mirror of
https://github.com/NixOS/patchelf.git
synced 2025-10-21 23:10:49 +08:00
* More duplicate code removal.
This commit is contained in:
Eelco Dolstra
207
src/patchelf.cc
207
src/patchelf.cc
@@ -57,11 +57,16 @@ class ElfFile
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string sectionNames; /* content of the .shstrtab section */
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/* Align on 4 or 8 bytes boundaries on 32- or 64-bit platforms
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respectively. */
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unsigned int sectionAlignment;
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public:
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ElfFile()
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{
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changed = false;
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sectionAlignment = sizeof(Elf_Off);
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}
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bool isChanged()
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@@ -114,12 +119,19 @@ private:
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string & replaceSection(const SectionName & sectionName,
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unsigned int size);
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void writeReplacedSections(Elf_Off & curOff,
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Elf_Addr startAddr, Elf_Off startOffset);
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void rewriteHeaders(Elf_Addr phdrAddress);
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void rewriteSectionsLibrary();
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void rewriteSectionsExecutable();
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public:
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void rewriteSections();
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void rewriteHeaders(Elf_Addr phdrAddress);
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string getInterpreter();
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void setInterpreter(const string & newInterpreter);
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@@ -459,69 +471,11 @@ string & ElfFile<ElfFileParamNames>::replaceSection(const SectionName & sectionN
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template<ElfFileParams>
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void ElfFile<ElfFileParamNames>::rewriteSections()
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void ElfFile<ElfFileParamNames>::writeReplacedSections(Elf_Off & curOff,
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Elf_Addr startAddr, Elf_Off startOffset)
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{
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if (replacedSections.empty()) return;
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); ++i)
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debug("replacing section `%s' with size %d\n",
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i->first.c_str(), i->second.size());
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/* Align on 4 or 8 bytes boundaries on 32- or 64-bit platforms
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respectively. */
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unsigned int sectionAlignment = sizeof(Elf_Off);
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if (!findSection2(".interp")) {
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debug("no .interp section; this is a dynamic library\n");
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/* For dynamic libraries, we just place the replacement
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sections at the end of the file. They're mapped into
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memory by a PT_LOAD segment located directly after the last
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virtual address page of other segments. */
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Elf_Addr startPage = 0;
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for (unsigned int i = 0; i < phdrs.size(); ++i) {
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Elf_Addr thisPage = roundUp(rdi(phdrs[i].p_vaddr) + rdi(phdrs[i].p_memsz), pageSize);
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if (thisPage > startPage) startPage = thisPage;
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}
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debug("last page is 0x%llx\n", (unsigned long long) startPage);
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/* Compute the total space needed for the replaced sections
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and the program headers. */
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off_t neededSpace = (phdrs.size() + 1) * sizeof(Elf_Phdr);
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); ++i)
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neededSpace += roundUp(i->second.size(), sectionAlignment);
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debug("needed space is %d\n", neededSpace);
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off_t startOffset = roundUp(fileSize, pageSize);
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growFile(startOffset + neededSpace);
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/* Add a segment that maps the replaced sections and program
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headers into memory.. */
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phdrs.resize(rdi(hdr->e_phnum) + 1);
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wri(hdr->e_phnum, rdi(hdr->e_phnum) + 1);
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Elf_Phdr & phdr = phdrs[rdi(hdr->e_phnum) - 1];
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wri(phdr.p_type, PT_LOAD);
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wri(phdr.p_offset, startOffset);
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wri(phdr.p_vaddr, wri(phdr.p_paddr, startPage));
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wri(phdr.p_filesz, wri(phdr.p_memsz, neededSpace));
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wri(phdr.p_flags, PF_R | PF_W);
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wri(phdr.p_align, 4096);
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/* Write out the replaced sections. */
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off_t curOff = startOffset + phdrs.size() * sizeof(Elf_Phdr);
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); )
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{
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string sectionName = i->first;
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Elf_Shdr & shdr = findSection(sectionName);
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@@ -534,7 +488,7 @@ void ElfFile<ElfFileParamNames>::rewriteSections()
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/* Update the section header for this section. */
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wri(shdr.sh_offset, curOff);
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wri(shdr.sh_addr, startPage + (curOff - startOffset));
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wri(shdr.sh_addr, startAddr + (curOff - startOffset));
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wri(shdr.sh_size, i->second.size());
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wri(shdr.sh_addralign, sectionAlignment);
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@@ -561,12 +515,58 @@ void ElfFile<ElfFileParamNames>::rewriteSections()
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}
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curOff += roundUp(i->second.size(), sectionAlignment);
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++i;
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replacedSections.erase(sectionName);
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}
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assert(replacedSections.empty());
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replacedSections.clear();
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}
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template<ElfFileParams>
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void ElfFile<ElfFileParamNames>::rewriteSectionsLibrary()
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{
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/* For dynamic libraries, we just place the replacement sections
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at the end of the file. They're mapped into memory by a
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PT_LOAD segment located directly after the last virtual address
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page of other segments. */
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Elf_Addr startPage = 0;
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for (unsigned int i = 0; i < phdrs.size(); ++i) {
