled
+current-subdir			:= $(firstword $(subdirs--$(recursion-level)))
+subdirs--$(recursion-level)	:= $(filter-out $(current-subdir),$(subdirs--$(recursion-level)))
+
+# Traverse down to selected subdir
+parent-dir--$(next-recursion-level)	:= $(current-dir)
+parent-dirc--$(next-recursion-level)	:= $(current-dirc)
+current-dir				:= $(current-dir)$(current-subdir)
+current-dirc				+= $(current-subdir)
+
+$(foreach m,$(local-vars),$(eval $(call PushVariable,$(m))))
+
+#$(warning Enter $(current-dir))
diff --git a/include/libtf/atomic.h b/include/libtf/atomic.h
new file mode 100644
index 0000000..ec9f1e0
--- /dev/null
+++ b/include/libtf/atomic.h
@@ -0,0 +1,19 @@
+/* atomic.h - wrapper for atomic gcc built-ins
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#ifndef TF_ATOMIC_H
+#define TF_ATOMIC_H
+
+#define tf_atomic_inc(var) __sync_add_and_fetch(&(var), 1)
+#define tf_atomic_dec(var) __sync_add_and_fetch(&(var), -1)
+
+#endif
diff --git a/include/libtf/defines.h b/include/libtf/defines.h
new file mode 100644
index 0000000..7e35ff7
--- /dev/null
+++ b/include/libtf/defines.h
@@ -0,0 +1,67 @@
+/* tf.h - libtf helper defines
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#ifndef TF_DEFINES_H
+#define TF_DEFINES_H
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#ifndef NULL
+#define NULL 0L
+#endif
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#ifndef array_size
+#define array_size(array) (sizeof(array) / sizeof((array)[0]))
+#endif
+
+#ifndef offsetof
+#define offsetof(type, member)  __builtin_offsetof (type, member)
+#endif
+
+#ifndef container_of
+#define container_of(ptr, type, member) ({                      \
+        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+#endif
+
+#ifndef likely
+#define likely(x)			__builtin_expect(!!(x), 1)
+#endif
+
+#ifndef unlikely
+#define unlikely(x)			__builtin_expect(!!(x), 0)
+#endif
+
+#define attribute_never_inline		__attribute__((noinline))
+#define attribute_weak_function		__attribute__((weak))
+
+#define TF_BUG_ON(cond) if (cond) { \
+	fprintf(stderr, "BUG: failure at %s:%d/%s(): %s!\n",	\
+		__FILE__, __LINE__, __func__, #cond);		\
+	abort();						\
+}
+
+#define TF_ALIGN(size,align)	((((size_t)(size)) + (align)-1) & ~((align)-1))
+
+#define TF_EMPTY_ARRAY 0
+
+#endif
diff --git a/include/libtf/fiber.h b/include/libtf/fiber.h
new file mode 100644
index 0000000..48d4924
--- /dev/null
+++ b/include/libtf/fiber.h
@@ -0,0 +1,52 @@
+/* tf.h - libtf main include
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#ifndef TF_FIBER_H
+#define TF_FIBER_H
+
+#include <errno.h>
+#include <libtf/defines.h>
+#include <libtf/atomic.h>
+#include <libtf/list.h>
+
+#ifndef TF_STACK_SIZE
+#define TF_STACK_SIZE		4096
+#endif
+
+struct tf_fiber {
+	unsigned int		ref_count;
+	struct tf_list_node	queue_node;
+	char			data[TF_EMPTY_ARRAY];
+};
+
+typedef void (*tf_fiber_proc)(void *fiber);
+
+int tf_main(tf_fiber_proc fiber_main);
+
+void *tf_fiber_create(tf_fiber_proc fiber_main, int private_size);
+void *tf_fiber_get(void *data);
+void tf_fiber_put(void *data);
+
+int tf_schedule(int err);
+void tf_kill(void *fiber);
+
+static inline int tf_yield(void)
+{
+	return tf_schedule(EAGAIN);
+}
+
+static inline int tf_exit(void)
+{
+	return tf_schedule(EFAULT);
+}
+
+#endif
diff --git a/include/libtf/list.h b/include/libtf/list.h
new file mode 100644
index 0000000..22b76a8
--- /dev/null
+++ b/include/libtf/list.h
@@ -0,0 +1,194 @@
+/* list.h - libtf single and double linked list macros
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ *
+ * This based to some degree to the code in the linux kernel. This is subset
+ * of the functionality, and tf_list has separate head and node types.
