diff options
Diffstat (limited to 'plugins')
| -rw-r--r-- | plugins/elf.lua | 102 |
1 files changed, 88 insertions, 14 deletions
diff --git a/plugins/elf.lua b/plugins/elf.lua index f891af7..a9a0d81 100644 --- a/plugins/elf.lua +++ b/plugins/elf.lua @@ -16,6 +16,8 @@ -- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. -- +-- See man 5 elf, /usr/include/elf.h and /usr/include/llvm/Support/ELF.h + local detect = function (c) return c:read (4) == "\x7FELF" end @@ -33,11 +35,11 @@ local ph_type_table = { local xform_ph_flags = function (u32) local info = {} - if u32 & 4 ~= 0 then table.insert (info, "read") end - if u32 & 2 ~= 0 then table.insert (info, "write") end - if u32 & 1 ~= 0 then table.insert (info, "execute") end + if u32 & 0x4 ~= 0 then table.insert (info, "read") end + if u32 & 0x2 ~= 0 then table.insert (info, "write") end + if u32 & 0x1 ~= 0 then table.insert (info, "execute") end - local junk = u32 & ~7 + local junk = u32 & ~0x7 if junk ~= 0 then table.insert (info, ("unknown: %#x"):format (junk)) end @@ -65,10 +67,67 @@ local decode_ph = function (elf, c) ph.memsz = elf.uwide (c, "sise in memory: %d") if elf.class == 1 then ph.flags = c:u32 ("flags: %s", xform_ph_flags) end ph.align = elf.uwide (c, "alignment: %d") + return ph +end + +local sh_type_table = { + [0] = "null entry", + [1] = "program-defined contents", + [2] = "symbol table", + [3] = "string table", + [4] = "relocation entries", + [5] = "symbol hash table", + [6] = "dynamic linking information", + [7] = "information about the file", + [8] = "data occupies no space in file", + [9] = "relocation entries", + [10] = "reserved", + [11] = "symbol table", + [14] = "pointers to initialization functions", + [15] = "pointers to terminnation functions", + [16] = "pointers to pre-init functions", + [17] = "section group", + [18] = "indices for SHN_XINDEX entries" +} + +local xform_sh_flags = function (u) + -- TODO: there are more known weird values and ranges + local info = {} + if u & 0x1 ~= 0 then table.insert (info, "write") end + if u & 0x2 ~= 0 then table.insert (info, "alloc") end + if u & 0x4 ~= 0 then table.insert (info, "execinstr") end + + local junk = u & ~0x7 + if junk ~= 0 then + table.insert (info, ("unknown: %#x"):format (junk)) + end + + if #info == 0 then return 0 end + + local result = info[1] + for i = 2, #info do result = result .. ", " .. info[i] end + return result end local decode_sh = function (elf, c) - -- TODO + local sh = {} + -- TODO: decode the values, give the fields meaning + sh.name = c:u32 ("name index: %d") + sh.type = c:u32 ("type: %s", function (u32) + -- TODO: there are more known weird values and ranges + name = sh_type_table[u32] + if name then return name end + return "unknown: %#x", u32 + end) + sh.flags = elf.uwide (c, "flags: %s", xform_sh_flags) + sh.addr = elf.uwide (c, "load address: %#x") + sh.offset = elf.uwide (c, "offset in file: %#x") + sh.size = elf.uwide (c, "size: %d") + sh.link = c:u32 ("header table index link: %d") + sh.info = c:u32 ("extra information: %d") + sh.addralign = elf.uwide (c, "address alignment: %d") + sh.entsize = elf.uwide (c, "size of records: %d") + return sh end local abi_table = { @@ -353,21 +412,36 @@ local decode = function (c) elf.sh_number = c:u16 ("section header count: %d") elf.sh_string_index = c:u16 ("section header index for strings: %d") - -- TODO: decode all headers as well, see man 5 elf, - -- /usr/include/elf.h and /usr/include/llvm/Support/ELF.h for i = 1, elf.ph_number do local start = elf.ph_offset + (i - 1) * elf.ph_entry_size - local ph = c (1 + start, start + elf.ph_entry_size) - ph:mark ("ELF program header %d", i - 1) - decode_ph (elf, ph) + local pchunk = c (1 + start, start + elf.ph_entry_size) + pchunk:mark ("ELF program header %d", i - 1) + decode_ph (elf, pchunk) end - -- TODO: we will need to decode "sh_string_index" first to get names + -- Only mark section headers after we've decoded them all, + -- so that we can name them using the section containing section names + local shs = {} for i = 1, elf.sh_number do local start = elf.sh_offset + (i - 1) * elf.sh_entry_size - local sh = c (1 + start, start + elf.sh_entry_size) - sh:mark ("ELF section header %d", i - 1) - decode_sh (elf, sh) + local schunk = c (1 + start, start + elf.sh_entry_size) + sh = decode_sh (elf, schunk) + shs[i], shs[sh] = sh, schunk + end + + local strings + if elf.sh_string_index ~= 0 and elf.sh_string_index < elf.sh_number then + local sh = shs[elf.sh_string_index + 1] + strings = c (sh.offset + 1, sh.offset + sh.size) + end + for i, sh in ipairs (shs) do + local schunk = shs[sh] + if strings and sh.name < #strings then + sh.name_string = strings (sh.name + 1):cstring () + schunk:mark ("ELF section header %d (%s)", i - 1, sh.name_string) + else + schunk:mark ("ELF section header %d", i - 1) + end end end |