From: Waldemar Kozaczuk <jwkozac...@gmail.com>
Committer: Nadav Har'El <n...@scylladb.com>
Branch: master
elf: handle new DT_RUNPATH
This patch enhances dynamic linker to resolve dependent
objects that rely on DT_RUNPATH entry to specify directories to search for.
Some ELFs have both DT_RUNPATH and DT_RPATH in which case our
linker disregards the latter per specification.
For details read slide "Finding shared libraries at run time" under
http://man7.org/training/download/shlib_dynlinker_slides.pdf.
Fixes #1039
Signed-off-by: Waldemar Kozaczuk <jwkozac...@gmail.com>
Message-Id: <20190517220153.22066-1-jwkozac...@gmail.com>
---
diff --git a/core/elf.cc b/core/elf.cc
--- a/core/elf.cc
+++ b/core/elf.cc
@@ -932,8 +932,17 @@ static std::string dirname(std::string path)
void object::load_needed(std::vector<std::shared_ptr<object>>&
loaded_objects)
{
std::vector<std::string> rpath;
- if (dynamic_exists(DT_RPATH)) {
- std::string rpath_str = dynamic_str(DT_RPATH);
+
+ std::string rpath_str;
+ // Prefer newer DT_RUNPATH
+ if (dynamic_exists(DT_RUNPATH)) {
+ rpath_str = dynamic_str(DT_RUNPATH);
+ // Otherwise fall back to older DT_RPATH
+ } else if (dynamic_exists(DT_RPATH)) {
+ rpath_str = dynamic_str(DT_RPATH);
+ }
+
+ if (!rpath_str.empty()) {
boost::replace_all(rpath_str, "$ORIGIN", dirname(_pathname));
boost::split(rpath, rpath_str, boost::is_any_of(":"));
}
diff --git a/include/osv/elf.hh b/include/osv/elf.hh
--- a/include/osv/elf.hh
+++ b/include/osv/elf.hh
@@ -167,7 +167,7 @@ enum {
DT_INIT = 12, // d_ptr Address of the initialization function.
DT_FINI = 13, // d_ptr Address of the termination function.
DT_SONAME = 14, // d_val The string table offset of the name of this
shared object.
- DT_RPATH = 15, // d_val The string table offset of a shared library
search path string.
+ DT_RPATH = 15, // d_val The string table offset of a shared library
search path string (deprecated)
DT_SYMBOLIC = 16, // ignored The presence of this dynamic table entry
modifies the
// symbol resolution algorithm for references within the
// library. Symbols defined within the library are used to
@@ -191,6 +191,7 @@ enum {
DT_FINI_ARRAY = 26, // d_ptr Pointer to an array of pointers to
termination functions.
DT_INIT_ARRAYSZ = 27, // d_val Size, in bytes, of the array of
initialization functions.
DT_FINI_ARRAYSZ = 28, // d_val Size, in bytes, of the array of
termination functions.
+ DT_RUNPATH = 29, // d_val The string table offset of a shared library
search path string.
DT_FLAGS = 30, // value is various flags, bits from DF_*.
DT_FLAGS_1 = 0x6ffffffb, // value is various flags, bits from DF_1_*.
DT_LOOS = 0x60000000, // Defines a range of dynamic table tags that
are reserved for
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