irixelf.c

LINUX 2.6.17.4的源码

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * irixelf.c: Code to load IRIX ELF executables conforming to the MIPS ABI.
 *            Based off of work by Eric Youngdale.
 *
 * Copyright (C) 1993 - 1994 Eric Youngdale <[e-mail]>
 * Copyright (C) 1996 - 2004 David S. Miller <[e-mail]>
 * Copyright (C) 2004 - 2005 Steven J. Hill <[e-mail]>
 */
#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/init.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/smp_lock.h>

#include <asm/mipsregs.h>
#include <asm/namei.h>
#include <asm/prctl.h>
#include <asm/uaccess.h>

#define DLINFO_ITEMS 12

#include <linux/elf.h>

#undef DEBUG

static int load_irix_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_irix_library(struct file *);
static int irix_core_dump(long signr, struct pt_regs * regs,
                          struct file *file);

static struct linux_binfmt irix_format = {
	NULL, THIS_MODULE, load_irix_binary, load_irix_library,
	irix_core_dump, PAGE_SIZE
};

#ifndef elf_addr_t
#define elf_addr_t unsigned long
#endif

#ifdef DEBUG
/* Debugging routines. */
static char *get_elf_p_type(Elf32_Word p_type)
{
	int i = (int) p_type;

	switch(i) {
	case PT_NULL: return("PT_NULL"); break;
	case PT_LOAD: return("PT_LOAD"); break;
	case PT_DYNAMIC: return("PT_DYNAMIC"); break;
	case PT_INTERP: return("PT_INTERP"); break;
	case PT_NOTE: return("PT_NOTE"); break;
	case PT_SHLIB: return("PT_SHLIB"); break;
	case PT_PHDR: return("PT_PHDR"); break;
	case PT_LOPROC: return("PT_LOPROC/REGINFO"); break;
	case PT_HIPROC: return("PT_HIPROC"); break;
	default: return("PT_BOGUS"); break;
	}
}

static void print_elfhdr(struct elfhdr *ehp)
{
	int i;

	printk("ELFHDR: e_ident<");
	for(i = 0; i < (EI_NIDENT - 1); i++) printk("%x ", ehp->e_ident[i]);
	printk("%x>\n", ehp->e_ident[i]);
	printk("        e_type[%04x] e_machine[%04x] e_version[%08lx]\n",
	       (unsigned short) ehp->e_type, (unsigned short) ehp->e_machine,
	       (unsigned long) ehp->e_version);
	printk("        e_entry[%08lx] e_phoff[%08lx] e_shoff[%08lx] "
	       "e_flags[%08lx]\n",
	       (unsigned long) ehp->e_entry, (unsigned long) ehp->e_phoff,
	       (unsigned long) ehp->e_shoff, (unsigned long) ehp->e_flags);
	printk("        e_ehsize[%04x] e_phentsize[%04x] e_phnum[%04x]\n",
	       (unsigned short) ehp->e_ehsize, (unsigned short) ehp->e_phentsize,
	       (unsigned short) ehp->e_phnum);
	printk("        e_shentsize[%04x] e_shnum[%04x] e_shstrndx[%04x]\n",
	       (unsigned short) ehp->e_shentsize, (unsigned short) ehp->e_shnum,
	       (unsigned short) ehp->e_shstrndx);
}

static void print_phdr(int i, struct elf_phdr *ep)
{
	printk("PHDR[%d]: p_type[%s] p_offset[%08lx] p_vaddr[%08lx] "
	       "p_paddr[%08lx]\n", i, get_elf_p_type(ep->p_type),
	       (unsigned long) ep->p_offset, (unsigned long) ep->p_vaddr,
	       (unsigned long) ep->p_paddr);
	printk("         p_filesz[%08lx] p_memsz[%08lx] p_flags[%08lx] "
	       "p_align[%08lx]\n", (unsigned long) ep->p_filesz,
	       (unsigned long) ep->p_memsz, (unsigned long) ep->p_flags,
	       (unsigned long) ep->p_align);
}

static void dump_phdrs(struct elf_phdr *ep, int pnum)
{
	int i;

	for(i = 0; i < pnum; i++, ep++) {
		if((ep->p_type == PT_LOAD) ||
		   (ep->p_type == PT_INTERP) ||
		   (ep->p_type == PT_PHDR))
			print_phdr(i, ep);
	}
}
#endif /* DEBUG */

static void set_brk(unsigned long start, unsigned long end)
{
	start = PAGE_ALIGN(start);
	end = PAGE_ALIGN(end);
	if (end <= start)
		return;
	down_write(&current->mm->mmap_sem);
	do_brk(start, end - start);
	up_write(&current->mm->mmap_sem);
}


