[25] | 1 | /* |
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| 2 | * tclUnixNotify.c -- |
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| 3 | * |
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| 4 | * This file contains the implementation of the select()-based |
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| 5 | * Unix-specific notifier, which is the lowest-level part of the Tcl |
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| 6 | * event loop. This file works together with generic/tclNotify.c. |
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| 7 | * |
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| 8 | * Copyright (c) 1995-1997 Sun Microsystems, Inc. |
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| 9 | * |
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| 10 | * See the file "license.terms" for information on usage and redistribution of |
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| 11 | * this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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| 12 | * |
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| 13 | * RCS: @(#) $Id: tclUnixNotfy.c,v 1.34 2008/03/11 22:23:50 das Exp $ |
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| 14 | */ |
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| 15 | |
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| 16 | #include "tclInt.h" |
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| 17 | #ifndef HAVE_COREFOUNDATION /* Darwin/Mac OS X CoreFoundation notifier is |
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| 18 | * in tclMacOSXNotify.c */ |
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| 19 | #include <signal.h> |
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| 20 | |
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| 21 | /* |
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| 22 | * This code does deep stub magic to allow replacement of the notifier at |
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| 23 | * runtime. |
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| 24 | */ |
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| 25 | |
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| 26 | extern TclStubs tclStubs; |
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| 27 | extern Tcl_NotifierProcs tclOriginalNotifier; |
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| 28 | |
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| 29 | /* |
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| 30 | * This structure is used to keep track of the notifier info for a registered |
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| 31 | * file. |
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| 32 | */ |
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| 33 | |
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| 34 | typedef struct FileHandler { |
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| 35 | int fd; |
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| 36 | int mask; /* Mask of desired events: TCL_READABLE, |
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| 37 | * etc. */ |
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| 38 | int readyMask; /* Mask of events that have been seen since |
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| 39 | * the last time file handlers were invoked |
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| 40 | * for this file. */ |
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| 41 | Tcl_FileProc *proc; /* Function to call, in the style of |
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| 42 | * Tcl_CreateFileHandler. */ |
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| 43 | ClientData clientData; /* Argument to pass to proc. */ |
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| 44 | struct FileHandler *nextPtr;/* Next in list of all files we care about. */ |
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| 45 | } FileHandler; |
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| 46 | |
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| 47 | /* |
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| 48 | * The following structure is what is added to the Tcl event queue when file |
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| 49 | * handlers are ready to fire. |
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| 50 | */ |
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| 51 | |
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| 52 | typedef struct FileHandlerEvent { |
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| 53 | Tcl_Event header; /* Information that is standard for all |
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| 54 | * events. */ |
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| 55 | int fd; /* File descriptor that is ready. Used to find |
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| 56 | * the FileHandler structure for the file |
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| 57 | * (can't point directly to the FileHandler |
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| 58 | * structure because it could go away while |
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| 59 | * the event is queued). */ |
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| 60 | } FileHandlerEvent; |
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| 61 | |
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| 62 | /* |
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| 63 | * The following structure contains a set of select() masks to track readable, |
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| 64 | * writable, and exceptional conditions. |
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| 65 | */ |
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| 66 | |
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| 67 | typedef struct SelectMasks { |
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| 68 | fd_set readable; |
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| 69 | fd_set writable; |
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| 70 | fd_set exceptional; |
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| 71 | } SelectMasks; |
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| 72 | |
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| 73 | /* |
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| 74 | * The following static structure contains the state information for the |
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| 75 | * select based implementation of the Tcl notifier. One of these structures is |
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| 76 | * created for each thread that is using the notifier. |
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| 77 | */ |
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| 78 | |
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| 79 | typedef struct ThreadSpecificData { |
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| 80 | FileHandler *firstFileHandlerPtr; |
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| 81 | /* Pointer to head of file handler list. */ |
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| 82 | SelectMasks checkMasks; /* This structure is used to build up the |
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| 83 | * masks to be used in the next call to |
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| 84 | * select. Bits are set in response to calls |
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| 85 | * to Tcl_CreateFileHandler. */ |
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| 86 | SelectMasks readyMasks; /* This array reflects the readable/writable |
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| 87 | * conditions that were found to exist by the |
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| 88 | * last call to select. */ |
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| 89 | int numFdBits; /* Number of valid bits in checkMasks (one |
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| 90 | * more than highest fd for which |
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| 91 | * Tcl_WatchFile has been called). */ |
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| 92 | #ifdef TCL_THREADS |
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| 93 | int onList; /* True if it is in this list */ |
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| 94 | unsigned int pollState; /* pollState is used to implement a polling |
