emaste added you to the CC list for the revision Move elf-core ELFNote to
ObjectFileELF and use it for build id parsing.
Hi mikesart, jwolfe,
http://llvm-reviews.chandlerc.com/D1902
Files:
source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
source/Plugins/ObjectFile/ELF/ObjectFileELF.h
source/Plugins/Process/elf-core/ProcessElfCore.cpp
Index: source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
===
--- source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -16,6 +16,7 @@
#include lldb/Core/DataBuffer.h
#include lldb/Core/Error.h
#include lldb/Core/FileSpecList.h
+#include lldb/Core/Log.h
#include lldb/Core/Module.h
#include lldb/Core/ModuleSpec.h
#include lldb/Core/PluginManager.h
@@ -143,6 +144,44 @@
} // end anonymous namespace
+bool
+ELFNote::Parse(const DataExtractor data, lldb::offset_t *offset)
+{
+// Read all fields.
+if (data.GetU32(offset, n_namesz, 3) == NULL)
+return false;
+
+// The name field is required to be nul-terminated, and n_namesz
+// includes the terminating nul in observed implementations (contrary
+// to the ELF-64 spec). A special case is needed for cores generated
+// by some older Linux versions, which write a note named CORE
+// without a nul terminator and n_namesz = 4.
+if (n_namesz == 4)
+{
+char buf[4];
+if (data.ExtractBytes (*offset, 4, data.GetByteOrder(), buf) != 4)
+return false;
+if (strncmp (buf, CORE, 4) == 0)
+{
+n_name = CORE;
+*offset += 4;
+return true;
+}
+}
+
+const char *cstr = data.GetCStr(offset, llvm::RoundUpToAlignment (n_namesz, 4));
+if (cstr == NULL)
+{
+Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_SYMBOLS));
+if (log)
+log-Printf(Failed to parse note name lacking nul terminator);
+
+return false;
+}
+n_name = cstr;
+return true;
+}
+
//--
// Static methods.
//--
@@ -685,42 +724,26 @@
{
// Try to parse the note section (ie .note.gnu.build-id|.notes|.note|...) and get the build id.
// BuildID documentation: https://fedoraproject.org/wiki/Releases/FeatureBuildId
-struct
-{
-uint32_t name_len; // Length of note name
-uint32_t desc_len; // Length of note descriptor
-uint32_t type; // Type of note (1 is ABI_TAG, 3 is BUILD_ID)
-} notehdr;
lldb::offset_t offset = 0;
static const uint32_t g_gnu_build_id = 3; // NT_GNU_BUILD_ID from elf.h
while (true)
{
-if (data.GetU32 (offset, notehdr, 3) == NULL)
+ELFNote note = ELFNote();
+if (!note.Parse(data, offset))
return false;
-notehdr.name_len = llvm::RoundUpToAlignment (notehdr.name_len, 4);
-notehdr.desc_len = llvm::RoundUpToAlignment (notehdr.desc_len, 4);
-
-lldb::offset_t offset_next_note = offset + notehdr.name_len + notehdr.desc_len;
-
// 16 bytes is UUID|MD5, 20 bytes is SHA1
-if ((notehdr.type == g_gnu_build_id) (notehdr.name_len == 4)
-(notehdr.desc_len == 16 || notehdr.desc_len == 20))
+if (note.n_name == GNU (note.n_type == g_gnu_build_id)
+(note.n_descsz == 16 || note.n_descsz == 20))
{
-char name[4];
-if (data.GetU8 (offset, name, 4) == NULL)
+uint8_t uuidbuf[20];
+if (data.GetU8 (offset, uuidbuf, note.n_descsz) == NULL)
return false;
-if (!strcmp(name, GNU))
-{
-uint8_t uuidbuf[20];
-if (data.GetU8 (offset, uuidbuf, notehdr.desc_len) == NULL)
-return false;
-uuid.SetBytes (uuidbuf, notehdr.desc_len);
-return true;
-}
+uuid.SetBytes (uuidbuf, note.n_descsz);
+return true;
}
-offset = offset_next_note;
+offset += llvm::RoundUpToAlignment(note.n_descsz, 4);
}
return false;
}
Index: source/Plugins/ObjectFile/ELF/ObjectFileELF.h
===
--- source/Plugins/ObjectFile/ELF/ObjectFileELF.h
+++ source/Plugins/ObjectFile/ELF/ObjectFileELF.h
@@ -20,6 +20,34 @@
#include ELFHeader.h
+struct ELFNote
+{
+elf::elf_word n_namesz;
+elf::elf_word n_descsz;
+elf::elf_word n_type;
+
+std::string n_name;
+
+ELFNote() : n_namesz(0), n_descsz(0), n_type(0)
+{
+}
+
+/// Parse an ELFNote entry from the given DataExtractor starting at position
+/// \p offset.
+///
+/// @param[in] data
+///The DataExtractor to read from.
+///
+/// @param[in,out] offset
+///Pointer to an offset in the data. On return
