1 // The MIT License (MIT)
2 //
3 // 	Copyright (c) 2015 Sergey Makeev, Vadim Slyusarev
4 //
5 // 	Permission is hereby granted, free of charge, to any person obtaining a copy
6 // 	of this software and associated documentation files (the "Software"), to deal
7 // 	in the Software without restriction, including without limitation the rights
8 // 	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // 	copies of the Software, and to permit persons to whom the Software is
10 // 	furnished to do so, subject to the following conditions:
11 //
12 //  The above copyright notice and this permission notice shall be included in
13 // 	all copies or substantial portions of the Software.
14 //
15 // 	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // 	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // 	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // 	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // 	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // 	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // 	THE SOFTWARE.
22 
23 #pragma once
24 
25 #include <ucontext.h>
26 #include <stdlib.h>
27 #include <string.h>
28 
29 #define _DARWIN_C_SOURCE
30 #include <sys/mman.h>
31 
32 #ifndef MAP_ANONYMOUS
33     #define MAP_ANONYMOUS MAP_ANON
34 #endif
35 
36 #ifndef MAP_STACK
37     #define MAP_STACK (0)
38 #endif
39 
40 namespace MT
41 {
42 
43 	//
44 	//
45 	//
46 	class Fiber
47 	{
48 		void * funcData;
49 		TThreadEntryPoint func;
50 
51 		char* stackRawMemory;
52 		size_t stackRawMemorySize;
53 
54 		ucontext_t fiberContext;
55 		bool isInitialized;
56 
57 		static void FiberFuncInternal(void *pFiber)
58 		{
59 			MT_ASSERT(pFiber != nullptr, "Invalid fiber");
60 			Fiber* self = (Fiber*)pFiber;
61 
62 			MT_ASSERT(self->isInitialized == true, "Using non initialized fiber");
63 
64 			MT_ASSERT(self->func != nullptr, "Invalid fiber func");
65 			self->func(self->funcData);
66 		}
67 
68 	private:
69 
70 		Fiber(const Fiber &) {}
71 		void operator=(const Fiber &) {}
72 
73 	public:
74 
75 		Fiber()
76 			: funcData(nullptr)
77 			, func(nullptr)
78 			, stackRawMemory(nullptr)
79 			, stackRawMemorySize(0)
80 			, isInitialized(false)
81 		{
82 			memset(&fiberContext, 0, sizeof(ucontext_t));
83 		}
84 
85 		~Fiber()
86 		{
87 			if (isInitialized)
88 			{
89 				// if func != null than we have memory ownership
90 				if (func != nullptr)
91 				{
92 					int res = munmap(stackRawMemory, stackRawMemorySize);
93 					MT_ASSERT(res == 0, "Can't free memory");
94 				}
95 
96 				isInitialized = false;
97 			}
98 		}
99 
100 
101 		void CreateFromThread(Thread & thread)
102 		{
103 			MT_ASSERT(!isInitialized, "Already initialized");
104 			MT_ASSERT(thread.IsCurrentThread(), "ERROR: Can create fiber only from current thread!");
105 
106 			int res = getcontext(&fiberContext);
107 			MT_ASSERT(res == 0, "getcontext - failed");
108 
109 			fiberContext.uc_link = nullptr;
110 			fiberContext.uc_stack.ss_sp = thread.GetStackBottom();
111 			fiberContext.uc_stack.ss_size = thread.GetStackSize();
112 			fiberContext.uc_stack.ss_flags = 0;
113 
114 			func = nullptr;
115 			funcData = nullptr;
116 
117 			isInitialized = true;
118 		}
119 
120 
121 		void Create(size_t stackSize, TThreadEntryPoint entryPoint, void *userData)
122 		{
123 			MT_ASSERT(!isInitialized, "Already initialized");
124             MT_ASSERT(stackSize >= PTHREAD_STACK_MIN, "Stack to small");
125 
126 			func = entryPoint;
127 			funcData = userData;
128 
129 			int res = getcontext(&fiberContext);
130 			MT_ASSERT(res == 0, "getcontext - failed");
131 
132 
133 			int pageSize = sysconf(_SC_PAGE_SIZE);
134 			int pagesCount = stackSize / pageSize;
135 
136 			//need additional page for stack tail
137 			if ((stackSize % pageSize) > 0)
138 			{
139 				pagesCount++;
140 			}
141 
142 			//protected guard page
143 			pagesCount++;
144 
145 			stackRawMemorySize = pagesCount * pageSize;
146 
147 			stackRawMemory = (char*)mmap(NULL, stackRawMemorySize, PROT_READ | PROT_WRITE,  MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
148 
149 			MT_ASSERT((void *)stackRawMemory != (void *)-1, "Can't allocate memory");
150 
151 			char* stackBottom = stackRawMemory + pageSize;
152 			//char* stackTop = stackRawMemory + stackMemorySize;
153 
154 			res = mprotect(stackRawMemory, pageSize, PROT_NONE);
155 			MT_ASSERT(res == 0, "Can't protect memory");
156 
157 			fiberContext.uc_link = nullptr;
158 			fiberContext.uc_stack.ss_sp = stackBottom;
159 			fiberContext.uc_stack.ss_size = stackRawMemorySize - pageSize;
160 			fiberContext.uc_stack.ss_flags = 0;
161 
162 			makecontext(&fiberContext, (void(*)())&FiberFuncInternal, 1, (void *)this);
163 
164 			isInitialized = true;
165 		}
166 
167 		static void SwitchTo(Fiber & from, Fiber & to)
168 		{
169 			 __sync_synchronize();
170 
171 			MT_ASSERT(from.isInitialized, "Invalid from fiber");
172 			MT_ASSERT(to.isInitialized, "Invalid to fiber");
173 
174 			int res = swapcontext(&from.fiberContext, &to.fiberContext);
175 			MT_ASSERT(res == 0, "setcontext - failed");
176 
177 		}
178 
179 
180 
181 	};
182 
183 
184 }
185 
186 
187