This will allow go program to get the vdso library address.
Signed-off-by: Benoît Canet <[email protected]>
---
core/app.cc | 21 ++++++++++++++++++---
include/osv/app.hh | 7 ++++++-
2 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/core/app.cc b/core/app.cc
index ad8018c..a8cf4b2 100644
--- a/core/app.cc
+++ b/core/app.cc
@@ -173,7 +173,7 @@ application::application(const std::string& command,
}
merge_in_environ(new_program, env);
- prepare_argv();
+ prepare_argv(current_program);
std::vector<std::string> extra_path;
_lib = current_program->get_library(_command, extra_path, true);
} catch(const std::exception &e) {
@@ -297,7 +297,7 @@ void application::main()
// _entry_point() doesn't return
}
-void application::prepare_argv()
+void application::prepare_argv(elf::program *program)
{
// Prepare program_* variable used by the libc
char *c_path = (char *)(_command.c_str());
@@ -324,7 +324,7 @@ void application::prepare_argv()
}
// Allocate the continuous buffer for argv[] and envp[]
- _argv.reset(new char*[_args.size() + 1 + envcount + 1]);
+ _argv.reset(new char*[_args.size() + 1 + envcount + 1 +
sizeof(Elf64_auxv_t) * 2]);
// Fill the argv part of these buffers
char *ab = _argv_buf.get();
@@ -343,6 +343,21 @@ void application::prepare_argv()
contig_argv[_args.size() + 1 + i] = environ[i];
}
contig_argv[_args.size() + 1 + envcount] = nullptr;
+
+ _libvdso = program->get_library("libvdso.so");
+ if (!_libvdso) {
+ abort("could not load libvdso.so\n");
+ return;
+ }
+
+ // Pass the VDSO library to the application.
+ Elf64_auxv_t* _auxv =
+ reinterpret_cast<Elf64_auxv_t *>(&contig_argv[_args.size() + 1 +
envcount + 1]);
+ _auxv[0].a_type = AT_SYSINFO_EHDR;
+ _auxv[0].a_un.a_val = reinterpret_cast<uint64_t>(_libvdso->base());
+
+ _auxv[1].a_type = AT_NULL;
+ _auxv[1].a_un.a_val = 0;
}
void application::run_main()
diff --git a/include/osv/app.hh b/include/osv/app.hh
index 62fd406..423e34d 100644
--- a/include/osv/app.hh
+++ b/include/osv/app.hh
@@ -22,6 +22,10 @@
#include <unordered_map>
#include <string>
+#include "musl/include/elf.h"
+#undef AT_UID // prevent collisions
+#undef AT_GID
+
extern "C" void __libc_start_main(int(*)(int, char**), int, char**, void(*)(),
void(*)(), void(*)(), void*);
@@ -194,7 +198,7 @@ private:
void start_and_join(waiter* setup_waiter);
void main();
void run_main(std::string path, int argc, char** argv);
- void prepare_argv();
+ void prepare_argv(elf::program *program);
void run_main();
friend void ::__libc_start_main(int(*)(int, char**), int, char**,
void(*)(),
void(*)(), void(*)(), void*);
@@ -211,6 +215,7 @@ private:
mutex _termination_mutex;
std::shared_ptr<elf::object> _lib;
std::shared_ptr<elf::object> _libenviron;
+ std::shared_ptr<elf::object> _libvdso;
main_func_t* _main;
void (*_entry_point)();
static app_registry apps;
--
2.7.4
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