include/mach-o/dyld_images.h

   1 /*
   2  * Copyright (c) 2006-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #ifndef _DYLD_IMAGES_
  24 #define _DYLD_IMAGES_
  25
  26 #include <stdbool.h>
  27 #include <unistd.h>
  28 #include <mach/mach.h>
  29 #include <uuid/uuid.h>
  30
  31 #if defined(__cplusplus) && (BUILDING_LIBDYLD || BUILDING_DYLD)
  32 #include <atomic>
  33 #endif
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39
  40
  41 /*
  42  *      Beginning in Mac OS X 10.4, this is how gdb discovers which mach-o images are loaded in a process.
  43  *
  44  *      gdb looks for the symbol "_dyld_all_image_infos" in dyld.  It contains the fields below.
  45  *
  46  *      For a snashot of what images are currently loaded, the infoArray fields contain a pointer
  47  *      to an array of all images. If infoArray is NULL, it means it is being modified, come back later.
  48  *
  49  *      To be notified of changes, gdb sets a break point on the address pointed to by the notificationn
  50  *      field.  The function it points to is called by dyld with an array of information about what images
  51  *      have been added (dyld_image_adding) or are about to be removed (dyld_image_removing).
  52  *
  53  * The notification is called after infoArray is updated.  This means that if gdb attaches to a process
  54  * and infoArray is NULL, gdb can set a break point on notification and let the proccess continue to
  55  * run until the break point.  Then gdb can inspect the full infoArray.
  56  *
  57  * The dyldVersion field always points to a C string that contains the dyld version.  For instance,
  58  * in dyld-127.3, dyldVersion would contain a pointer to "127.3".
  59  *
  60  * The errorMessage and terminationFlags fields are normally zero.  If dyld terminates a process
  61  * (for instance because a required dylib or symbol is missing), then the errorMessage field will
  62  * be set to point to a C string message buffer containing the reason dyld terminate the process.
  63  * The low bit of the terminationFlags will be set if dyld terminated the process before any user
  64  * code ran, in which case there is no need for the crash log to contain the backtrace.
  65  *
  66  * When dyld terminates a process because some required dylib or symbol cannot be bound, in
  67  * addition to the errorMessage field, it now sets the errorKind field and the corresponding
  68  * fields: errorClientOfDylibPath, errorTargetDylibPath, errorSymbol.
  69  *
  70  */
  71
  72 enum dyld_image_mode { dyld_image_adding=0, dyld_image_removing=1, dyld_image_info_change=2 };
  73
  74 struct dyld_image_info {
  75         const struct mach_header*       imageLoadAddress;       /* base address image is mapped into */
  76         const char*                                     imageFilePath;          /* path dyld used to load the image */
  77         uintptr_t                                       imageFileModDate;       /* time_t of image file */
  78                                                                                                         /* if stat().st_mtime of imageFilePath does not match imageFileModDate, */
  79                                                                                                         /* then file has been modified since dyld loaded it */
  80 };
  81
  82 struct dyld_uuid_info {
  83         const struct mach_header*       imageLoadAddress;       /* base address image is mapped into */
  84         uuid_t                                          imageUUID;                      /* UUID of image */
  85 };
  86
  87 typedef void (*dyld_image_notifier)(enum dyld_image_mode mode, uint32_t infoCount, const struct dyld_image_info info[]);
  88
  89 /* for use in dyld_all_image_infos.errorKind field */
  90 enum {  dyld_error_kind_none=0,
  91                 dyld_error_kind_dylib_missing=1,
  92                 dyld_error_kind_dylib_wrong_arch=2,
  93                 dyld_error_kind_dylib_version=3,
  94                 dyld_error_kind_symbol_missing=4
  95         };
  96
  97 /* internal limit */
  98 #define DYLD_MAX_PROCESS_INFO_NOTIFY_COUNT  8
  99
 100 struct dyld_all_image_infos {
 101         uint32_t                                                version;                /* 1 in Mac OS X 10.4 and 10.5 */
 102         uint32_t                                                infoArrayCount;
 103 #if defined(__cplusplus) && (BUILDING_LIBDYLD || BUILDING_DYLD)
 104     std::atomic<const struct dyld_image_info*>  infoArray;
 105 #else
 106     const struct dyld_image_info*    infoArray;
 107 #endif
 108         dyld_image_notifier                             notification;
 109         bool                                                    processDetachedFromSharedRegion;
 110         /* the following fields are only in version 2 (Mac OS X 10.6, iPhoneOS 2.0) and later */
 111         bool                                                    libSystemInitialized;
