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/*
 * linux/fs/binfmt_elf.c
 *
 * These are the functions used to load ELF format executables as used
 * on SVr4 machines.  Information on the format may be found in the book
 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
 * Tools".
 *
 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 */
 
#include <linux/module.h>
 
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/malloc.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
 
#include <asm/segment.h>
#include <asm/pgtable.h>
 
#include <linux/config.h>
 
#define DLINFO_ITEMS 12
 
#include <linux/elf.h>
 
#define STACK_SIZE (1*PAGE_SIZE)
 
static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
 
#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_EXEC_PAGESIZE-1))
#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_EXEC_PAGESIZE-1))
 
static struct linux_binfmt elf_format =
{
#ifndef MODULE
	NULL, NULL, load_elf_binary, NULL, NULL
#else
  NULL, &mod_use_count_, load_elf_binary, load_elf_library, elf_core_dump
#endif
};
 
struct sec_add {
	unsigned long pm_add;
	unsigned long vm_add;
	int len;
} sec[ELF_SECTION_NB];
 
unsigned short *or32_consth_add = (unsigned short *)NULL;
unsigned long or32_consth_rel;
 
unsigned long *create_elf_tables(char *p, int argc, int envc, struct pt_regs *regs)
{
	unsigned long *argv, *envp;
	unsigned long *sp;
 
	/*
	 * Force 16 byte alignment here for generality.
	 */
	sp = (unsigned long *) (~15UL & (unsigned long) p);
	sp -= 2;
	sp -= envc + 1;
	envp = sp;
	sp -= argc + 1;
	argv = sp;
 
	regs->gprs[1] = argc;
	put_user((unsigned long) argc, --sp);
	current->mm->arg_start = (unsigned long) p;
	regs->gprs[2] = (unsigned long) argv;
	while (argc-- > 0) {
		put_user(p, argv++);
		while (get_user(p++))	/* nothing */
			;
	}
	put_user(0, argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	regs->gprs[3] = (unsigned long) envp;
	while (envc-- > 0) {
		put_user(p, envp++);
		while (get_user(p++))	/* nothing */
			;
	}
	put_user(0, envp);
	current->mm->env_end = (unsigned long) p;
	return sp;
}
 
static unsigned long putstring(unsigned long p, char * string)
{
	unsigned long l = strlen(string)+1;
	p -= l;
	memcpy((void*)p, string, l);
	return p;
}
 
static unsigned long putstringarray(unsigned long p, int count, char ** array)
{
	while(count) {
		p=putstring(p, array[--count]);
	}
	return p;
}
 
int do_relocate(int dst_indx,
		int rel_nb,
		struct elf32_rel *rel_ptr, 
		struct elf32_sym *sym_ptr,
		struct sec_add *sec)
{
	struct elf32_sym *sym_tab;
	void *rel_loc;
	unsigned long tmp;
	int src_indx;
	int i;
 
	for(i = 0; i < rel_nb; i++, rel_ptr++) {
 
		/* Symbol tab */
		sym_tab = sym_ptr + (rel_ptr->r_info >> 8); 
		/* Section index of section that contains symbol */
		src_indx = sym_tab->st_shndx;
		/* Location in physical memory to which this relocation 
		   is refering to */
		rel_loc = (void *)(rel_ptr->r_offset + sec[dst_indx].pm_add);
 
