![Yann Sionneau](/assets/img/avatar_default.png)
Our patch 0003-Add-option-to-make-the-rpath-relative-under-a-specif.patch adds an option --make-rpath-relative, which we use to tweak RPATH of target binaries. However, one of the effect of this option is that it drops RPATH entries if the corresponding directory does not contain a library that is referenced by a DT_NEEDED entry of the binary. This unfortunately isn't correct, as RPATH entries are not only used by the dynamic linker to resolve the location of libraries listed through DT_NEEDED entries: RPATH entries are also used by dlopen() when resolving the location of libraries that are loaded at runtime. Therefore, the removal of RPATH entries that don't correspond to directories containing libraries referenced by DT_NEEDED entries break legitimate uses of RPATH for dlopen()ed libraries. This issue was even pointed out during the review of the upstream pull request: https://github.com/NixOS/patchelf/pull/118#discussion_r329660138 This fixes tst-origin uClibc-ng unit test: https://github.com/wbx-github/uclibc-ng-test/blob/master/test/dlopen/Makefile.in#L25 https://github.com/wbx-github/uclibc-ng-test/blob/master/test/dlopen/tst-origin.c#L15 Without this patch: $ gcc -o toto toto.c -Wl,-rpath,/tmp/test/bar $ readelf -d toto | grep PATH 0x000000000000000f (RPATH) Library rpath: [/tmp/test/bar] $ ./output/host/bin/patchelf --debug --make-rpath-relative /tmp/ toto patching ELF file `toto' Kernel page size is 4096 bytes removing directory '/tmp/test/bar' from RPATH because it does not contain needed libs new rpath is `' $ readelf -d toto | grep PATH 0x000000000000001d (RUNPATH) Library runpath: [] With the patch applied: $ gcc -o toto toto.c -Wl,-rpath,/tmp/test/bar $ readelf -d toto | grep PATH 0x000000000000000f (RPATH) Library rpath: [/tmp/test/bar] $ ./output/host/bin/patchelf --debug --make-rpath-relative /tmp/ toto patching ELF file `toto' Kernel page size is 4096 bytes keeping relative path of /tmp/test/bar new rpath is `test/bar' $ readelf -d toto | grep PATH 0x000000000000001d (RUNPATH) Library runpath: [test/bar] Signed-off-by: Yann Sionneau <ysionneau@kalray.eu> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
327 lines
12 KiB
Diff
327 lines
12 KiB
Diff
From 618220bfb55c875d6a4d197cb24fe632ac93ec85 Mon Sep 17 00:00:00 2001
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From: Wolfgang Grandegger <wg@grandegger.com>
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Date: Mon, 20 Feb 2017 16:29:24 +0100
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Subject: [PATCH] Add option to make the rpath relative under a specified root
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directory
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Running "patchelf" with the option "--make-rpath-relative ROOTDIR" will
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modify or delete the RPATHDIRs according the following rules
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similar to Martin's patches [1] making the Buildroot toolchaing/SDK
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relocatable.
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RPATHDIR starts with "$ORIGIN":
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The original build-system already took care of setting a relative
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RPATH, resolve it and test if it's valid (does exist)
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RPATHDIR starts with ROOTDIR:
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The original build-system added some absolute RPATH (absolute on
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the build machine). Test if it's valid (does exist).
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ROOTDIR/RPATHDIR exists:
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The original build-system already took care of setting an absolute
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RPATH (absolute in the final rootfs), resolve it and test if it's
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valid (does exist).
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RPATHDIR points somewhere else:
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(can be anywhere: build trees, staging tree, host location,
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non-existing location, etc.). Just discard such a path.
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The option "--no-standard-libs" will discard RPATHDIRs ROOTDIR/lib and
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ROOTDIR/usr/lib. Like "--shrink-rpath", RPATHDIRs are also discarded
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if the directories do not contain a library referenced by the
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DT_NEEDED fields.
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If the option "--relative-to-file" is given, the rpath will start
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with "$ORIGIN" making it relative to the ELF file, otherwise an
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absolute path relative to ROOTDIR will be used.
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A pull request for a similar patch [2] for mainline inclusion is
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pending.
