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  1. /*
  2.  * Copyright (c) 2006 Ondrej Palkovsky
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericipc
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <arch.h>
  36. #include <proc/task.h>
  37. #include <proc/thread.h>
  38. #include <errno.h>
  39. #include <memstr.h>
  40. #include <debug.h>
  41. #include <ipc/ipc.h>
  42. #include <ipc/sysipc.h>
  43. #include <ipc/irq.h>
  44. #include <ipc/ipcrsc.h>
  45. #include <arch/interrupt.h>
  46. #include <print.h>
  47. #include <syscall/copy.h>
  48. #include <security/cap.h>
  49. #include <mm/as.h>
  50. #include <print.h>
  51.  
  52. /**
  53.  * Maximum buffer size allowed for IPC_M_DATA_WRITE and IPC_M_DATA_READ
  54.  * requests.
  55.  */
  56. #define DATA_XFER_LIMIT     (64 * 1024)
  57.  
  58. #define GET_CHECK_PHONE(phone, phoneid, err) \
  59. { \
  60.     if (phoneid > IPC_MAX_PHONES) { \
  61.         err; \
  62.     } \
  63.     phone = &TASK->phones[phoneid]; \
  64. }
  65.  
  66. #define STRUCT_TO_USPACE(dst, src)  copy_to_uspace(dst, src, sizeof(*(src)))
  67.  
  68. /** Decide if the method is a system method.
  69.  *
  70.  * @param method    Method to be decided.
  71.  *
  72.  * @return      Return 1 if the method is a system method.
  73.  *          Otherwise return 0.
  74.  */
  75. static inline int method_is_system(unative_t method)
  76. {
  77.     if (method <= IPC_M_LAST_SYSTEM)
  78.         return 1;
  79.     return 0;
  80. }
  81.  
  82. /** Decide if the message with this method is forwardable.
  83.  *
  84.  * - some system messages may be forwarded, for some of them
  85.  *   it is useless
  86.  *
  87.  * @param method    Method to be decided.
  88.  *
  89.  * @return      Return 1 if the method is forwardable.
  90.  *          Otherwise return 0.
  91.  */
  92. static inline int method_is_forwardable(unative_t method)
  93. {
  94.     switch (method) {
  95.     case IPC_M_PHONE_HUNGUP:
  96.         /* This message is meant only for the original recipient. */
  97.         return 0;
  98.     default:
  99.         return 1;
  100.     }
  101. }
  102.  
  103. /** Decide if the message with this method is immutable on forward.
  104.  *
  105.  * - some system messages may be forwarded but their content cannot be altered
  106.  *
  107.  * @param method    Method to be decided.
  108.  *
  109.  * @return      Return 1 if the method is immutable on forward.
  110.  *          Otherwise return 0.
  111.  */
  112. static inline int method_is_immutable(unative_t method)
  113. {
  114.     switch (method) {
  115.     case IPC_M_SHARE_OUT:
  116.     case IPC_M_SHARE_IN:
  117.     case IPC_M_DATA_WRITE:
  118.     case IPC_M_DATA_READ:
  119.         return 1;
  120.         break;
  121.     default:
  122.         return 0;
  123.     }
  124. }
  125.  
  126.  
  127. /***********************************************************************
  128.  * Functions that preprocess answer before sending it to the recepient.
  129.  ***********************************************************************/
  130.  
  131. /** Decide if the caller (e.g. ipc_answer()) should save the old call contents
  132.  * for answer_preprocess().
  133.  *
  134.  * @param call      Call structure to be decided.
  135.  *
  136.  * @return      Return 1 if the old call contents should be saved.
  137.  *          Return 0 otherwise.
  138.  */
  139. static inline int answer_need_old(call_t *call)
  140. {
  141.     switch (IPC_GET_METHOD(call->data)) {
  142.     case IPC_M_CONNECT_TO_ME:
  143.     case IPC_M_CONNECT_ME_TO:
  144.     case IPC_M_SHARE_OUT:
  145.     case IPC_M_SHARE_IN:
  146.     case IPC_M_DATA_WRITE:
  147.     case IPC_M_DATA_READ:
  148.         return 1;
  149.     default:
  150.         return 0;
  151.     }
  152. }
  153.  