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| 95 | * handshake between each thread and the |
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| 96 | * notifier thread. Bits defined below. */ |
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| 97 | struct ThreadSpecificData *nextPtr, *prevPtr; |
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| 98 | /* All threads that are currently waiting on |
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| 99 | * an event have their ThreadSpecificData |
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| 100 | * structure on a doubly-linked listed formed |
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| 101 | * from these pointers. You must hold the |
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| 102 | * notifierMutex lock before accessing these |
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| 103 | * fields. */ |
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| 104 | Tcl_Condition waitCV; /* Any other thread alerts a notifier that an |
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| 105 | * event is ready to be processed by signaling |
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| 106 | * this condition variable. */ |
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| 107 | int eventReady; /* True if an event is ready to be processed. |
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| 108 | * Used as condition flag together with waitCV |
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| 109 | * above. */ |
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| 110 | #endif |
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| 111 | } ThreadSpecificData; |
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| 112 | |
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| 113 | static Tcl_ThreadDataKey dataKey; |
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| 114 | |
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| 115 | #ifdef TCL_THREADS |
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| 116 | /* |
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| 117 | * The following static indicates the number of threads that have initialized |
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| 118 | * notifiers. |
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| 119 | * |
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| 120 | * You must hold the notifierMutex lock before accessing this variable. |
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| 121 | */ |
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| 122 | |
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| 123 | static int notifierCount = 0; |
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| 124 | |
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| 125 | /* |
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| 126 | * The following variable points to the head of a doubly-linked list of |
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| 127 | * ThreadSpecificData structures for all threads that are currently waiting on |
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| 128 | * an event. |
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| 129 | * |
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| 130 | * You must hold the notifierMutex lock before accessing this list. |
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| 131 | */ |
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| 132 | |
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| 133 | static ThreadSpecificData *waitingListPtr = NULL; |
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| 134 | |
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| 135 | /* |
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| 136 | * The notifier thread spends all its time in select() waiting for a file |
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| 137 | * descriptor associated with one of the threads on the waitingListPtr list to |
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| 138 | * do something interesting. But if the contents of the waitingListPtr list |
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| 139 | * ever changes, we need to wake up and restart the select() system call. You |
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| 140 | * can wake up the notifier thread by writing a single byte to the file |
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| 141 | * descriptor defined below. This file descriptor is the input-end of a pipe |
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| 142 | * and the notifier thread is listening for data on the output-end of the same |
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| 143 | * pipe. Hence writing to this file descriptor will cause the select() system |
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| 144 | * call to return and wake up the notifier thread. |
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| 145 | * |
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| 146 | * You must hold the notifierMutex lock before accessing this list. |
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| 147 | */ |
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| 148 | |
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| 149 | static int triggerPipe = -1; |
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| 150 | |
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| 151 | /* |
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| 152 | * The notifierMutex locks access to all of the global notifier state. |
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| 153 | */ |
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| 154 | |
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| 155 | TCL_DECLARE_MUTEX(notifierMutex) |
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| 156 | |
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| 157 | /* |
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| 158 | * The notifier thread signals the notifierCV when it has finished |
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| 159 | * initializing the triggerPipe and right before the notifier thread |
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| 160 | * terminates. |
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| 161 | */ |
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| 162 | |
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| 163 | static Tcl_Condition notifierCV; |
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| 164 | |
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| 165 | /* |
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| 166 | * The pollState bits |
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| 167 | * POLL_WANT is set by each thread before it waits on its condition |
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| 168 | * variable. It is checked by the notifier before it does select. |
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| 169 | * POLL_DONE is set by the notifier if it goes into select after seeing |
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| 170 | * POLL_WANT. The idea is to ensure it tries a select with the |
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| 171 | * same bits the initial thread had set. |
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| 172 | */ |
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| 173 | |
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| 174 | #define POLL_WANT 0x1 |
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| 175 | #define POLL_DONE 0x2 |
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| 176 | |
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| 177 | /* |
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| 178 | * This is the thread ID of the notifier thread that does select. |
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| 179 | */ |
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| 180 | |
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| 181 | static Tcl_ThreadId notifierThread; |
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| 182 | |
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| 183 | #endif |
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| 184 | |
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| 185 | /* |
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| 186 | * Static routines defined in this file. |
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| 187 | */ |
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| 188 | |
