src/xbt/xbt_ucontext.c

   1 \r
   2 #include "ucontext_stack.h"\r
   3 #include "xbt/ex_interface.h"\r
   4 #include "xbt/xbt_context_factory.h"\r
   5 \r
   6 #include "ucontext_stack.h"             /* loads context system definitions                             */\r
   7 #include <ucontext.h>                   /* context relative declarations                                */                              \r
   8 #define STACK_SIZE 128*1024             /* lower this if you want to reduce the memory consumption      */\r
   9 \r
  10 typedef struct s_xbt_ucontext {\r
  11    XBT_CTX_BASE_T;\r
  12         ucontext_t uc;                  /* the thread that execute the code                             */\r
  13         char stack[STACK_SIZE];         /* the thread stack size                                        */\r
  14         struct s_xbt_ucontext* prev;    /* the previous thread                                          */\r
  15 } s_xbt_ucontext_t,* xbt_ucontext_t;\r
  16 \r
  17 \r
  18 /* callback: context fetching */\r
  19 static ex_ctx_t*\r
  20 xbt_jcontext_ex_ctx(void);\r
  21 \r
  22 /* callback: termination */\r
  23 static void \r
  24 xbt_jcontext_ex_terminate(xbt_ex_t *e);\r
  25 \r
  26 static xbt_context_t \r
  27 xbt_ucontext_factory_create_context(const char* name, xbt_main_func_t code, void_f_pvoid_t startup_func, void* startup_arg, void_f_pvoid_t cleanup_func, void* cleanup_arg, int argc, char** argv);\r
  28 \r
  29 static int\r
  30 xbt_ucontext_factory_finalize(xbt_context_factory_t* factory);\r
  31 \r
  32 static int \r
  33 xbt_ucontext_factory_create_maestro_context(xbt_context_t* maestro);\r
  34 \r
  35 static void \r
  36 xbt_ucontext_free(xbt_context_t context);\r
  37 \r
  38 static void \r
  39 xbt_ucontext_kill(xbt_context_t context);\r
  40 \r
  41 static void \r
  42 xbt_ucontext_schedule(xbt_context_t context);\r
  43 \r
  44 static void \r
  45 xbt_ucontext_yield(void);\r
  46 \r
  47 static void \r
  48 xbt_ucontext_start(xbt_context_t context);\r
  49 \r
  50 static void \r
  51 xbt_ucontext_stop(int exit_code);\r
  52 \r
  53 static void \r
  54 xbt_ucontext_swap(xbt_context_t context);\r
  55 \r
  56 static void\r
  57 xbt_ucontext_schedule(xbt_context_t context);\r
  58 \r
  59 static void\r
  60 xbt_ucontext_yield(void);\r
  61 \r
  62 static void\r
  63 xbt_ucontext_suspend(xbt_context_t context);\r
  64 \r
  65 static void\r
  66 xbt_ucontext_resume(xbt_context_t context);\r
  67 \r
  68 static void* \r
  69 xbt_ucontext_wrapper(void* param);\r
  70 \r
  71 /* callback: context fetching */\r
  72 static ex_ctx_t*\r
  73 xbt_ucontext_ex_ctx(void) \r
  74 {\r
  75         return current_context->exception;\r
  76 }\r
  77 \r
  78 /* callback: termination */\r
  79 static void \r
  80 xbt_ucontext_ex_terminate(xbt_ex_t *e) \r
  81 {\r
  82         xbt_ex_display(e);\r
  83         abort();\r
  84 }\r
  85 \r
  86 \r
  87 int\r
  88 xbt_ucontext_factory_init(xbt_context_factory_t* factory)\r
  89 {\r
  90         /* context exception */\r
  91         *factory = xbt_new0(s_xbt_context_factory_t,1);\r
  92         \r
  93         (*factory)->create_context = xbt_ucontext_factory_create_context;\r
  94         (*factory)->finalize = xbt_ucontext_factory_finalize;\r
  95         (*factory)->create_maestro_context = xbt_ucontext_factory_create_maestro_context;\r
  96         (*factory)->name = "ucontext_context_factory";\r
  97         \r
  98         /* context exception handlers */\r
  99         __xbt_ex_ctx       = xbt_ucontext_ex_ctx;\r
 100     __xbt_ex_terminate = xbt_ucontext_ex_terminate;     \r
 101     \r
 102         return 0;\r
 103 }\r
 104 \r
 105 static int \r