  154. /** Interpret process answer as control information.
  155.  *
  156.  * This function is called directly after sys_ipc_answer().
  157.  *
  158.  * @param answer    Call structure with the answer.
  159.  * @param olddata   Saved data of the request.
  160.  *
  161.  * @return      Return 0 on success or an error code.
  162.  */
  163. static inline int answer_preprocess(call_t *answer, ipc_data_t *olddata)
  164. {
  165.     int phoneid;
  166.  
  167.     if ((native_t) IPC_GET_RETVAL(answer->data) == EHANGUP) {
  168.         /* In case of forward, hangup the forwared phone,
  169.          * not the originator
  170.          */
  171.         spinlock_lock(&answer->data.phone->lock);
  172.         spinlock_lock(&TASK->answerbox.lock);
  173.         if (answer->data.phone->state == IPC_PHONE_CONNECTED) {
  174.             list_remove(&answer->data.phone->link);
  175.             answer->data.phone->state = IPC_PHONE_SLAMMED;
  176.         }
  177.         spinlock_unlock(&TASK->answerbox.lock);
  178.         spinlock_unlock(&answer->data.phone->lock);
  179.     }
  180.  
  181.     if (!olddata)
  182.         return 0;
  183.  
  184.     if (IPC_GET_METHOD(*olddata) == IPC_M_CONNECT_TO_ME) {
  185.         phoneid = IPC_GET_ARG5(*olddata);
  186.         if (IPC_GET_RETVAL(answer->data)) {
  187.             /* The connection was not accepted */
  188.             phone_dealloc(phoneid);
  189.         } else {
  190.             /* The connection was accepted */
  191.             phone_connect(phoneid, &answer->sender->answerbox);
  192.             /* Set 'phone hash' as arg5 of response */
  193.             IPC_SET_ARG5(answer->data,
  194.                 (unative_t) &TASK->phones[phoneid]);
  195.         }
  196.     } else if (IPC_GET_METHOD(*olddata) == IPC_M_CONNECT_ME_TO) {
  197.         /* If the users accepted call, connect */
  198.         if (!IPC_GET_RETVAL(answer->data)) {
  199.             ipc_phone_connect((phone_t *) IPC_GET_ARG5(*olddata),
  200.                 &TASK->answerbox);
  201.         }
  202.     } else if (IPC_GET_METHOD(*olddata) == IPC_M_SHARE_OUT) {
  203.         if (!IPC_GET_RETVAL(answer->data)) {
  204.             /* Accepted, handle as_area receipt */
  205.             ipl_t ipl;
  206.             int rc;
  207.             as_t *as;
  208.            
  209.             ipl = interrupts_disable();
  210.             spinlock_lock(&answer->sender->lock);
  211.             as = answer->sender->as;
  212.             spinlock_unlock(&answer->sender->lock);
  213.             interrupts_restore(ipl);
  214.            
  215.             rc = as_area_share(as, IPC_GET_ARG1(*olddata),
  216.                 IPC_GET_ARG2(*olddata), AS,
  217.                 IPC_GET_ARG1(answer->data), IPC_GET_ARG3(*olddata));
  218.             IPC_SET_RETVAL(answer->data, rc);
  219.             return rc;
  220.         }
  221.     } else if (IPC_GET_METHOD(*olddata) == IPC_M_SHARE_IN) {
  222.         if (!IPC_GET_RETVAL(answer->data)) {
  223.             ipl_t ipl;
  224.             as_t *as;
  225.             int rc;
  226.            
  227.             ipl = interrupts_disable();
  228.             spinlock_lock(&answer->sender->lock);
  229.             as = answer->sender->as;
  230.             spinlock_unlock(&answer->sender->lock);
  231.             interrupts_restore(ipl);
  232.            
