int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs,
struct image_info * info)
{
struct elfhdr elf_ex;
struct elfhdr interp_elf_ex;
struct exec interp_ex;
int interpreter_fd = -1; /* avoid warning */
abi_ulong load_addr, load_bias;
int load_addr_set = 0;
unsigned int interpreter_type = INTERPRETER_NONE;
unsigned char ibcs2_interpreter;
int i;
abi_ulong mapped_addr;
struct elf_phdr * elf_ppnt;
struct elf_phdr *elf_phdata;
abi_ulong elf_bss, k, elf_brk;
int retval;
char * elf_interpreter;
abi_ulong elf_entry, interp_load_addr = 0;
int status;
abi_ulong start_code, end_code, start_data, end_data;
abi_ulong reloc_func_desc = 0;
abi_ulong elf_stack;
char passed_fileno[6];
ibcs2_interpreter = 0;
status = 0;
load_addr = 0;
load_bias = 0;
elf_ex = *((struct elfhdr *) bprm->buf); /* exec-header */
#ifdef BSWAP_NEEDED
bswap_ehdr(&elf_ex);
#endif
/* First of all, some simple consistency checks */
if ((elf_ex.e_type != ET_EXEC && elf_ex.e_type != ET_DYN) ||
(! elf_check_arch(elf_ex.e_machine))) {
return -ENOEXEC;
}
bprm->p = copy_elf_strings(1, &bprm->filename, bprm->page, bprm->p);
bprm->p = copy_elf_strings(bprm->envc,bprm->envp,bprm->page,bprm->p);
bprm->p = copy_elf_strings(bprm->argc,bprm->argv,bprm->page,bprm->p);
if (!bprm->p) {
retval = -E2BIG;
}
/* Now read in all of the header information */
elf_phdata = (struct elf_phdr *)malloc(elf_ex.e_phentsize*elf_ex.e_phnum);
if (elf_phdata == NULL) {
return -ENOMEM;
}
retval = lseek(bprm->fd, elf_ex.e_phoff, SEEK_SET);
if(retval > 0) {
retval = read(bprm->fd, (char *) elf_phdata,
elf_ex.e_phentsize * elf_ex.e_phnum);
}
if (retval < 0) {
perror("load_elf_binary");
exit(-1);
free (elf_phdata);
return -errno;
}
#ifdef BSWAP_NEEDED
elf_ppnt = elf_phdata;
for (i=0; i<elf_ex.e_phnum; i++, elf_ppnt++) {
bswap_phdr(elf_ppnt);
}
#endif
elf_ppnt = elf_phdata;
elf_bss = 0;
elf_brk = 0;
elf_stack = ~((abi_ulong)0UL);
elf_interpreter = NULL;
start_code = ~((abi_ulong)0UL);
end_code = 0;
start_data = 0;
end_data = 0;
interp_ex.a_info = 0;
for(i=0;i < elf_ex.e_phnum; i++) {
if (elf_ppnt->p_type == PT_INTERP) {
if ( elf_interpreter != NULL )
{
free (elf_phdata);
free(elf_interpreter);
close(bprm->fd);
return -EINVAL;
}
/* This is the program interpreter used for
* shared libraries - for now assume that this
* is an a.out format binary
*/
elf_interpreter = (char *)malloc(elf_ppnt->p_filesz);
if (elf_interpreter == NULL) {
free (elf_phdata);
close(bprm->fd);
return -ENOMEM;
}
retval = lseek(bprm->fd, elf_ppnt->p_offset, SEEK_SET);
if(retval >= 0) {
retval = read(bprm->fd, elf_interpreter, elf_ppnt->p_filesz);
}
if(retval < 0) {
perror("load_elf_binary2");
exit(-1);
}
/* If the program interpreter is one of these two,
then assume an iBCS2 image. Otherwise assume
a native linux image. */
/* JRP - Need to add X86 lib dir stuff here... */
if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0) {
ibcs2_interpreter = 1;
}
#if 0
printf("Using ELF interpreter %s\n", elf_interpreter);
#endif
if (retval >= 0) {
retval = open(path(elf_interpreter), O_RDONLY);
if(retval >= 0) {
interpreter_fd = retval;
}
else {
perror(elf_interpreter);
exit(-1);
/* retval = -errno; */
}
}
if (retval >= 0) {
retval = lseek(interpreter_fd, 0, SEEK_SET);
if(retval >= 0) {
retval = read(interpreter_fd,bprm->buf,128);
}
}
if (retval >= 0) {
interp_ex = *((struct exec *) bprm->buf); /* aout exec-header */
interp_elf_ex=*((struct elfhdr *) bprm->buf); /* elf exec-header */
}
