diff options
Diffstat (limited to 'tests/elfcopy.c')
| -rw-r--r-- | tests/elfcopy.c | 99 |
1 files changed, 91 insertions, 8 deletions
diff --git a/tests/elfcopy.c b/tests/elfcopy.c index 9000cc96..4542222e 100644 --- a/tests/elfcopy.c +++ b/tests/elfcopy.c @@ -69,9 +69,11 @@ setshstrndx (Elf *elf, size_t ndx) /* Copies all elements of an ELF file either using mmap or read. */ static void -copy_elf (const char *in, const char *out, bool use_mmap) +copy_elf (const char *in, const char *out, bool use_mmap, bool reverse_offs) { - printf ("\ncopy_elf: %s -> %s (%s)\n", in, out, use_mmap ? "mmap" : "read"); + printf ("\ncopy_elf: %s -> %s (%s,%s)\n", in, out, + use_mmap ? "mmap" : "read", + reverse_offs ? "reverse" : "same"); /* Existing ELF file. */ int fda = open (in, O_RDONLY); @@ -182,8 +184,28 @@ copy_elf (const char *in, const char *out, bool use_mmap) } } + GElf_Off *offs = NULL; + size_t shnum; + if (reverse_offs) + { + if (elf_getshdrnum (elfa, &shnum) < 0) + { + printf ("couldn't get shdrnum: %s\n", elf_errmsg (-1)); + exit (1); + } + + offs = (GElf_Off *) malloc (shnum * sizeof (GElf_Off)); + if (offs == NULL) + { + printf ("couldn't allocate memory for offs\n"); + exit (1); + } + } + /* Copy all sections, headers and data. */ Elf_Scn *scn = NULL; + size_t last_off = 0; + GElf_Shdr last_shdr = { .sh_type = SHT_NULL }; while ((scn = elf_nextscn (elfa, scn)) != NULL) { /* Get the header. */ @@ -194,6 +216,35 @@ copy_elf (const char *in, const char *out, bool use_mmap) exit (1); } + if (reverse_offs) + { + offs[last_off] = shdr.sh_offset; + + if (last_shdr.sh_type != SHT_NULL + && last_shdr.sh_addralign == shdr.sh_addralign + && shdr.sh_addralign == 1 + && last_shdr.sh_type != SHT_NOBITS + && shdr.sh_type != SHT_NOBITS + && last_shdr.sh_offset + last_shdr.sh_size == shdr.sh_offset + && (phnum == 0 + || ((shdr.sh_flags & SHF_ALLOC) == 0 + && (last_shdr.sh_flags & SHF_ALLOC) == 0))) + { + printf ("Swapping offsets of section %zd and %zd\n", + last_off, last_off + 1); + GElf_Word off = offs[last_off - 1]; + offs[last_off - 1] = off + shdr.sh_size; + offs[last_off] = off; + last_shdr.sh_type = SHT_NULL; + } + else + { + last_shdr = shdr; + offs[last_off] = shdr.sh_offset; + } + last_off++; + } + /* Create new section. */ Elf_Scn *new_scn = elf_newscn (elfb); if (new_scn == NULL) @@ -223,9 +274,34 @@ copy_elf (const char *in, const char *out, bool use_mmap) } } - /* Write everything to disk. If there are any phdrs then we want - the exact same layout. Do we want ELF_F_PERMISSIVE? */ - if (phnum > 0) + if (reverse_offs) + { + last_off = 0; + scn = NULL; + while ((scn = elf_nextscn (elfb, scn)) != NULL) + { + GElf_Shdr shdr; + if (gelf_getshdr (scn, &shdr) == NULL) + { + printf ("couldn't get shdr for updating: %s\n", elf_errmsg (-1)); + exit (1); + } + + shdr.sh_offset = offs[last_off++]; + + if (gelf_update_shdr (scn, &shdr) == 0) + { + printf ("couldn't update shdr sh_off: %s\n", elf_errmsg (-1)); + exit (1); + } + } + free (offs); + } + + /* Write everything to disk. If there are any phdrs, or we want to + update the offsets, then we want the exact same layout. Do we + want ELF_F_PERMISSIVE? */ + if (phnum > 0 || reverse_offs) elf_flagelf (elfb, ELF_C_SET, ELF_F_LAYOUT); if (elf_update (elfb, ELF_C_WRITE) < 0) { @@ -264,9 +340,9 @@ main (int argc, const char *argv[]) elf_version (EV_CURRENT); /* Takes the given file, and create a new identical one. */ - if (argc < 3 || argc > 4) + if (argc < 3 || argc > 5) { - fprintf (stderr, "elfcopy [--mmap] in.elf out.elf\n"); + fprintf (stderr, "elfcopy [--mmap] [--reverse-offs] in.elf out.elf\n"); exit (1); } @@ -278,9 +354,16 @@ main (int argc, const char *argv[]) argn++; } + bool reverse_offs = false; + if (strcmp (argv[argn], "--reverse-offs") == 0) + { + reverse_offs = true; + argn++; + } + const char *in = argv[argn++]; const char *out = argv[argn]; - copy_elf (in, out, use_mmap); + copy_elf (in, out, use_mmap, reverse_offs); return 0; } |