ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_index(struct elf_binary *elf, unsigned index)
{
uint64_t count = elf_shdr_count(elf);
elf_ptrval ptr;
if ( index >= count )
return ELF_INVALID_HANDLE(elf_shdr);
ptr = (ELF_IMAGE_BASE(elf)
+ elf_uval(elf, elf->ehdr, e_shoff)
+ elf_uval(elf, elf->ehdr, e_shentsize) * index);
return ELF_MAKE_HANDLE(elf_shdr, ptr);
}
ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_name(struct elf_binary *elf, const char *name)
{
uint64_t count = elf_shdr_count(elf);
ELF_HANDLE_DECL(elf_shdr) shdr;
const char *sname;
unsigned i;
for ( i = 0; i < count; i++ )
{
shdr = elf_shdr_by_index(elf, i);
if ( !elf_access_ok(elf, ELF_HANDLE_PTRVAL(shdr), 1) )
/* input has an insane section header count field */
break;
sname = elf_section_name(elf, shdr);
if ( sname && !strcmp(sname, name) )
return shdr;
}
return ELF_INVALID_HANDLE(elf_shdr);
}
static int xc_dom_load_elf_symtab(struct xc_dom_image *dom,
struct elf_binary *elf, int load)
{
struct elf_binary syms;
const elf_shdr *shdr, *shdr2;
xen_vaddr_t symtab, maxaddr;
char *hdr;
size_t size;
int h, count, type, i, tables = 0;
if ( elf_swap(elf) )
{
xc_dom_printf("%s: non-native byte order, bsd symtab not supported\n",
__FUNCTION__);
return 0;
}
if ( load )
{
if ( !dom->bsd_symtab_start )
return 0;
size = dom->kernel_seg.vend - dom->bsd_symtab_start;
hdr = xc_dom_vaddr_to_ptr(dom, dom->bsd_symtab_start);
*(int *)hdr = size - sizeof(int);
}
else
{
size = sizeof(int) + elf_size(elf, elf->ehdr) +
elf_shdr_count(elf) * elf_size(elf, shdr);
hdr = xc_dom_malloc(dom, size);
if ( hdr == NULL )
return 0;
dom->bsd_symtab_start = elf_round_up(&syms, dom->kernel_seg.vend);
}
memcpy(hdr + sizeof(int),
elf->image,
elf_size(elf, elf->ehdr));
memcpy(hdr + sizeof(int) + elf_size(elf, elf->ehdr),
elf->image + elf_uval(elf, elf->ehdr, e_shoff),
elf_shdr_count(elf) * elf_size(elf, shdr));
if ( elf_64bit(elf) )
{
Elf64_Ehdr *ehdr = (Elf64_Ehdr *)(hdr + sizeof(int));
ehdr->e_phoff = 0;
ehdr->e_phentsize = 0;
ehdr->e_phnum = 0;
ehdr->e_shoff = elf_size(elf, elf->ehdr);
ehdr->e_shstrndx = SHN_UNDEF;
}
else
{
Elf32_Ehdr *ehdr = (Elf32_Ehdr *)(hdr + sizeof(int));
ehdr->e_phoff = 0;
ehdr->e_phentsize = 0;
ehdr->e_phnum = 0;
ehdr->e_shoff = elf_size(elf, elf->ehdr);
ehdr->e_shstrndx = SHN_UNDEF;
}
if ( elf_init(&syms, hdr + sizeof(int), size - sizeof(int)) )
return -1;
if ( xc_dom_logfile )
elf_set_logfile(&syms, xc_dom_logfile, 1);
symtab = dom->bsd_symtab_start + sizeof(int);
maxaddr = elf_round_up(&syms, symtab + elf_size(&syms, syms.ehdr) +
elf_shdr_count(&syms) * elf_size(&syms, shdr));
xc_dom_printf("%s/%s: bsd_symtab_start=%" PRIx64 ", kernel.end=0x%" PRIx64
" -- symtab=0x%" PRIx64 ", maxaddr=0x%" PRIx64 "\n",
__FUNCTION__, load ? "load" : "parse",
dom->bsd_symtab_start, dom->kernel_seg.vend,
symtab, maxaddr);
count = elf_shdr_count(&syms);
for ( h = 0; h < count; h++ )
{
shdr = elf_shdr_by_index(&syms, h);
type = elf_uval(&syms, shdr, sh_type);
if ( type == SHT_STRTAB )
{
/* Look for a strtab @i linked to symtab @h. */
for ( i = 0; i < count; i++ )
{
shdr2 = elf_shdr_by_index(&syms, i);