  233.             rc = as_area_share(AS, IPC_GET_ARG1(answer->data),
  234.                 IPC_GET_ARG2(*olddata), as, IPC_GET_ARG1(*olddata),
  235.                 IPC_GET_ARG2(answer->data));
  236.             IPC_SET_RETVAL(answer->data, rc);
  237.         }
  238.     } else if (IPC_GET_METHOD(*olddata) == IPC_M_DATA_READ) {
  239.         ASSERT(!answer->buffer);
  240.         if (!IPC_GET_RETVAL(answer->data)) {
  241.             /* The recipient agreed to send data. */
  242.             uintptr_t src = IPC_GET_ARG1(answer->data);
  243.             uintptr_t dst = IPC_GET_ARG1(*olddata);
  244.             size_t max_size = IPC_GET_ARG2(*olddata);
  245.             size_t size = IPC_GET_ARG2(answer->data);
  246.             if (size <= max_size) {
  247.                 /*
  248.                  * Copy the destination VA so that this piece of
  249.                  * information is not lost.
  250.                  */
  251.                 IPC_SET_ARG1(answer->data, dst);
  252.  
  253.                 answer->buffer = malloc(size, 0);
  254.                 int rc = copy_from_uspace(answer->buffer,
  255.                     (void *) src, size);
  256.                 if (rc) {
  257.                     IPC_SET_RETVAL(answer->data, rc);
  258.                     free(answer->buffer);
  259.                     answer->buffer = NULL;
  260.                 }
  261.             } else {
  262.                 IPC_SET_RETVAL(answer->data, ELIMIT);
  263.             }
  264.         }
  265.     } else if (IPC_GET_METHOD(*olddata) == IPC_M_DATA_WRITE) {
  266.         ASSERT(answer->buffer);
  267.         if (!IPC_GET_RETVAL(answer->data)) {
  268.             /* The recipient agreed to receive data. */
  269.             int rc;
  270.             uintptr_t dst;
  271.             uintptr_t size;
  272.             uintptr_t max_size;
  273.  
  274.             dst = IPC_GET_ARG1(answer->data);
  275.             size = IPC_GET_ARG2(answer->data);
  276.             max_size = IPC_GET_ARG2(*olddata);
  277.  
  278.             if (size <= max_size) {
  279.                 rc = copy_to_uspace((void *) dst,
  280.                     answer->buffer, size);
  281.                 if (rc)
  282.                     IPC_SET_RETVAL(answer->data, rc);
  283.             } else {
  284.                 IPC_SET_RETVAL(answer->data, ELIMIT);
  285.             }
  286.         }
  287.         free(answer->buffer);
  288.         answer->buffer = NULL;
  289.     }
  290.     return 0;
  291. }
  292.  
  293. /** Called before the request is sent.
  294.  *
  295.  * @param call      Call structure with the request.
  296.  *
  297.  * @return      Return 0 on success, ELIMIT or EPERM on error.
  298.  */
  299. static int request_preprocess(call_t *call)
  300. {
  301.     int newphid;
  302.     size_t size;
  303.     uintptr_t src;
  304.     int rc;
  305.  
  306.     switch (IPC_GET_METHOD(call->data)) {
  307.     case IPC_M_CONNECT_ME_TO:
  308.         newphid = phone_alloc();
  309.         if (newphid < 0)
  310.             return ELIMIT;
  311.         /* Set arg5 for server */
  312.         IPC_SET_ARG5(call->data, (unative_t) &TASK->phones[newphid]);
  313.         call->flags |= IPC_CALL_CONN_ME_TO;
  314.         call->priv = newphid;
  315.         break;
  316.     case IPC_M_SHARE_OUT:
  317.         size = as_area_get_size(IPC_GET_ARG1(call->data));
  318.         if (!size)
  319.             return EPERM;
  320.         IPC_SET_ARG2(call->data, size);
  321.         break;
  322.     case IPC_M_DATA_READ:
  323.         size = IPC_GET_ARG2(call->data);
  324.         if ((size <= 0 || (size > DATA_XFER_LIMIT)))
  325.             return ELIMIT;
  326.         break;
  327.     case IPC_M_DATA_WRITE:
  328.         src = IPC_GET_ARG1(call->data);
  329.         size = IPC_GET_ARG2(call->data);
  330.        
  331.         if ((size <= 0) || (size > DATA_XFER_LIMIT))
  332.             return ELIMIT;
  333.        
  334.         call->buffer = (uint8_t *) malloc(size, 0);
  335.         rc = copy_from_uspace(call->buffer, (void *) src, size);
  336.         if (rc != 0) {
  337.             free(call->buffer);
  338.             return rc;
  339.         }
  340.         break;
  341.     default:
  342.         break;
  343.     }
  344.     return 0;
  345. }
  346.  