if (retval < 0) {
perror("load_elf_binary3");
exit(-1);
free (elf_phdata);
free(elf_interpreter);
close(bprm->fd);
return retval;
}
}
elf_ppnt++;
}
/* Some simple consistency checks for the interpreter */
if (elf_interpreter){
interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;
/* Now figure out which format our binary is */
if ((N_MAGIC(interp_ex) != OMAGIC) && (N_MAGIC(interp_ex) != ZMAGIC) &&
(N_MAGIC(interp_ex) != QMAGIC)) {
interpreter_type = INTERPRETER_ELF;
}
if (interp_elf_ex.e_ident[0] != 0x7f ||
strncmp((char *)&interp_elf_ex.e_ident[1], "ELF",3) != 0) {
interpreter_type &= ~INTERPRETER_ELF;
}
if (!interpreter_type) {
free(elf_interpreter);
free(elf_phdata);
close(bprm->fd);
return -ELIBBAD;
}
}
/* OK, we are done with that, now set up the arg stuff,
and then start this sucker up */
{
char * passed_p;
if (interpreter_type == INTERPRETER_AOUT) {
snprintf(passed_fileno, sizeof(passed_fileno), "%d", bprm->fd);
passed_p = passed_fileno;
if (elf_interpreter) {
bprm->p = copy_elf_strings(1,&passed_p,bprm->page,bprm->p);
bprm->argc++;
}
}
if (!bprm->p) {
if (elf_interpreter) {
free(elf_interpreter);
}
free (elf_phdata);
close(bprm->fd);
return -E2BIG;
}
}
/* OK, This is the point of no return */
info->end_data = 0;
info->end_code = 0;
info->start_mmap = (abi_ulong)ELF_START_MMAP;
info->mmap = 0;
info->elf_flags = elf_ex.e_flags;
elf_entry = (abi_ulong) elf_ex.e_entry;
/* Do this so that we can load the interpreter, if need be. We will
change some of these later */
info->rss = 0;
bprm->p = setup_arg_pages(bprm->p, bprm, info);
info->start_stack = bprm->p;
/* Now we do a little grungy work by mmaping the ELF image into
* the correct location in memory. At this point, we assume that
* the image should be loaded at fixed address, not at a variable
* address.
*/
for(i = 0, elf_ppnt = elf_phdata; i < elf_ex.e_phnum; i++, elf_ppnt++) {
int elf_prot = 0;
int elf_flags = 0;
abi_ulong error;
if (elf_ppnt->p_type != PT_LOAD)
continue;
if (elf_ppnt->p_flags & PF_R) elf_prot |= PROT_READ;
if (elf_ppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
if (elf_ppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
elf_flags = MAP_PRIVATE | MAP_DENYWRITE;
if (elf_ex.e_type == ET_EXEC || load_addr_set) {
elf_flags |= MAP_FIXED;
} else if (elf_ex.e_type == ET_DYN) {
/* Try and get dynamic programs out of the way of the default mmap
base, as well as whatever program they might try to exec. This
is because the brk will follow the loader, and is not movable. */
/* NOTE: for qemu, we do a big mmap to get enough space
without hardcoding any address */
error = target_mmap(0, ET_DYN_MAP_SIZE,
PROT_NONE, MAP_PRIVATE | MAP_ANON,
-1, 0);
if (error == -1) {
perror("mmap");
exit(-1);
}
load_bias = TARGET_ELF_PAGESTART(error - elf_ppnt->p_vaddr);
}
error = target_mmap(TARGET_ELF_PAGESTART(load_bias + elf_ppnt->p_vaddr),
(elf_ppnt->p_filesz +
TARGET_ELF_PAGEOFFSET(elf_ppnt->p_vaddr)),
elf_prot,
(MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE),
bprm->fd,
(elf_ppnt->p_offset -
TARGET_ELF_PAGEOFFSET(elf_ppnt->p_vaddr)));
if (error == -1) {
perror("mmap");
exit(-1);
}
#ifdef LOW_ELF_STACK
if (TARGET_ELF_PAGESTART(elf_ppnt->p_vaddr) < elf_stack)
elf_stack = TARGET_ELF_PAGESTART(elf_ppnt->p_vaddr);
#endif
if (!load_addr_set) {
load_addr_set = 1;
load_addr = elf_ppnt->p_vaddr - elf_ppnt->p_offset;
if (elf_ex.e_type == ET_DYN) {
load_bias += error -
TARGET_ELF_PAGESTART(load_bias + elf_ppnt->p_vaddr);
