| 1 | /* $Id: kLdr.c 2 2007-11-16 16:07:14Z 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 <[email protected]>
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| 8 | *
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| 9 | * This file is part of kStuff.
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| 10 | *
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| 11 | * kStuff is free software; you can redistribute it and/or
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| 12 | * modify it under the terms of the GNU Lesser General Public
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| 13 | * License as published by the Free Software Foundation; either
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| 14 | * version 2.1 of the License, or (at your option) any later version.
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| 15 | *
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| 16 | * In addition to the permissions in the GNU Lesser General Public
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| 17 | * License, you are granted unlimited permission to link the compiled
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| 18 | * version of this file into combinations with other programs, and to
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| 19 | * distribute those combinations without any restriction coming from
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| 20 | * the use of this file.
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| 21 | *
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| 22 | * kStuff is distributed in the hope that it will be useful,
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| 23 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 24 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 25 | * Lesser General Public License for more details.
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| 26 | *
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| 27 | * You should have received a copy of the GNU Lesser General Public
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| 28 | * License along with kStuff; if not, write to the Free Software
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| 29 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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| 30 | * 02110-1301, USA
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| 31 | */
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| 32 |
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| 33 |
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| 34 | /** @mainpage kLdr - The Dynamic Loader
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| 35 | *
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| 36 | * The purpose of kLdr is to provide a generic interface for querying
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| 37 | * information about and loading executable image modules.
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| 38 | *
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| 39 | * kLdr defines the term executable image to include all kinds of files that contains
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| 40 | * binary code that can be executed on a CPU - linker objects (OBJs/Os), shared
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| 41 | * objects (SOs), dynamic link libraries (DLLs), executables (EXEs), and all kinds
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| 42 | * of kernel modules / device drivers (SYSs).
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| 43 | *
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| 44 | * kLdr provides two types of services:
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| 45 | * -# Inspect or/and load individual modules (kLdrMod).
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| 46 | * -# Work as a dynamic loader - construct and maintain an address space (kLdrDy).
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| 47 | *
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| 48 | * The kLdrMod API works on KLDRMOD structures where all the internals are exposed, while
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| 49 | * the kLdrDy API works opque KLDRDY structures. KLDRDY are in reality simple wrappers
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| 50 | * around KLDRMOD with some extra linking and attributes.
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| 51 | *
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| 52 | */
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| 53 |
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| 54 |
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| 55 | /*******************************************************************************
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| 56 | * Header Files *
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| 57 | *******************************************************************************/
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| 58 | #include <k/kLdr.h>
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| 59 | #include "kLdrInternal.h"
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| 60 |
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| 61 |
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| 62 | /*******************************************************************************
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| 63 | * Global Variables *
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| 64 | *******************************************************************************/
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| 65 | /** Flag indicating whether we've initialized the loader or not.
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| 66 | *
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| 67 | * 0 if not initialized.
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| 68 | * -1 if we're initializing or terminating.
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| 69 | * 1 if we've successfully initialized it.
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| 70 | * -2 if initialization failed.
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| 71 | */
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| 72 | static int volatile g_fInitialized;
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| 73 |
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| 74 |
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| 75 |
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| 76 | /**
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| 77 | * Initializes the loader.
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| 78 | * @returns 0 on success, non-zero OS status code on failure.
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| 79 | */
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| 80 | int kldrInit(void)
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| 81 | {
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| 82 | int rc;
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| 83 |
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| 84 | /* check we're already good. */
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| 85 | if (g_fInitialized == 1)
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| 86 | return 0;
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| 87 |
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| 88 | /* a tiny serialization effort. */
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| 89 | for (;;)
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| 90 | {
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| 91 | if (g_fInitialized == 1)
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| 92 | return 0;
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| 93 | if (g_fInitialized == -2)
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| 94 | return -1;
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| 95 | /** @todo atomic test and set if we care. */
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| 96 | if (g_fInitialized == 0)
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| 97 | {
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| 98 | g_fInitialized = -1;
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| 99 | break;
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| 100 | }
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| 101 | kHlpSleep(1);
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| 102 | }
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| 103 |
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| 104 | /*
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| 105 | * Do the initialization.
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| 106 | */
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| 107 | rc = kHlpHeapInit();
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| 108 | if (!rc)
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| 109 | {
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| 110 | rc = kLdrDyldSemInit();
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| 111 | if (!rc)
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| 112 | {
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| 113 | rc = kldrDyldInit();
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| 114 | if (!rc)
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| 115 | {
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| 116 | g_fInitialized = 1;
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| 117 | return 0;
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| 118 | }
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| 119 | kLdrDyldSemTerm();
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| 120 | }
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| 121 | kHlpHeapTerm();
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| 122 | }
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| 123 | g_fInitialized = -2;
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| 124 | return rc;
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| 125 | }
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| 126 |
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| 127 |
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| 128 | /**
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| 129 | * Terminates the loader.
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| 130 | */
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| 131 | void kldrTerm(void)
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| 132 | {
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| 133 | /* can't terminate unless it's initialized. */
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| 134 | if (g_fInitialized != 1)
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| 135 | return;
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| 136 | g_fInitialized = -1;
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| 137 |
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| 138 | /*
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| 139 | * Do the termination.
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| 140 | */
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| 141 | kLdrDyldSemTerm();
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| 142 | kHlpHeapTerm();
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| 143 |
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| 144 | /* done */
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| 145 | g_fInitialized = 0;
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| 146 | }
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| 147 |
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