		if((rel_ptr->r_info & 0x000000ff) == R_OR32_32) {
			*(unsigned long *)rel_loc = *(unsigned long *)rel_loc 
						- sec[src_indx].vm_add
						+ sec[src_indx].pm_add;
		}
		else if((rel_ptr->r_info & 0x000000ff) == R_OR32_16) {
			*(unsigned short *)rel_loc = *(unsigned short *)rel_loc
                                                - sec[src_indx].vm_add
                                                + sec[src_indx].pm_add;
		}
		else if((rel_ptr->r_info & 0x000000ff) == R_OR32_8) {
			*(unsigned char *)rel_loc = *(unsigned char *)rel_loc
                                                - sec[src_indx].vm_add
                                                + sec[src_indx].pm_add;
		}
		else if((rel_ptr->r_info & 0x000000ff) == R_OR32_CONSTH) {
			or32_consth_add = (((unsigned short *)rel_loc) + 1);
			or32_consth_rel = *or32_consth_add << 16;
		}
		else if((rel_ptr->r_info & 0x000000ff) == R_OR32_CONST) {
			tmp = or32_consth_rel | *(((unsigned short *)rel_loc) + 1);
                        tmp = tmp/* + sym_tab->st_value*/ - sec[src_indx].vm_add +
						sec[src_indx].pm_add;
			*(((unsigned short *)rel_loc) + 1) = tmp & 0x0000ffff;
			if(or32_consth_add != (unsigned short *)NULL) {
				*or32_consth_add = tmp >> 16;
				or32_consth_add = (unsigned short *)NULL;
				or32_consth_rel = 0;	
			}
                }
		else if((rel_ptr->r_info & 0x000000ff) == R_OR32_JUMPTARG) {
                       	tmp = ((*(unsigned long *)rel_loc) & 0x03ffffff);
			tmp = (tmp & 0x02000000) ? (tmp | 0xfc000000) : tmp;
			tmp = tmp + ((sym_tab->st_value - 
				sec[src_indx].vm_add + 
				sec[src_indx].pm_add -
				sec[dst_indx].pm_add) >> 2);
			*(unsigned long *)rel_loc = 
				((*(unsigned long *)rel_loc) & 0xfc000000) |
				(tmp & 0x03ffffff);
		}
		else {
			return -ELNRNG; 
		}
	}
	return 0;
}
 
unsigned long do_find_main(int sym_nb, struct elf32_sym *sym_prt, char *str_ptr)
{
	int i;
 
	for(i = 0; i < sym_nb; i++, sym_prt++) {
		if(sym_prt->st_name == 0)
			continue;
 
		if(strcmp(&str_ptr[sym_prt->st_name], "_main") == 0) 
			return (sym_prt->st_value + sec[sym_prt->st_shndx].pm_add);
	}
	return 0;
}
/*
 * These are the functions used to load ELF style executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */
 
#define INTERPRETER_NONE 0
#define INTERPRETER_AOUT 1
#define INTERPRETER_ELF 2
 
 
static inline int do_load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
{
	struct elfhdr elf_ex;
	struct file *file;
	unsigned char ibcs2_interpreter;
	int i,j;
	int old_fs;
	struct elf32_shdr *elf_spnt, *elf_shdata;
	int elf_exec_fileno;
	unsigned long elf_entry = 0;
	int status;
	unsigned long start_code, end_code, start_data, end_data, start_brk, brk;
	unsigned long elf_stack;
	int rel_indx, symtab_indx = 0, strtab_indx = 0;
	struct elf32_rel *rel_ptr;
	struct elf32_sym *sym_ptr = (struct elf32_sym *)0;
	char *str_ptr = (char *)0;
	int retval;
 
	or32_consth_add = 0;
	or32_consth_rel = 0;
	ibcs2_interpreter = 0;
	status = 0;
	elf_ex = *((struct elfhdr *) bprm->buf);	/* exec-header */
 
	if (elf_ex.e_ident[0] != 0x7f ||
	    strncmp(&elf_ex.e_ident[1], "ELF", 3) != 0) {
		return -ENOEXEC;
	}
 
	/* First of all, some simple consistency checks */
	if (elf_ex.e_type != ET_REL ||
	    (!elf_check_arch(elf_ex.e_machine)) ||
	    (!bprm->inode->i_op || !bprm->inode->i_op->default_file_ops ||
	     !bprm->inode->i_op->default_file_ops->mmap)) {
		return -ENOEXEC;
	}
 
	if(elf_ex.e_shnum > ELF_SECTION_NB)
		return -ETOOMANYSECT;
 
	for(i = 0; i < ELF_SECTION_NB; i++)
		sec[i].len = 0;
 