+ */
+
+#ifndef TF_LIST_H
+#define TF_LIST_H
+
+#include <libtf/defines.h>
+
+struct tf_hlist_head {
+	struct tf_hlist_node *first;
+};
+
+struct tf_hlist_node {
+	struct tf_hlist_node *next;
+	struct tf_hlist_node **pprev;
+};
+
+static inline int tf_hlist_empty(const struct tf_hlist_head *h)
+{
+	return !h->first;
+}
+
+static inline int tf_hlist_hashed(const struct tf_hlist_node *n)
+{
+	return n->pprev != NULL;
+}
+
+static inline void tf_hlist_del(struct tf_hlist_node *n)
+{
+	*n->pprev = n->next;
+	n->next = NULL;
+	n->pprev = NULL;
+}
+
+static inline void tf_hlist_add_head(struct tf_hlist_node *n, struct tf_hlist_head *h)
+{
+	struct tf_hlist_node *first = h->first;
+
+	n->next = first;
+	n->pprev = &h->first;
+	h->first = n;
+}
+
+static inline void tf_hlist_add_after(struct tf_hlist_node *n, struct tf_hlist_node *prev)
+{
+	n->next = prev->next;
+	n->pprev = &prev->next;
+	prev->next = n;
+}
+
+static inline struct tf_hlist_node **tf_hlist_tail_ptr(struct tf_hlist_head *h)
+{
+	struct tf_hlist_node *n = h->first;
+	if (n == NULL)
+		return &h->first;
+	while (n->next != NULL)
+		n = n->next;
+	return &n->next;
+}
+
+#define tf_hlist_entry(ptr, type, member) container_of(ptr,type,member)
+
+#define tf_hlist_for_each(pos, head) \
+	for (pos = (head)->first; pos; pos = pos->next)
+
+#define tf_hlist_for_each_safe(pos, n, head) \
+	for (pos = (head)->first; pos && ({ n = pos->next; 1; }); pos = n)
+
+#define tf_hlist_for_each_entry(tpos, pos, head, member)			 \
+	for (pos = (head)->first; pos && 				 \
+		({ tpos = tf_hlist_entry(pos, typeof(*tpos), member); 1;}); \
+	     pos = pos->next)
+
+#define tf_hlist_for_each_entry_safe(tpos, pos, n, head, member) 		 \
+	for (pos = (head)->first;					 \
+	     pos && ({ n = pos->next; 1; }) &&				 \
+		({ tpos = tf_hlist_entry(pos, typeof(*tpos), member); 1;}); \
+	     pos = n)
+
+
+struct tf_list_node {
+	struct tf_list_node *next, *prev;
+};
+
+struct tf_list_head {
+	struct tf_list_node node;
+};
+
+#define TF_LIST_INITIALIZER(l) { .next = &l, .prev = &l }
+#define TF_LIST_HEAD_INITIALIZER(l) { .node = TF_LIST_INITIALIZER((l).node) }
+
+static inline void tf_list_init(struct tf_list_node *list)
+{
+	list->next = list;
+	list->prev = list;
+}
+
+static inline void tf_list_init_head(struct tf_list_head *head)
+{
+	tf_list_init(&head->node);
+}
+
+static inline void __tf_list_add(struct tf_list_node *new,
+			      struct tf_list_node *prev,
+			      struct tf_list_node *next)
+{
+	next->prev = new;
+	new->next = next;
+	new->prev = prev;
+	prev->next = new;
+}
+
+static inline void tf_list_add_after(struct tf_list_node *new, struct tf_list_node *head)
+{
+	__tf_list_add(new, head, head->next);
+}
+
+static inline void tf_list_add_before(struct tf_list_node *new, struct tf_list_node *head)
+{
+	__tf_list_add(new, head->prev, head);
+}
+
