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Merge pull request #311 from NixOS/refactoring 

make modify rpath function smaller
This commit is contained in:
Jörg Thalheim 2021-09-08 10:11:55 +01:00 committed by GitHub
parent c62988a2a8 52a5bb061a
commit e9be1641b1
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 95 additions and 83 deletions
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178
src/patchelf.cc
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@ -203,6 +203,8 @@ public:
typedef enum { rpPrint, rpShrink, rpSet, rpAdd, rpRemove } RPathOp;
void modifyRPath(RPathOp op, const std::vector<std::string> & allowedRpathPrefixes, std::string newRPath);
std::string shrinkRPath(char* rpath, std::vector<std::string> &neededLibs, const std::vector<std::string> & allowedRpathPrefixes);
void removeRPath(Elf_Shdr & shdrDynamic);
void addNeeded(const std::set<std::string> & libs);
@ -1317,12 +1319,80 @@ void ElfFile<ElfFileParamNames>::setInterpreter(const std::string & newInterpret
}
static void concatToRPath(std::string & rpath, const std::string & path)
static void appendRPath(std::string & rpath, const std::string & path)
{
if (!rpath.empty()) rpath += ":";
rpath += path;
}
/* For each directory in the RPATH, check if it contains any
needed library. */
template<ElfFileParams>
std::string ElfFile<ElfFileParamNames>::shrinkRPath(char* rpath, std::vector<std::string> &neededLibs, const std::vector<std::string> & allowedRpathPrefixes) {
std::vector<bool> neededLibFound(neededLibs.size(), false);
std::string newRPath = "";
for (auto & dirName : splitColonDelimitedString(rpath)) {
/* Non-absolute entries are allowed (e.g., the special
"$ORIGIN" hack). */
if (dirName[0] != '/') {
appendRPath(newRPath, dirName);
continue;
}
/* If --allowed-rpath-prefixes was given, reject directories
not starting with any of the (colon-delimited) prefixes. */
if (!allowedRpathPrefixes.empty() && !hasAllowedPrefix(dirName, allowedRpathPrefixes)) {
debug("removing directory '%s' from RPATH because of non-allowed prefix\n", dirName.c_str());
continue;
}
/* For each library that we haven't found yet, see if it
exists in this directory. */
bool libFound = false;
for (unsigned int j = 0; j < neededLibs.size(); ++j)
if (!neededLibFound[j]) {
std::string libName = dirName + "/" + neededLibs[j];
try {
Elf32_Half library_e_machine = getElfType(readFile(libName, sizeof(Elf32_Ehdr))).machine;
if (rdi(library_e_machine) == rdi(hdr->e_machine)) {
neededLibFound[j] = true;
libFound = true;
} else
debug("ignoring library '%s' because its machine type differs\n", libName.c_str());
} catch (SysError & e) {
if (e.errNo != ENOENT) throw;
}
}
if (!libFound)
debug("removing directory '%s' from RPATH\n", dirName.c_str());
else
appendRPath(newRPath, dirName);
}
return newRPath;
}
template<ElfFileParams>
void ElfFile<ElfFileParamNames>::removeRPath(Elf_Shdr & shdrDynamic) {
auto dyn = (Elf_Dyn *)(contents + rdi(shdrDynamic.sh_offset));
Elf_Dyn * last = dyn;
for ( ; rdi(dyn->d_tag) != DT_NULL; dyn++) {
if (rdi(dyn->d_tag) == DT_RPATH) {
debug("removing DT_RPATH entry\n");
changed = true;
} else if (rdi(dyn->d_tag) == DT_RUNPATH) {
debug("removing DT_RUNPATH entry\n");
changed = true;
} else {
*last++ = *dyn;
}
}
memset(last, 0, sizeof(Elf_Dyn) * (dyn - last));
}
template<ElfFileParams>
void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op,
@ -1372,89 +1442,36 @@ void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op,
neededLibs.push_back(std::string(strTab + rdi(dyn->d_un.d_val)));
}
if (op == rpPrint) {
printf("%s\n", rpath ? rpath : "");
return;
}
if (op == rpShrink && !rpath) {
debug("no RPATH to shrink\n");
return;
}
/* For each directory in the RPATH, check if it contains any
needed library. */
if (op == rpShrink) {
std::vector<bool> neededLibFound(neededLibs.size(), false);
newRPath = "";
for (auto & dirName : splitColonDelimitedString(rpath)) {
/* Non-absolute entries are allowed (e.g., the special
"$ORIGIN" hack). */
if (dirName[0] != '/') {
concatToRPath(newRPath, dirName);
continue;
switch (op) {
case rpPrint: {
printf("%s\n", rpath ? rpath : "");
return;
};
case rpRemove: {
if (!rpath) {
debug("no RPATH to delete\n");
return;
}
/* If --allowed-rpath-prefixes was given, reject directories
not starting with any of the (colon-delimited) prefixes. */
if (!allowedRpathPrefixes.empty() && !hasAllowedPrefix(dirName, allowedRpathPrefixes)) {
debug("removing directory '%s' from RPATH because of non-allowed prefix\n", dirName.c_str());
continue;
}
/* For each library that we haven't found yet, see if it
exists in this directory. */
bool libFound = false;
for (unsigned int j = 0; j < neededLibs.size(); ++j)
if (!neededLibFound[j]) {
std::string libName = dirName + "/" + neededLibs[j];
try {
Elf32_Half library_e_machine = getElfType(readFile(libName, sizeof(Elf32_Ehdr))).machine;
if (rdi(library_e_machine) == rdi(hdr->e_machine)) {
neededLibFound[j] = true;
libFound = true;
} else
debug("ignoring library '%s' because its machine type differs\n", libName.c_str());
} catch (SysError & e) {
if (e.errNo != ENOENT) throw;
}
}
if (!libFound)
debug("removing directory '%s' from RPATH\n", dirName.c_str());
else
concatToRPath(newRPath, dirName);
}
}
if (op == rpRemove) {
if (!rpath) {
debug("no RPATH to delete\n");
removeRPath(shdrDynamic);
return;
}
dyn = (Elf_Dyn *)(contents + rdi(shdrDynamic.sh_offset));
Elf_Dyn * last = dyn;
for ( ; rdi(dyn->d_tag) != DT_NULL; dyn++) {
if (rdi(dyn->d_tag) == DT_RPATH) {
debug("removing DT_RPATH entry\n");
changed = true;
} else if (rdi(dyn->d_tag) == DT_RUNPATH) {
debug("removing DT_RUNPATH entry\n");
changed = true;
} else {
*last++ = *dyn;
}
case rpShrink: {
if (!rpath) {
debug("no RPATH to shrink\n");
return;
;}
newRPath = shrinkRPath(rpath, neededLibs, allowedRpathPrefixes);
break;
}
memset(last, 0, sizeof(Elf_Dyn) * (dyn - last));
return;
case rpAdd: {
auto temp = std::string(rpath ? rpath : "");
appendRPath(temp, newRPath);
newRPath = temp;
break;
}
case rpSet: { break; } /* new rpath was provied as input to this function */
}
if (!forceRPath && dynRPath && !dynRunPath) { /* convert DT_RPATH to DT_RUNPATH */
wri(dynRPath->d_tag, DT_RUNPATH);
dynRunPath = dynRPath;
@ -1470,11 +1487,6 @@ void ElfFile<ElfFileParamNames>::modifyRPath(RPathOp op,
if (rpath && rpath == newRPath) {
return;
}
if (op == rpAdd) {
newRPath = std::string(rpath ? rpath : "") + ":" + newRPath;
}
changed = true;
/* Zero out the previous rpath to prevent retained dependencies in