	/* Now read in all of the header information */
 
	elf_shdata = (struct elf32_shdr *) kmalloc(elf_ex.e_shnum *
					     elf_ex.e_shentsize, GFP_KERNEL);
	if (elf_shdata == NULL) {
		return -ENOMEM;
	}
	retval = read_exec(bprm->inode, elf_ex.e_shoff, (char *) elf_shdata,
			   elf_ex.e_shentsize * elf_ex.e_shnum, 1);
	if (retval < 0) {
		kfree(elf_shdata);
		return retval;
	}
 
	elf_exec_fileno = open_inode(bprm->inode, O_RDONLY);
 
	if (elf_exec_fileno < 0) {
		kfree(elf_shdata);
		return elf_exec_fileno;
	}
	file = current->files->fd[elf_exec_fileno];
 
	elf_stack = ~0UL;
	start_code = ~0UL;
	end_code = 0;
	start_data = ~0UL;
	end_data = 0;
	start_brk = ~0UL;
	brk = 0;
 
	if (flush_old_exec(bprm)) {
		return -ENOMEM;
	}
 
	/* OK, This is the point of no return */
 
	current->mm->end_data = 0;
	current->mm->end_code = 0;
 
	/* Now we do a little grungy work by mmaping the ELF image into
	   the memory.  At this point, we assume that at a variable
	   address. */
 
	old_fs = get_fs();
	set_fs(get_ds());
 
	for(i = 0, elf_spnt = elf_shdata; i < elf_ex.e_shnum; i++, elf_spnt++) {
		if((elf_spnt->sh_flags & SHF_ALLOC)) {
			int elf_prot = PROT_READ;
			unsigned long retval;
                        if (elf_spnt->sh_flags & SHF_WRITE)
                                elf_prot |= PROT_WRITE;
                        if (elf_spnt->sh_flags & SHF_EXECINSTR)
                                elf_prot |= PROT_EXEC;
 
			if(elf_spnt->sh_size == 0)
				continue;
 
			retval = (unsigned long)do_mmap(NULL,
						0,
                                		elf_spnt->sh_size,
                                		elf_prot,
                                		0,
                                		0);
 
			if(retval > (unsigned long)-4096) {
				for(j = 0; j < elf_ex.e_shnum; j++)
					if(sec[j].len)
						do_munmap(sec[j].pm_add, sec[j].len);
				kfree(elf_shdata);
				return retval;
			}
 
		 	sec[i].pm_add = retval;
			sec[i].vm_add = elf_spnt->sh_addr;
			sec[i].len = elf_spnt->sh_size;
 
			if(elf_spnt->sh_type == SHT_PROGBITS) {
				retval = read_exec(bprm->inode, elf_spnt->sh_offset,
        	                                (char *)retval, elf_spnt->sh_size, 1);
                	        if (retval < 0) {
                        	        for(j = 0; j < elf_ex.e_shnum; j++)
                                	        if(sec[j].len)
                                        	        do_munmap(sec[j].pm_add, sec[j].len);
                               		kfree(elf_shdata);
                                	return retval;
                        	}
			}
 
			if(elf_spnt->sh_type == SHT_PROGBITS) {
				if(elf_spnt->sh_flags & SHF_EXECINSTR) {
					if(sec[i].pm_add < start_code)
						start_code = sec[i].pm_add;
					if((sec[i].pm_add + elf_spnt->sh_size) > end_code)
						end_code = sec[i].pm_add + elf_spnt->sh_size;
				}
				else {
					if(sec[i].pm_add < start_data)
                                                start_data = sec[i].pm_add;
                                        if((sec[i].pm_add + elf_spnt->sh_size) > end_data)
                                                end_data = sec[i].pm_add + elf_spnt->sh_size;
				}
			}
			else if(elf_spnt->sh_type == SHT_NOBITS) {
				if(sec[i].pm_add < start_brk)
					start_brk = sec[i].pm_add;
                                if((sec[i].pm_add + elf_spnt->sh_size) > brk)
                                        brk = sec[i].pm_add + elf_spnt->sh_size;
			}
		}
	}
 
	for(i = 0, elf_spnt = elf_shdata; i < elf_ex.e_shnum; elf_spnt++, i++) {
                if(elf_spnt->sh_type == SHT_SYMTAB && (elf_spnt->sh_size != 0)) {
			struct elf32_shdr *link_shdr;
			int sym_nb;
			unsigned long retval;
 