 106 xbt_ucontext_factory_create_maestro_context(xbt_context_t* maestro)\r
 107 {\r
 108                 \r
 109         xbt_ucontext_t context = xbt_new0(s_xbt_ucontext_t, 1);\r
 110         \r
 111         context->exception = xbt_new(ex_ctx_t,1);\r
 112     XBT_CTX_INITIALIZE(context->exception);\r
 113     \r
 114     *maestro = (xbt_context_t)context;\r
 115     \r
 116     return 0;\r
 117     \r
 118 }\r
 119 \r
 120 \r
 121 static int\r
 122 xbt_ucontext_factory_finalize(xbt_context_factory_t* factory)\r
 123 {\r
 124         free(maestro_context->exception);\r
 125         free(*factory);\r
 126         *factory = NULL;\r
 127         return 0;\r
 128 }\r
 129 \r
 130 static xbt_context_t \r
 131 xbt_ucontext_factory_create_context(const char* name, xbt_main_func_t code, void_f_pvoid_t startup_func, void* startup_arg, void_f_pvoid_t cleanup_func, void* cleanup_arg, int argc, char** argv)\r
 132 {\r
 133         xbt_ucontext_t context = xbt_new0(s_xbt_ucontext_t, 1);\r
 134         \r
 135         context->code = code;\r
 136         context->name = xbt_strdup(name);\r
 137         \r
 138         xbt_assert2(getcontext(&(context->uc)) == 0,"Error in context saving: %d (%s)", errno, strerror(errno));\r
 139         context->uc.uc_link = NULL;\r
 140         context->uc.uc_stack.ss_sp = pth_skaddr_makecontext(context->stack, STACK_SIZE);\r
 141         context->uc.uc_stack.ss_size = pth_sksize_makecontext(context->stack, STACK_SIZE);\r
 142         \r
 143         context->exception = xbt_new(ex_ctx_t, 1);\r
 144         XBT_CTX_INITIALIZE(context->exception);\r
 145         context->iwannadie = 0;           /* useless but makes valgrind happy */\r
 146         context->argc = argc;\r
 147         context->argv = argv;\r
 148         context->startup_func = startup_func;\r
 149         context->startup_arg = startup_arg;\r
 150         context->cleanup_func = cleanup_func;\r
 151         context->cleanup_arg = cleanup_arg;\r
 152         \r
 153         \r
 154         context->free = xbt_ucontext_free;                      \r
 155         context->kill = xbt_ucontext_kill;                      \r
 156         context->schedule = xbt_ucontext_schedule;\r
 157         context->yield = xbt_ucontext_yield;                    \r
 158         context->start = xbt_ucontext_start;                    \r
 159         context->stop = xbt_ucontext_stop;                      \r
 160         \r
 161         return (xbt_context_t)context;\r
 162 }\r
 163 \r
 164 static void \r
 165 xbt_ucontext_free(xbt_context_t context)\r
 166 {\r
 167         if(context)\r
 168         {\r
 169                 free(context->name);\r
 170                 \r
 171                 if(context->argv)\r
 172                 {\r
 173                         int i;\r
 174                         \r
 175                         for(i = 0; i < context->argc; i++)\r
 176                                 if(context->argv[i])\r
 177                                         free(context->argv[i]);\r
 178                                         \r
 179                         free(context->argv);\r
 180                 }\r
 181                 \r
 182                 if(context->exception) \r
 183                         free(context->exception);\r
 184                 \r
 185                 /* finally destroy the context */\r
 186                 free(context);\r
 187         }\r
 188 }\r
 189 \r
 190 static void \r
 191 xbt_ucontext_kill(xbt_context_t context)\r
 192 {\r
 193         context->iwannadie = 1;\r
 194         xbt_ucontext_swap(context);\r
 195 }\r
 196 \r
 197 /** \r
 198  * \param context the winner\r
 199  *\r
 200  * Calling this function blocks the current context and schedule \a context.  \r