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| 189 | #ifdef TCL_THREADS |
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| 190 | static void NotifierThreadProc(ClientData clientData); |
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| 191 | #endif |
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| 192 | static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); |
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| 193 | |
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| 194 | /* |
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| 195 | *---------------------------------------------------------------------- |
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| 196 | * |
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| 197 | * Tcl_InitNotifier -- |
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| 198 | * |
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| 199 | * Initializes the platform specific notifier state. |
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| 200 | * |
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| 201 | * Results: |
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| 202 | * Returns a handle to the notifier state for this thread.. |
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| 203 | * |
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| 204 | * Side effects: |
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| 205 | * None. |
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| 206 | * |
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| 207 | *---------------------------------------------------------------------- |
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| 208 | */ |
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| 209 | |
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| 210 | ClientData |
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| 211 | Tcl_InitNotifier(void) |
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| 212 | { |
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| 213 | ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); |
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| 214 | |
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| 215 | #ifdef TCL_THREADS |
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| 216 | tsdPtr->eventReady = 0; |
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| 217 | |
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| 218 | /* |
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| 219 | * Start the Notifier thread if necessary. |
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| 220 | */ |
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| 221 | |
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| 222 | Tcl_MutexLock(¬ifierMutex); |
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| 223 | if (notifierCount == 0) { |
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| 224 | if (TclpThreadCreate(¬ifierThread, NotifierThreadProc, NULL, |
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| 225 | TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) { |
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| 226 | Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread"); |
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| 227 | } |
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| 228 | } |
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| 229 | notifierCount++; |
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| 230 | |
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| 231 | /* |
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| 232 | * Wait for the notifier pipe to be created. |
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| 233 | */ |
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| 234 | |
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| 235 | while (triggerPipe < 0) { |
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| 236 | Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); |
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| 237 | } |
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| 238 | |
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| 239 | Tcl_MutexUnlock(¬ifierMutex); |
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| 240 | #endif |
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| 241 | return (ClientData) tsdPtr; |
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| 242 | } |
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| 243 | |
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| 244 | /* |
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| 245 | *---------------------------------------------------------------------- |
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| 246 | * |
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| 247 | * Tcl_FinalizeNotifier -- |
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| 248 | * |
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| 249 | * This function is called to cleanup the notifier state before a thread |
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| 250 | * is terminated. |
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| 251 | * |
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| 252 | * Results: |
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| 253 | * None. |
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| 254 | * |
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| 255 | * Side effects: |
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| 256 | * May terminate the background notifier thread if this is the last |
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| 257 | * notifier instance. |
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| 258 | * |
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| 259 | *---------------------------------------------------------------------- |
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| 260 | */ |
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| 261 | |
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| 262 | void |
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| 263 | Tcl_FinalizeNotifier( |
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| 264 | ClientData clientData) /* Not used. */ |
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| 265 | { |
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| 266 | #ifdef TCL_THREADS |
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| 267 | ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); |
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| 268 | |
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| 269 | Tcl_MutexLock(¬ifierMutex); |
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| 270 | notifierCount--; |
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| 271 | |
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| 272 | /* |
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| 273 | * If this is the last thread to use the notifier, close the notifier pipe |
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| 274 | * and wait for the background thread to terminate. |
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| 275 | */ |
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| 276 | |
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| 277 | if (notifierCount == 0) { |
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| 278 | int result; |
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| 279 | |
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| 280 | if (triggerPipe < 0) { |
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| 281 | Tcl_Panic("Tcl_FinalizeNotifier: notifier pipe not initialized"); |
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| 282 | } |
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| 283 | |
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| 284 | /* |
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| 285 | * Send "q" message to the notifier thread so that it will terminate. |
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| 286 | * The notifier will return from its call to select() and notice that |
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| 287 | * a "q" message has arrived, it will then close its side of the pipe |
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| 288 | * and terminate its thread. Note the we can not just close the pipe |
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| 289 | * and check for EOF in the notifier thread because if a background |
