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authorIan Lance Taylor <ian@airs.com>2008-03-25 05:11:41 +0000
committerIan Lance Taylor <ian@airs.com>2008-03-25 05:11:41 +0000
commit8ed814a99c1393f82d754fba230c6187eecc2e2e (patch)
treec13bb1cf83fb27336aae697f94e8a1fb69ec9380
parentbaf4901374130b96e5d3792794b29b8dfb46dd32 (diff)
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* options.h (class General_options): Define build_id option.
* layout.h (class Layout): Declare write_build_id, create_note, create_build_id. Add build_id_note_ member. * layout.cc: Include <cerrno>, <fcntl.h>, <unistd.h>, "libiberty.h", "md5.h", "sha1.h". (Layout::Layout): Initialize eh_frame_data_, eh_frame_hdr_section_, and build_id_note_. (Layout::finalize): Call create_build_id. (Layout::create_note): New function, broken out of Layout::create_gold_note. (Layout::create_gold_note): Call create_note. (Layout::create_build_id): New function. (Layout::write_build_id): New function. (Close_task_runner::run): Call write_build_id.
-rw-r--r--gold/ChangeLog15
-rw-r--r--gold/layout.cc216
-rw-r--r--gold/layout.h15
-rw-r--r--gold/options.h4
4 files changed, 230 insertions, 20 deletions
diff --git a/gold/ChangeLog b/gold/ChangeLog
index af137fc..8b75a4a 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,5 +1,20 @@
2008-03-24 Ian Lance Taylor <iant@google.com>
+ * options.h (class General_options): Define build_id option.
+ * layout.h (class Layout): Declare write_build_id, create_note,
+ create_build_id. Add build_id_note_ member.
+ * layout.cc: Include <cerrno>, <fcntl.h>, <unistd.h>,
+ "libiberty.h", "md5.h", "sha1.h".
+ (Layout::Layout): Initialize eh_frame_data_,
+ eh_frame_hdr_section_, and build_id_note_.
+ (Layout::finalize): Call create_build_id.
+ (Layout::create_note): New function, broken out of
+ Layout::create_gold_note.
+ (Layout::create_gold_note): Call create_note.
+ (Layout::create_build_id): New function.
+ (Layout::write_build_id): New function.
+ (Close_task_runner::run): Call write_build_id.
+
* x86_64.cc: Correct license to GPLv3.
2008-03-23 Ian Lance Taylor <iant@google.com>
diff --git a/gold/layout.cc b/gold/layout.cc
index 9758597..1bbfcb6 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -22,10 +22,16 @@
#include "gold.h"
+#include <cerrno>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <utility>
+#include <fcntl.h>
+#include <unistd.h>
+#include "libiberty.h"
+#include "md5.h"
+#include "sha1.h"
#include "parameters.h"
#include "options.h"
@@ -76,7 +82,8 @@ Layout::Layout(const General_options& options, Script_options* script_options)
unattached_section_list_(), special_output_list_(),
section_headers_(NULL), tls_segment_(NULL), symtab_section_(NULL),
dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
- eh_frame_section_(NULL), group_signatures_(), output_file_size_(-1),
+ eh_frame_section_(NULL), eh_frame_data_(NULL), eh_frame_hdr_section_(NULL),
+ build_id_note_(NULL), group_signatures_(), output_file_size_(-1),
input_requires_executable_stack_(false),
input_with_gnu_stack_note_(false),
input_without_gnu_stack_note_(false),
@@ -1035,6 +1042,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
this->create_gold_note();
this->create_executable_stack_info(target);
+ this->create_build_id();
Output_segment* phdr_seg = NULL;
if (!parameters->options().relocatable() && !parameters->doing_static_link())
@@ -1181,15 +1189,16 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
return off;
}
-// Create a .note section for an executable or shared library. This
-// records the version of gold used to create the binary.
+// Create a note header following the format defined in the ELF ABI.
+// NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the
+// descriptor. ALLOCATE is true if the section should be allocated in
+// memory. This returns the new note section. It sets
+// *TRAILING_PADDING to the number of trailing zero bytes required.
-void
-Layout::create_gold_note()
+Output_section*
+Layout::create_note(const char* name, int note_type, size_t descsz,
+ bool allocate, size_t* trailing_padding)
{
- if (parameters->options().relocatable())
- return;
-
// Authorities all agree that the values in a .note field should
// be aligned on 4-byte boundaries for 32-bit binaries. However,
// they differ on what the alignment is for 64-bit binaries.
@@ -1208,19 +1217,14 @@ Layout::create_gold_note()
#endif
// The contents of the .note section.
