LibELF: Add a find_symbol() API that finds a Symbol for an address

Also add ELFImage::Symbol::raw_data() to get a StringView containing
the entire symbol contents.

4 files changed, 60 insertions, 1 deletions

diff --git a/Libraries/LibELF/ELFImage.cpp b/Libraries/LibELF/ELFImage.cpp
index 815b272561..a2bff5b2ce 100644
--- a/Libraries/LibELF/ELFImage.cpp
+++ b/Libraries/LibELF/ELFImage.cpp
@@ -414,3 +414,9 @@ bool ELFImage::validate_program_headers(const Elf32_Ehdr& elf_header, size_t fil
     }
     return true;
 }
+
+StringView ELFImage::Symbol::raw_data() const
+{
+    auto& section = this->section();
+    return { section.raw_data() + (value() - section.address()), size() };
+}
diff --git a/Libraries/LibELF/ELFImage.h b/Libraries/LibELF/ELFImage.h
index 2dc0aa857a..61f912079d 100644
--- a/Libraries/LibELF/ELFImage.h
+++ b/Libraries/LibELF/ELFImage.h
@@ -73,6 +73,7 @@ public:
         unsigned type() const { return ELF32_ST_TYPE(m_sym.st_info); }
         unsigned bind() const { return ELF32_ST_BIND(m_sym.st_info); }
         const Section section() const { return m_image.section(section_index()); }
+        StringView raw_data() const;
 
     private:
         const ELFImage& m_image;
diff --git a/Libraries/LibELF/ELFLoader.cpp b/Libraries/LibELF/ELFLoader.cpp
index b2952d1ad5..27c5cd0bed 100644
--- a/Libraries/LibELF/ELFLoader.cpp
+++ b/Libraries/LibELF/ELFLoader.cpp
@@ -151,6 +151,56 @@ char* ELFLoader::symbol_ptr(const char* name)
     return found_ptr;
 }
 
+#ifndef KERNEL
+Optional<ELFImage::Symbol> ELFLoader::find_symbol(u32 address, u32* out_offset) const
+{
+    if (!m_symbol_count)
+        return {};
+
+    SortedSymbol* sorted_symbols = nullptr;
+#ifdef KERNEL
+    if (!m_sorted_symbols_region) {
+        m_sorted_symbols_region = MM.allocate_kernel_region(PAGE_ROUND_UP(m_symbol_count * sizeof(SortedSymbol)), "Sorted symbols", Kernel::Region::Access::Read | Kernel::Region::Access::Write);
+        sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
+        size_t index = 0;
+        m_image.for_each_symbol([&](auto& symbol) {
+            sorted_symbols[index++] = { symbol.value(), symbol.name() };
+            return IterationDecision::Continue;
+        });
+        quick_sort(sorted_symbols, sorted_symbols + m_symbol_count, [](auto& a, auto& b) {
+            return a.address < b.address;
+        });
+    } else {
+        sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
+    }
+#else
+    if (m_sorted_symbols.is_empty()) {
+        m_sorted_symbols.ensure_capacity(m_symbol_count);
+        m_image.for_each_symbol([this](auto& symbol) {
+            m_sorted_symbols.append({ symbol.value(), symbol.name(), {}, symbol });
+            return IterationDecision::Continue;
+        });
+        quick_sort(m_sorted_symbols, [](auto& a, auto& b) {
+            return a.address < b.address;
+        });
+    }
+    sorted_symbols = m_sorted_symbols.data();
+#endif
+
+    for (size_t i = 0; i < m_symbol_count; ++i) {
+        if (sorted_symbols[i].address > address) {
+            if (i == 0)
+                return {};
+            auto& symbol = sorted_symbols[i - 1];
+            if (out_offset)
+                *out_offset = address - symbol.address;
+            return symbol.symbol;
+        }
+    }
+    return {};
+}
+#endif
+
 String ELFLoader::symbolicate(u32 address, u32* out_offset) const
 {
     if (!m_symbol_count) {
@@ -178,7 +228,7 @@ String ELFLoader::symbolicate(u32 address, u32* out_offset) const
     if (m_sorted_symbols.is_empty()) {
         m_sorted_symbols.ensure_capacity(m_symbol_count);
         m_image.for_each_symbol([this](auto& symbol) {
-            m_sorted_symbols.append({ symbol.value(), symbol.name(), {} });
+            m_sorted_symbols.append({ symbol.value(), symbol.name(), {}, {} });
             return IterationDecision::Continue;
         });
         quick_sort(m_sorted_symbols, [](auto& a, auto& b) {
diff --git a/Libraries/LibELF/ELFLoader.h b/Libraries/LibELF/ELFLoader.h
index d2ab9627ac..49fe5ad414 100644
--- a/Libraries/LibELF/ELFLoader.h
+++ b/Libraries/LibELF/ELFLoader.h
@@ -57,6 +57,7 @@ public:
     bool has_symbols() const { return m_symbol_count; }
 
     String symbolicate(u32 address, u32* offset = nullptr) const;
+    Optional<ELFImage::Symbol> find_symbol(u32 address, u32* offset = nullptr) const;
 
 private:
     bool layout();
@@ -85,6 +86,7 @@ private:
         StringView name;
 #ifndef KERNEL
         String demangled_name;
+        Optional<ELFImage::Symbol> symbol;
 #endif
     };
 #ifdef KERNEL