			/* Map symtab section */
			retval = (unsigned long)do_mmap(NULL,
							0,
							elf_spnt->sh_size,
							PROT_READ,
							0,
							0);
			if(retval > (unsigned long)-4096) {
				for(j = 0; j < elf_ex.e_shnum; j++)
						if(sec[j].len)
							do_munmap(sec[j].pm_add, sec[j].len);
				kfree(elf_shdata);
				return retval;
			}
 
			symtab_indx = i;
			sec[symtab_indx].pm_add = retval;
			sym_ptr = (struct elf32_sym *)retval;
			sec[symtab_indx].len = elf_spnt->sh_size;
 
			retval = read_exec(bprm->inode, elf_spnt->sh_offset, 
					(char *)retval, elf_spnt->sh_size, 1);
        		if (retval < 0) {
				for(j = 0; j < elf_ex.e_shnum; j++)
                                        if(sec[j].len)
                                                do_munmap(sec[j].pm_add, sec[j].len);
                		kfree(elf_shdata);
                		return retval;
        		} 
 
			strtab_indx = elf_spnt->sh_link;
			link_shdr = elf_shdata + strtab_indx;
 
			/* Map strtab section */
			retval = (unsigned long)do_mmap(NULL,
							0,
							link_shdr->sh_size,
							PROT_READ,
							0,
							0);
			if(retval > (unsigned long)-4096) {
				for(j = 0; j < elf_ex.e_shnum; j++)
					if(sec[j].len)
						do_munmap(sec[j].pm_add, sec[j].len);
			kfree(elf_shdata);
			return retval;
			}
 
			sec[strtab_indx].pm_add = retval;
			str_ptr = (char *)retval;
			sec[strtab_indx].len = link_shdr->sh_size;
 
			retval = read_exec(bprm->inode, link_shdr->sh_offset, 
					(char *)retval, link_shdr->sh_size, 1);
        		if (retval < 0) {
				for(j = 0; j < elf_ex.e_shnum; j++)
                                        if(sec[j].len)
                                                do_munmap(sec[j].pm_add, sec[j].len);
                		kfree(elf_shdata);
                		return retval;
        		} 
 
			sym_nb = sec[symtab_indx].len / sizeof(struct elf32_sym);
			elf_entry = do_find_main(sym_nb, sym_ptr, str_ptr);
 
			break;
		}
	}
 
	for(i = 0, elf_spnt = elf_shdata; i < elf_ex.e_shnum; elf_spnt++, i++) {
		if(elf_spnt->sh_type == SHT_REL && (elf_spnt->sh_size != 0)) {
			struct elf32_shdr *link_shdr;
			int rel_nb;
			unsigned long retval;
 
			/* Map rel section */
			retval = (unsigned long)do_mmap(NULL,
							0,
							elf_spnt->sh_size,
							PROT_READ,
							0,
       						      	0);	
			if(retval > (unsigned long)-4096) {
				for(j = 0; j < elf_ex.e_shnum; j++)
       					if(sec[j].len)
						do_munmap(sec[j].pm_add, sec[j].len);
			kfree(elf_shdata);
			return retval;
			}
 
			sec[i].pm_add = retval;
			rel_ptr = (struct elf32_rel *)retval;
			sec[i].len = elf_spnt->sh_size;
 
			retval = read_exec(bprm->inode, elf_spnt->sh_offset, 
					(char *)retval, elf_spnt->sh_size, 1);
        		if (retval < 0) {
				for(j = 0; j < elf_ex.e_shnum; j++)
                                        if(sec[j].len)
                                                do_munmap(sec[j].pm_add, sec[j].len);
                		kfree(elf_shdata);
                		return retval;
        		} 
 
			rel_indx = i;
			symtab_indx = elf_spnt->sh_link;
			link_shdr = elf_shdata + symtab_indx;
 