/* We need to explicitly zero any fractional pages
 * after the data section (i.e. bss).  This would
 * contain the junk from the file that should not
 * be in memory.
 */
static void padzero(unsigned long elf_bss)
{
	unsigned long nbyte;

	nbyte = elf_bss & (PAGE_SIZE-1);
	if (nbyte) {
		nbyte = PAGE_SIZE - nbyte;
		clear_user((void __user *) elf_bss, nbyte);
	}
}

static unsigned long * create_irix_tables(char * p, int argc, int envc,
	struct elfhdr * exec, unsigned int load_addr,
	unsigned int interp_load_addr, struct pt_regs *regs,
	struct elf_phdr *ephdr)
{
	elf_addr_t *argv;
	elf_addr_t *envp;
	elf_addr_t *sp, *csp;

#ifdef DEBUG
	printk("create_irix_tables: p[%p] argc[%d] envc[%d] "
	       "load_addr[%08x] interp_load_addr[%08x]\n",
	       p, argc, envc, load_addr, interp_load_addr);
#endif
	sp = (elf_addr_t *) (~15UL & (unsigned long) p);
	csp = sp;
	csp -= exec ? DLINFO_ITEMS*2 : 2;
	csp -= envc+1;
	csp -= argc+1;
	csp -= 1;		/* argc itself */
	if ((unsigned long)csp & 15UL) {
		sp -= (16UL - ((unsigned long)csp & 15UL)) / sizeof(*sp);
	}

	/*
	 * Put the ELF interpreter info on the stack
	 */
#define NEW_AUX_ENT(nr, id, val) \
	  __put_user ((id), sp+(nr*2)); \
	  __put_user ((val), sp+(nr*2+1)); \

	sp -= 2;
	NEW_AUX_ENT(0, AT_NULL, 0);

	if(exec) {
		sp -= 11*2;

		NEW_AUX_ENT (0, AT_PHDR, load_addr + exec->e_phoff);
		NEW_AUX_ENT (1, AT_PHENT, sizeof (struct elf_phdr));
		NEW_AUX_ENT (2, AT_PHNUM, exec->e_phnum);
		NEW_AUX_ENT (3, AT_PAGESZ, ELF_EXEC_PAGESIZE);
		NEW_AUX_ENT (4, AT_BASE, interp_load_addr);
		NEW_AUX_ENT (5, AT_FLAGS, 0);
		NEW_AUX_ENT (6, AT_ENTRY, (elf_addr_t) exec->e_entry);
		NEW_AUX_ENT (7, AT_UID, (elf_addr_t) current->uid);
		NEW_AUX_ENT (8, AT_EUID, (elf_addr_t) current->euid);
		NEW_AUX_ENT (9, AT_GID, (elf_addr_t) current->gid);
		NEW_AUX_ENT (10, AT_EGID, (elf_addr_t) current->egid);
	}
#undef NEW_AUX_ENT

	sp -= envc+1;
	envp = sp;
	sp -= argc+1;
	argv = sp;

	__put_user((elf_addr_t)argc,--sp);
	current->mm->arg_start = (unsigned long) p;
	while (argc-->0) {
		__put_user((unsigned long)p,argv++);
		p += strlen_user(p);
	}
	__put_user((unsigned long) NULL, argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	while (envc-->0) {
		__put_user((unsigned long)p,envp++);
		p += strlen_user(p);
	}
	__put_user((unsigned long) NULL, envp);
	current->mm->env_end = (unsigned long) p;
	return sp;
}


/* This is much more generalized than the library routine read function,
 * so we keep this separate.  Technically the library read function
 * is only provided so that we can read a.out libraries that have
 * an ELF header.
 */
static unsigned int load_irix_interp(struct elfhdr * interp_elf_ex,
				     struct file * interpreter,
				     unsigned int *interp_load_addr)
{
	struct elf_phdr *elf_phdata  =  NULL;
	struct elf_phdr *eppnt;
	unsigned int len;
	unsigned int load_addr;
	int elf_bss;
	int retval;
	unsigned int last_bss;
	int error;
	int i;
	unsigned int k;

	elf_bss = 0;
	last_bss = 0;
	error = load_addr = 0;

#ifdef DEBUG
	print_elfhdr(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) ||
	     !interpreter->f_op->mmap) {
		printk("IRIX interp has bad e_type %d\n", interp_elf_ex->e_type);
		return 0xffffffff;
	}

	/* Now read in all of the header information */
	if(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > PAGE_SIZE) {
	    printk("IRIX interp header bigger than a page (%d)\n",
		   (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum));
	    return 0xffffffff;
	}

	elf_phdata = kmalloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum,
			     GFP_KERNEL);

	if(!elf_phdata) {
          printk("Cannot kmalloc phdata for IRIX interp.\n");
	  return 0xffffffff;
	}

	/* If the size of this structure has changed, then punt, since
	 * we will be doing the wrong thing.
	 */
	if(interp_elf_ex->e_phentsize != 32) {
		printk("IRIX interp e_phentsize == %d != 32 ",
		       interp_elf_ex->e_phentsize);
		kfree(elf_phdata);
		return 0xffffffff;
	}

	retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
			   (char *) elf_phdata,
			   sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);