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| 290 | * child process was created with exec, select() would not register |
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| 291 | * the EOF on the pipe until the child processes had terminated. [Bug: |
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| 292 | * 4139] [Bug: 1222872] |
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| 293 | */ |
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| 294 | |
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| 295 | write(triggerPipe, "q", 1); |
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| 296 | close(triggerPipe); |
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| 297 | while(triggerPipe >= 0) { |
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| 298 | Tcl_ConditionWait(¬ifierCV, ¬ifierMutex, NULL); |
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| 299 | } |
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| 300 | |
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| 301 | result = Tcl_JoinThread(notifierThread, NULL); |
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| 302 | if (result) { |
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| 303 | Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier thread"); |
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| 304 | } |
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| 305 | } |
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| 306 | |
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| 307 | /* |
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| 308 | * Clean up any synchronization objects in the thread local storage. |
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| 309 | */ |
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| 310 | |
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| 311 | Tcl_ConditionFinalize(&(tsdPtr->waitCV)); |
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| 312 | |
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| 313 | Tcl_MutexUnlock(¬ifierMutex); |
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| 314 | #endif |
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| 315 | } |
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| 316 | |
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| 317 | /* |
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| 318 | *---------------------------------------------------------------------- |
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| 319 | * |
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| 320 | * Tcl_AlertNotifier -- |
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| 321 | * |
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| 322 | * Wake up the specified notifier from any thread. This routine is called |
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| 323 | * by the platform independent notifier code whenever the Tcl_ThreadAlert |
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| 324 | * routine is called. This routine is guaranteed not to be called on a |
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| 325 | * given notifier after Tcl_FinalizeNotifier is called for that notifier. |
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| 326 | * |
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| 327 | * Results: |
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| 328 | * None. |
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| 329 | * |
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| 330 | * Side effects: |
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| 331 | * Signals the notifier condition variable for the specified notifier. |
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| 332 | * |
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| 333 | *---------------------------------------------------------------------- |
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| 334 | */ |
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| 335 | |
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| 336 | void |
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| 337 | Tcl_AlertNotifier( |
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| 338 | ClientData clientData) |
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| 339 | { |
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| 340 | #ifdef TCL_THREADS |
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| 341 | ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData; |
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| 342 | Tcl_MutexLock(¬ifierMutex); |
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| 343 | tsdPtr->eventReady = 1; |
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| 344 | Tcl_ConditionNotify(&tsdPtr->waitCV); |
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| 345 | Tcl_MutexUnlock(¬ifierMutex); |
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| 346 | #endif |
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| 347 | } |
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| 348 | |
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| 349 | /* |
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| 350 | *---------------------------------------------------------------------- |
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| 351 | * |
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| 352 | * Tcl_SetTimer -- |
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| 353 | * |
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| 354 | * This function sets the current notifier timer value. This interface is |
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| 355 | * not implemented in this notifier because we are always running inside |
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| 356 | * of Tcl_DoOneEvent. |
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| 357 | * |
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| 358 | * Results: |
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| 359 | * None. |
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| 360 | * |
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| 361 | * Side effects: |
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| 362 | * None. |
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| 363 | * |
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| 364 | *---------------------------------------------------------------------- |
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| 365 | */ |
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| 366 | |
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| 367 | void |
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| 368 | Tcl_SetTimer( |
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| 369 | Tcl_Time *timePtr) /* Timeout value, may be NULL. */ |
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| 370 | { |
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| 371 | /* |
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| 372 | * The interval timer doesn't do anything in this implementation, because |
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| 373 | * the only event loop is via Tcl_DoOneEvent, which passes timeout values |
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| 374 | * to Tcl_WaitForEvent. |
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| 375 | */ |
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| 376 | |
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| 377 | if (tclStubs.tcl_SetTimer != tclOriginalNotifier.setTimerProc) { |
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| 378 | tclStubs.tcl_SetTimer(timePtr); |
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| 379 | } |
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| 380 | } |
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| 381 | |
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| 382 | /* |
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| 383 | *---------------------------------------------------------------------- |
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| 384 | * |
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| 385 | * Tcl_ServiceModeHook -- |
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| 386 | * |
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| 387 | * This function is invoked whenever the service mode changes. |
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| 388 | * |
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| 389 | * Results: |
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| 390 | * None. |