+static inline void tf_list_add_head(struct tf_list_node *new, struct tf_list_head *head)
+{
+	tf_list_add_after(new, &head->node);
+}
+
+static inline void tf_list_add_tail(struct tf_list_node *new, struct tf_list_head *head)
+{
+	tf_list_add_before(new, &head->node);
+}
+
+static inline void __tf_list_del(struct tf_list_node * prev, struct tf_list_node *next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+static inline void tf_list_del(struct tf_list_node *entry)
+{
+	__tf_list_del(entry->prev, entry->next);
+	entry->next = NULL;
+	entry->prev = NULL;
+}
+
+static inline int tf_list_hashed(const struct tf_list_node *n)
+{
+	return n->next != n && n->next != NULL;
+}
+
+static inline int tf_list_empty(const struct tf_list_head *h)
+{
+	return !tf_list_hashed(&h->node);
+}
+
+#define tf_list_next(ptr, type, member) \
+	(tf_list_hashed(ptr) ? container_of((ptr)->next,type,member) : NULL)
+
+#define tf_list_first(head, type, member) \
+	tf_list_next(&((head)->node), type, member)
+
+#define tf_list_entry(ptr, type, member) container_of(ptr,type,member)
+
+#define tf_list_for_each(pos, head) \
+	for (pos = (head)->next; pos != (head); pos = pos->next)
+
+#define tf_list_for_each_safe(pos, n, head) \
+	for (pos = (head)->next, n = pos->next; pos != (head); \
+		pos = n, n = pos->next)
+
+#define tf_list_for_each_entry(pos, head, member)				\
+	for (pos = tf_list_entry((head)->next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = tf_list_entry(pos->member.next, typeof(*pos), member))
+
+#define tf_list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = tf_list_entry((head)->next, typeof(*pos), member),	\
+		n = tf_list_entry(pos->member.next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = n, n = tf_list_entry(n->member.next, typeof(*n), member))
+
+#endif
diff --git a/include/libtf/tf.h b/include/libtf/tf.h
new file mode 100644
index 0000000..7ff7b25
--- /dev/null
+++ b/include/libtf/tf.h
@@ -0,0 +1,20 @@
+/* tf.h - libtf umbrella include
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#ifndef TF_H
+#define TF_H
+
+#define TF_UCTX_H "uctx-setjmp.h"
+
+#include <libtf/fiber.h>
+
+#endif
diff --git a/src/TFbuild b/src/TFbuild
new file mode 100644
index 0000000..211b734
--- /dev/null
+++ b/src/TFbuild
@@ -0,0 +1,5 @@
+libs-y			+= libtf
+
+libtf-objs-y		+= fiber.o dheap.o
+
+CFLAGS_dheap.c		+= -funroll-all-loops
diff --git a/src/fiber.c b/src/fiber.c
new file mode 100644
index 0000000..0db2984
--- /dev/null
+++ b/src/fiber.c
@@ -0,0 +1,131 @@
+/* fiber.c - fiber management and scheduling
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+#include <errno.h>
+#include <libtf/tf.h>
+#include TF_UCTX_H
+
+struct tf_scheduler {
+	struct tf_list_head	run_q;
+	struct tf_list_head	sleep_q;
+
+	struct tf_fiber *	active_fiber;
+	int			num_fibers;
+};
+
+/* FIXME: should be in thread local storage */
+static struct tf_scheduler *__scheduler;