#ifdef DEBUG
	dump_phdrs(elf_phdata, interp_elf_ex->e_phnum);
#endif

	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;
	    unsigned long vaddr = 0;
	    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;
	    elf_type |= MAP_FIXED;
	    vaddr = eppnt->p_vaddr;

	    pr_debug("INTERP do_mmap(%p, %08lx, %08lx, %08lx, %08lx, %08lx) ",
		   interpreter, vaddr,
		   (unsigned long) (eppnt->p_filesz + (eppnt->p_vaddr & 0xfff)),
		   (unsigned long) elf_prot, (unsigned long) elf_type,
		   (unsigned long) (eppnt->p_offset & 0xfffff000));
	    down_write(&current->mm->mmap_sem);
	    error = do_mmap(interpreter, vaddr,
			    eppnt->p_filesz + (eppnt->p_vaddr & 0xfff),
			    elf_prot, elf_type,
			    eppnt->p_offset & 0xfffff000);
	    up_write(&current->mm->mmap_sem);

	    if(error < 0 && error > -1024) {
		    printk("Aieee IRIX interp mmap error=%d\n", error);
		    break;  /* Real error */
	    }
	    pr_debug("error=%08lx ", (unsigned long) error);
	    if(!load_addr && interp_elf_ex->e_type == ET_DYN) {
	      load_addr = error;
              pr_debug("load_addr = error ");
	    }

	    /* Find the end of the file  mapping for this phdr, and keep
	     * track of the largest address we see for this.
	     */
	    k = 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 = eppnt->p_memsz + eppnt->p_vaddr;
	    if(k > last_bss) last_bss = k;
	    pr_debug("\n");
	  }
	}

	/* Now use mmap to map the library into memory. */
	if(error < 0 && error > -1024) {
		pr_debug("got error %d\n", error);
		kfree(elf_phdata);
		return 0xffffffff;
	}

	/* 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 zero-mapped pages up to and including the
	 * last bss page.
	 */
	pr_debug("padzero(%08lx) ", (unsigned long) (elf_bss));
	padzero(elf_bss);
	len = (elf_bss + 0xfff) & 0xfffff000; /* What we have mapped so far */

	pr_debug("last_bss[%08lx] len[%08lx]\n", (unsigned long) last_bss,
	         (unsigned long) len);

	/* Map the last of the bss segment */
	if (last_bss > len) {
		down_write(&current->mm->mmap_sem);
		do_brk(len, (last_bss - len));
		up_write(&current->mm->mmap_sem);
	}
	kfree(elf_phdata);

	*interp_load_addr = load_addr;
	return ((unsigned int) interp_elf_ex->e_entry);
}

/* Check sanity of IRIX elf executable header. */
static int verify_binary(struct elfhdr *ehp, struct linux_binprm *bprm)
{
	if (memcmp(ehp->e_ident, ELFMAG, SELFMAG) != 0)
		return -ENOEXEC;

	/* First of all, some simple consistency checks */
	if((ehp->e_type != ET_EXEC && ehp->e_type != ET_DYN) ||
	    !bprm->file->f_op->mmap) {
		return -ENOEXEC;
	}

	/* XXX Don't support N32 or 64bit binaries yet because they can
	 * XXX and do execute 64 bit instructions and expect all registers
	 * XXX to be 64 bit as well.  We need to make the kernel save
	 * XXX all registers as 64bits on cpu's capable of this at
	 * XXX exception time plus frob the XTLB exception vector.
	 */
	if((ehp->e_flags & EF_MIPS_ABI2))
		return -ENOEXEC;

	return 0;
}

/*
 * This is where the detailed check is performed. Irix binaries
 * use interpreters with 'libc.so' in the name, so this function
 * can differentiate between Linux and Irix binaries.
 */
static inline int look_for_irix_interpreter(char **name,
					    struct file **interpreter,
					    struct elfhdr *interp_elf_ex,
					    struct elf_phdr *epp,
					    struct linux_binprm *bprm, int pnum)
{
	int i;
	int retval = -EINVAL;
	struct file *file = NULL;

	*name = NULL;
	for(i = 0; i < pnum; i++, epp++) {
		if (epp->p_type != PT_INTERP)
			continue;

		/* It is illegal to have two interpreters for one executable. */
		if (*name != NULL)
			goto out;

		*name = kmalloc(epp->p_filesz + strlen(IRIX_EMUL), GFP_KERNEL);
		if (!*name)
			return -ENOMEM;

		strcpy(*name, IRIX_EMUL);
		retval = kernel_read(bprm->file, epp->p_offset, (*name + 16),
		                     epp->p_filesz);
		if (retval < 0)
			goto out;

		file = open_exec(*name);
		if (IS_ERR(file)) {
			retval = PTR_ERR(file);
			goto out;
		}
		retval = kernel_read(file, 0, bprm->buf, 128);
		if (retval < 0)
			goto dput_and_out;

		*interp_elf_ex = *(struct elfhdr *) bprm->buf;
	}
	*interpreter = file;
	return 0;