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| 391 | * |
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| 392 | * Side effects: |
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| 393 | * None. |
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| 394 | * |
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| 395 | *---------------------------------------------------------------------- |
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| 396 | */ |
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| 397 | |
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| 398 | void |
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| 399 | Tcl_ServiceModeHook( |
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| 400 | int mode) /* Either TCL_SERVICE_ALL, or |
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| 401 | * TCL_SERVICE_NONE. */ |
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| 402 | { |
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| 403 | } |
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| 404 | |
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| 405 | /* |
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| 406 | *---------------------------------------------------------------------- |
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| 407 | * |
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| 408 | * Tcl_CreateFileHandler -- |
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| 409 | * |
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| 410 | * This function registers a file handler with the select notifier. |
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| 411 | * |
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| 412 | * Results: |
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| 413 | * None. |
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| 414 | * |
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| 415 | * Side effects: |
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| 416 | * Creates a new file handler structure. |
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| 417 | * |
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| 418 | *---------------------------------------------------------------------- |
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| 419 | */ |
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| 420 | |
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| 421 | void |
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| 422 | Tcl_CreateFileHandler( |
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| 423 | int fd, /* Handle of stream to watch. */ |
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| 424 | int mask, /* OR'ed combination of TCL_READABLE, |
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| 425 | * TCL_WRITABLE, and TCL_EXCEPTION: indicates |
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| 426 | * conditions under which proc should be |
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| 427 | * called. */ |
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| 428 | Tcl_FileProc *proc, /* Function to call for each selected |
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| 429 | * event. */ |
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| 430 | ClientData clientData) /* Arbitrary data to pass to proc. */ |
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| 431 | { |
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| 432 | ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); |
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| 433 | FileHandler *filePtr; |
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| 434 | |
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| 435 | if (tclStubs.tcl_CreateFileHandler != |
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| 436 | tclOriginalNotifier.createFileHandlerProc) { |
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| 437 | tclStubs.tcl_CreateFileHandler(fd, mask, proc, clientData); |
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| 438 | return; |
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| 439 | } |
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| 440 | |
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| 441 | for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; |
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| 442 | filePtr = filePtr->nextPtr) { |
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| 443 | if (filePtr->fd == fd) { |
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| 444 | break; |
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| 445 | } |
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| 446 | } |
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| 447 | if (filePtr == NULL) { |
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| 448 | filePtr = (FileHandler*) ckalloc(sizeof(FileHandler)); |
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| 449 | filePtr->fd = fd; |
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| 450 | filePtr->readyMask = 0; |
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| 451 | filePtr->nextPtr = tsdPtr->firstFileHandlerPtr; |
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| 452 | tsdPtr->firstFileHandlerPtr = filePtr; |
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| 453 | } |
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| 454 | filePtr->proc = proc; |
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| 455 | filePtr->clientData = clientData; |
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| 456 | filePtr->mask = mask; |
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| 457 | |
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| 458 | /* |
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| 459 | * Update the check masks for this file. |
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| 460 | */ |
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| 461 | |
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| 462 | if (mask & TCL_READABLE) { |
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| 463 | FD_SET(fd, &(tsdPtr->checkMasks.readable)); |
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| 464 | } else { |
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| 465 | FD_CLR(fd, &(tsdPtr->checkMasks.readable)); |
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| 466 | } |
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| 467 | if (mask & TCL_WRITABLE) { |
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| 468 | FD_SET(fd, &(tsdPtr->checkMasks.writable)); |
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| 469 | } else { |
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| 470 | FD_CLR(fd, &(tsdPtr->checkMasks.writable)); |
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| 471 | } |
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| 472 | if (mask & TCL_EXCEPTION) { |
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| 473 | FD_SET(fd, &(tsdPtr->checkMasks.exceptional)); |
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| 474 | } else { |
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| 475 | FD_CLR(fd, &(tsdPtr->checkMasks.exceptional)); |
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| 476 | } |
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| 477 | if (tsdPtr->numFdBits <= fd) { |
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| 478 | tsdPtr->numFdBits = fd+1; |
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| 479 | } |
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| 480 | } |
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| 481 | |
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| 482 | /* |
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| 483 | *---------------------------------------------------------------------- |
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| 484 | * |
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| 485 | * Tcl_DeleteFileHandler -- |
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| 486 | * |
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| 487 | * Cancel a previously-arranged callback arrangement for a file. |
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| 488 | * |
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| 489 | * Results: |
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| 490 | * None. |
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| 491 | * |
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| 492 | * Side effects: |