- const char* name = "GNU";
- std::string desc(std::string("gold ") + gold::get_version_string());
size_t namesz = strlen(name) + 1;
size_t aligned_namesz = align_address(namesz, size / 8);
- size_t descsz = desc.length() + 1;
size_t aligned_descsz = align_address(descsz, size / 8);
- const int note_type = 4;
- size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
+ size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
- unsigned char buffer[128];
- gold_assert(sizeof buffer >= notesz);
- memset(buffer, 0, notesz);
+ unsigned char* buffer = new unsigned char[notehdrsz];
+ memset(buffer, 0, notehdrsz);
bool is_big_endian = parameters->target().is_big_endian();
@@ -1258,15 +1262,46 @@ Layout::create_gold_note()
gold_unreachable();
memcpy(buffer + 3 * (size / 8), name, namesz);
- memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
const char* note_name = this->namepool_.add(".note", false, NULL);
+ elfcpp::Elf_Xword flags = 0;
+ if (allocate)
+ flags = elfcpp::SHF_ALLOC;
Output_section* os = this->make_output_section(note_name,
elfcpp::SHT_NOTE,
- 0);
- Output_section_data* posd = new Output_data_const(buffer, notesz,
- size / 8);
+ flags);
+ Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
+ size / 8);
+ os->add_output_section_data(posd);
+
+ *trailing_padding = aligned_descsz - descsz;
+
+ return os;
+}
+
+// For an executable or shared library, create a note to record the
+// version of gold used to create the binary.
+
+void
+Layout::create_gold_note()
+{
+ if (parameters->options().relocatable())
+ return;
+
+ std::string desc = std::string("gold ") + gold::get_version_string();
+
+ size_t trailing_padding;
+ Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
+ desc.size(), false, &trailing_padding);
+
+ Output_section_data* posd = new Output_data_const(desc, 4);
os->add_output_section_data(posd);
+
+ if (trailing_padding > 0)
+ {
+ posd = new Output_data_fixed_space(trailing_padding, 0);
+ os->add_output_section_data(posd);
+ }
}
// Record whether the stack should be executable. This can be set
@@ -1318,6 +1353,104 @@ Layout::create_executable_stack_info(const Target* target)
}
}
+// If --build-id was used, set up the build ID note.
+
+void
+Layout::create_build_id()
+{
+ if (!parameters->options().user_set_build_id())
+ return;
+
+ const char* style = parameters->options().build_id();
+ if (strcmp(style, "none") == 0)
+ return;
+
+ // Set DESCSZ to the size of the note descriptor. When possible,
+ // set DESC to the note descriptor contents.
+ size_t descsz;
+ std::string desc;
+ if (strcmp(style, "md5") == 0)
+ descsz = 128 / 8;
+ else if (strcmp(style, "sha1") == 0)
+ descsz = 160 / 8;
+ else if (strcmp(style, "uuid") == 0)
+ {
+ const size_t uuidsz = 128 / 8;
+
+ char buffer[uuidsz];
+ memset(buffer, 0, uuidsz);
+
+ int descriptor = ::open("/dev/urandom", O_RDONLY);
+ if (descriptor < 0)
+ gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
+ strerror(errno));
+ else
+ {
+ ssize_t got = ::read(descriptor, buffer, uuidsz);
+ ::close(descriptor);
+ if (got < 0)
+ gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
+ else if (static_cast<size_t>(got) != uuidsz)
+ gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
+ uuidsz, got);
+ }
+
+ desc.assign(buffer, uuidsz);
+ descsz = uuidsz;
+ }
+ else if (strncmp(style, "0x", 2) == 0)
+ {
+ hex_init();
+ const char* p = style + 2;
+ while (*p != '\0')
+ {
+ if (hex_p(p[0]) && hex_p(p[1]))
+ {
+ char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
+ desc += c;
+ p += 2;
+ }
+ else if (*p == '-' || *p == ':')
+ ++p;
+ else
+ gold_fatal(_("--build-id argument '%s' not a valid hex number"),
+ style);
+ }
+ descsz = desc.size();
+ }
+ else
+ gold_fatal(_("unrecognized --build-id argument '%s'"), style);
+
+ // Create the note.
+ size_t trailing_padding;
+ Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
+ descsz, true, &trailing_padding);
+
+ if (!desc.empty())
+ {
+ // We know the value already, so we fill it in now.
+ gold_assert(desc.size() == descsz);
+
+ Output_section_data* posd = new Output_data_const(desc, 4);
+ os->add_output_section_data(posd);
+
+ if (trailing_padding != 0)
+ {
+ posd = new Output_data_fixed_space(trailing_padding, 0);
+ os->add_output_section_data(posd);
+ }
+ }
+ else
+ {
+ // We need to compute a checksum after we have completed the
+ // link.
