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irixelf.c

/*
 * 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 <ericy@cais.com>
 * Copyright (C) 1996 - 2004 David S. Miller <dm@engr.sgi.com>
 * Copyright (C) 2004 - 2005 Steven J. Hill <sjhill@realitydiluted.com>
 */
#undef DEBUG

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

#define DLINFO_ITEMS 12

#include <linux/elf.h>

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, unsigned long limit);

static struct linux_binfmt irix_format = {
      .module           = THIS_MODULE,
      .load_binary      = load_irix_binary,
      .load_shlib = load_irix_library,
      .core_dump  = irix_core_dump,
      .min_coredump     = PAGE_SIZE,
};

/* Debugging routines. */
static char *get_elf_p_type(Elf32_Word p_type)
{
#ifdef DEBUG
      switch (p_type) {
      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;
      }
#endif
}

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

      pr_debug("ELFHDR: e_ident<");
      for (i = 0; i < (EI_NIDENT - 1); i++)
            pr_debug("%x ", ehp->e_ident[i]);
      pr_debug("%x>\n", ehp->e_ident[i]);
      pr_debug("        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);
      pr_debug("        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);
      pr_debug("        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);
      pr_debug("        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)
{
      pr_debug("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);
      pr_debug("         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);
      }
}

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;

      pr_debug("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);

      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;

      print_elfhdr(interp_elf_ex);

      /* 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);

      dump_phdrs(elf_phdata, interp_elf_ex->e_phnum);

      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;

dput_and_out:
      fput(file);
out:
      kfree(*name);
      return retval;
}

static inline int verify_irix_interpreter(struct elfhdr *ihp)
{
      if (memcmp(ihp->e_ident, ELFMAG, SELFMAG) != 0)
            return -ELIBBAD;
      return 0;
}

#define EXEC_MAP_FLAGS (MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE)

static inline void map_executable(struct file *fp, struct elf_phdr *epp, int pnum,
                          unsigned int *estack, unsigned int *laddr,
                          unsigned int *scode, unsigned int *ebss,
                          unsigned int *ecode, unsigned int *edata,
                          unsigned int *ebrk)
{
      unsigned int tmp;
      int i, prot;

      for (i = 0; i < pnum; i++, epp++) {
            if (epp->p_type != PT_LOAD)
                  continue;

            /* Map it. */
            prot  = (epp->p_flags & PF_R) ? PROT_READ : 0;
            prot |= (epp->p_flags & PF_W) ? PROT_WRITE : 0;
            prot |= (epp->p_flags & PF_X) ? PROT_EXEC : 0;
              down_write(&current->mm->mmap_sem);
            (void) do_mmap(fp, (epp->p_vaddr & 0xfffff000),
                         (epp->p_filesz + (epp->p_vaddr & 0xfff)),
                         prot, EXEC_MAP_FLAGS,
                         (epp->p_offset & 0xfffff000));
              up_write(&current->mm->mmap_sem);

            /* Fixup location tracking vars. */
            if ((epp->p_vaddr & 0xfffff000) < *estack)
                  *estack = (epp->p_vaddr & 0xfffff000);
            if (!*laddr)
                  *laddr = epp->p_vaddr - epp->p_offset;
            if (epp->p_vaddr < *scode)
                  *scode = epp->p_vaddr;

            tmp = epp->p_vaddr + epp->p_filesz;
            if (tmp > *ebss)
                  *ebss = tmp;
            if ((epp->p_flags & PF_X) && *ecode < tmp)
                  *ecode = tmp;
            if (*edata < tmp)
                  *edata = tmp;

            tmp = epp->p_vaddr + epp->p_memsz;
            if (tmp > *ebrk)
                  *ebrk = tmp;
      }

}

static inline int map_interpreter(struct elf_phdr *epp, struct elfhdr *ihp,
                          struct file *interp, unsigned int *iladdr,
                          int pnum, mm_segment_t old_fs,
                          unsigned int *eentry)
{
      int i;

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

            /* We should have fielded this error elsewhere... */
            if (*eentry != 0xffffffff)
                  return -1;

            set_fs(old_fs);
            *eentry = load_irix_interp(ihp, interp, iladdr);
            old_fs = get_fs();
            set_fs(get_ds());

            fput(interp);

            if (*eentry == 0xffffffff)
                  return -1;
      }
      return 0;
}

/*
 * IRIX maps a page at 0x200000 that holds information about the
 * process and the system, here we map the page and fill the
 * structure
 */
static void irix_map_prda_page(void)
{
      unsigned long v;
      struct prda *pp;

      down_write(&current->mm->mmap_sem);
      v =  do_brk(PRDA_ADDRESS, PAGE_SIZE);
      up_write(&current->mm->mmap_sem);

      if (v < 0)
            return;

      pp = (struct prda *) v;
      pp->prda_sys.t_pid  = current->pid;
      pp->prda_sys.t_prid = read_c0_prid();
      pp->prda_sys.t_rpid = current->pid;

