| 1 | /* $Id: kLdr.c 29 2009-07-01 20:30:29Z bird $ */
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| 2 | /** @file
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| 3 | * kLdr - The Dynamic Loader.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (c) 2006-2007 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net>
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| 8 | *
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| 9 | * Permission is hereby granted, free of charge, to any person
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| 10 | * obtaining a copy of this software and associated documentation
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| 11 | * files (the "Software"), to deal in the Software without
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| 12 | * restriction, including without limitation the rights to use,
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| 13 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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| 14 | * copies of the Software, and to permit persons to whom the
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| 15 | * Software is furnished to do so, subject to the following
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| 16 | * conditions:
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| 17 | *
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| 18 | * The above copyright notice and this permission notice shall be
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| 19 | * included in all copies or substantial portions of the Software.
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| 20 | *
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| 21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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| 22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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| 23 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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| 24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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| 25 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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| 26 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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| 27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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| 28 | * OTHER DEALINGS IN THE SOFTWARE.
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| 29 | */
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| 30 |
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| 31 |
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| 32 | /** @mainpage kLdr - The Dynamic Loader
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| 33 | *
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| 34 | * The purpose of kLdr is to provide a generic interface for querying
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| 35 | * information about and loading executable image modules.
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| 36 | *
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| 37 | * kLdr defines the term executable image to include all kinds of files that contains
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| 38 | * binary code that can be executed on a CPU - linker objects (OBJs/Os), shared
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| 39 | * objects (SOs), dynamic link libraries (DLLs), executables (EXEs), and all kinds
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| 40 | * of kernel modules / device drivers (SYSs).
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| 41 | *
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| 42 | * kLdr provides two types of services:
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| 43 | * -# Inspect or/and load individual modules (kLdrMod).
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| 44 | * -# Work as a dynamic loader - construct and maintain an address space (kLdrDy).
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| 45 | *
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| 46 | * The kLdrMod API works on KLDRMOD structures where all the internals are exposed, while
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| 47 | * the kLdrDy API works opque KLDRDY structures. KLDRDY are in reality simple wrappers
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| 48 | * around KLDRMOD with some extra linking and attributes.
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| 49 | *
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| 50 | */
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| 51 |
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| 52 |
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| 53 | /*******************************************************************************
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| 54 | * Header Files *
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| 55 | *******************************************************************************/
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| 56 | #include <k/kLdr.h>
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| 57 | #include "kLdrInternal.h"
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| 58 |
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| 59 |
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| 60 | /*******************************************************************************
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| 61 | * Global Variables *
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| 62 | *******************************************************************************/
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| 63 | /** Flag indicating whether we've initialized the loader or not.
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| 64 | *
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| 65 | * 0 if not initialized.
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| 66 | * -1 if we're initializing or terminating.
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| 67 | * 1 if we've successfully initialized it.
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| 68 | * -2 if initialization failed.
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| 69 | */
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| 70 | static int volatile g_fInitialized;
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| 71 |
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| 72 |
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| 73 |
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| 74 | /**
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| 75 | * Initializes the loader.
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| 76 | * @returns 0 on success, non-zero OS status code on failure.
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| 77 | */
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| 78 | int kldrInit(void)
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| 79 | {
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| 80 | int rc;
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| 81 |
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| 82 | /* check we're already good. */
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| 83 | if (g_fInitialized == 1)
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| 84 | return 0;
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| 85 |
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| 86 | /* a tiny serialization effort. */
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| 87 | for (;;)
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| 88 | {
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| 89 | if (g_fInitialized == 1)
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| 90 | return 0;
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| 91 | if (g_fInitialized == -2)
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| 92 | return -1;
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| 93 | /** @todo atomic test and set if we care. */
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| 94 | if (g_fInitialized == 0)
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| 95 | {
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| 96 | g_fInitialized = -1;
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| 97 | break;
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| 98 | }
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| 99 | kHlpSleep(1);
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| 100 | }
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| 101 |
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| 102 | /*
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| 103 | * Do the initialization.
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| 104 | */
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| 105 | rc = kHlpHeapInit();
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| 106 | if (!rc)
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| 107 | {
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| 108 | rc = kLdrDyldSemInit();
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| 109 | if (!rc)
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| 110 | {
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| 111 | rc = kldrDyldInit();
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| 112 | if (!rc)
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| 113 | {
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| 114 | g_fInitialized = 1;
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| 115 | return 0;
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| 116 | }
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| 117 | kLdrDyldSemTerm();
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| 118 | }
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| 119 | kHlpHeapTerm();
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| 120 | }
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| 121 | g_fInitialized = -2;
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| 122 | return rc;
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| 123 | }
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| 124 |
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| 125 |
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| 126 | /**
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| 127 | * Terminates the loader.
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| 128 | */
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| 129 | void kldrTerm(void)
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| 130 | {
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| 131 | /* can't terminate unless it's initialized. */
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| 132 | if (g_fInitialized != 1)
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| 133 | return;
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| 134 | g_fInitialized = -1;
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| 135 |
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| 136 | /*
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| 137 | * Do the termination.
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| 138 | */
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| 139 | kLdrDyldSemTerm();
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| 140 | kHlpHeapTerm();
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| 141 |
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| 142 | /* done */
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| 143 | g_fInitialized = 0;
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| 144 | }
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| 145 |
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