  347. /*******************************************************************************
  348.  * Functions called to process received call/answer before passing it to uspace.
  349.  *******************************************************************************/
  350.  
  351. /** Do basic kernel processing of received call answer.
  352.  *
  353.  * @param call      Call structure with the answer.
  354.  */
  355. static void process_answer(call_t *call)
  356. {
  357.     if (((native_t) IPC_GET_RETVAL(call->data) == EHANGUP) &&
  358.         (call->flags & IPC_CALL_FORWARDED))
  359.         IPC_SET_RETVAL(call->data, EFORWARD);
  360.  
  361.     if (call->flags & IPC_CALL_CONN_ME_TO) {
  362.         if (IPC_GET_RETVAL(call->data))
  363.             phone_dealloc(call->priv);
  364.         else
  365.             IPC_SET_ARG5(call->data, call->priv);
  366.     }
  367.  
  368.     if (call->buffer) {
  369.         /* This must be an affirmative answer to IPC_M_DATA_READ. */
  370.         uintptr_t dst = IPC_GET_ARG1(call->data);
  371.         size_t size = IPC_GET_ARG2(call->data);
  372.         int rc = copy_to_uspace((void *) dst, call->buffer, size);
  373.         if (rc)
  374.             IPC_SET_RETVAL(call->data, rc);
  375.         free(call->buffer);
  376.         call->buffer = NULL;
  377.     }
  378. }
  379.  
  380. /** Do basic kernel processing of received call request.
  381.  *
  382.  * @param box       Destination answerbox structure.
  383.  * @param call      Call structure with the request.
  384.  *
  385.  * @return      Return 0 if the call should be passed to userspace.
  386.  *          Return -1 if the call should be ignored.
  387.  */
  388. static int process_request(answerbox_t *box, call_t *call)
  389. {
  390.     int phoneid;
  391.  
  392.     if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_TO_ME) {
  393.         phoneid = phone_alloc();
  394.         if (phoneid < 0) { /* Failed to allocate phone */
  395.             IPC_SET_RETVAL(call->data, ELIMIT);
  396.             ipc_answer(box, call);
  397.             return -1;
  398.         }
  399.         IPC_SET_ARG5(call->data, phoneid);
  400.     }
  401.     return 0;
  402. }
  403.  
  404. /** Make a fast call over IPC, wait for reply and return to user.
  405.  *
  406.  * This function can handle only three arguments of payload, but is faster than
  407.  * the generic function (i.e. sys_ipc_call_sync_slow()).
  408.  *
  409.  * @param phoneid   Phone handle for the call.
  410.  * @param method    Method of the call.
  411.  * @param arg1      Service-defined payload argument.
  412.  * @param arg2      Service-defined payload argument.
  413.  * @param arg3      Service-defined payload argument.
  414.  * @param data      Address of userspace structure where the reply call will
  415.  *          be stored.
  416.  *
  417.  * @return      Returns 0 on success.
  418.  *          Return ENOENT if there is no such phone handle.
  419.  */
  420. unative_t sys_ipc_call_sync_fast(unative_t phoneid, unative_t method,
  421.     unative_t arg1, unative_t arg2, unative_t arg3, ipc_data_t *data)
  422. {
  423.     call_t call;
  424.     phone_t *phone;
  425.     int res;
  426.     int rc;
  427.  
  428.     GET_CHECK_PHONE(phone, phoneid, return ENOENT);
  429.  
  430.     ipc_call_static_init(&call);
  431.     IPC_SET_METHOD(call.data, method);
  432.     IPC_SET_ARG1(call.data, arg1);
  433.     IPC_SET_ARG2(call.data, arg2);
  434.     IPC_SET_ARG3(call.data, arg3);
  435.     /*
  436.      * To achieve deterministic behavior, zero out arguments that are beyond
  437.      * the limits of the fast version.
  438.      */
  439.     IPC_SET_ARG4(call.data, 0);
  440.     IPC_SET_ARG5(call.data, 0);
  441.  