 112         const struct mach_header*               dyldImageLoadAddress;
 113         /* the following field is only in version 3 (Mac OS X 10.6, iPhoneOS 3.0) and later */
 114         void*                                                   jitInfo;
 115         /* the following fields are only in version 5 (Mac OS X 10.6, iPhoneOS 3.0) and later */
 116         const char*                                             dyldVersion;
 117         const char*                                             errorMessage;
 118         uintptr_t                                               terminationFlags;
 119         /* the following field is only in version 6 (Mac OS X 10.6, iPhoneOS 3.1) and later */
 120         void*                                                   coreSymbolicationShmPage;
 121         /* the following field is only in version 7 (Mac OS X 10.6, iPhoneOS 3.1) and later */
 122         uintptr_t                                               systemOrderFlag;
 123         /* the following field is only in version 8 (Mac OS X 10.7, iPhoneOS 3.1) and later */
 124         uintptr_t                                               uuidArrayCount;
 125         const struct dyld_uuid_info*    uuidArray;              /* only images not in dyld shared cache */
 126         /* the following field is only in version 9 (Mac OS X 10.7, iOS 4.0) and later */
 127         struct dyld_all_image_infos*    dyldAllImageInfosAddress;
 128         /* the following field is only in version 10 (Mac OS X 10.7, iOS 4.2) and later */
 129         uintptr_t                                               initialImageCount;
 130         /* the following field is only in version 11 (Mac OS X 10.7, iOS 4.2) and later */
 131         uintptr_t                                               errorKind;
 132         const char*                                             errorClientOfDylibPath;
 133         const char*                                             errorTargetDylibPath;
 134         const char*                                             errorSymbol;
 135         /* the following field is only in version 12 (Mac OS X 10.7, iOS 4.3) and later */
 136         uintptr_t                                               sharedCacheSlide;
 137         /* the following field is only in version 13 (Mac OS X 10.9, iOS 7.0) and later */
 138         uint8_t                                                 sharedCacheUUID[16];
 139         /* the following field is only in version 15 (macOS 10.12, iOS 10.0) and later */
 140         uintptr_t                                               sharedCacheBaseAddress;
 141 #if defined(__cplusplus) && (BUILDING_LIBDYLD || BUILDING_DYLD)
 142     // We want this to be atomic in libdyld so that we can see updates when we map it shared
 143     std::atomic<uint64_t>           infoArrayChangeTimestamp;
 144 #else
 145         uint64_t                                                infoArrayChangeTimestamp;
 146 #endif
 147         const char*                                             dyldPath;
 148         mach_port_t                                             notifyPorts[DYLD_MAX_PROCESS_INFO_NOTIFY_COUNT];
 149 #if __LP64__
 150         uintptr_t                                               reserved[13-(DYLD_MAX_PROCESS_INFO_NOTIFY_COUNT/2)];
 151 #else
 152         uintptr_t                                               reserved[13-DYLD_MAX_PROCESS_INFO_NOTIFY_COUNT];
 153 #endif
 154         /* the following field is only in version 16 (macOS 10.13, iOS 11.0) and later */
 155     uintptr_t                       compact_dyld_image_info_addr;
 156     size_t                          compact_dyld_image_info_size;
 157     uint32_t                        platform; // FIXME: really a dyld_platform_t, but those aren't exposed here.
 158 };
 159
 160 /*
 161  * Beginning in Mac OS X 10.5, this is how gdb discovers where the shared cache is in a process.
 162  * Images that are in the shared cache have their segments rearranged, so when using imageFilePath
 163  * to load the file from disk, you have to know to adjust addresses based on how their segment
 164  * was rearranged.
 165  *
 166  * gdb looks for the symbol "_dyld_shared_region_ranges" in dyld.
 167  *
 168  * It contains information the count of shared regions used by the process.  The count is
 169  * the number of start/length pairs.
 170  */
 171 struct dyld_shared_cache_ranges {
 172         uintptr_t                                       sharedRegionsCount;     /* how many ranges follow */
 173         struct {
 174                 uintptr_t       start;
 175                 uintptr_t       length;
 176         }                                                       ranges[4];                      /* max regions */
 177 };
 178 extern struct dyld_shared_cache_ranges dyld_shared_cache_ranges __attribute__((visibility("hidden")));
 179
 180
 181
 182 #ifdef __cplusplus
 183 }
 184 #endif
 185
 186 #endif /* _DYLD_IMAGES_ */