+
+void *tf_fiber_create(tf_fiber_proc fiber_main, int private_size)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *fiber;
+
+	fiber = tf_uctx_create(fiber_main, private_size);
+
+	/* The initial references for caller and scheduler */
+	*fiber = (struct tf_fiber) {
+		.ref_count = 2,
+		.queue_node = TF_LIST_INITIALIZER(fiber->queue_node),
+	};
+
+	tf_list_add_tail(&fiber->queue_node, &sched->run_q);
+	sched->num_fibers++;
+
+	return fiber->data;
+}
+
+void __tf_fiber_destroy(struct tf_fiber *fiber)
+{
+	tf_uctx_destroy(fiber);
+}
+
+void *tf_fiber_get(void *data)
+{
+	struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
+	tf_atomic_inc(fiber->ref_count);
+	return data;
+}
+
+void tf_fiber_put(void *data)
+{
+	struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
+	if (tf_atomic_dec(fiber->ref_count) == 0)
+		__tf_fiber_destroy(fiber);
+}
+
+static void run_fiber(void)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
+	struct tf_fiber *f;
+
+	if (tf_list_empty(&sched->run_q))
+		return;
+
+	f = tf_list_first(&sched->run_q, struct tf_fiber, queue_node);
+	tf_list_del(&f->queue_node);
+
+	sched->active_fiber = f;
+	switch (tf_uctx_transfer(schedf, f, 1)) {
+	case EFAULT: /* Fiber is dead */
+		tf_fiber_put(f->data);
+		sched->num_fibers--;
+		break;
+	case EAGAIN: /* Yielded, reshedule */
+		tf_list_add_tail(&f->queue_node, &sched->run_q);
+		break;
+	case EIO: /* Blocked, in sleep */
+		tf_list_add_tail(&f->queue_node, &sched->sleep_q);
+		break;
+	default:
+		TF_BUG_ON("bad scheduler call from fiber");
+	}
+}
+
+int tf_main(tf_fiber_proc main_fiber)
+{
+	struct tf_uctx *ctx = alloca(sizeof(struct tf_uctx) + sizeof(struct tf_scheduler));
+	struct tf_scheduler *sched = (struct tf_scheduler*) ctx->fiber.data;
+	int stack_guard = STACK_GUARD;
+
+	ctx->stack_guard = &stack_guard;
+	*sched = (struct tf_scheduler){
+		.run_q = TF_LIST_HEAD_INITIALIZER(sched->run_q),
+		.sleep_q = TF_LIST_HEAD_INITIALIZER(sched->sleep_q),
+	};
+	__scheduler = sched;
+	tf_fiber_put(tf_fiber_create(main_fiber, 0));
+	do {
+		run_fiber();
+	} while (likely(sched->num_fibers));
+	__scheduler = NULL;
+
+	return 0;
+}
+
+int tf_schedule(int err)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
+	struct tf_fiber *f = sched->active_fiber;
+	int r;
+
+	r = tf_uctx_transfer(f, schedf, err);
+	if (r == 1)
+		return 0;
+
+	return r;
+}
+
+void tf_kill(void *fiber)
+{
+}
diff --git a/src/uctx-setjmp.h b/src/uctx-setjmp.h
new file mode 100644
index 0000000..33e187e
--- /dev/null
+++ b/src/uctx-setjmp.h
@@ -0,0 +1,109 @@
+/* uctx-setjmp.h - setjmp based user-space context switching
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+
+#include <libtf/fiber.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <setjmp.h>
+#ifdef VALGRIND
+#include <valgrind/valgrind.h>
+#endif
+
+#define STACK_GUARD		0xbad57ac4