  442.     if (!(res = request_preprocess(&call))) {
  443.         ipc_call_sync(phone, &call);
  444.         process_answer(&call);
  445.     } else {
  446.         IPC_SET_RETVAL(call.data, res);
  447.     }
  448.     rc = STRUCT_TO_USPACE(&data->args, &call.data.args);
  449.     if (rc != 0)
  450.         return rc;
  451.  
  452.     return 0;
  453. }
  454.  
  455. /** Make a synchronous IPC call allowing to transmit the entire payload.
  456.  *
  457.  * @param phoneid   Phone handle for the call.
  458.  * @param question  Userspace address of call data with the request.
  459.  * @param reply     Userspace address of call data where to store the
  460.  *          answer.
  461.  *
  462.  * @return      Zero on success or an error code.
  463.  */
  464. unative_t sys_ipc_call_sync_slow(unative_t phoneid, ipc_data_t *question,
  465.     ipc_data_t *reply)
  466. {
  467.     call_t call;
  468.     phone_t *phone;
  469.     int res;
  470.     int rc;
  471.  
  472.     ipc_call_static_init(&call);
  473.     rc = copy_from_uspace(&call.data.args, &question->args,
  474.         sizeof(call.data.args));
  475.     if (rc != 0)
  476.         return (unative_t) rc;
  477.  
  478.     GET_CHECK_PHONE(phone, phoneid, return ENOENT);
  479.  
  480.     if (!(res = request_preprocess(&call))) {
  481.         ipc_call_sync(phone, &call);
  482.         process_answer(&call);
  483.     } else
  484.         IPC_SET_RETVAL(call.data, res);
  485.  
  486.     rc = STRUCT_TO_USPACE(&reply->args, &call.data.args);
  487.     if (rc != 0)
  488.         return rc;
  489.  
  490.     return 0;
  491. }
  492.  
  493. /** Check that the task did not exceed the allowed limit of asynchronous calls.
  494.  *
  495.  * @return      Return 0 if limit not reached or -1 if limit exceeded.
  496.  */
  497. static int check_call_limit(void)
  498. {
  499.     if (atomic_preinc(&TASK->active_calls) > IPC_MAX_ASYNC_CALLS) {
  500.         atomic_dec(&TASK->active_calls);
  501.         return -1;
  502.     }
  503.     return 0;
  504. }
  505.  
  506. /** Make a fast asynchronous call over IPC.
  507.  *
  508.  * This function can only handle four arguments of payload, but is faster than
  509.  * the generic function sys_ipc_call_async_slow().
  510.  *
  511.  * @param phoneid   Phone handle for the call.
  512.  * @param method    Method of the call.
  513.  * @param arg1      Service-defined payload argument.
  514.  * @param arg2      Service-defined payload argument.
  515.  * @param arg3      Service-defined payload argument.
  516.  * @param arg4      Service-defined payload argument.
  517.  *
  518.  * @return      Return call hash on success.
  519.  *          Return IPC_CALLRET_FATAL in case of a fatal error and
  520.  *          IPC_CALLRET_TEMPORARY if there are too many pending
  521.  *          asynchronous requests; answers should be handled first.
  522.  */
  523. unative_t sys_ipc_call_async_fast(unative_t phoneid, unative_t method,
  524.     unative_t arg1, unative_t arg2, unative_t arg3, unative_t arg4)
  525. {
  526.     call_t *call;
  527.     phone_t *phone;
  528.     int res;
  529.  
  530.     if (check_call_limit())
  531.         return IPC_CALLRET_TEMPORARY;
  532.  
  533.     GET_CHECK_PHONE(phone, phoneid, return IPC_CALLRET_FATAL);
  534.  
  535.     call = ipc_call_alloc(0);
  536.     IPC_SET_METHOD(call->data, method);
  537.     IPC_SET_ARG1(call->data, arg1);
  538.     IPC_SET_ARG2(call->data, arg2);
  539.     IPC_SET_ARG3(call->data, arg3);
  540.     IPC_SET_ARG4(call->data, arg4);
  541.     /*
  542.      * To achieve deterministic behavior, zero out arguments that are beyond
  543.      * the limits of the fast version.
  544.      */
  545.     IPC_SET_ARG5(call->data, 0);
  546.  