 201  * When \a context will call xbt_context_yield, it will return\r
 202  * to this function as if nothing had happened.\r
 203  * \r
 204  * Only the maestro can call this function to run a given process.\r
 205  */\r
 206 static void \r
 207 xbt_ucontext_schedule(xbt_context_t context)\r
 208 {\r
 209         xbt_assert0((current_context == maestro_context),"You are not supposed to run this function here!");\r
 210         xbt_ucontext_swap(context);\r
 211 }\r
 212 \r
 213 /** \r
 214  * Calling this function makes the current context yield. The context\r
 215  * that scheduled it returns from xbt_context_schedule as if nothing\r
 216  * had happened.\r
 217  * \r
 218  * Only the processes can call this function, giving back the control\r
 219  * to the maestro\r
 220  */\r
 221 static void \r
 222 xbt_ucontext_yield(void)\r
 223 {\r
 224         xbt_assert0((current_context != maestro_context),"You are not supposed to run this function here!");\r
 225         xbt_ucontext_swap(current_context);\r
 226 }\r
 227 \r
 228 static void \r
 229 xbt_ucontext_start(xbt_context_t context)\r
 230 {\r
 231         makecontext(&(((xbt_ucontext_t)context)->uc), (void (*)(void)) xbt_ucontext_wrapper, 1, context);\r
 232 }\r
 233 \r
 234 static void \r
 235 xbt_ucontext_stop(int exit_code)\r
 236 {\r
 237         if(current_context->cleanup_func) \r
 238                 ((*current_context->cleanup_func))(current_context->cleanup_arg);\r
 239         \r
 240         xbt_swag_remove(current_context, context_living);\r
 241         xbt_swag_insert(current_context, context_to_destroy);   \r
 242         \r
 243         xbt_ucontext_swap(current_context);\r
 244 }\r
 245 \r
 246 static void \r
 247 xbt_ucontext_swap(xbt_context_t context)\r
 248 {\r
 249         xbt_assert0(current_context, "You have to call context_init() first.");\r
 250         xbt_assert0(context, "Invalid argument");\r
 251         \r
 252         if(((xbt_ucontext_t)context)->prev == NULL) \r
 253                 xbt_ucontext_resume(context);\r
 254         else \r
 255                 xbt_ucontext_suspend(context);\r
 256         \r
 257         if(current_context->iwannadie)\r
 258                 xbt_ucontext_stop(1);\r
 259 }\r
 260 \r
 261 static void* \r
 262 xbt_ucontext_wrapper(void* param)\r
 263 {\r
 264         if (current_context->startup_func)\r
 265                 (*current_context->startup_func)(current_context->startup_arg);\r
 266         \r
 267         xbt_ucontext_stop((*(current_context->code))(current_context->argc, current_context->argv));\r
 268         return NULL;\r
 269 }\r
 270 \r
 271 static void\r
 272 xbt_ucontext_suspend(xbt_context_t context)\r
 273 {\r
 274         int rv;\r
 275         \r
 276         xbt_ucontext_t prev_context = ((xbt_ucontext_t)context)->prev;\r
 277         \r
 278         current_context = (xbt_context_t)(((xbt_ucontext_t)context)->prev);\r
 279         \r
 280         ((xbt_ucontext_t)context)->prev = NULL;\r
 281         \r
 282         rv = swapcontext(&(((xbt_ucontext_t)context)->uc), &(prev_context->uc));\r
 283                 \r
 284         xbt_assert0((rv == 0), "Context swapping failure");\r
 285 }\r
 286 \r
 287 static void\r
 288 xbt_ucontext_resume(xbt_context_t context)\r
 289 {\r
 290         int rv;\r
 291         \r
 292         ((xbt_ucontext_t)context)->prev = (xbt_ucontext_t)current_context;\r
 293         \r
 294         current_context = context;\r
 295         \r
 296         rv = swapcontext(&(((xbt_ucontext_t)context)->prev->uc), &(((xbt_ucontext_t)context)->uc));\r
 297                 \r
 298         xbt_assert0((rv == 0), "Context swapping failure");\r
 299 }\r
 300 \r
 301 \r
 302 \r