satip-axe/kernel/scripts/mod/elflib.c

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7.4 KiB
C
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#include "elflib.h"
#define PRINTF __attribute__ ((format (printf, 1, 2)))
PRINTF void fatal(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "FATAL: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
exit(1);
}
PRINTF void warn(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "WARNING: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
}
PRINTF void merror(const char *fmt, ...)
{
va_list arglist;
fprintf(stderr, "ERROR: ");
va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
}
static void *grab_file_rw(const char *filename, unsigned long *size,
unsigned char write)
{
struct stat st;
void *map;
int fd, open_flag, map_flag;
if (write) {
open_flag = O_RDWR;
map_flag = MAP_SHARED;
} else {
open_flag = O_RDONLY;
map_flag = MAP_PRIVATE;
}
fd = open(filename, open_flag);
if (fd < 0 || fstat(fd, &st) != 0)
return NULL;
*size = st.st_size;
map = mmap(NULL, *size, PROT_READ|PROT_WRITE, map_flag, fd, 0);
close(fd);
if (map == MAP_FAILED)
return NULL;
return map;
}
static void set_ksymtable(struct elf_info *info, enum ksymtab_type type,
Elf_Ehdr *hdr, Elf_Shdr *sechdrs, unsigned int secidx,
const char *secname)
{
info->ksym_tables[type].start = (struct kernel_symbol *) \
((void *) hdr + sechdrs[secidx].sh_offset);
info->ksym_tables[type].stop = (struct kernel_symbol *) \
((void *) hdr + sechdrs[secidx].sh_offset + sechdrs[secidx].sh_size);
info->ksym_tables[type].name = strdup(secname);
info->ksym_tables[type].sec = secidx;
}
static int parse_elf_rw(struct elf_info *info, const char *filename,
unsigned char write)
{
unsigned int i;
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
Elf_Sym *sym;
char *lkm_suffix;
hdr = grab_file_rw(filename, &info->size, write);
if (!hdr) {
perror(filename);
exit(1);
}
info->hdr = hdr;
if (info->size < sizeof(*hdr)) {
/* file too small, assume this is an empty .o file */
return 0;
}
/* Is this a valid ELF file? */
if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
(hdr->e_ident[EI_MAG1] != ELFMAG1) ||
(hdr->e_ident[EI_MAG2] != ELFMAG2) ||
(hdr->e_ident[EI_MAG3] != ELFMAG3)) {
/* Not an ELF file - silently ignore it */
return 0;
}
/* Fix endianness in ELF header */
hdr->e_type = TO_NATIVE(hdr->e_type);
hdr->e_machine = TO_NATIVE(hdr->e_machine);
hdr->e_version = TO_NATIVE(hdr->e_version);
hdr->e_entry = TO_NATIVE(hdr->e_entry);
hdr->e_phoff = TO_NATIVE(hdr->e_phoff);
hdr->e_shoff = TO_NATIVE(hdr->e_shoff);
hdr->e_flags = TO_NATIVE(hdr->e_flags);
hdr->e_ehsize = TO_NATIVE(hdr->e_ehsize);
hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
hdr->e_phnum = TO_NATIVE(hdr->e_phnum);
hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
hdr->e_shnum = TO_NATIVE(hdr->e_shnum);
hdr->e_shstrndx = TO_NATIVE(hdr->e_shstrndx);
sechdrs = (void *)hdr + hdr->e_shoff;
info->sechdrs = sechdrs;
/* Check if file offset is correct */
if (hdr->e_shoff > info->size) {
fatal("section header offset=%lu in file '%s' is bigger than "
"filesize=%lu\n", (unsigned long)hdr->e_shoff,
filename, info->size);
return 0;
}
/* Fix endianness in section headers */
for (i = 0; i < hdr->e_shnum; i++) {
sechdrs[i].sh_name = TO_NATIVE(sechdrs[i].sh_name);
sechdrs[i].sh_type = TO_NATIVE(sechdrs[i].sh_type);
sechdrs[i].sh_flags = TO_NATIVE(sechdrs[i].sh_flags);
sechdrs[i].sh_addr = TO_NATIVE(sechdrs[i].sh_addr);
sechdrs[i].sh_offset = TO_NATIVE(sechdrs[i].sh_offset);
sechdrs[i].sh_size = TO_NATIVE(sechdrs[i].sh_size);
sechdrs[i].sh_link = TO_NATIVE(sechdrs[i].sh_link);