			/* Now do relocations for the n-th section. n is read from 
			   real setiona hader info field. */
 
			rel_nb = sec[rel_indx].len / sizeof(struct elf32_rel);
			retval = do_relocate(elf_spnt->sh_info, rel_nb, rel_ptr, sym_ptr,  sec);
 
			if (retval < 0) {
                                for(j = 0; j < elf_ex.e_shnum; j++)
                                        if(sec[j].len)
                                                do_munmap(sec[j].pm_add, sec[j].len);
                                kfree(elf_shdata);
                                return retval;
                        }
 
			/* Now unmap rel section */
			do_munmap(sec[rel_indx].pm_add, sec[rel_indx].len);
			sec[rel_indx].len = 0;
		}
	}
 
	/* Now unmap sym and str sections */
	do_munmap(sec[symtab_indx].pm_add, sec[symtab_indx].len);
	sec[symtab_indx].len = 0;
	do_munmap(sec[strtab_indx].pm_add, sec[strtab_indx].len);
	sec[strtab_indx].len = 0;
 
	set_fs(old_fs);
	kfree(elf_shdata);
 
	sys_close(elf_exec_fileno);
 
	current->personality = PER_LINUX;
 
	if (current->exec_domain && current->exec_domain->use_count)
		(*current->exec_domain->use_count)--;
	if (current->binfmt && current->binfmt->use_count)
		(*current->binfmt->use_count)--;
	current->exec_domain = lookup_exec_domain(current->personality);
	current->binfmt = &elf_format;
	if (current->exec_domain && current->exec_domain->use_count)
		(*current->exec_domain->use_count)++;
	if (current->binfmt && current->binfmt->use_count)
		(*current->binfmt->use_count)++;
 
	bprm->p = do_mmap(0, 0, STACK_SIZE, PROT_READ|PROT_WRITE, 0, 0) + STACK_SIZE;
 
	bprm->p = putstringarray(bprm->p, 1, &bprm->filename);
 
	bprm->p = putstringarray(bprm->p, bprm->envc, bprm->envp);
 
	bprm->p = putstringarray(bprm->p, bprm->argc, bprm->argv);
 
	current->suid = current->euid = current->fsuid = bprm->e_uid;
	current->sgid = current->egid = current->fsgid = bprm->e_gid;
	current->flags &= ~PF_FORKNOEXEC;
	bprm->p = (unsigned long)create_elf_tables((char *) bprm->p, bprm->argc, bprm->envc, regs);
 
	current->mm->start_brk = start_brk;
	current->mm->brk = brk;
	current->mm->start_code	 = start_code;
	current->mm->end_code = end_code;
	current->mm->start_data	 = start_data;
	current->mm->end_data = end_data;
	current->mm->start_stack = bprm->p;
 
	if(start_brk != ~0UL) {
		int nbyte = brk - start_brk;
		char *fpnt = (char *)brk;
 
		do {
        		put_user(0, fpnt++);
        	} while (--nbyte);
	}
 
	start_thread(regs, elf_entry, bprm->p);
 
	if (current->flags & PF_PTRACED)
		send_sig(SIGTRAP, current, 0);
 
	return 0;
}
 
static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
{
	int retval;
 
	MOD_INC_USE_COUNT;
	retval = do_load_elf_binary(bprm, regs);
	MOD_DEC_USE_COUNT;
	return retval;
}
 
int init_elf_binfmt(void)
{
	return register_binfmt(&elf_format);
}
 
#ifdef MODULE
 
int init_module(void)
{
	/* Install the COFF, ELF and XOUT loaders.
	 * N.B. We *rely* on the table being the right size with the
	 * right number of free slots...
	 */
	return init_elf_binfmt();
}
 
 
void cleanup_module(void)
{
	/* Remove the COFF and ELF loaders. */
	unregister_binfmt(&elf_format);
}
 
#endif