  547.     if (!(res = request_preprocess(call)))
  548.         ipc_call(phone, call);
  549.     else
  550.         ipc_backsend_err(phone, call, res);
  551.  
  552.     return (unative_t) call;
  553. }
  554.  
  555. /** Make an asynchronous IPC call allowing to transmit the entire payload.
  556.  *
  557.  * @param phoneid   Phone handle for the call.
  558.  * @param data      Userspace address of call data with the request.
  559.  *
  560.  * @return      See sys_ipc_call_async_fast().
  561.  */
  562. unative_t sys_ipc_call_async_slow(unative_t phoneid, ipc_data_t *data)
  563. {
  564.     call_t *call;
  565.     phone_t *phone;
  566.     int res;
  567.     int rc;
  568.  
  569.     if (check_call_limit())
  570.         return IPC_CALLRET_TEMPORARY;
  571.  
  572.     GET_CHECK_PHONE(phone, phoneid, return IPC_CALLRET_FATAL);
  573.  
  574.     call = ipc_call_alloc(0);
  575.     rc = copy_from_uspace(&call->data.args, &data->args,
  576.         sizeof(call->data.args));
  577.     if (rc != 0) {
  578.         ipc_call_free(call);
  579.         return (unative_t) rc;
  580.     }
  581.     if (!(res = request_preprocess(call)))
  582.         ipc_call(phone, call);
  583.     else
  584.         ipc_backsend_err(phone, call, res);
  585.  
  586.     return (unative_t) call;
  587. }
  588.  
  589. /** Forward a received call to another destination.
  590.  *
  591.  * @param callid    Hash of the call to forward.
  592.  * @param phoneid   Phone handle to use for forwarding.
  593.  * @param method    New method to use for the forwarded call.
  594.  * @param arg1      New value of the first argument for the forwarded call.
  595.  * @param arg2      New value of the second argument for the forwarded call.
  596.  * @param mode      Flags that specify mode of the forward operation.
  597.  *
  598.  * @return      Return 0 on succes, otherwise return an error code.
  599.  *
  600.  * In case the original method is a system method, ARG1, ARG2 and ARG3 are
  601.  * overwritten in the forwarded message with the new method and the new arg1 and
  602.  * arg2, respectively. Otherwise the METHOD, ARG1 and ARG2 are rewritten with
  603.  * the new method, arg1 and arg2, respectively. Also note there is a set of
  604.  * immutable methods, for which the new method and argument is not set and
  605.  * these values are ignored.
  606.  *
  607.  * Warning: When implementing support for changing additional payload
  608.  *      arguments, make sure that ARG5 is not rewritten for certain
  609.  *      system IPC
  610.  */
  611. unative_t sys_ipc_forward_fast(unative_t callid, unative_t phoneid,
  612.     unative_t method, unative_t arg1, unative_t arg2, int mode)
  613. {
  614.     call_t *call;
  615.     phone_t *phone;
  616.  
  617.     call = get_call(callid);
  618.     if (!call)
  619.         return ENOENT;
  620.  
  621.     call->flags |= IPC_CALL_FORWARDED;
  622.  
  623.     GET_CHECK_PHONE(phone, phoneid, {
  624.         IPC_SET_RETVAL(call->data, EFORWARD);
  625.         ipc_answer(&TASK->answerbox, call);
  626.         return ENOENT;
  627.     });    
  628.  
  629.     if (!method_is_forwardable(IPC_GET_METHOD(call->data))) {
  630.         IPC_SET_RETVAL(call->data, EFORWARD);
  631.         ipc_answer(&TASK->answerbox, call);
  632.         return EPERM;
  633.     }
  634.  
  635.     /*
  636.      * Userspace is not allowed to change method of system methods on
  637.      * forward, allow changing ARG1, ARG2 and ARG3 by means of method,
  638.      * arg1 and arg2.
  639.      * If the method is immutable, don't change anything.
  640.      */
  641.     if (!method_is_immutable(IPC_GET_METHOD(call->data))) {
  642.         if (method_is_system(IPC_GET_METHOD(call->data))) {
  643.             if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_TO_ME)
  644.                 phone_dealloc(IPC_GET_ARG5(call->data));
  645.  
