src/xbt/xbt_context_sysv.c

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