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authorEelco Dolstra <eelco.dolstra@logicblox.com>2016-09-19 15:50:13 (GMT)
committerEelco Dolstra <eelco.dolstra@logicblox.com>2016-09-19 15:50:13 (GMT)
commit5f37ae6b41e8ffdb3e80988922732893f84928ed (patch)
tree6ee61fa4f64ef94bbadc4d175851e3f85aa7c65f /src
parenta365bcb7d7025da51b33165ef7ebc7180199a05e (diff)
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Factor out fetching ELF type
Diffstat (limited to 'src')
-rw-r--r--src/patchelf.cc58
1 files changed, 34 insertions, 24 deletions
diff --git a/src/patchelf.cc b/src/patchelf.cc
index b489111..4cf715e 100644
--- a/src/patchelf.cc
+++ b/src/patchelf.cc
@@ -292,6 +292,35 @@ static FileContents readFile(std::string fileName)
}
+struct ElfType
+{
+ bool is32Bit;
+ int machine; // one of EM_*
+};
+
+
+ElfType getElfType(const FileContents & fileContents)
+{
+ /* Check the ELF header for basic validity. */
+ if (fileContents->size() < (off_t) sizeof(Elf32_Ehdr)) error("missing ELF header");
+
+ auto contents = fileContents->data();
+
+ if (memcmp(contents, ELFMAG, SELFMAG) != 0)
+ error("not an ELF executable");
+
+ if (contents[EI_VERSION] != EV_CURRENT)
+ error("unsupported ELF version");
+
+ if (contents[EI_CLASS] != ELFCLASS32 && contents[EI_CLASS] != ELFCLASS64)
+ error("ELF executable is not 32 or 64 bit");
+
+ bool is32Bit = contents[EI_CLASS] == ELFCLASS32;
+
+ return ElfType{is32Bit, is32Bit ? ((Elf32_Ehdr *) contents)->e_machine : ((Elf64_Ehdr *) contents)->e_machine};
+}
+
+
static void checkPointer(const FileContents & contents, void * p, unsigned int size)
{
unsigned char * q = (unsigned char *) p;
@@ -1480,7 +1509,7 @@ static bool printNeeded = false;
static bool noDefaultLib = false;
template<class ElfFile>
-static void patchElf2(ElfFile & elfFile)
+static void patchElf2(ElfFile && elfFile)
{
if (printInterpreter)
printf("%s\n", elfFile.getInterpreter().c_str());
@@ -1529,29 +1558,10 @@ static void patchElf()
auto fileContents = readFile(fileName);
- /* Check the ELF header for basic validity. */
- if (fileContents->size() < (off_t) sizeof(Elf32_Ehdr)) error("missing ELF header");
-
- auto contents = fileContents->data();
-
- if (memcmp(contents, ELFMAG, SELFMAG) != 0)
- error("not an ELF executable");
-
- if (contents[EI_CLASS] == ELFCLASS32 &&
- contents[EI_VERSION] == EV_CURRENT)
- {
- ElfFile<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr, Elf32_Addr, Elf32_Off, Elf32_Dyn, Elf32_Sym, Elf32_Verneed> elfFile(fileContents);
- patchElf2(elfFile);
- }
- else if (contents[EI_CLASS] == ELFCLASS64 &&
- contents[EI_VERSION] == EV_CURRENT)
- {
- ElfFile<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr, Elf64_Addr, Elf64_Off, Elf64_Dyn, Elf64_Sym, Elf64_Verneed> elfFile(fileContents);
- patchElf2(elfFile);
- }
- else {
- error("ELF executable is not 32/64-bit, little/big-endian, version 1");
- }
+ if (getElfType(fileContents).is32Bit)
+ patchElf2(ElfFile<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr, Elf32_Addr, Elf32_Off, Elf32_Dyn, Elf32_Sym, Elf32_Verneed>(fileContents));
+ else
+ patchElf2(ElfFile<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr, Elf64_Addr, Elf64_Off, Elf64_Dyn, Elf64_Sym, Elf64_Verneed>(fileContents));
}