LibELF: Add find_demangled_function

Also, added AK::String::index_of and fixed a bug in ELF::Loader::symbol_ptr

AK/String.cpp

@@ -317,6 +317,18 @@ bool String::contains(const String& needle) const
     return strstr(characters(), needle.characters());
 }
 
+Optional<size_t> String::index_of(const String& needle) const
+{
+    if (is_null() || needle.is_null())
+        return {};
+
+    const char* self_characters = characters();
+    const char* result = strstr(self_characters, needle.characters());
+    if (!result)
+        return {};
+    return Optional<size_t> { result - self_characters };
+}
+
 bool String::equals_ignoring_case(const StringView& other) const
 {
     return StringUtils::equals_ignoring_case(view(), other);

AK/String.h

@@ -117,6 +117,7 @@ public:
     bool equals_ignoring_case(const StringView&) const;
 
     bool contains(const String&) const;
+    Optional<size_t> index_of(const String&) const;
 
     Vector<String> split_limit(char separator, size_t limit, bool keep_empty = false) const;
     Vector<String> split(char separator, bool keep_empty = false) const;

Applications/Debugger/DebugSession.cpp

@@ -30,8 +30,8 @@
 
 DebugSession::DebugSession(int pid)
     : m_debugee_pid(pid)
-    , m_executable(make<MappedFile>(String::format("/proc/%d/exe", pid)))
-    , m_elf_image(make<ELF::Image>(reinterpret_cast<u8*>(m_executable->data()), m_executable->size()))
+    , m_executable(String::format("/proc/%d/exe", pid))
+    , m_elf(reinterpret_cast<u8*>(m_executable.data()), m_executable.size())
 {
 }
 
@@ -176,8 +176,3 @@ void DebugSession::continue_debugee()
         ASSERT_NOT_REACHED();
     }
 }
-
-VirtualAddress DebugSession::get_entry_point() const
-{
-    return m_elf_image->entry();
-}

Applications/Debugger/DebugSession.h

@@ -26,13 +26,14 @@
 
 #pragma once
 
+#include <AK/Demangle.h>
 #include <AK/HashMap.h>
 #include <AK/MappedFile.h>
 #include <AK/Optional.h>
 #include <AK/OwnPtr.h>
 #include <AK/String.h>
 #include <LibC/sys/arch/i386/regs.h>
-#include <LibELF/Image.h>
+#include <LibELF/Loader.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/ptrace.h>
@@ -69,7 +70,7 @@ public:
     template<typename Callback>
     void run(Callback callback);
 
-    VirtualAddress get_entry_point() const;
+    const ELF::Loader& elf() const { return m_elf; }
 
     enum DebugDecision {
         Continue,
@@ -90,8 +91,8 @@ private:
     int m_debugee_pid { -1 };
     bool m_is_debugee_dead { false };
 
-    NonnullOwnPtr<MappedFile> m_executable;
-    NonnullOwnPtr<ELF::Image> m_elf_image;
+    MappedFile m_executable;
+    ELF::Loader m_elf;
 
     HashMap<void*, BreakPoint> m_breakpoints;
 };

Applications/Debugger/main.cpp

@@ -27,6 +27,7 @@
 #include "DebugSession.h"
 #include <AK/Assertions.h>
 #include <AK/ByteBuffer.h>
+#include <AK/Demangle.h>
 #include <AK/LogStream.h>
 #include <AK/StringBuilder.h>
 #include <AK/kmalloc.h>
@@ -137,14 +138,28 @@ bool handle_breakpoint_command(const String& command)
     if (parts.size() != 2)
         return false;
 
-    u32 breakpoint_address = strtoul(parts[1].characters(), nullptr, 16);
-    if (errno != 0)
+    auto argument = parts[1];
+    if (argument.is_empty())
         return false;
+
+    u32 breakpoint_address = 0;
+
+    if ((argument[0] >= '0' && argument[0] <= '9')) {
+        breakpoint_address = strtoul(argument.characters(), nullptr, 16);
+    } else {
+        auto symbol = g_debug_session->elf().find_demangled_function(argument);
+        if (!symbol.has_value()) {
+            printf("symbol %s not found\n", parts[1].characters());
+            return false;
+        }
+        breakpoint_address = reinterpret_cast<u32>(symbol.value().value());
+    }
     bool success = g_debug_session->insert_breakpoint(reinterpret_cast<void*>(breakpoint_address));
     if (!success) {
-        fprintf(stderr, "coult not insert breakpoint at: 0x%x\n", breakpoint_address);
+        fprintf(stderr, "coult not insert breakpoint at: %08x\n", breakpoint_address);
         return false;
     }
+    printf("breakpoint insterted at: %08x\n", breakpoint_address);
     return true;
 }
 