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Elf_Addr thisPage = roundUp(rdi(phdrs[i].p_vaddr) + rdi(phdrs[i].p_memsz), pageSize);
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if (thisPage > startPage) startPage = thisPage;
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}
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debug("last page is 0x%llx\n", (unsigned long long) startPage);
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/* Compute the total space needed for the replaced sections and
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the program headers. */
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off_t neededSpace = (phdrs.size() + 1) * sizeof(Elf_Phdr);
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); ++i)
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neededSpace += roundUp(i->second.size(), sectionAlignment);
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debug("needed space is %d\n", neededSpace);
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off_t startOffset = roundUp(fileSize, pageSize);
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growFile(startOffset + neededSpace);
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/* Add a segment that maps the replaced sections and program
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headers into memory.. */
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phdrs.resize(rdi(hdr->e_phnum) + 1);
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wri(hdr->e_phnum, rdi(hdr->e_phnum) + 1);
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Elf_Phdr & phdr = phdrs[rdi(hdr->e_phnum) - 1];
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wri(phdr.p_type, PT_LOAD);
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wri(phdr.p_offset, startOffset);
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wri(phdr.p_vaddr, wri(phdr.p_paddr, startPage));
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wri(phdr.p_filesz, wri(phdr.p_memsz, neededSpace));
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wri(phdr.p_flags, PF_R | PF_W);
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wri(phdr.p_align, 4096);
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/* Write out the replaced sections. */
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Elf_Off curOff = startOffset + phdrs.size() * sizeof(Elf_Phdr);
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writeReplacedSections(curOff, startPage, startOffset);
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assert((off_t) curOff == startOffset + neededSpace);
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@@ -574,11 +574,12 @@ void ElfFile<ElfFileParamNames>::rewriteSections()
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wri(hdr->e_phoff, startOffset);
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rewriteHeaders(startPage);
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return;
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}
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}
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template<ElfFileParams>
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void ElfFile<ElfFileParamNames>::rewriteSectionsExecutable()
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{
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/* Sort the sections by offset, otherwise we won't correctly find
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all the sections before the last replaced section. */
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sortShdrs();
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@@ -679,51 +680,7 @@ void ElfFile<ElfFileParamNames>::rewriteSections()
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/* Write out the replaced sections. */
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); )
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{
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string sectionName = i->first;
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debug("rewriting section `%s' to offset %d\n",
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sectionName.c_str(), curOff);
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memcpy(contents + curOff, (unsigned char *) i->second.c_str(),
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i->second.size());
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/* Update the section header for this section. */
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Elf_Shdr & shdr = findSection(sectionName);
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wri(shdr.sh_offset, curOff);
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wri(shdr.sh_addr, firstPage + curOff);
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wri(shdr.sh_size, i->second.size());
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wri(shdr.sh_addralign, sectionAlignment);
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/* If this is the .interp section, then the PT_INTERP segment
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must be sync'ed with it. */
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if (sectionName == ".interp") {
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for (unsigned int j = 0; j < phdrs.size(); ++j)
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if (rdi(phdrs[j].p_type) == PT_INTERP) {
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phdrs[j].p_offset = shdr.sh_offset;
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phdrs[j].p_vaddr = phdrs[j].p_paddr = shdr.sh_addr;
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phdrs[j].p_filesz = phdrs[j].p_memsz = shdr.sh_size;
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}
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}
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/* If this is the .dynamic section, then the PT_DYNAMIC segment
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must be sync'ed with it. */
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if (sectionName == ".dynamic") {
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for (unsigned int j = 0; j < phdrs.size(); ++j)
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if (rdi(phdrs[j].p_type) == PT_DYNAMIC) {
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phdrs[j].p_offset = shdr.sh_offset;
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phdrs[j].p_vaddr = phdrs[j].p_paddr = shdr.sh_addr;
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phdrs[j].p_filesz = phdrs[j].p_memsz = shdr.sh_size;
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}
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}
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curOff += roundUp(i->second.size(), sectionAlignment);
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++i;
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replacedSections.erase(sectionName);
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}
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assert(replacedSections.empty());
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writeReplacedSections(curOff, firstPage, 0);
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assert((off_t) curOff == neededSpace);
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@@ -731,6 +688,26 @@ void ElfFile<ElfFileParamNames>::rewriteSections()
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}
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template<ElfFileParams>
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void ElfFile<ElfFileParamNames>::rewriteSections()
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{
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if (replacedSections.empty()) return;
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for (ReplacedSections::iterator i = replacedSections.begin();
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i != replacedSections.end(); ++i)
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debug("replacing section `%s' with size %d\n",
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i->first.c_str(), i->second.size());
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if (!findSection2(".interp")) {
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debug("no .interp section; this is a dynamic library\n");
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rewriteSectionsLibrary();
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} else {
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debug("found .interp section; this is an executable\n");
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rewriteSectionsExecutable();
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}
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}
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template<ElfFileParams>
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void ElfFile<ElfFileParamNames>::rewriteHeaders(Elf_Addr phdrAddress)
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{
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