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[1] http://lists.busybox.net/pipermail/buildroot/2016-April/159422.html
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[2] https://github.com/NixOS/patchelf/pull/118
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Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
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---
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src/patchelf.cc | 196 ++++++++++++++++++++++++++++++++++++++++++++++++++------
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1 file changed, 175 insertions(+), 21 deletions(-)
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diff --git a/src/patchelf.cc b/src/patchelf.cc
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index 1d9a772..35b4a33 100644
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--- a/src/patchelf.cc
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+++ b/src/patchelf.cc
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@@ -46,6 +46,10 @@ static bool debugMode = false;
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static bool forceRPath = false;
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+static bool noStandardLibDirs = false;
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+
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+static bool relativeToFile = false;
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+
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static string fileName;
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static int pageSize = PAGESIZE;
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@@ -77,6 +81,49 @@ static unsigned int getPageSize(){
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return pageSize;
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}
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+static bool absolutePathExists(const string & path, string & canonicalPath)
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+{
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+ char *cpath = realpath(path.c_str(), NULL);
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+ if (cpath) {
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+ canonicalPath = cpath;
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+ free(cpath);
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+ return true;
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+ } else {
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+ return false;
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+ }
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+}
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+
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+static string makePathRelative(const string & path,
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+ const string & refPath)
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+{
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+ string relPath = "$ORIGIN";
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+ string p = path, refP = refPath;
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+ size_t pos;
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+
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+ /* Strip the common part of path and refPath */
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+ while (true) {
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+ pos = p.find_first_of('/', 1);
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+ if (refP.find_first_of('/', 1) != pos)
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+ break;
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+ if (p.substr(0, pos) != refP.substr(0, pos))
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+ break;
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+ if (pos == string::npos)
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+ break;
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+ p = p.substr(pos);
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+ refP = refP.substr(pos);
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+ }
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+ /* Check if both pathes are equal */
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+ if (p != refP) {
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+ pos = 0;
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+ while (pos != string::npos) {
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+ pos =refP.find_first_of('/', pos + 1);
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+ relPath.append("/..");
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+ }
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+ relPath.append(p);
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+ }
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+
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+ return relPath;
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+}
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template<ElfFileParams>
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class ElfFile
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@@ -183,9 +230,13 @@ public:
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void setInterpreter(const string & newInterpreter);
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- typedef enum { rpPrint, rpShrink, rpSet, rpRemove } RPathOp;
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+ typedef enum { rpPrint, rpShrink, rpMakeRelative, rpSet, rpRemove} RPathOp;
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+
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+ bool libFoundInRPath(const string & dirName,
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+ const vector<string> neededLibs,
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+ vector<bool> & neededLibFound);
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- void modifyRPath(RPathOp op, string newRPath);
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+ void modifyRPath(RPathOp op, string rootDir, string newRPath);
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void addNeeded(set<string> libs);
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@@ -1041,7 +1092,27 @@ static void concatToRPath(string & rpath, const string & path)
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template<ElfFileParams>
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-void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op, string newRPath)
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+bool ElfFile<ElfFileParamNames>::libFoundInRPath(const string & dirName,
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+ const vector<string> neededLibs, vector<bool> & neededLibFound)
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+{
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+ /* For each library that we haven't found yet, see if it
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+ exists in this directory. */
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+ bool libFound = false;
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+ for (unsigned int j = 0; j < neededLibs.size(); ++j)
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+ if (!neededLibFound[j]) {
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+ string libName = dirName + "/" + neededLibs[j];
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+ struct stat st;
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+ if (stat(libName.c_str(), &st) == 0) {
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+ neededLibFound[j] = true;
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+ libFound = true;
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+ }
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+ }
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+ return libFound;
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+}
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+
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+
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+template<ElfFileParams>
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+void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op, string rootDir, string newRPath)
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{
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Elf_Shdr & shdrDynamic = findSection(".dynamic");
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@@ -1096,6 +1167,11 @@ void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op, string newRPath)
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return;
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}
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+ if (op == rpMakeRelative && !rpath) {
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+ debug("no RPATH to make relative\n");
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+ return;
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+ }
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+
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if (op == rpShrink && !rpath) {
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debug("no RPATH to shrink\n");
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return;
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@@ -1120,26 +1196,80 @@ void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op, string newRPath)
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continue;
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}
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- /* For each library that we haven't found yet, see if it
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- exists in this directory. */
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- bool libFound = false;
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- for (unsigned int j = 0; j < neededLibs.size(); ++j)
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- if (!neededLibFound[j]) {
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- string libName = dirName + "/" + neededLibs[j];
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- struct stat st;
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- if (stat(libName.c_str(), &st) == 0) {
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- neededLibFound[j] = true;
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- libFound = true;
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- }
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- }
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-
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- if (!libFound)
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+ if (!libFoundInRPath(dirName, neededLibs, neededLibFound))
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debug("removing directory `%s' from RPATH\n", dirName.c_str());
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else
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concatToRPath(newRPath, dirName);
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}
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}
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+ /* Make the the RPATH relative to the specified path */
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+ if (op == rpMakeRelative) {
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+ vector<bool> neededLibFound(neededLibs.size(), false);
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+ string fileDir = fileName.substr(0, fileName.find_last_of("/"));
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+
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+ newRPath = "";
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+
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+ vector<string> rpathDirs = splitColonDelimitedString(rpath);
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+ for (vector<string>::iterator it = rpathDirs.begin(); it != rpathDirs.end(); ++it) {
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+ const string & dirName = *it;
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+
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+ string canonicalPath;
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+
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+ /* Figure out if we should keep or discard the path. There are several
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+ cases to be handled:
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+ "dirName" starts with "$ORIGIN":
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+ The original build-system already took care of setting a relative
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+ RPATH. Resolve it and test if it's valid (does exist).