  646.             IPC_SET_ARG1(call->data, method);
  647.             IPC_SET_ARG2(call->data, arg1);
  648.             IPC_SET_ARG3(call->data, arg2);
  649.         } else {
  650.             IPC_SET_METHOD(call->data, method);
  651.             IPC_SET_ARG1(call->data, arg1);
  652.             IPC_SET_ARG2(call->data, arg2);
  653.         }
  654.     }
  655.  
  656.     return ipc_forward(call, phone, &TASK->answerbox, mode);
  657. }
  658.  
  659. /** Answer an IPC call - fast version.
  660.  *
  661.  * This function can handle only two return arguments of payload, but is faster
  662.  * than the generic sys_ipc_answer().
  663.  *
  664.  * @param callid    Hash of the call to be answered.
  665.  * @param retval    Return value of the answer.
  666.  * @param arg1      Service-defined return value.
  667.  * @param arg2      Service-defined return value.
  668.  * @param arg3      Service-defined return value.
  669.  * @param arg4      Service-defined return value.
  670.  *
  671.  * @return      Return 0 on success, otherwise return an error code.   
  672.  */
  673. unative_t sys_ipc_answer_fast(unative_t callid, unative_t retval,
  674.     unative_t arg1, unative_t arg2, unative_t arg3, unative_t arg4)
  675. {
  676.     call_t *call;
  677.     ipc_data_t saved_data;
  678.     int saveddata = 0;
  679.     int rc;
  680.  
  681.     /* Do not answer notification callids */
  682.     if (callid & IPC_CALLID_NOTIFICATION)
  683.         return 0;
  684.  
  685.     call = get_call(callid);
  686.     if (!call)
  687.         return ENOENT;
  688.  
  689.     if (answer_need_old(call)) {
  690.         memcpy(&saved_data, &call->data, sizeof(call->data));
  691.         saveddata = 1;
  692.     }
  693.  
  694.     IPC_SET_RETVAL(call->data, retval);
  695.     IPC_SET_ARG1(call->data, arg1);
  696.     IPC_SET_ARG2(call->data, arg2);
  697.     IPC_SET_ARG3(call->data, arg3);
  698.     IPC_SET_ARG4(call->data, arg4);
  699.     /*
  700.      * To achieve deterministic behavior, zero out arguments that are beyond
  701.      * the limits of the fast version.
  702.      */
  703.     IPC_SET_ARG5(call->data, 0);
  704.     rc = answer_preprocess(call, saveddata ? &saved_data : NULL);
  705.  
  706.     ipc_answer(&TASK->answerbox, call);
  707.     return rc;
  708. }
  709.  
  710. /** Answer an IPC call.
  711.  *
  712.  * @param callid    Hash of the call to be answered.
  713.  * @param data      Userspace address of call data with the answer.
  714.  *
  715.  * @return      Return 0 on success, otherwise return an error code.
  716.  */
  717. unative_t sys_ipc_answer_slow(unative_t callid, ipc_data_t *data)
  718. {
  719.     call_t *call;
  720.     ipc_data_t saved_data;
  721.     int saveddata = 0;
  722.     int rc;
  723.  
  724.     /* Do not answer notification callids */
  725.     if (callid & IPC_CALLID_NOTIFICATION)
  726.         return 0;
  727.  
  728.     call = get_call(callid);
  729.     if (!call)
  730.         return ENOENT;
  731.  
  732.     if (answer_need_old(call)) {
  733.         memcpy(&saved_data, &call->data, sizeof(call->data));
  734.         saveddata = 1;
  735.     }
  736.     rc = copy_from_uspace(&call->data.args, &data->args,
  737.         sizeof(call->data.args));
  738.     if (rc != 0)
  739.         return rc;
  740.  
  741.     rc = answer_preprocess(call, saveddata ? &saved_data : NULL);
  742.    
  743.     ipc_answer(&TASK->answerbox, call);
  744.  
  745.     return rc;
  746. }
  747.  
  748. /** Hang up a phone.
  749.  *
  750.  * @param       Phone handle of the phone to be hung up.
  751.  *
  752.  * @return      Return 0 on success or an error code.
  753.  */
  754. unative_t sys_ipc_hangup(int phoneid)
  755. {
  756.     phone_t *phone;
  757.  