sechdrs[i].sh_info = TO_NATIVE(sechdrs[i].sh_info);
sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
sechdrs[i].sh_entsize = TO_NATIVE(sechdrs[i].sh_entsize);
}
/* Find symbol tables and text section. */
for (i = 1; i < hdr->e_shnum; i++) {
const char *secstrings
= (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
const char *secname;
int nobits = sechdrs[i].sh_type == SHT_NOBITS;
if (!nobits && sechdrs[i].sh_offset > info->size) {
fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
"sizeof(*hrd)=%zu\n", filename,
(unsigned long)sechdrs[i].sh_offset,
sizeof(*hdr));
return 0;
}
secname = secstrings + sechdrs[i].sh_name;
if (strcmp(secname, ".text") == 0)
info->base_addr = sechdrs[i].sh_addr -
sechdrs[i].sh_offset;
else if (strcmp(secname, ".modinfo") == 0) {
if (nobits)
fatal("%s has NOBITS .modinfo\n", filename);
info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
info->modinfo_len = sechdrs[i].sh_size;
} else if (strcmp(secname, "__ksymtab") == 0)
set_ksymtable(info, KSYMTAB, hdr, sechdrs, i, secname);
else if (strcmp(secname, "__ksymtab_unused") == 0)
set_ksymtable(info, KSYMTAB_UNUSED, hdr, sechdrs, i,
secname);
else if (strcmp(secname, "__ksymtab_gpl") == 0)
set_ksymtable(info, KSYMTAB_GPL, hdr, sechdrs, i,
secname);
else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
set_ksymtable(info, KSYMTAB_UNUSED_GPL, hdr, sechdrs, i,
secname);
else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
set_ksymtable(info, KSYMTAB_GPL_FUTURE, hdr, sechdrs, i,
secname);
else if (strcmp(secname, "__ksymtab_strings") == 0)
info->kstrings = (void *)hdr + sechdrs[i].sh_offset;
else if (strcmp(secname, "__markers_strings") == 0)
info->markers_strings_sec = i;
else if (strcmp(secname, ".undef.hash") == 0) {
info->undef_hash.start = (void *)
hdr + sechdrs[i].sh_offset;
info->undef_hash.stop = (void *)
hdr + sechdrs[i].sh_offset + sechdrs[i].sh_size;
}
if (sechdrs[i].sh_type != SHT_SYMTAB)
continue;
info->symtab_start = (void *)hdr + sechdrs[i].sh_offset;
info->symtab_stop = (void *)hdr + sechdrs[i].sh_offset
+ sechdrs[i].sh_size;
info->strtab = (void *)hdr +
sechdrs[sechdrs[i].sh_link].sh_offset;
}
if (!info->symtab_start)
fatal("%s has no symtab?\n", filename);
/* Check if it is the vmlinux or lkm */
lkm_suffix = strstr(filename, ".ko");
if (lkm_suffix && (strlen(lkm_suffix) == 3))
/* Likely this is a lkm */
/*
* ksym->name is an offset with respect to the start of the
* __ksymtab_strings
*/
info->kstr_offset = (long) info->kstrings;
else
/*
* In this case, ksym->name is the absolute value of the string
* into the __ksymtab_strings
*/
info->kstr_offset = (long)info->hdr - (long)info->base_addr;
/* Fix endianness in symbols */
for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
sym->st_shndx = TO_NATIVE(sym->st_shndx);
sym->st_name = TO_NATIVE(sym->st_name);
sym->st_value = TO_NATIVE(sym->st_value);
sym->st_size = TO_NATIVE(sym->st_size);
}
return 1;
}
ksym_hash_t gnu_hash(const unsigned char *name)
{
ksym_hash_t h = 5381;
unsigned char c;
for (c = *name; c != '\0'; c = *++name)
h = h * 33 + c;
return h & 0xffffffff;
}
void *grab_file(const char *filename, unsigned long *size)
{
/* Read-only */
return grab_file_rw(filename, size, 0);
}
void release_file(void *file, unsigned long size)
{
munmap(file, size);
}
int parse_elf(struct elf_info *info, const char *filename)
{
/* Read-only */
return parse_elf_rw(info, filename, 0);
}
int parse_writable_elf(struct elf_info *info, const char *filename)
{
return parse_elf_rw(info, filename, 1);
}
void parse_elf_finish(struct elf_info *info)
{
release_file(info->hdr, info->size);
}