load_addr += load_bias;
reloc_func_desc = load_bias;
}
}
k = elf_ppnt->p_vaddr;
if (k < start_code)
start_code = k;
if (start_data < k)
start_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
if (k > elf_bss)
elf_bss = k;
if ((elf_ppnt->p_flags & PF_X) && end_code < k)
end_code = k;
if (end_data < k)
end_data = k;
k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
if (k > elf_brk) elf_brk = k;
}
elf_entry += load_bias;
elf_bss += load_bias;
elf_brk += load_bias;
start_code += load_bias;
end_code += load_bias;
start_data += load_bias;
end_data += load_bias;
if (elf_interpreter) {
if (interpreter_type & 1) {
elf_entry = load_aout_interp(&interp_ex, interpreter_fd);
}
else if (interpreter_type & 2) {
elf_entry = load_elf_interp(&interp_elf_ex, interpreter_fd,
&interp_load_addr);
}
reloc_func_desc = interp_load_addr;
close(interpreter_fd);
free(elf_interpreter);
if (elf_entry == ~((abi_ulong)0UL)) {
printf("Unable to load interpreter\n");
free(elf_phdata);
exit(-1);
return 0;
}
}
free(elf_phdata);
if (loglevel)
load_symbols(&elf_ex, bprm->fd);
if (interpreter_type != INTERPRETER_AOUT) close(bprm->fd);
info->personality = (ibcs2_interpreter ? PER_SVR4 : PER_LINUX);
#ifdef LOW_ELF_STACK
info->start_stack = bprm->p = elf_stack - 4;
#endif
bprm->p = create_elf_tables(bprm->p,
bprm->argc,
bprm->envc,
&elf_ex,
load_addr, load_bias,
interp_load_addr,
(interpreter_type == INTERPRETER_AOUT ? 0 : 1),
info);
info->load_addr = reloc_func_desc;
info->start_brk = info->brk = elf_brk;
info->end_code = end_code;
info->start_code = start_code;
info->start_data = start_data;
info->end_data = end_data;
info->start_stack = bprm->p;
/* Calling set_brk effectively mmaps the pages that we need for the bss and break
sections */
set_brk(elf_bss, elf_brk);
padzero(elf_bss, elf_brk);
#if 0
printf("(start_brk) %x\n" , info->start_brk);
printf("(end_code) %x\n" , info->end_code);
printf("(start_code) %x\n" , info->start_code);
printf("(end_data) %x\n" , info->end_data);
printf("(start_stack) %x\n" , info->start_stack);
printf("(brk) %x\n" , info->brk);
#endif
if ( info->personality == PER_SVR4 )
{
/* Why this, you ask??? Well SVr4 maps page 0 as read-only,
and some applications "depend" upon this behavior.
Since we do not have the power to recompile these, we
emulate the SVr4 behavior. Sigh. */
mapped_addr = target_mmap(0, qemu_host_page_size, PROT_READ | PROT_EXEC,
MAP_FIXED | MAP_PRIVATE, -1, 0);
}
info->entry = elf_entry;
return 0;
}
static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex,
int interpreter_fd,
abi_ulong *interp_load_addr)
{
struct elf_phdr *elf_phdata = NULL;
struct elf_phdr *eppnt;
abi_ulong load_addr = 0;
int load_addr_set = 0;
int retval;
abi_ulong last_bss, elf_bss;
abi_ulong error;
int i;
elf_bss = 0;
last_bss = 0;
error = 0;
#ifdef BSWAP_NEEDED
bswap_ehdr(interp_elf_ex);
#endif
/* First of all, some simple consistency checks */
if ((interp_elf_ex->e_type != ET_EXEC &&
interp_elf_ex->e_type != ET_DYN) ||
!elf_check_arch(interp_elf_ex->e_machine)) {
return ~((abi_ulong)0UL);
}
/* Now read in all of the header information */
if (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > TARGET_PAGE_SIZE)
return ~(abi_ulong)0UL;
elf_phdata = (struct elf_phdr *)
malloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);
if (!elf_phdata)
return ~((abi_ulong)0UL);
/*
* If the size of this structure has changed, then punt, since
* we will be doing the wrong thing.