  758.     GET_CHECK_PHONE(phone, phoneid, return ENOENT);
  759.  
  760.     if (ipc_phone_hangup(phone))
  761.         return -1;
  762.  
  763.     return 0;
  764. }
  765.  
  766. /** Wait for an incoming IPC call or an answer.
  767.  *
  768.  * @param calldata  Pointer to buffer where the call/answer data is stored.
  769.  * @param usec      Timeout. See waitq_sleep_timeout() for explanation.
  770.  * @param flags     Select mode of sleep operation. See waitq_sleep_timeout()
  771.  *          for explanation.
  772.  *
  773.  * @return      Hash of the call.
  774.  *          If IPC_CALLID_NOTIFICATION bit is set in the hash, the
  775.  *          call is a notification. IPC_CALLID_ANSWERED denotes an
  776.  *          answer.
  777.  */
  778. unative_t sys_ipc_wait_for_call(ipc_data_t *calldata, uint32_t usec, int flags)
  779. {
  780.     call_t *call;
  781.  
  782. restart:   
  783.     call = ipc_wait_for_call(&TASK->answerbox, usec,
  784.         flags | SYNCH_FLAGS_INTERRUPTIBLE);
  785.     if (!call)
  786.         return 0;
  787.  
  788.     if (call->flags & IPC_CALL_NOTIF) {
  789.         ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
  790.  
  791.         /* Set in_phone_hash to the interrupt counter */
  792.         call->data.phone = (void *) call->priv;
  793.        
  794.         STRUCT_TO_USPACE(calldata, &call->data);
  795.  
  796.         ipc_call_free(call);
  797.        
  798.         return ((unative_t) call) | IPC_CALLID_NOTIFICATION;
  799.     }
  800.  
  801.     if (call->flags & IPC_CALL_ANSWERED) {
  802.         process_answer(call);
  803.  
  804.         ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
  805.  
  806.         atomic_dec(&TASK->active_calls);
  807.  
  808.         if (call->flags & IPC_CALL_DISCARD_ANSWER) {
  809.             ipc_call_free(call);
  810.             goto restart;
  811.         }
  812.  
  813.         STRUCT_TO_USPACE(&calldata->args, &call->data.args);
  814.         ipc_call_free(call);
  815.  
  816.         return ((unative_t) call) | IPC_CALLID_ANSWERED;
  817.     }
  818.  
  819.     if (process_request(&TASK->answerbox, call))
  820.         goto restart;
  821.  
  822.     /* Include phone address('id') of the caller in the request,
  823.      * copy whole call->data, not only call->data.args */
  824.     if (STRUCT_TO_USPACE(calldata, &call->data)) {
  825.         return 0;
  826.     }
  827.     return (unative_t)call;
  828. }
  829.  
  830. /** Connect an IRQ handler to a task.
  831.  *
  832.  * @param inr       IRQ number.
  833.  * @param devno     Device number.
  834.  * @param method    Method to be associated with the notification.
  835.  * @param ucode     Uspace pointer to the top-half pseudocode.
  836.  *
  837.  * @return      EPERM or a return code returned by ipc_irq_register().
  838.  */
  839. unative_t sys_ipc_register_irq(inr_t inr, devno_t devno, unative_t method,
  840.     irq_code_t *ucode)
  841. {
  842.     if (!(cap_get(TASK) & CAP_IRQ_REG))
  843.         return EPERM;
  844.  
  845.     return ipc_irq_register(&TASK->answerbox, inr, devno, method, ucode);
  846. }
  847.  
  848. /** Disconnect an IRQ handler from a task.
  849.  *
  850.  * @param inr       IRQ number.
  851.  * @param devno     Device number.
  852.  *
  853.  * @return      Zero on success or EPERM on error..
  854.  */
  855. unative_t sys_ipc_unregister_irq(inr_t inr, devno_t devno)
  856. {
  857.     if (!(cap_get(TASK) & CAP_IRQ_REG))
  858.         return EPERM;
  859.  
  860.     ipc_irq_unregister(&TASK->answerbox, inr, devno);
  861.  
  862.     return 0;
  863. }
  864.  
  865. /** @}
  866.  */
  867.