1 /* 2 3 Copyright (c) 2015 Martin Sustrik 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"), 7 to deal in the Software without restriction, including without limitation 8 the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 and/or sell copies of the Software, and to permit persons to whom 10 the Software is furnished to do so, subject to the following conditions: 11 12 The above copyright notice and this permission notice shall be included 13 in 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 18 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 IN THE SOFTWARE. 22 23 */ 24 25 #ifndef MILL_CR_INCLUDED 26 #define MILL_CR_INCLUDED 27 28 #include <setjmp.h> 29 #include <stdint.h> 30 31 #include "chan.h" 32 #include "debug.h" 33 #include "list.h" 34 #include "slist.h" 35 #include "timer.h" 36 #include "utils.h" 37 38 enum mill_state { 39 MILL_READY, 40 MILL_MSLEEP, 41 MILL_FDWAIT, 42 MILL_CHR, 43 MILL_CHS, 44 MILL_CHOOSE 45 }; 46 47 /* The coroutine. The memory layout looks like this: 48 49 +----------------------------------------------------+--------+---------+ 50 | stack | valbuf | mill_cr | 51 +----------------------------------------------------+--------+---------+ 52 53 - mill_cr contains generic book-keeping info about the coroutine 54 - valbuf is a buffer for temporarily storing values received from channels 55 - stack is a standard C stack; it grows downwards (at the moment libmill 56 doesn't support microarchitectures where stack grows upwards) 57 58 */ 59 struct mill_cr { 60 /* Status of the coroutine. Used for debugging purposes. */ 61 enum mill_state state; 62 63 /* The coroutine is stored in this list if it is not blocked and it is 64 waiting to be executed. In such case 'is_ready' is set to 1, otherwise 65 it's set to 0. */ 66 int is_ready; 67 struct mill_slist_item ready; 68 69 /* If the coroutine is waiting for a deadline, it uses this timer. */ 70 struct mill_timer timer; 71 72 /* The file descriptor for which the coroutine waits for an event 73 when blocked in fdwait(). -1 when it isn't waiting for any event. */ 74 int fd; 75 76 /* When the coroutine is blocked in fdwait(), the events that the function 77 waits for. This is used only for debugging purposes. */ 78 int events; 79 80 /* This structure is used when the coroutine is executing a choose 81 statement. */ 82 struct mill_choosedata choosedata; 83 84 /* Stored coroutine context while it is not executing. */ 85 #if defined(__x86_64__) 86 uint64_t ctx[10]; 87 #else 88 sigjmp_buf ctx; 89 #endif 90 91 /* Argument to resume() call being passed to the blocked suspend() call. */ 92 int result; 93 94 /* If size of the valbuf needs to be larger than mill_valbuf size it is 95 allocated dyncamically and the pointer, along with the size of the buffer 96 is stored here. */ 97 void *valbuf; 98 size_t valbuf_sz; 99 100 /* Coroutine-local storage. */ 101 void *clsval; 102 103 #if defined MILL_VALGRIND 104 /* Valgrind stack identifier. */ 105 int sid; 106 #endif 107 108 /* Debugging info. */ 109 struct mill_debug_cr debug; 110 }; 111 112 /* Fake coroutine corresponding to the main thread of execution. */ 113 extern struct mill_cr mill_main; 114 115 /* The coroutine that is running at the moment. */ 116 extern struct mill_cr *mill_running; 117 118 /* Suspend running coroutine. Move to executing different coroutines. Once 119 someone resumes this coroutine using mill_resume function 'result' argument 120 of that function will be returned. */ 121 int mill_suspend(void); 122 123 /* Schedules preiously suspended coroutine for execution. Keep in mind that 124 it doesn't immediately run it, just puts it into the queue of ready 125 coroutines. */ 126 void mill_resume(struct mill_cr *cr, int result); 127 128 /* Returns pointer to the value buffer. The returned buffer is guaranteed 129 to be at least 'size' bytes long. */ 130 void *mill_valbuf(struct mill_cr *cr, size_t size); 131 132 /* Called in the child process after fork to stop all the coroutines 133 inherited from the parent. */ 134 void mill_cr_postfork(void); 135 136 #endif 137