*/
if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr)) {
free(elf_phdata);
return ~((abi_ulong)0UL);
}
retval = lseek(interpreter_fd, interp_elf_ex->e_phoff, SEEK_SET);
if(retval >= 0) {
retval = read(interpreter_fd,
(char *) elf_phdata,
sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);
}
if (retval < 0) {
perror("load_elf_interp");
exit(-1);
free (elf_phdata);
return retval;
}
#ifdef BSWAP_NEEDED
eppnt = elf_phdata;
for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
bswap_phdr(eppnt);
}
#endif
if (interp_elf_ex->e_type == ET_DYN) {
/* in order to avoid hardcoding the interpreter load
address in qemu, we allocate a big enough memory zone */
error = target_mmap(0, INTERP_MAP_SIZE,
PROT_NONE, MAP_PRIVATE | MAP_ANON,
-1, 0);
if (error == -1) {
perror("mmap");
exit(-1);
}
load_addr = error;
load_addr_set = 1;
}
eppnt = elf_phdata;
for(i=0; i<interp_elf_ex->e_phnum; i++, eppnt++)
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
int elf_prot = 0;
abi_ulong vaddr = 0;
abi_ulong k;
if (eppnt->p_flags & PF_R) elf_prot = PROT_READ;
if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set) {
elf_type |= MAP_FIXED;
vaddr = eppnt->p_vaddr;
}
error = target_mmap(load_addr+TARGET_ELF_PAGESTART(vaddr),
eppnt->p_filesz + TARGET_ELF_PAGEOFFSET(eppnt->p_vaddr),
elf_prot,
elf_type,
interpreter_fd,
eppnt->p_offset - TARGET_ELF_PAGEOFFSET(eppnt->p_vaddr));
if (error == -1) {
/* Real error */
close(interpreter_fd);
free(elf_phdata);
return ~((abi_ulong)0UL);
}
if (!load_addr_set && interp_elf_ex->e_type == ET_DYN) {
load_addr = error;
load_addr_set = 1;
}
/*
* Find the end of the file mapping for this phdr, and keep
* track of the largest address we see for this.
*/
k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
if (k > elf_bss) elf_bss = k;
/*
* Do the same thing for the memory mapping - between
* elf_bss and last_bss is the bss section.
*/
k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
if (k > last_bss) last_bss = k;
}
/* Now use mmap to map the library into memory. */
close(interpreter_fd);
/*
* Now fill out the bss section. First pad the last page up
* to the page boundary, and then perform a mmap to make sure
* that there are zeromapped pages up to and including the last
* bss page.
*/
padzero(elf_bss, last_bss);
elf_bss = TARGET_ELF_PAGESTART(elf_bss + qemu_host_page_size - 1); /* What we have mapped so far */
/* Map the last of the bss segment */
if (last_bss > elf_bss) {
target_mmap(elf_bss, last_bss-elf_bss,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
}
free(elf_phdata);
*interp_load_addr = load_addr;
return ((abi_ulong) interp_elf_ex->e_entry) + load_addr;
}
/*
* Create an instance of lttng_ust_elf for the ELF file located at
* `path`.
*
* Return a pointer to the instance on success, NULL on failure.
*/
struct lttng_ust_elf *lttng_ust_elf_create(const char *path)
{
uint8_t e_ident[EI_NIDENT];
struct lttng_ust_elf_shdr *section_names_shdr;
struct lttng_ust_elf *elf = NULL;
elf = zmalloc(sizeof(struct lttng_ust_elf));
if (!elf) {
goto error;
}
elf->path = strdup(path);
if (!elf->path) {
goto error;
}
elf->fd = open(elf->path, O_RDONLY | O_CLOEXEC);
if (elf->fd < 0) {
goto error;
}
if (lttng_ust_read(elf->fd, e_ident, EI_NIDENT) < EI_NIDENT) {
goto error;
}
elf->bitness = e_ident[EI_CLASS];
elf->endianness = e_ident[EI_DATA];
if (lseek(elf->fd, 0, SEEK_SET) < 0) {
goto error;
}
elf->ehdr = zmalloc(sizeof(struct lttng_ust_elf_ehdr));
if (!elf->ehdr) {
goto error;
}
if (is_elf_32_bit(elf)) {
Elf32_Ehdr elf_ehdr;
if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
< sizeof(elf_ehdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
bswap_ehdr(elf_ehdr);
}
copy_ehdr(elf_ehdr, *(elf->ehdr));
} else {
Elf64_Ehdr elf_ehdr;
if (lttng_ust_read(elf->fd, &elf_ehdr, sizeof(elf_ehdr))
< sizeof(elf_ehdr)) {
goto error;
}
if (!is_elf_native_endian(elf)) {
bswap_ehdr(elf_ehdr);
}
copy_ehdr(elf_ehdr, *(elf->ehdr));
}
section_names_shdr = lttng_ust_elf_get_shdr(elf, elf->ehdr->e_shstrndx);
if (!section_names_shdr) {
goto error;
}
elf->section_names_offset = section_names_shdr->sh_offset;
elf->section_names_size = section_names_shdr->sh_size;
free(section_names_shdr);
return elf;
error:
if (elf) {
free(elf->ehdr);
if (elf->fd >= 0) {
if (close(elf->fd)) {
abort();
}
}
free(elf->path);
free(elf);
}
return NULL;
}