if ( (elf_uval(&syms, shdr2, sh_type) == SHT_SYMTAB) &&
(elf_uval(&syms, shdr2, sh_link) == h) )
break;
}
/* Skip symtab @h if we found no corresponding strtab @i. */
if ( i == count )
{
if ( elf_64bit(&syms) )
*(Elf64_Off*)(&shdr->e64.sh_offset) = 0;
else
*(Elf32_Off*)(&shdr->e32.sh_offset) = 0;
continue;
}
}
if ( (type == SHT_STRTAB) || (type == SHT_SYMTAB) )
{
/* Mangled to be based on ELF header location. */
if ( elf_64bit(&syms) )
*(Elf64_Off*)(&shdr->e64.sh_offset) = maxaddr - symtab;
else
*(Elf32_Off*)(&shdr->e32.sh_offset) = maxaddr - symtab;
size = elf_uval(&syms, shdr, sh_size);
maxaddr = elf_round_up(&syms, maxaddr + size);
tables++;
xc_dom_printf("%s: h=%d %s, size=0x%zx, maxaddr=0x%" PRIx64 "\n",
__FUNCTION__, h,
type == SHT_SYMTAB ? "symtab" : "strtab",
size, maxaddr);
if ( load )
{
shdr2 = elf_shdr_by_index(elf, h);
memcpy((void*)elf_section_start(&syms, shdr),
elf_section_start(elf, shdr2),
size);
}
}
/* Name is NULL. */
if ( elf_64bit(&syms) )
*(Elf64_Half*)(&shdr->e64.sh_name) = 0;
else
*(Elf32_Word*)(&shdr->e32.sh_name) = 0;
}
if ( tables == 0 )
{
xc_dom_printf("%s: no symbol table present\n", __FUNCTION__);
dom->bsd_symtab_start = 0;
return 0;
}
if ( !load )
dom->kernel_seg.vend = maxaddr;
return 0;
}
int main(int argc, char **argv)
{
const char *f;
int fd,h,size,usize,count;
void *image,*tmp;
struct stat st;
struct elf_binary elf;
const elf_shdr *shdr;
int notes_found = 0;
if (argc != 2)
{
fprintf(stderr, "Usage: readnotes <elfimage>\n");
return 1;
}
f = argv[1];
fd = open(f, O_RDONLY);
if (fd == -1)
{
fprintf(stderr, "Unable to open %s: %s\n", f, strerror(errno));
return 1;
}
if (fstat(fd, &st) == -1)
{
fprintf(stderr, "Unable to determine size of %s: %s\n",
f, strerror(errno));
return 1;
}
image = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (image == MAP_FAILED)
{
fprintf(stderr, "Unable to map %s: %s\n", f, strerror(errno));
return 1;
}
size = st.st_size;
usize = xc_dom_check_gzip(image, st.st_size);
if (usize)
{
tmp = malloc(usize);
xc_dom_do_gunzip(image, st.st_size, tmp, usize);
image = tmp;
size = usize;
}
if (0 != elf_init(&elf, image, size))
{
fprintf(stderr, "File %s is not an ELF image\n", f);
return 1;
}
elf_set_logfile(&elf, stderr, 0);
count = elf_phdr_count(&elf);
for ( h=0; h < count; h++)
{
const elf_phdr *phdr;
phdr = elf_phdr_by_index(&elf, h);
if (elf_uval(&elf, phdr, p_type) != PT_NOTE)
continue;
/* Some versions of binutils do not correctly set
* p_offset for note segments.
*/
if (elf_uval(&elf, phdr, p_offset) == 0)
continue;
notes_found = print_notes(&elf,
elf_segment_start(&elf, phdr),
elf_segment_end(&elf, phdr));
}
if ( notes_found == 0 )
{
count = elf_shdr_count(&elf);
for ( h=0; h < count; h++)
{
const elf_shdr *shdr;
shdr = elf_shdr_by_index(&elf, h);
if (elf_uval(&elf, shdr, sh_type) != SHT_NOTE)
continue;
notes_found = print_notes(&elf,
elf_section_start(&elf, shdr),
elf_section_end(&elf, shdr));
if ( notes_found )
fprintf(stderr, "using notes from SHT_NOTE section\n");
}
}
shdr = elf_shdr_by_name(&elf, "__xen_guest");
if (shdr)
printf("__xen_guest: %s\n", (char*)elf_section_start(&elf, shdr));
return 0;
}