@@ -153,8 +168,8 @@ void print_help()
     printf("Options:\n"
            "cont - Continue execution\n"
            "regs - Print registers\n"
-           "dis <number of instructions> - Print disassembly\n"
-           "bp <address> - Insert a breakpoint\n");
+           "dis [number of instructions] - Print disassembly\n"
+           "bp <address/symbol> - Insert a breakpoint\n");
 }
 
 int main(int argc, char** argv)
@@ -185,7 +200,7 @@ int main(int argc, char** argv)
     sa.sa_handler = handle_sigint;
     sigaction(SIGINT, &sa, nullptr);
 
-    bool rc = g_debug_session->insert_breakpoint(g_debug_session->get_entry_point().as_ptr());
+    bool rc = g_debug_session->insert_breakpoint(g_debug_session->elf().entry().as_ptr());
     ASSERT(rc);
 
     g_debug_session->run([&](DebugSession::DebugBreakReason reason, Optional<PtraceRegisters> optional_regs) {

Libraries/LibELF/Loader.cpp

@@ -136,13 +136,13 @@ bool Loader::layout()
     return !failed;
 }
 
-char* Loader::symbol_ptr(const char* name)
+char* Loader::symbol_ptr(const char* name) const
 {
     char* found_ptr = nullptr;
     m_image.for_each_symbol([&](const Image::Symbol symbol) {
         if (symbol.type() != STT_FUNC)
             return IterationDecision::Continue;
-        if (symbol.name() == name)
+        if (symbol.name() != name)
             return IterationDecision::Continue;
         if (m_image.is_executable())
             found_ptr = (char*)(size_t)symbol.value();
@@ -153,6 +153,25 @@ char* Loader::symbol_ptr(const char* name)
     return found_ptr;
 }
 
+Optional<Image::Symbol> Loader::find_demangled_function(const String& name) const
+{
+    Optional<Image::Symbol> found;
+    m_image.for_each_symbol([&](const Image::Symbol symbol) {
+        if (symbol.type() != STT_FUNC)
+            return IterationDecision::Continue;
+        auto demangled = demangle(symbol.name());
+        auto index_of_paren = demangled.index_of("(");
+        if (index_of_paren.has_value()) {
+            demangled = demangled.substring(0, index_of_paren.value());
+        }
+        if (demangled != name)
+            return IterationDecision::Continue;
+        found = symbol;
+        return IterationDecision::Break;
+    });
+    return found;
+}
+
 #ifndef KERNEL
 Optional<Image::Symbol> Loader::find_symbol(u32 address, u32* out_offset) const
 {
@@ -160,7 +179,7 @@ Optional<Image::Symbol> Loader::find_symbol(u32 address, u32* out_offset) const
         return {};
 
     SortedSymbol* sorted_symbols = nullptr;
-#ifdef KERNEL
+#    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();
@@ -175,7 +194,7 @@ Optional<Image::Symbol> Loader::find_symbol(u32 address, u32* out_offset) const
     } else {
         sorted_symbols = (SortedSymbol*)m_sorted_symbols_region->vaddr().as_ptr();
     }
-#else
+#    else
     if (m_sorted_symbols.is_empty()) {
         m_sorted_symbols.ensure_capacity(m_symbol_count);
         m_image.for_each_symbol([this](auto& symbol) {
@@ -187,7 +206,7 @@ Optional<Image::Symbol> Loader::find_symbol(u32 address, u32* out_offset) const
         });
     }
     sorted_symbols = m_sorted_symbols.data();
-#endif
+#    endif
 
     for (size_t i = 0; i < m_symbol_count; ++i) {
         if (sorted_symbols[i].address > address) {

Libraries/LibELF/Loader.h

@@ -52,9 +52,13 @@ public:
     Function<void*(VirtualAddress, size_t, size_t, bool, bool, const String&)> alloc_section_hook;
     Function<void*(size_t, size_t)> tls_section_hook;
     Function<void*(VirtualAddress, size_t, size_t, size_t, bool r, bool w, bool x, const String&)> map_section_hook;
-    VirtualAddress entry() const { return m_image.entry(); }
 #endif
-    char* symbol_ptr(const char* name);
+    VirtualAddress entry() const
+    {
+        return m_image.entry();
+    }
+    char* symbol_ptr(const char* name) const;
+    Optional<Image::Symbol> find_demangled_function(const String& name) const;
 
     bool has_symbols() const { return m_symbol_count; }