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+ "dirName" start with "rootDir":
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+ The original build-system added some absolute RPATH (absolute on
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+ the build machine). Test if it's valid (does exist).
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+ "rootDir"/"dirName" exists:
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+ The original build-system already took care of setting an absolute
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+ RPATH (absolute in the final rootfs). Resolve it and test if it's
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+ valid (does exist).
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+ "dirName" points somewhere else:
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+ (can be anywhere: build trees, staging tree, host location,
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+ non-existing location, etc.). Just discard such a path. */
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+ if (!dirName.compare(0, 7, "$ORIGIN")) {
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+ string path = fileDir + dirName.substr(7);
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+ if (!absolutePathExists(path, canonicalPath)) {
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+ debug("removing directory '%s' from RPATH because '%s' doesn't exist\n",
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+ dirName.c_str(), path.c_str());
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+ continue;
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+ }
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+ } else if (!dirName.compare(0, rootDir.length(), rootDir)) {
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+ if (!absolutePathExists(dirName, canonicalPath)) {
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+ debug("removing directory '%s' from RPATH because it doesn't exist\n", dirName.c_str());
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+ continue;
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+ }
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+ } else {
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+ string path = rootDir + dirName;
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+ if (!absolutePathExists(path, canonicalPath)) {
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+ debug("removing directory '%s' from RPATH because it's not in rootdir\n",
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+ dirName.c_str());
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+ continue;
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+ }
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+ }
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+
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+ if (noStandardLibDirs) {
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+ if (!canonicalPath.compare(rootDir + "/lib") ||
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+ !canonicalPath.compare(rootDir + "/usr/lib")) {
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+ debug("removing directory '%s' from RPATH because it's a standard library directory\n",
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+ dirName.c_str());
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+ continue;
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+ }
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+ }
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+
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+ /* Finally make "canonicalPath" relative to "filedir" in "rootDir" */
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+ if (relativeToFile)
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+ concatToRPath(newRPath, makePathRelative(canonicalPath, fileDir));
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+ else
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+ concatToRPath(newRPath, canonicalPath.substr(rootDir.length()));
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+ debug("keeping relative path of %s\n", canonicalPath.c_str());
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+ }
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+ }
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+
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if (op == rpRemove) {
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if (!rpath) {
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debug("no RPATH to delete\n");
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@@ -1413,7 +1543,9 @@ static bool shrinkRPath = false;
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static bool removeRPath = false;
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static bool setRPath = false;
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static bool printRPath = false;
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+static bool makeRPathRelative = false;
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static string newRPath;
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+static string rootDir;
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static set<string> neededLibsToRemove;
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static map<string, string> neededLibsToReplace;
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static set<string> neededLibsToAdd;
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@@ -1438,14 +1570,16 @@ static void patchElf2(ElfFile & elfFile)
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elfFile.setInterpreter(newInterpreter);
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if (printRPath)
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- elfFile.modifyRPath(elfFile.rpPrint, "");
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+ elfFile.modifyRPath(elfFile.rpPrint, "", "");
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if (shrinkRPath)
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- elfFile.modifyRPath(elfFile.rpShrink, "");
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+ elfFile.modifyRPath(elfFile.rpShrink, "", "");
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else if (removeRPath)
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- elfFile.modifyRPath(elfFile.rpRemove, "");
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+ elfFile.modifyRPath(elfFile.rpRemove, "", "");
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else if (setRPath)
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- elfFile.modifyRPath(elfFile.rpSet, newRPath);
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+ elfFile.modifyRPath(elfFile.rpSet, "", newRPath);
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+ else if (makeRPathRelative)
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+ elfFile.modifyRPath(elfFile.rpMakeRelative, rootDir, "");
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if (printNeeded) elfFile.printNeededLibs();
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@@ -1508,6 +1642,9 @@ void showHelp(const string & progName)
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[--set-rpath RPATH]\n\
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[--remove-rpath]\n\
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[--shrink-rpath]\n\
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+ [--make-rpath-relative ROOTDIR]\n\
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+ [--no-standard-lib-dirs]\n\
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+ [--relative-to-file]\n\
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[--print-rpath]\n\
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[--force-rpath]\n\
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[--add-needed LIBRARY]\n\
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@@ -1564,6 +1701,17 @@ int main(int argc, char * * argv)
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setRPath = true;
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newRPath = argv[i];
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}
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+ else if (arg == "--make-rpath-relative") {
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+ if (++i == argc) error("missing argument to --make-rpath-relative");
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+ makeRPathRelative = true;
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+ rootDir = argv[i];
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+ }
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+ else if (arg == "--no-standard-lib-dirs") {
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+ noStandardLibDirs = true;
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+ }
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+ else if (arg == "--relative-to-file") {
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+ relativeToFile = true;
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+ }
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else if (arg == "--print-rpath") {
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printRPath = true;
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}
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--
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1.9.1
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