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      1 /*
      2  *
      3  * Copyright 2015 gRPC authors.
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  *
     17  */
     18 
     19 #ifndef GRPC_CORE_LIB_IOMGR_EV_POSIX_H
     20 #define GRPC_CORE_LIB_IOMGR_EV_POSIX_H
     21 
     22 #include <grpc/support/port_platform.h>
     23 
     24 #include <poll.h>
     25 
     26 #include "src/core/lib/debug/trace.h"
     27 #include "src/core/lib/iomgr/exec_ctx.h"
     28 #include "src/core/lib/iomgr/pollset.h"
     29 #include "src/core/lib/iomgr/pollset_set.h"
     30 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
     31 
     32 extern grpc_core::TraceFlag grpc_fd_trace;      /* Disabled by default */
     33 extern grpc_core::TraceFlag grpc_polling_trace; /* Disabled by default */
     34 
     35 #define GRPC_FD_TRACE(format, ...)                        \
     36   if (grpc_fd_trace.enabled()) {                          \
     37     gpr_log(GPR_INFO, "(fd-trace) " format, __VA_ARGS__); \
     38   }
     39 
     40 typedef struct grpc_fd grpc_fd;
     41 
     42 typedef struct grpc_event_engine_vtable {
     43   size_t pollset_size;
     44   bool can_track_err;
     45 
     46   grpc_fd* (*fd_create)(int fd, const char* name, bool track_err);
     47   int (*fd_wrapped_fd)(grpc_fd* fd);
     48   void (*fd_orphan)(grpc_fd* fd, grpc_closure* on_done, int* release_fd,
     49                     const char* reason);
     50   void (*fd_shutdown)(grpc_fd* fd, grpc_error* why);
     51   void (*fd_notify_on_read)(grpc_fd* fd, grpc_closure* closure);
     52   void (*fd_notify_on_write)(grpc_fd* fd, grpc_closure* closure);
     53   void (*fd_notify_on_error)(grpc_fd* fd, grpc_closure* closure);
     54   void (*fd_set_readable)(grpc_fd* fd);
     55   void (*fd_set_writable)(grpc_fd* fd);
     56   void (*fd_set_error)(grpc_fd* fd);
     57   bool (*fd_is_shutdown)(grpc_fd* fd);
     58 
     59   void (*pollset_init)(grpc_pollset* pollset, gpr_mu** mu);
     60   void (*pollset_shutdown)(grpc_pollset* pollset, grpc_closure* closure);
     61   void (*pollset_destroy)(grpc_pollset* pollset);
     62   grpc_error* (*pollset_work)(grpc_pollset* pollset,
     63                               grpc_pollset_worker** worker,
     64                               grpc_millis deadline);
     65   grpc_error* (*pollset_kick)(grpc_pollset* pollset,
     66                               grpc_pollset_worker* specific_worker);
     67   void (*pollset_add_fd)(grpc_pollset* pollset, struct grpc_fd* fd);
     68 
     69   grpc_pollset_set* (*pollset_set_create)(void);
     70   void (*pollset_set_destroy)(grpc_pollset_set* pollset_set);
     71   void (*pollset_set_add_pollset)(grpc_pollset_set* pollset_set,
     72                                   grpc_pollset* pollset);
     73   void (*pollset_set_del_pollset)(grpc_pollset_set* pollset_set,
     74                                   grpc_pollset* pollset);
     75   void (*pollset_set_add_pollset_set)(grpc_pollset_set* bag,
     76                                       grpc_pollset_set* item);
     77   void (*pollset_set_del_pollset_set)(grpc_pollset_set* bag,
     78                                       grpc_pollset_set* item);
     79   void (*pollset_set_add_fd)(grpc_pollset_set* pollset_set, grpc_fd* fd);
     80   void (*pollset_set_del_fd)(grpc_pollset_set* pollset_set, grpc_fd* fd);
     81 
     82   void (*shutdown_engine)(void);
     83 } grpc_event_engine_vtable;
     84 
     85 /* register a new event engine factory */
     86 void grpc_register_event_engine_factory(
     87     const char* name, const grpc_event_engine_vtable* (*factory)(bool),
     88     bool add_at_head);
     89 
     90 void grpc_event_engine_init(void);
     91 void grpc_event_engine_shutdown(void);
     92 
     93 /* Return the name of the poll strategy */
     94 const char* grpc_get_poll_strategy_name();
     95 
     96 /* Returns true if polling engine can track errors separately, false otherwise.