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| 493 | * If a callback was previously registered on file, remove it. |
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| 494 | * |
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| 495 | *---------------------------------------------------------------------- |
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| 496 | */ |
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| 497 | |
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| 498 | void |
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| 499 | Tcl_DeleteFileHandler( |
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| 500 | int fd) /* Stream id for which to remove callback |
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| 501 | * function. */ |
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| 502 | { |
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| 503 | FileHandler *filePtr, *prevPtr; |
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| 504 | int i; |
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| 505 | ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); |
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| 506 | |
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| 507 | if (tclStubs.tcl_DeleteFileHandler != |
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| 508 | tclOriginalNotifier.deleteFileHandlerProc) { |
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| 509 | tclStubs.tcl_DeleteFileHandler(fd); |
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| 510 | return; |
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| 511 | } |
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| 512 | |
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| 513 | /* |
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| 514 | * Find the entry for the given file (and return if there isn't one). |
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| 515 | */ |
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| 516 | |
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| 517 | for (prevPtr = NULL, filePtr = tsdPtr->firstFileHandlerPtr; ; |
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| 518 | prevPtr = filePtr, filePtr = filePtr->nextPtr) { |
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| 519 | if (filePtr == NULL) { |
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| 520 | return; |
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| 521 | } |
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| 522 | if (filePtr->fd == fd) { |
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| 523 | break; |
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| 524 | } |
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| 525 | } |
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| 526 | |
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| 527 | /* |
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| 528 | * Update the check masks for this file. |
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| 529 | */ |
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| 530 | |
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| 531 | if (filePtr->mask & TCL_READABLE) { |
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| 532 | FD_CLR(fd, &(tsdPtr->checkMasks.readable)); |
---|
| 533 | } |
---|
| 534 | if (filePtr->mask & TCL_WRITABLE) { |
---|
| 535 | FD_CLR(fd, &(tsdPtr->checkMasks.writable)); |
---|
| 536 | } |
---|
| 537 | if (filePtr->mask & TCL_EXCEPTION) { |
---|
| 538 | FD_CLR(fd, &(tsdPtr->checkMasks.exceptional)); |
---|
| 539 | } |
---|
| 540 | |
---|
| 541 | /* |
---|
| 542 | * Find current max fd. |
---|
| 543 | */ |
---|
| 544 | |
---|
| 545 | if (fd+1 == tsdPtr->numFdBits) { |
---|
| 546 | tsdPtr->numFdBits = 0; |
---|
| 547 | for (i = fd-1; i >= 0; i--) { |
---|
| 548 | if (FD_ISSET(i, &(tsdPtr->checkMasks.readable)) |
---|
| 549 | || FD_ISSET(i, &(tsdPtr->checkMasks.writable)) |
---|
| 550 | || FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) { |
---|
| 551 | tsdPtr->numFdBits = i+1; |
---|
| 552 | break; |
---|
| 553 | } |
---|
| 554 | } |
---|
| 555 | } |
---|
| 556 | |
---|
| 557 | /* |
---|
| 558 | * Clean up information in the callback record. |
---|
| 559 | */ |
---|
| 560 | |
---|
| 561 | if (prevPtr == NULL) { |
---|
| 562 | tsdPtr->firstFileHandlerPtr = filePtr->nextPtr; |
---|
| 563 | } else { |
---|
| 564 | prevPtr->nextPtr = filePtr->nextPtr; |
---|
| 565 | } |
---|
| 566 | ckfree((char *) filePtr); |
---|
| 567 | } |
---|
| 568 | |
---|
| 569 | /* |
---|
| 570 | *---------------------------------------------------------------------- |
---|
| 571 | * |
---|
| 572 | * FileHandlerEventProc -- |
---|
| 573 | * |
---|
| 574 | * This function is called by Tcl_ServiceEvent when a file event reaches |
---|
| 575 | * the front of the event queue. This function is responsible for |
---|
| 576 | * actually handling the event by invoking the callback for the file |
---|
| 577 | * handler. |
---|
| 578 | * |
---|
| 579 | * Results: |
---|
| 580 | * Returns 1 if the event was handled, meaning it should be removed from |
---|
| 581 | * the queue. Returns 0 if the event was not handled, meaning it should |
---|
| 582 | * stay on the queue. The only time the event isn't handled is if the |
---|
| 583 | * TCL_FILE_EVENTS flag bit isn't set. |
---|
| 584 | * |
---|
| 585 | * Side effects: |
---|
| 586 | * Whatever the file handler's callback function does. |
---|
| 587 | * |
---|
| 588 | *---------------------------------------------------------------------- |
---|
| 589 | */ |
---|
| 590 | |
---|
| 591 | static int |
---|
| 592 | FileHandlerEventProc( |
---|
| 593 | Tcl_Event *evPtr, /* Event to service. */ |
---|
| 594 | int flags) /* Flags that indicate what events to handle, |
---|
| 595 | * such as TCL_FILE_EVENTS. */ |
---|
| 596 | { |
---|
| 597 | int mask; |
---|
| 598 | FileHandler *filePtr; |
---|
| 599 | FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr; |
---|
| 600 | ThreadSpecificData *tsdPtr; |
---|
| 601 | |
---|
| 602 | if (!(flags & TCL_FILE_EVENTS)) { |
---|
| 603 | return 0; |
---|
| 604 | } |
---|
| 605 | |
---|
| 606 | /* |
---|
| 607 | * Search through the file handlers to find the one whose handle matches |
---|
| 608 | * the event. We do this rather than keeping a pointer to the file handler |
---|
| 609 | * directly in the event, so that the handler can be deleted while the |
---|
| 610 | * event is queued without leaving a dangling pointer. |
---|
| 611 | */ |
---|
| 612 | |
---|
| 613 | tsdPtr = TCL_TSD_INIT(&dataKey); |
---|
| 614 | for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; |
---|
| 615 | filePtr = filePtr->nextPtr) { |
---|
| 616 | if (filePtr->fd != fileEvPtr->fd) { |
---|
| 617 | continue; |
---|
| 618 | } |
---|
| 619 | |
---|
| 620 | /* |
---|
| 621 | * The code is tricky for two reasons: |
---|
| 622 | * 1. The file handler's desired events could have changed since the |
---|
| 623 | * time when the event was queued, so AND the ready mask with the |
---|
| 624 | * desired mask. |
---|
| 625 | * 2. The file could have been closed and re-opened since the time |
---|
| 626 | * when the event was queued. This is why the ready mask is stored |
---|
| 627 | * in the file handler rather than the queued event: it will be |
---|
| 628 | * zeroed when a new file handler is created for the newly opened |
---|
| 629 | * file. |
---|
| 630 | */ |
---|
| 631 | |
---|
| 632 | mask = filePtr->readyMask & filePtr->mask; |
---|
| 633 | filePtr->readyMask = 0; |
---|
| 634 | if (mask != 0) { |
---|
| 635 | (*filePtr->proc)(filePtr->clientData, mask); |
---|
| 636 | } |
---|
| 637 | break; |
---|
| 638 | } |
---|
| 639 | return 1; |
---|
| 640 | } |
---|
| 641 | |
---|
| 642 | /* |
---|
| 643 | *---------------------------------------------------------------------- |
---|
| 644 | * |
---|
| 645 | * Tcl_WaitForEvent -- |
---|
| 646 | * |
---|
| 647 | * This function is called by Tcl_DoOneEvent to wait for new events on |
---|
| 648 | * the message queue. If the block time is 0, then Tcl_WaitForEvent just |
---|
| 649 | * polls without blocking. |
---|
| 650 | * |
---|
| 651 | * Results: |
---|
| 652 | * Returns -1 if the select would block forever, otherwise returns 0. |
---|
| 653 | * |
---|
| 654 | * Side effects: |
---|
| 655 | * Queues file events that are detected by the select. |
---|
| 656 | * |
---|
| 657 | *---------------------------------------------------------------------- |
---|
| 658 | */ |
---|
| 659 | |
---|
| 660 | int |
---|
| 661 | Tcl_WaitForEvent( |
---|
| 662 | Tcl_Time *timePtr) /* Maximum block time, or NULL. */ |
