1919#if defined(__ELF__) || defined(__ANDROID__)
2020
2121#include " ImageInspection.h"
22+ #include " ../SwiftShims/Visibility.h"
23+ #include < atomic>
2224#include < elf.h>
2325#include < link.h>
2426#include < dlfcn.h>
@@ -35,67 +37,124 @@ static const char ProtocolConformancesSymbol[] =
3537static const char TypeMetadataRecordsSymbol[] =
3638 " .swift2_type_metadata_start"
3739
40+ static std::atomic<bool > didInitializeProtocolConformanceLookup;
41+ static std::atomic<bool > didInitializeTypeMetadataLookup;
42+
3843// / Context arguments passed down from dl_iterate_phdr to its callback.
3944struct InspectArgs {
4045 // / Symbol name to look up.
4146 const char *symbolName;
4247 // / Callback function to invoke with the metadata block.
4348 void (*addBlock)(const void *start, uintptr_t size);
49+ // / Set to true when initialize*Lookup() is called.
50+ std::atomic<bool > *didInitializeLookup;
4451};
4552
46- static int iteratePHDRCallback (struct dl_phdr_info *info,
47- size_t size, void *data) {
48- const InspectArgs *inspectArgs = reinterpret_cast <const InspectArgs *>(data);
49- void *handle;
50- if (!info->dlpi_name || info->dlpi_name [0 ] == ' \0 '
51- handle = dlopen (nullptr , RTLD_LAZY);
52- } else {
53- handle = dlopen (info->dlpi_name , RTLD_LAZY | RTLD_NOLOAD);
54- }
53+ static InspectArgs ProtocolConformanceArgs = {
54+ ProtocolConformancesSymbol,
55+ addImageProtocolConformanceBlockCallback,
56+ &didInitializeProtocolConformanceLookup
57+ };
5558
56- if (!handle) {
57- // Not a shared library.
58- return 0 ;
59- }
59+ static InspectArgs TypeMetadataRecordArgs = {
60+ TypeMetadataRecordsSymbol,
61+ addImageTypeMetadataRecordBlockCallback,
62+ &didInitializeTypeMetadataLookup
63+ };
6064
61- const char *conformances =
62- reinterpret_cast <const char *>(dlsym (handle, inspectArgs->symbolName ));
6365
64- if (!conformances) {
65- // if there are no conformances, don't hold this handle open.
66+ // Extract the section information for a named section in an image. imageName
67+ // can be nullptr to specify the main executable.
68+ static SectionInfo getSectionInfo (const char *imageName,
69+ const char *sectionName) {
70+ SectionInfo sectionInfo = { 0 , nullptr };
71+ void *handle = dlopen (imageName, RTLD_LAZY);
72+ if (handle) {
73+ void *symbol = dlsym (handle, sectionName);
74+ if (symbol) {
75+ // Extract the size of the section data from the head of the section.
76+ const char *section = reinterpret_cast <const char *>(symbol);
77+ memcpy (§ionInfo.size , section, sizeof (uint64_t ));
78+ sectionInfo.data = section + sizeof (uint64_t );
79+ }
6680 dlclose (handle);
81+ }
82+ return sectionInfo;
83+ }
84+
85+ static int iteratePHDRCallback (struct dl_phdr_info *info,
86+ size_t size, void *data) {
87+ const InspectArgs *inspectArgs = reinterpret_cast <const InspectArgs *>(data);
88+ const char *fname = info->dlpi_name ;
89+
90+ // While dl_iterate_phdr() is in progress it holds a lock to prevent other
91+ // images being loaded. The initialize flag is set here inside the callback so
92+ // that addNewDSOImage() sees a consistent state. If it was set outside the
93+ // dl_interate_phdr() call then it could result in images being missed or
94+ // added twice.
95+ inspectArgs->didInitializeLookup ->store (true , std::memory_order_release);
96+
97+ if (fname == nullptr || fname[0 ] == ' \0 '
98+ // The filename may be null for both the dynamic loader and main executable.
99+ // So ignore null image name here and explictly add the main executable
100+ // in initialize*Lookup() to avoid adding the data twice.
67101 return 0 ;
68102 }
69103
70- // Extract the size of the conformances block from the head of the section.
71- uint64_t conformancesSize;
72- memcpy (&conformancesSize, conformances, sizeof (conformancesSize));
73- conformances += sizeof (conformancesSize);
104+ SectionInfo block = getSectionInfo (fname, inspectArgs->symbolName );
105+ if (block.size > 0 ) {
106+ inspectArgs->addBlock (block.data , block.size );
107+ }
108+ return 0 ;
109+ }
74110
75- inspectArgs->addBlock (conformances, conformancesSize);
111+ // Add the section information in an image specified by an address in that
112+ // image.
113+ static void addBlockInImage (const InspectArgs *inspectArgs, const void *addr) {
114+ const char *fname = nullptr ;
115+ if (addr) {
116+ Dl_info info;
117+ if (dladdr (addr, &info) == 0 || info.dli_fname == nullptr ) {
118+ return ;
119+ }
120+ fname = info.dli_fname ;
121+ }
122+ SectionInfo block = getSectionInfo (fname, inspectArgs->symbolName );
123+ if (block.size > 0 ) {
124+ inspectArgs->addBlock (block.data , block.size );
125+ }
126+ }
76127
77- dlclose (handle);
78- return 0 ;
128+ static void initializeSectionLookup (InspectArgs *inspectArgs) {
129+ // Add section data in the main executable.
130+ addBlockInImage (inspectArgs, nullptr );
131+ // Search the loaded dls. This only searches the already
132+ // loaded ones. Any images loaded after this are processed by
133+ // addNewDSOImage() below.
134+ dl_iterate_phdr (iteratePHDRCallback, reinterpret_cast <void *>(inspectArgs));
79135}
80136
81137void swift::initializeProtocolConformanceLookup () {
82- // Search the loaded dls. This only searches the already
83- // loaded ones.
84- // FIXME: Find a way to have this continue to happen for dlopen-ed images.
85- // rdar://problem/19045112
86- InspectArgs ProtocolConformanceArgs = {
87- ProtocolConformancesSymbol,
88- addImageProtocolConformanceBlockCallback
89- };
90- dl_iterate_phdr (iteratePHDRCallback, &ProtocolConformanceArgs);
138+ initializeSectionLookup (&ProtocolConformanceArgs);
91139}
92140
93141void swift::initializeTypeMetadataRecordLookup () {
94- InspectArgs TypeMetadataRecordArgs = {
95- TypeMetadataRecordsSymbol,
96- addImageTypeMetadataRecordBlockCallback
97- };
98- dl_iterate_phdr (iteratePHDRCallback, &TypeMetadataRecordArgs);
142+ initializeSectionLookup (&TypeMetadataRecordArgs);
143+ }
144+
145+ // As ELF images are loaded, ImageInspectionInit:sectionDataInit() will call
146+ // addNewDSOImage() with an address in the image that can later be used via
147+ // dladdr() to dlopen() the image after the appropiate initialize*Lookup()
148+ // function has been called.
149+ SWIFT_RUNTIME_EXPORT
150+ void swift::addNewDSOImage (const void *addr) {
151+ if (didInitializeProtocolConformanceLookup.load (std::memory_order_acquire)) {
152+ addBlockInImage (&ProtocolConformanceArgs, addr);
153+ }
154+
155+ if (didInitializeTypeMetadataLookup.load (std::memory_order_acquire)) {
156+ addBlockInImage (&TypeMetadataRecordArgs, addr);
157+ }
99158}
100159
101160int swift::lookupSymbol (const void *address, SymbolInfo *info) {
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