+
+struct tf_uctx {
+	int *stack_guard;
+	void *alloc;
+	jmp_buf jmpbuf;
+#ifdef VALGRIND
+	unsigned int stack_id;
+#endif
+	struct tf_fiber fiber;
+};
+
+#define set_stack(ptr) ({ __asm__("movl %0, %%esp" : : "r"(ptr)); })
+#define get_stack() ({ void *ptr; __asm__("movl %%esp, %0" : "=r"(ptr)); ptr; })
+
+attribute_never_inline
+static void *tf_uctx_start(tf_fiber_proc fiber_main, size_t private_size)
+{
+	struct tf_uctx *uctx;
+
+	uctx = alloca(private_size);
+	if (setjmp(uctx->jmpbuf) != 0) {
+		fiber_main(uctx->fiber.data);
+		tf_exit();
+	}
+	return uctx;
+}
+
+static inline
+struct tf_fiber *tf_uctx_create(tf_fiber_proc fiber_main, int private_size)
+{
+	size_t size = TF_STACK_SIZE;
+	struct tf_uctx *uctx;
+	void *stack, *old_stack, *stack_head, *stack_tail;
+#ifdef VALGRIND
+	int stack_id;
+#endif
+
+	stack = malloc(size);
+	if (stack == NULL)
+		return NULL;
+#ifdef VALGRIND
+	stack_id = VALGRIND_STACK_REGISTER(stack, size);
+#endif
+
+	/* Assumes stack grows up */
+	stack_head = stack + size - 8;
+	stack_tail = stack;
+
+	old_stack = get_stack();
+	set_stack(stack_head);
+	uctx = tf_uctx_start(fiber_main, private_size + sizeof(struct tf_uctx));
+	set_stack(old_stack);
+
+#ifdef VALGRIND
+	uctx->stack_id = stack_id;
+#endif
+	uctx->alloc = stack;
+	uctx->stack_guard = stack_tail;
+	*uctx->stack_guard = STACK_GUARD;
+
+	return &uctx->fiber;
+}
+
+static inline
+void tf_uctx_destroy(struct tf_fiber *fiber)
+{
+	struct tf_uctx *uctx = container_of(fiber, struct tf_uctx, fiber);
+#ifdef VALGRIND
+	VALGRIND_STACK_DEREGISTER(uctx->stack_id);
+#endif
+	free(uctx->alloc);
+}
+
+static inline
+int tf_uctx_transfer(struct tf_fiber *from, struct tf_fiber *to, int value)
+{
+	struct tf_uctx *ufrom = container_of(from, struct tf_uctx, fiber);
+	struct tf_uctx *uto   = container_of(to,   struct tf_uctx, fiber);
+	int r;
+
+	TF_BUG_ON(unlikely(*ufrom->stack_guard != STACK_GUARD));
+
+	r = setjmp(ufrom->jmpbuf);
+	if (r == 0)
+		longjmp(uto->jmpbuf, value);
+	return r;
+}
diff --git a/test/TFbuild b/test/TFbuild
new file mode 100644
index 0000000..d2648ed
--- /dev/null
+++ b/test/TFbuild
@@ -0,0 +1,3 @@
+progs-$(TEST)		+= simple1 sleep
+
+LIBS			+= $(objtree)src/libtf.a
diff --git a/test/simple1.c b/test/simple1.c
new file mode 100644
index 0000000..65a787c
--- /dev/null
+++ b/test/simple1.c
@@ -0,0 +1,32 @@
+#include <libtf/tf.h>
+#include <stdio.h>
+
+struct ctx {
+	int id;
+};
+
+static void work_fiber(void *ptr)
+{
+	struct ctx *c = (struct ctx*) ptr;
+
+	printf("Hello%d.1\n", c->id);
+	tf_yield();
+	printf("Hello%d.2\n", c->id);
+}
+
+static void init_fiber(void *ptr)
+{
+	struct ctx *c;
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		c = tf_fiber_create(work_fiber, sizeof(struct ctx));
+		c->id = i;
+		tf_fiber_put(c);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	return tf_main(init_fiber);
+}