---|
| 663 | { |
---|
| 664 | FileHandler *filePtr; |
---|
| 665 | FileHandlerEvent *fileEvPtr; |
---|
| 666 | int mask; |
---|
| 667 | Tcl_Time myTime; |
---|
| 668 | #ifdef TCL_THREADS |
---|
| 669 | int waitForFiles; |
---|
| 670 | Tcl_Time *myTimePtr; |
---|
| 671 | #else |
---|
| 672 | /* |
---|
| 673 | * Impl. notes: timeout & timeoutPtr are used if, and only if threads are |
---|
| 674 | * not enabled. They are the arguments for the regular select() used when |
---|
| 675 | * the core is not thread-enabled. |
---|
| 676 | */ |
---|
| 677 | |
---|
| 678 | struct timeval timeout, *timeoutPtr; |
---|
| 679 | int numFound; |
---|
| 680 | #endif /* TCL_THREADS */ |
---|
| 681 | ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); |
---|
| 682 | |
---|
| 683 | if (tclStubs.tcl_WaitForEvent != tclOriginalNotifier.waitForEventProc) { |
---|
| 684 | return tclStubs.tcl_WaitForEvent(timePtr); |
---|
| 685 | } |
---|
| 686 | |
---|
| 687 | /* |
---|
| 688 | * Set up the timeout structure. Note that if there are no events to check |
---|
| 689 | * for, we return with a negative result rather than blocking forever. |
---|
| 690 | */ |
---|
| 691 | |
---|
| 692 | if (timePtr != NULL) { |
---|
| 693 | /* |
---|
| 694 | * TIP #233 (Virtualized Time). Is virtual time in effect? And do we |
---|
| 695 | * actually have something to scale? If yes to both then we call the |
---|
| 696 | * handler to do this scaling. |
---|
| 697 | */ |
---|
| 698 | |
---|
| 699 | myTime.sec = timePtr->sec; |
---|
| 700 | myTime.usec = timePtr->usec; |
---|
| 701 | |
---|
| 702 | if (myTime.sec != 0 || myTime.usec != 0) { |
---|
| 703 | (*tclScaleTimeProcPtr) (&myTime, tclTimeClientData); |
---|
| 704 | } |
---|
| 705 | |
---|
| 706 | #ifdef TCL_THREADS |
---|
| 707 | myTimePtr = &myTime; |
---|
| 708 | #else |
---|
| 709 | timeout.tv_sec = myTime.sec; |
---|
| 710 | timeout.tv_usec = myTime.usec; |
---|
| 711 | timeoutPtr = &timeout; |
---|
| 712 | #endif /* TCL_THREADS */ |
---|
| 713 | |
---|
| 714 | #ifndef TCL_THREADS |
---|
| 715 | } else if (tsdPtr->numFdBits == 0) { |
---|
| 716 | /* |
---|
| 717 | * If there are no threads, no timeout, and no fds registered, then |
---|
| 718 | * there are no events possible and we must avoid deadlock. Note that |
---|
| 719 | * this is not entirely correct because there might be a signal that |
---|
| 720 | * could interrupt the select call, but we don't handle that case if |
---|
| 721 | * we aren't using threads. |
---|
| 722 | */ |
---|
| 723 | |
---|
| 724 | return -1; |
---|
| 725 | #endif /* !TCL_THREADS */ |
---|
| 726 | } else { |
---|
| 727 | #ifdef TCL_THREADS |
---|
| 728 | myTimePtr = NULL; |
---|
| 729 | #else |
---|
| 730 | timeoutPtr = NULL; |
---|
| 731 | #endif /* TCL_THREADS */ |
---|
| 732 | } |
---|
| 733 | |
---|
| 734 | #ifdef TCL_THREADS |
---|
| 735 | /* |
---|
| 736 | * Place this thread on the list of interested threads, signal the |
---|
| 737 | * notifier thread, and wait for a response or a timeout. |
---|
| 738 | */ |
---|
| 739 | |
---|
| 740 | Tcl_MutexLock(¬ifierMutex); |
---|
| 741 | |
---|
| 742 | waitForFiles = (tsdPtr->numFdBits > 0); |
---|
| 743 | if (myTimePtr != NULL && myTimePtr->sec == 0 && (myTimePtr->usec == 0 |
---|
| 744 | #if defined(__APPLE__) && defined(__LP64__) |
---|
| 745 | /* |
---|
| 746 | * On 64-bit Darwin, pthread_cond_timedwait() appears to have a bug |
---|
| 747 | * that causes it to wait forever when passed an absolute time which |
---|
| 748 | * has already been exceeded by the system time; as a workaround, |
---|
| 749 | * when given a very brief timeout, just do a poll. [Bug 1457797] |
---|
| 750 | */ |
---|
| 751 | || myTimePtr->usec < 10 |
---|
| 752 | #endif |
---|
| 753 | )) { |
---|
| 754 | /* |
---|
| 755 | * Cannot emulate a polling select with a polling condition variable. |
---|
| 756 | * Instead, pretend to wait for files and tell the notifier thread |
---|
| 757 | * what we are doing. The notifier thread makes sure it goes through |
---|
| 758 | * select with its select mask in the same state as ours currently is. |
---|
| 759 | * We block until that happens. |
---|
| 760 | */ |
---|
| 761 | |
---|
| 762 | waitForFiles = 1; |
---|
| 763 | tsdPtr->pollState = POLL_WANT; |
---|
| 764 | myTimePtr = NULL; |
---|
| 765 | } else { |
---|
| 766 | tsdPtr->pollState = 0; |
---|
| 767 | } |
---|
| 768 | |
---|
| 769 | if (waitForFiles) { |
---|
| 770 | /* |
---|
| 771 | * Add the ThreadSpecificData structure of this thread to the list of |
---|
| 772 | * ThreadSpecificData structures of all threads that are waiting on |
---|
| 773 | * file events. |
---|
| 774 | */ |
---|
| 775 | |
---|
| 776 | tsdPtr->nextPtr = waitingListPtr; |
---|
| 777 | if (waitingListPtr) { |
---|
| 778 | waitingListPtr->prevPtr = tsdPtr; |
---|
| 779 | } |
---|
| 780 | tsdPtr->prevPtr = 0; |
---|
| 781 | waitingListPtr = tsdPtr; |
---|
| 782 | tsdPtr->onList = 1; |
---|
| 783 | |
---|
| 784 | write(triggerPipe, "", 1); |
---|
| 785 | } |
---|
| 786 | |
---|
| 787 | FD_ZERO(&(tsdPtr->readyMasks.readable)); |
---|
| 788 | FD_ZERO(&(tsdPtr->readyMasks.writable)); |
---|
| 789 | FD_ZERO(&(tsdPtr->readyMasks.exceptional)); |
---|
| 790 | |
---|
| 791 | if (!tsdPtr->eventReady) { |
---|
| 792 | Tcl_ConditionWait(&tsdPtr->waitCV, ¬ifierMutex, myTimePtr); |
---|
| 793 | } |
---|
| 794 | tsdPtr->eventReady = 0; |
---|
| 795 | |
---|
| 796 | if (waitForFiles && tsdPtr->onList) { |
---|
| 797 | /* |
---|
| 798 | * Remove the ThreadSpecificData structure of this thread from the |
---|
| 799 | * waiting list. Alert the notifier thread to recompute its select |
---|
| 800 | * masks - skipping this caused a hang when trying to close a pipe |
---|
| 801 | * which the notifier thread was still doing a select on. |
---|
| 802 | */ |
---|
| 803 | |
---|
| 804 | if (tsdPtr->prevPtr) { |
---|
| 805 | tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr; |
---|
| 806 | } else { |
---|
| 807 | waitingListPtr = tsdPtr->nextPtr; |
---|
| 808 | } |
---|
| 809 | if (tsdPtr->nextPtr) { |
---|
| 810 | tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr; |
---|
| 811 | } |
---|
| 812 | tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; |
---|
| 813 | tsdPtr->onList = 0; |
---|
| 814 | write(triggerPipe, "", 1); |
---|
| 815 | } |
---|
| 816 | |
---|
| 817 | #else |
---|
| 818 | tsdPtr->readyMasks = tsdPtr->checkMasks; |
---|
| 819 | numFound = select(tsdPtr->numFdBits, &(tsdPtr->readyMasks.readable), |
---|
| 820 | &(tsdPtr->readyMasks.writable), &(tsdPtr->readyMasks.exceptional), |
---|
| 821 | timeoutPtr); |
---|
| 822 | |
---|
| 823 | /* |
---|
| 824 | * Some systems don't clear the masks after an error, so we have to do it |
---|
| 825 | * here. |
---|
| 826 | */ |
---|
| 827 | |
---|
| 828 | if (numFound == -1) { |
---|
| 829 | FD_ZERO(&(tsdPtr->readyMasks.readable)); |
---|
| 830 | FD_ZERO(&(tsdPtr->readyMasks.writable)); |
---|
| 831 | FD_ZERO(&(tsdPtr->readyMasks.exceptional)); |
---|
| 832 | } |
---|
| 833 | #endif /* TCL_THREADS */ |
---|
| 834 | |
---|
| 835 | /* |
---|
| 836 | * Queue all detected file events before returning. |
---|
| 837 | */ |
---|
| 838 | |
---|
| 839 | for (filePtr = tsdPtr->firstFileHandlerPtr; (filePtr != NULL); |
---|
| 840 | filePtr = filePtr->nextPtr) { |
---|
| 841 | |
---|
| 842 | mask = 0; |
---|
| 843 | if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.readable))) { |
---|
| 844 | mask |= TCL_READABLE; |
---|
| 845 | } |
---|
| 846 | if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.writable))) { |
---|
| 847 | mask |= TCL_WRITABLE; |
---|
| 848 | } |
---|
| 849 | if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.exceptional))) { |
---|
| 850 | mask |= TCL_EXCEPTION; |
---|
| 851 | } |
---|
| 852 | |
---|
| 853 | if (!mask) { |
---|
| 854 | continue; |
---|
| 855 | } |
---|
| 856 | |
---|
| 857 | /* |
---|
| 858 | * Don't bother to queue an event if the mask was previously non-zero |
---|
| 859 | * since an event must still be on the queue. |
---|
| 860 | */ |
---|
| 861 | |
---|
| 862 | if (filePtr->readyMask == 0) { |
---|
| 863 | fileEvPtr = (FileHandlerEvent *) ckalloc(sizeof(FileHandlerEvent)); |
---|
| 864 | fileEvPtr->header.proc = FileHandlerEventProc; |
---|
| 865 | fileEvPtr->fd = filePtr->fd; |
---|
| 866 | Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); |
---|
| 867 | } |
---|
| 868 | filePtr->readyMask = mask; |
---|
| 869 | } |
---|
| 870 | #ifdef TCL_THREADS |
---|
| 871 | Tcl_MutexUnlock(¬ifierMutex); |
---|
| 872 | #endif /* TCL_THREADS */ |
---|
| 873 | return 0; |
---|
| 874 | } |
---|
| 875 | |
---|
| 876 | #ifdef TCL_THREADS |
---|
| 877 | /* |
---|
