template<typename ElfHeaderType /*Elf{32,64}_Ehdr*/,
typename ElfSectionHeaderType /*Elf{32,64}_Shdr*/,
typename ElfDynamicSectionEntryType /* Elf{32,64}_Dyn */>
-bool process_elf(uint8_t* bytes, size_t elf_file_size)
+bool process_elf(uint8_t* bytes, size_t elf_file_size, char const* file_name)
{
if (sizeof(ElfSectionHeaderType) > elf_file_size) {
- fprintf(stderr, "ERROR: Elf header would end at %lu but file size only %lu\n", sizeof(ElfSectionHeaderType), elf_file_size);
+ fprintf(stderr, "termux-elf-cleaner: Elf header for '%s' would end at %zu but file size only %zu\n", file_name, sizeof(ElfSectionHeaderType), elf_file_size);
return false;
}
ElfHeaderType* elf_hdr = reinterpret_cast<ElfHeaderType*>(bytes);
size_t last_section_header_byte = elf_hdr->e_shoff + sizeof(ElfSectionHeaderType) * elf_hdr->e_shnum;
if (last_section_header_byte > elf_file_size) {
- fprintf(stderr, "ERROR: Section header would end at %lu but file size only %lu\n", last_section_header_byte, elf_file_size);
+ fprintf(stderr, "termux-elf-cleaner: Section header for '%s' would end at %zu but file size only %zu\n", file_name, last_section_header_byte, elf_file_size);
return false;
}
ElfSectionHeaderType* section_header_table = reinterpret_cast<ElfSectionHeaderType*>(bytes + elf_hdr->e_shoff);
if (section_header_entry->sh_type == SHT_DYNAMIC) {
size_t const last_dynamic_section_byte = section_header_entry->sh_offset + section_header_entry->sh_size;
if (last_dynamic_section_byte > elf_file_size) {
- fprintf(stderr, "ERROR: Dynamic section would end at %lu but file size only %lu\n", last_dynamic_section_byte, elf_file_size);
+ fprintf(stderr, "termux-elf-cleaner: Dynamic section for '%s' would end at %zu but file size only %zu\n", file_name, last_dynamic_section_byte, elf_file_size);
return false;
}
for (unsigned int j = 0; j < dynamic_section_entries; j++) {
ElfDynamicSectionEntryType* dynamic_section_entry = dynamic_section + j;
+ char const* removed_name = nullptr;
switch (dynamic_section_entry->d_tag) {
- case DT_VERNEEDED:
- case DT_VERNEEDNUM:
- case DT_RPATH:
- case DT_RUNPATH:
- char const* removed_name;
- switch (dynamic_section_entry->d_tag) {
- case DT_VERNEEDED: removed_name = "DT_VERNEEDED"; break;
- case DT_VERNEEDNUM: removed_name = "DT_VERNEEDNUM"; break;
- case DT_RPATH: removed_name = "DT_RPATH"; break;
- case DT_RUNPATH: removed_name = "DT_RUNPATH"; break;
- }
- printf("Removing the %s dynamic section entry\n", removed_name);
- // Tag the entry with DT_NULL and put it last:
- dynamic_section_entry->d_tag = DT_NULL;
- // Decrease j to process new entry index:
- std::swap(dynamic_section[j--], dynamic_section[last_nonnull_entry_idx--]);
- break;
+ case DT_VERNEEDED: removed_name = "DT_VERNEEDED"; break;
+ case DT_VERNEEDNUM: removed_name = "DT_VERNEEDNUM"; break;
+ case DT_VERDEF: removed_name = "DT_VERDEF"; break;
+ case DT_VERDEFNUM: removed_name = "DT_VERDEFNUM"; break;
+ case DT_RPATH: removed_name = "DT_RPATH"; break;
+ case DT_RUNPATH: removed_name = "DT_RUNPATH"; break;
+ }
+ if (removed_name != nullptr) {
+ printf("termux-elf-cleaner: Removing the %s dynamic section entry from '%s'\n", removed_name, file_name);
+ // Tag the entry with DT_NULL and put it last:
+ dynamic_section_entry->d_tag = DT_NULL;
+ // Decrease j to process new entry index:
+ std::swap(dynamic_section[j--], dynamic_section[last_nonnull_entry_idx--]);
}
}
}
}
-int main(int argc, char **argv)
+int main(int argc, char const** argv)
{
if (argc < 2 || (argc == 2 && strcmp(argv[1], "-h")==0)) {
fprintf(stderr, "usage: %s <filename>\n", argv[0]);
}
for (int i = 1; i < argc; i++) {
- int fd = open(argv[i], O_RDWR);
- if (fd < 0) { perror("open()"); return 1; }
+ char const* file_name = argv[i];
+ int fd = open(file_name, O_RDWR);
+ if (fd < 0) {
+ char* error_message;
+ if (asprintf(&error_message, "open(\"%s\")", file_name) == -1) error_message = (char*) "open()";
+ perror(error_message);
+ return 1;
+ }
struct stat st;
if (fstat(fd, &st) < 0) { perror("fstat()"); return 1; }
- if (st.st_size < (long long) sizeof(Elf32_Ehdr)) continue;
+ if (st.st_size < (long long) sizeof(Elf32_Ehdr)) {
+ close(fd);
+ continue;
+ }
void* mem = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (mem == MAP_FAILED) { perror("mmap()"); return 1; }
uint8_t* bytes = reinterpret_cast<uint8_t*>(mem);
if (!(bytes[0] == 0x7F && bytes[1] == 'E' && bytes[2] == 'L' && bytes[3] == 'F')) {
+ // Not the ELF magic number.
munmap(mem, st.st_size);
close(fd);
continue;
}
- uint8_t bit_value = bytes[4];
- if (!(bit_value == 1 || bit_value == 2)) {
- printf("ERROR: Incorrect bit value: %d\n", bit_value);
- return 1;
- } else if (bit_value == 1) {
- if (!process_elf<Elf32_Ehdr, Elf32_Shdr, Elf32_Dyn>(bytes, st.st_size)) return 1;
+ if (bytes[/*EI_DATA*/5] != 1) {
+ fprintf(stderr, "termux-elf-cleaner: Not little endianness in '%s'\n", file_name);
+ munmap(mem, st.st_size);
+ close(fd);
+ continue;
+ }
+
+ uint8_t const bit_value = bytes[/*EI_CLASS*/4];
+ if (bit_value == 1) {
+ if (!process_elf<Elf32_Ehdr, Elf32_Shdr, Elf32_Dyn>(bytes, st.st_size, file_name)) return 1;
+ } else if (bit_value == 2) {
+ if (!process_elf<Elf64_Ehdr, Elf64_Shdr, Elf64_Dyn>(bytes, st.st_size, file_name)) return 1;
} else {
- if (!process_elf<Elf64_Ehdr, Elf64_Shdr, Elf64_Dyn>(bytes, st.st_size)) return 1;
+ printf("termux-elf-cleaner: Incorrect bit value %d in '%s'\n", bit_value, file_name);
+ return 1;
}
if (msync(mem, st.st_size, MS_SYNC) < 0) { perror("msync()"); return 1; }