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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /mozglue/linker/CustomElf.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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diff --git a/mozglue/linker/CustomElf.h b/mozglue/linker/CustomElf.h
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef CustomElf_h
+#define CustomElf_h
+
+#include "ElfLoader.h"
+#include "BaseElf.h"
+#include "Logging.h"
+#include "Elfxx.h"
+
+/**
+ * Library Handle class for ELF libraries we don't let the system linker
+ * handle.
+ */
+class CustomElf: public BaseElf, private ElfLoader::link_map
+{
+ friend class ElfLoader;
+ friend class SEGVHandler;
+public:
+ /**
+ * Returns a new CustomElf using the given file descriptor to map ELF
+ * content. The file descriptor ownership is stolen, and it will be closed
+ * in CustomElf's destructor if an instance is created, or by the Load
+ * method otherwise. The path corresponds to the file descriptor, and flags
+ * are the same kind of flags that would be given to dlopen(), though
+ * currently, none are supported and the behaviour is more or less that of
+ * RTLD_GLOBAL | RTLD_BIND_NOW.
+ */
+ static already_AddRefed<LibHandle> Load(Mappable *mappable,
+ const char *path, int flags);
+
+ /**
+ * Inherited from LibHandle/BaseElf
+ */
+ virtual ~CustomElf();
+
+protected:
+ virtual Mappable *GetMappable() const;
+
+public:
+ /**
+ * Shows some stats about the Mappable instance. The when argument is to be
+ * used by the caller to give an identifier of the when the stats call is
+ * made.
+ */
+ virtual void stats(const char *when) const;
+
+ /**
+ * Returns the instance, casted as BaseElf. (short of a better way to do
+ * this without RTTI)
+ */
+ virtual BaseElf *AsBaseElf() { return this; }
+
+private:
+ /**
+ * Scan dependent libraries to find the address corresponding to the
+ * given symbol name. This is used to find symbols that are undefined
+ * in the Elf object.
+ */
+ void *GetSymbolPtrInDeps(const char *symbol) const;
+
+ /**
+ * Private constructor
+ */
+ CustomElf(Mappable *mappable, const char *path)
+ : BaseElf(path, mappable)
+ , link_map()
+ , init(0)
+ , fini(0)
+ , initialized(false)
+ , has_text_relocs(false)
+ { }
+
+ /**
+ * Loads an Elf segment defined by the given PT_LOAD header.
+ * Returns whether this succeeded or failed.
+ */
+ bool LoadSegment(const Elf::Phdr *pt_load) const;
+
+ /**
+ * Initializes the library according to information found in the given
+ * PT_DYNAMIC header.
+ * Returns whether this succeeded or failed.
+ */
+ bool InitDyn(const Elf::Phdr *pt_dyn);
+
+ /**
+ * Apply .rel.dyn/.rela.dyn relocations.
+ * Returns whether this succeeded or failed.
+ */
+ bool Relocate();
+
+ /**
+ * Apply .rel.plt/.rela.plt relocations.
+ * Returns whether this succeeded or failed.
+ */
+ bool RelocateJumps();
+
+ /**
+ * Call initialization functions (.init/.init_array)
+ * Returns true;
+ */
+ bool CallInit();
+
+ /**
+ * Call destructor functions (.fini_array/.fini)
+ * Returns whether this succeeded or failed.
+ */
+ void CallFini();
+
+ /**
+ * Call a function given a pointer to its location.
+ */
+ void CallFunction(void *ptr) const
+ {
+ /* C++ doesn't allow direct conversion between pointer-to-object
+ * and pointer-to-function. */
+ union {
+ void *ptr;
+ void (*func)(void);
+ } f;
+ f.ptr = ptr;
+ DEBUG_LOG("%s: Calling function @%p", GetPath(), ptr);
+ f.func();
+ }
+
+ /**
+ * Call a function given a an address relative to the library base
+ */
+ void CallFunction(Elf::Addr addr) const
+ {
+ return CallFunction(GetPtr(addr));
+ }
+
+ /* List of dependent libraries */
+ std::vector<RefPtr<LibHandle> > dependencies;
+
+ /* List of .rel.dyn/.rela.dyn relocations */
+ Array<Elf::Reloc> relocations;
+
+ /* List of .rel.plt/.rela.plt relocation */
+ Array<Elf::Reloc> jumprels;
+
+ /* Relative address of the initialization and destruction functions
+ * (.init/.fini) */
+ Elf::Addr init, fini;
+
+ /* List of initialization and destruction functions
+ * (.init_array/.fini_array) */
+ Array<void *> init_array, fini_array;
+
+ bool initialized;
+
+ bool has_text_relocs;
+};
+
+#endif /* CustomElf_h */