+ gold_assert(trailing_padding == 0);
+ this->build_id_note_ = new Output_data_fixed_space(descsz, 4);
+ os->add_output_section_data(this->build_id_note_);
+ os->set_after_input_sections();
+ }
+}
+
// Return whether SEG1 should be before SEG2 in the output file. This
// is based entirely on the segment type and flags. When this is
// called the segment addresses has normally not yet been set.
@@ -2676,6 +2809,46 @@ Layout::write_sections_after_input_sections(Output_file* of)
this->section_headers_->write(of);
}
+// If the build ID requires computing a checksum, do so here, and
+// write it out. We compute a checksum over the entire file because
+// that is simplest.
+
+void
+Layout::write_build_id(Output_file* of) const
+{
+ if (this->build_id_note_ == NULL)
+ return;
+
+ const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
+
+ unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
+ this->build_id_note_->data_size());
+
+ const char* style = parameters->options().build_id();
+ if (strcmp(style, "sha1") == 0)
+ {
+ sha1_ctx ctx;
+ sha1_init_ctx(&ctx);
+ sha1_process_bytes(iv, this->output_file_size_, &ctx);
+ sha1_finish_ctx(&ctx, ov);
+ }
+ else if (strcmp(style, "md5") == 0)
+ {
+ md5_ctx ctx;
+ md5_init_ctx(&ctx);
+ md5_process_bytes(iv, this->output_file_size_, &ctx);
+ md5_finish_ctx(&ctx, ov);
+ }
+ else
+ gold_unreachable();
+
+ of->write_output_view(this->build_id_note_->offset(),
+ this->build_id_note_->data_size(),
+ ov);
+
+ of->free_input_view(0, this->output_file_size_, iv);
+}
+
// Write out a binary file. This is called after the link is
// complete. IN is the temporary output file we used to generate the
// ELF code. We simply walk through the segments, read them from
@@ -2856,6 +3029,9 @@ Write_after_input_sections_task::run(Workqueue*)
void
Close_task_runner::run(Workqueue*, const Task*)
{
+ // If we need to compute a checksum for the BUILD if, we do so here.
+ this->layout_->write_build_id(this->of_);
+
// If we've been asked to create a binary file, we do so here.
if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
this->layout_->write_binary(this->of_);
diff --git a/gold/layout.h b/gold/layout.h
index 714c374..fe888c7 100644
--- a/gold/layout.h
+++ b/gold/layout.h
@@ -294,6 +294,10 @@ class Layout
script_options() const
{ return this->script_options_; }
+ // Compute and write out the build ID if needed.
+ void
+ write_build_id(Output_file*) const;
+
// Rewrite output file in binary format.
void
write_binary(Output_file* in) const;
@@ -370,6 +374,11 @@ class Layout
};
typedef std::vector<Group_signature> Group_signatures;
+ // Create a .note section, filling in the header.
+ Output_section*
+ create_note(const char* name, int note_type, size_t descsz,
+ bool allocate, size_t* trailing_padding);
+
// Create a .note section for gold.
void
create_gold_note();
@@ -378,6 +387,10 @@ class Layout
void
create_executable_stack_info(const Target*);
+ // Create a build ID note if needed.
+ void
+ create_build_id();
+
// Find the first read-only PT_LOAD segment, creating one if
// necessary.
Output_segment*
@@ -586,6 +599,8 @@ class Layout
Eh_frame* eh_frame_data_;
// The exception frame header output section if there is one.
Output_section* eh_frame_hdr_section_;
+ // The space for the build ID checksum if there is one.
+ Output_section_data* build_id_note_;
// A list of group sections and their signatures.
Group_signatures group_signatures_;
// The size of the output file.
diff --git a/gold/options.h b/gold/options.h
index a9b546b..b95a705 100644
--- a/gold/options.h
+++ b/gold/options.h
@@ -460,6 +460,10 @@ class General_options
DEFINE_bool(Bsymbolic, options::ONE_DASH, '\0', false,
N_("Bind defined symbols locally"), NULL);
+ DEFINE_optional_string(build_id, options::TWO_DASHES, '\0', "sha1",
+ N_("Generate build ID note"),
+ N_("[=STYLE]"));
+
#ifdef HAVE_ZLIB_H
DEFINE_enum(compress_debug_sections, options::TWO_DASHES, '\0', "none",
N_("Compress .debug_* sections in the output file"),