diff options
| -rw-r--r-- | toys/posix/file.c | 65 |
1 files changed, 39 insertions, 26 deletions
diff --git a/toys/posix/file.c b/toys/posix/file.c index 4827f8f5..bab59e57 100644 --- a/toys/posix/file.c +++ b/toys/posix/file.c @@ -50,7 +50,7 @@ static void do_elf_file(int fd, struct stat *sb) int stripped = 1; char *map; off_t phoff, shoff; - int phsize, phnum, shsize, shnum; + int phentsize, phnum, shsize, shnum; printf("ELF "); @@ -89,27 +89,33 @@ static void do_elf_file(int fd, struct stat *sb) bits--; // If what we've seen so far doesn't seem consistent, bail. - if (!((bits&1)==bits && endian && - (i = elf_int(toybuf+42+12*bits, 2)) == 32+24*bits)) { + if (!((bits&1)==bits && endian)) { printf(", corrupt?\n"); return; } // Stash what we need from the header; it's okay to reuse toybuf after this. - phsize = i; + phentsize = elf_int(toybuf+42+12*bits, 2); phnum = elf_int(toybuf+44+12*bits, 2); phoff = elf_int(toybuf+28+4*bits, 4+4*bits); shsize = elf_int(toybuf+46+12*bits, 2); shnum = elf_int(toybuf+48+12*bits, 2); shoff = elf_int(toybuf+32+8*bits, 4+4*bits); + // With binutils, phentsize seems to only be non-zero if phnum is non-zero. + // Such ELF files are rare, but do exist. (Android's crtbegin files, say.) + if (phnum && (phentsize != 32+24*bits)) { + printf(", corrupt phentsize %d?\n", phentsize); + return; + } + map = mmap(0, sb->st_size, PROT_READ, MAP_SHARED, fd, 0); if (!map) perror_exit("mmap"); - // We need to read the phdrs for dynamic vs static and any notes. + // We need to read the phdrs for dynamic vs static. // (Note: fields got reordered for 64 bit) for (i = 0; i<phnum; i++) { - char *phdr = map+phoff+i*phsize; + char *phdr = map+phoff+i*phentsize; int p_type = elf_int(phdr, 4); long long p_offset, p_filesz; @@ -122,46 +128,53 @@ static void do_elf_file(int fd, struct stat *sb) if (p_type==3 /*PT_INTERP*/) printf(", dynamic (%.*s)", (int)p_filesz, map+p_offset); - else { - char *note = map+p_offset; + } + if (!dynamic) printf(", static"); + + // We need to read the shdrs for stripped/unstripped and any notes. + // Notes are in program headers *and* section headers, but some files don't + // contain program headers, so we prefer to check here. + // (Note: fields got reordered for 64 bit) + for (i = 0; i<shnum; i++) { + char *shdr = map+shoff+i*shsize; + int sh_type = elf_int(shdr+4, 4); + long sh_offset = elf_int(shdr+8+8*(bits+1), 4*(bits+1)); + int sh_size = elf_int(shdr+8+12*(bits+1), 4); + + if (sh_type == 2 /*SHT_SYMTAB*/) { + stripped = 0; + break; + } else if (sh_type == 7 /*SHT_NOTE*/) { + char *note = map+sh_offset; - // A PT_NOTE phdr is a sequence of entries, each consisting of an + // An ELF note is a sequence of entries, each consisting of an // ndhr followed by n_namesz+n_descsz bytes of data (each of those // rounded up to the next 4 bytes, without this being reflected in // the header byte counts themselves). - while (p_filesz >= 3*4) { // Don't try to read a truncated entry. + while (sh_size >= 3*4) { // Don't try to read a truncated entry. int n_namesz = elf_int(note, 4); int n_descsz = elf_int(note+4, 4); int n_type = elf_int(note+8, 4); int notesz = 3*4 + ((n_namesz+3)&~3) + ((n_descsz+3)&~3); if (n_namesz==4 && !memcmp(note+12, "GNU", 4)) { - if (n_type == 3 /*NT_GNU_BUILD_ID*/) { + if (n_type==3 /*NT_GNU_BUILD_ID*/) { printf(", BuildID="); for (j = 0; j < n_descsz; ++j) printf("%02x", note[16 + j]); } } else if (n_namesz==8 && !memcmp(note+12, "Android", 8)) { - if (n_type==1) printf(", for Android %d", (int)elf_int(note+20, 4)); + if (n_type==1 /*.android.note.ident*/) { + printf(", for Android %d", (int)elf_int(note+20, 4)); + if (n_descsz > 24) + printf(", built by NDK %.64s (%.64s)", note+24, note+24+64); + } } note += notesz; - p_filesz -= notesz; + sh_size -= notesz; } } } - if (!dynamic) printf(", static"); - - // We need to read the shdrs for stripped/unstripped. - // (Note: fields got reordered for 64 bit) - for (i = 0; i<shnum; i++) { - char *shdr = map+shoff+i*shsize; - int sh_type = elf_int(shdr+4, 4); - - if (sh_type == 2 /*SHT_SYMTAB*/) { - stripped = 0; - break; - } - } printf(", %sstripped", stripped ? "" : "not "); xputc('\n'); |