| 878 | *---------------------------------------------------------------------- |
---|
| 879 | * |
---|
| 880 | * NotifierThreadProc -- |
---|
| 881 | * |
---|
| 882 | * This routine is the initial (and only) function executed by the |
---|
| 883 | * special notifier thread. Its job is to wait for file descriptors to |
---|
| 884 | * become readable or writable or to have an exception condition and then |
---|
| 885 | * to notify other threads who are interested in this information by |
---|
| 886 | * signalling a condition variable. Other threads can signal this |
---|
| 887 | * notifier thread of a change in their interests by writing a single |
---|
| 888 | * byte to a special pipe that the notifier thread is monitoring. |
---|
| 889 | * |
---|
| 890 | * Result: |
---|
| 891 | * None. Once started, this routine never exits. It dies with the overall |
---|
| 892 | * process. |
---|
| 893 | * |
---|
| 894 | * Side effects: |
---|
| 895 | * The trigger pipe used to signal the notifier thread is created when |
---|
| 896 | * the notifier thread first starts. |
---|
| 897 | * |
---|
| 898 | *---------------------------------------------------------------------- |
---|
| 899 | */ |
---|
| 900 | |
---|
| 901 | static void |
---|
| 902 | NotifierThreadProc( |
---|
| 903 | ClientData clientData) /* Not used. */ |
---|
| 904 | { |
---|
| 905 | ThreadSpecificData *tsdPtr; |
---|
| 906 | fd_set readableMask; |
---|
| 907 | fd_set writableMask; |
---|
| 908 | fd_set exceptionalMask; |
---|
| 909 | int fds[2]; |
---|
| 910 | int i, numFdBits = 0, receivePipe; |
---|
| 911 | long found; |
---|
| 912 | struct timeval poll = {0., 0.}, *timePtr; |
---|
| 913 | char buf[2]; |
---|
| 914 | |
---|
| 915 | if (pipe(fds) != 0) { |
---|
| 916 | Tcl_Panic("NotifierThreadProc: could not create trigger pipe"); |
---|
| 917 | } |
---|
| 918 | |
---|
| 919 | receivePipe = fds[0]; |
---|
| 920 | |
---|
| 921 | if (TclUnixSetBlockingMode(receivePipe, TCL_MODE_NONBLOCKING) < 0) { |
---|
| 922 | Tcl_Panic("NotifierThreadProc: could not make receive pipe non blocking"); |
---|
| 923 | } |
---|
| 924 | if (TclUnixSetBlockingMode(fds[1], TCL_MODE_NONBLOCKING) < 0) { |
---|
| 925 | Tcl_Panic("NotifierThreadProc: could not make trigger pipe non blocking"); |
---|
| 926 | } |
---|
| 927 | |
---|
| 928 | /* |
---|
| 929 | * Install the write end of the pipe into the global variable. |
---|
| 930 | */ |
---|
| 931 | |
---|
| 932 | Tcl_MutexLock(¬ifierMutex); |
---|
| 933 | triggerPipe = fds[1]; |
---|
| 934 | |
---|
| 935 | /* |
---|
| 936 | * Signal any threads that are waiting. |
---|
| 937 | */ |
---|
| 938 | |
---|
| 939 | Tcl_ConditionNotify(¬ifierCV); |
---|
| 940 | Tcl_MutexUnlock(¬ifierMutex); |
---|
| 941 | |
---|
| 942 | /* |
---|
| 943 | * Look for file events and report them to interested threads. |
---|
| 944 | */ |
---|
| 945 | |
---|
| 946 | while (1) { |
---|
| 947 | FD_ZERO(&readableMask); |
---|
| 948 | FD_ZERO(&writableMask); |
---|
| 949 | FD_ZERO(&exceptionalMask); |
---|
| 950 | |
---|
| 951 | /* |
---|
| 952 | * Compute the logical OR of the select masks from all the waiting |
---|
| 953 | * notifiers. |
---|
| 954 | */ |
---|
| 955 | |
---|
| 956 | Tcl_MutexLock(¬ifierMutex); |
---|
| 957 | timePtr = NULL; |
---|
| 958 | for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { |
---|
| 959 | for (i = tsdPtr->numFdBits-1; i >= 0; --i) { |
---|
| 960 | if (FD_ISSET(i, &(tsdPtr->checkMasks.readable))) { |
---|
| 961 | FD_SET(i, &readableMask); |
---|
| 962 | } |
---|
| 963 | if (FD_ISSET(i, &(tsdPtr->checkMasks.writable))) { |
---|
| 964 | FD_SET(i, &writableMask); |
---|
| 965 | } |
---|
| 966 | if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) { |
---|
| 967 | FD_SET(i, &exceptionalMask); |
---|
| 968 | } |
---|
| 969 | } |
---|
| 970 | if (tsdPtr->numFdBits > numFdBits) { |
---|
| 971 | numFdBits = tsdPtr->numFdBits; |
---|
| 972 | } |
---|
| 973 | if (tsdPtr->pollState & POLL_WANT) { |
---|
| 974 | /* |
---|
| 975 | * Here we make sure we go through select() with the same mask |
---|
| 976 | * bits that were present when the thread tried to poll. |
---|
| 977 | */ |
---|
| 978 | |
---|
| 979 | tsdPtr->pollState |= POLL_DONE; |
---|
| 980 | timePtr = &poll; |
---|
| 981 | } |
---|
| 982 | } |
---|
| 983 | Tcl_MutexUnlock(¬ifierMutex); |
---|
| 984 | |
---|
| 985 | /* |
---|
| 986 | * Set up the select mask to include the receive pipe. |
---|
| 987 | */ |
---|
| 988 | |
---|
| 989 | if (receivePipe >= numFdBits) { |
---|
| 990 | numFdBits = receivePipe + 1; |
---|
| 991 | } |
---|
| 992 | FD_SET(receivePipe, &readableMask); |
---|
| 993 | |
---|
| 994 | if (select(numFdBits, &readableMask, &writableMask, &exceptionalMask, |
---|
| 995 | timePtr) == -1) { |
---|
| 996 | /* |
---|
| 997 | * Try again immediately on an error. |
---|
| 998 | */ |
---|
| 999 | |
---|
| 1000 | continue; |
---|
| 1001 | } |
---|
| 1002 | |
---|
| 1003 | /* |
---|
| 1004 | * Alert any threads that are waiting on a ready file descriptor. |
---|
| 1005 | */ |
---|
| 1006 | |
---|
| 1007 | Tcl_MutexLock(¬ifierMutex); |
---|
| 1008 | for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { |
---|
| 1009 | found = 0; |
---|
| 1010 | |
---|
| 1011 | for (i = tsdPtr->numFdBits-1; i >= 0; --i) { |
---|
| 1012 | if (FD_ISSET(i, &(tsdPtr->checkMasks.readable)) |
---|
| 1013 | && FD_ISSET(i, &readableMask)) { |
---|
| 1014 | FD_SET(i, &(tsdPtr->readyMasks.readable)); |
---|
| 1015 | found = 1; |
---|
| 1016 | } |
---|
| 1017 | if (FD_ISSET(i, &(tsdPtr->checkMasks.writable)) |
---|
| 1018 | && FD_ISSET(i, &writableMask)) { |
---|
| 1019 | FD_SET(i, &(tsdPtr->readyMasks.writable)); |
---|
| 1020 | found = 1; |
---|
| 1021 | } |
---|
| 1022 | if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional)) |
---|
| 1023 | && FD_ISSET(i, &exceptionalMask)) { |
---|
| 1024 | FD_SET(i, &(tsdPtr->readyMasks.exceptional)); |
---|
| 1025 | found = 1; |
---|
| 1026 | } |
---|
| 1027 | } |
---|
| 1028 | |
---|
| 1029 | if (found || (tsdPtr->pollState & POLL_DONE)) { |
---|
| 1030 | tsdPtr->eventReady = 1; |
---|
| 1031 | if (tsdPtr->onList) { |
---|
| 1032 | /* |
---|
| 1033 | * Remove the ThreadSpecificData structure of this thread |
---|
| 1034 | * from the waiting list. This prevents us from |
---|
| 1035 | * continuously spining on select until the other threads |
---|
| 1036 | * runs and services the file event. |
---|
| 1037 | */ |
---|
| 1038 | |
---|
| 1039 | if (tsdPtr->prevPtr) { |
---|
| 1040 | tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr; |
---|
| 1041 | } else { |
---|
| 1042 | waitingListPtr = tsdPtr->nextPtr; |
---|
| 1043 | } |
---|
| 1044 | if (tsdPtr->nextPtr) { |
---|
| 1045 | tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr; |
---|
| 1046 | } |
---|
| 1047 | tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; |
---|
| 1048 | tsdPtr->onList = 0; |
---|
| 1049 | tsdPtr->pollState = 0; |
---|
| 1050 | } |
---|
| 1051 | Tcl_ConditionNotify(&tsdPtr->waitCV); |
---|
| 1052 | } |
---|
| 1053 | } |
---|
| 1054 | Tcl_MutexUnlock(¬ifierMutex); |
---|
| 1055 | |
---|
| 1056 | /* |
---|
| 1057 | * Consume the next byte from the notifier pipe if the pipe was |
---|
| 1058 | * readable. Note that there may be multiple bytes pending, but to |
---|
| 1059 | * avoid a race condition we only read one at a time. |
---|
| 1060 | */ |
---|
| 1061 | |
---|
| 1062 | if (FD_ISSET(receivePipe, &readableMask)) { |
---|
| 1063 | i = read(receivePipe, buf, 1); |
---|
| 1064 | |
---|
| 1065 | if ((i == 0) || ((i == 1) && (buf[0] == 'q'))) { |
---|
| 1066 | /* |
---|
| 1067 | * Someone closed the write end of the pipe or sent us a Quit |
---|
| 1068 | * message [Bug: 4139] and then closed the write end of the |
---|
| 1069 | * pipe so we need to shut down the notifier thread. |
---|
| 1070 | */ |
---|
| 1071 | |
---|
| 1072 | break; |
---|
| 1073 | } |
---|
| 1074 | } |
---|
| 1075 | } |
---|
| 1076 | |
---|
| 1077 | /* |
---|
| 1078 | * Clean up the read end of the pipe and signal any threads waiting on |
---|
| 1079 | * termination of the notifier thread. |
---|
| 1080 | */ |
---|
| 1081 | |
---|
| 1082 | close(receivePipe); |
---|
| 1083 | Tcl_MutexLock(¬ifierMutex); |
---|
| 1084 | triggerPipe = -1; |
---|
| 1085 | Tcl_ConditionNotify(¬ifierCV); |
---|
| 1086 | Tcl_MutexUnlock(¬ifierMutex); |
---|
| 1087 | |
---|
| 1088 | TclpThreadExit (0); |
---|
| 1089 | } |
---|
| 1090 | #endif /* TCL_THREADS */ |
---|
| 1091 | |
---|
| 1092 | #endif /* HAVE_COREFOUNDATION */ |
---|
| 1093 | |
---|
| 1094 | /* |
---|
| 1095 | * Local Variables: |
---|
| 1096 | * mode: c |
---|
| 1097 | * c-basic-offset: 4 |
---|
| 1098 | * fill-column: 78 |
---|
| 1099 | * End: |
---|
| 1100 | */ |
---|