     97  * If this is true, fd can be created with track_err set. After this, error
     98  * events will be reported using fd_notify_on_error. If it is not set, errors
     99  * will continue to be reported through fd_notify_on_read and
    100  * fd_notify_on_write.
    101  */
    102 bool grpc_event_engine_can_track_errors();
    103 
    104 /* Create a wrapped file descriptor.
    105    Requires fd is a non-blocking file descriptor.
    106    \a track_err if true means that error events would be tracked separately
    107    using grpc_fd_notify_on_error. Currently, valid only for linux systems.
    108    This takes ownership of closing fd. */
    109 grpc_fd* grpc_fd_create(int fd, const char* name, bool track_err);
    110 
    111 /* Return the wrapped fd, or -1 if it has been released or closed. */
    112 int grpc_fd_wrapped_fd(grpc_fd* fd);
    113 
    114 /* Releases fd to be asynchronously destroyed.
    115    on_done is called when the underlying file descriptor is definitely close()d.
    116    If on_done is NULL, no callback will be made.
    117    If release_fd is not NULL, it's set to fd and fd will not be closed.
    118    Requires: *fd initialized; no outstanding notify_on_read or
    119    notify_on_write.
    120    MUST NOT be called with a pollset lock taken */
    121 void grpc_fd_orphan(grpc_fd* fd, grpc_closure* on_done, int* release_fd,
    122                     const char* reason);
    123 
    124 /* Has grpc_fd_shutdown been called on an fd? */
    125 bool grpc_fd_is_shutdown(grpc_fd* fd);
    126 
    127 /* Cause any current and future callbacks to fail. */
    128 void grpc_fd_shutdown(grpc_fd* fd, grpc_error* why);
    129 
    130 /* Register read interest, causing read_cb to be called once when fd becomes
    131    readable, on deadline specified by deadline, or on shutdown triggered by
    132    grpc_fd_shutdown.
    133    read_cb will be called with read_cb_arg when *fd becomes readable.
    134    read_cb is Called with status of GRPC_CALLBACK_SUCCESS if readable,
    135    GRPC_CALLBACK_TIMED_OUT if the call timed out,
    136    and CANCELLED if the call was cancelled.
    137 
    138    Requires:This method must not be called before the read_cb for any previous
    139    call runs. Edge triggered events are used whenever they are supported by the
    140    underlying platform. This means that users must drain fd in read_cb before
    141    calling notify_on_read again. Users are also expected to handle spurious
    142    events, i.e read_cb is called while nothing can be readable from fd  */
    143 void grpc_fd_notify_on_read(grpc_fd* fd, grpc_closure* closure);
    144 
    145 /* Exactly the same semantics as above, except based on writable events.  */
    146 void grpc_fd_notify_on_write(grpc_fd* fd, grpc_closure* closure);
    147 
    148 /* Exactly the same semantics as above, except based on error events. track_err
    149  * needs to have been set on grpc_fd_create */
    150 void grpc_fd_notify_on_error(grpc_fd* fd, grpc_closure* closure);
    151 
    152 /* Forcibly set the fd to be readable, resulting in the closure registered with
    153  * grpc_fd_notify_on_read being invoked.
    154  */
    155 void grpc_fd_set_readable(grpc_fd* fd);
    156 
    157 /* Forcibly set the fd to be writable, resulting in the closure registered with
    158  * grpc_fd_notify_on_write being invoked.
    159  */
    160 void grpc_fd_set_writable(grpc_fd* fd);
    161 
    162 /* Forcibly set the fd to have errored, resulting in the closure registered with
    163  * grpc_fd_notify_on_error being invoked.
    164  */
    165 void grpc_fd_set_error(grpc_fd* fd);
    166 
    167 /* pollset_posix functions */
    168 
    169 /* Add an fd to a pollset */
    170 void grpc_pollset_add_fd(grpc_pollset* pollset, struct grpc_fd* fd);
    171 
    172 /* pollset_set_posix functions */
    173 
    174 void grpc_pollset_set_add_fd(grpc_pollset_set* pollset_set, grpc_fd* fd);
    175 void grpc_pollset_set_del_fd(grpc_pollset_set* pollset_set, grpc_fd* fd);
    176 
    177 /* override to allow tests to hook poll() usage */
    178 typedef int (*grpc_poll_function_type)(struct pollfd*, nfds_t, int);
    179 extern grpc_poll_function_type grpc_poll_function;
    180 
    181 #endif /* GRPC_CORE_LIB_IOMGR_EV_POSIX_H */
    182