      /* We leave the rest set to zero */
}



/* These are the functions used to load ELF style executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */
static int load_irix_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
      struct elfhdr elf_ex, interp_elf_ex;
      struct file *interpreter;
      struct elf_phdr *elf_phdata, *elf_ihdr, *elf_ephdr;
      unsigned int load_addr, elf_bss, elf_brk;
      unsigned int elf_entry, interp_load_addr = 0;
      unsigned int start_code, end_code, end_data, elf_stack;
      int retval, has_interp, has_ephdr, size, i;
      char *elf_interpreter;
      mm_segment_t old_fs;

      load_addr = 0;
      has_interp = has_ephdr = 0;
      elf_ihdr = elf_ephdr = NULL;
      elf_ex = *((struct elfhdr *) bprm->buf);
      retval = -ENOEXEC;

      if (verify_binary(&elf_ex, bprm))
            goto out;

      /*
       * Telling -o32 static binaries from Linux and Irix apart from each
       * other is difficult. There are 2 differences to be noted for static
       * binaries from the 2 operating systems:
       *
       *    1) Irix binaries have their .text section before their .init
       *       section. Linux binaries are just the opposite.
       *
       *    2) Irix binaries usually have <= 12 sections and Linux
       *       binaries have > 20.
       *
       * We will use Method #2 since Method #1 would require us to read in
       * the section headers which is way too much overhead. This appears
       * to work for everything we have ran into so far. If anyone has a
       * better method to tell the binaries apart, I'm listening.
       */
      if (elf_ex.e_shnum > 20)
            goto out;

      print_elfhdr(&elf_ex);

      /* Now read in all of the header information */
      size = elf_ex.e_phentsize * elf_ex.e_phnum;
      if (size > 65536)
            goto out;
      elf_phdata = kmalloc(size, GFP_KERNEL);
      if (elf_phdata == NULL) {
            retval = -ENOMEM;
            goto out;
      }

      retval = kernel_read(bprm->file, elf_ex.e_phoff, (char *)elf_phdata, size);
      if (retval < 0)
            goto out_free_ph;

      dump_phdrs(elf_phdata, elf_ex.e_phnum);

      /* Set some things for later. */
      for (i = 0; i < elf_ex.e_phnum; i++) {
            switch (elf_phdata[i].p_type) {
            case PT_INTERP:
                  has_interp = 1;
                  elf_ihdr = &elf_phdata[i];
                  break;
            case PT_PHDR:
                  has_ephdr = 1;
                  elf_ephdr = &elf_phdata[i];
                  break;
            };
      }

      pr_debug("\n");

      elf_bss = 0;
      elf_brk = 0;

      elf_stack = 0xffffffff;
      elf_interpreter = NULL;
      start_code = 0xffffffff;
      end_code = 0;
      end_data = 0;

      /*
       * If we get a return value, we change the value to be ENOEXEC
       * so that we can exit gracefully and the main binary format
       * search loop in 'fs/exec.c' will move onto the next handler
       * which should be the normal ELF binary handler.
       */
      retval = look_for_irix_interpreter(&elf_interpreter, &interpreter,
                                 &interp_elf_ex, elf_phdata, bprm,
                                 elf_ex.e_phnum);
      if (retval) {
            retval = -ENOEXEC;
            goto out_free_file;
      }

      if (elf_interpreter) {
            retval = verify_irix_interpreter(&interp_elf_ex);
            if (retval)
                  goto out_free_interp;
      }

      /* OK, we are done with that, now set up the arg stuff,
       * and then start this sucker up.
       */
      retval = -E2BIG;
      if (!bprm->sh_bang && !bprm->p)
            goto out_free_interp;

      /* Flush all traces of the currently running executable */
      retval = flush_old_exec(bprm);
      if (retval)
            goto out_free_dentry;

      /* OK, This is the point of no return */
      current->mm->end_data = 0;
      current->mm->end_code = 0;
      current->mm->mmap = NULL;
      current->flags &= ~PF_FORKNOEXEC;
      elf_entry = (unsigned int) elf_ex.e_entry;

      /* Do this so that we can load the interpreter, if need be.  We will
       * change some of these later.
       */
      setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
      current->mm->start_stack = bprm->p;

      /* At this point, we assume that the image should be loaded at
       * fixed address, not at a variable address.
       */
      old_fs = get_fs();
      set_fs(get_ds());

      map_executable(bprm->file, elf_phdata, elf_ex.e_phnum, &elf_stack,
                     &load_addr, &start_code, &elf_bss, &end_code,
                     &end_data, &elf_brk);

      if (elf_interpreter) {
            retval = map_interpreter(elf_phdata, &interp_elf_ex,
                               interpreter, &interp_load_addr,
                               elf_ex.e_phnum, old_fs, &elf_entry);
            kfree(elf_interpreter);
            if (retval) {
                  set_fs(old_fs);
                  printk("Unable to load IRIX ELF interpreter\n");
                  send_sig(SIGSEGV, current, 0);
                  retval = 0;
                  goto out_free_file;
            }
      }

      set_fs(old_fs);

      kfree(elf_phdata);
      set_personality(PER_IRIX32);
      set_binfmt(&irix_format);
      compute_creds(bprm);
      current->flags &= ~PF_FORKNOEXEC;
      bprm->p = (unsigned long)
        create_irix_tables((char *)bprm->p, bprm->argc, bprm->envc,
                  (elf_interpreter ? &elf_ex : NULL),
                  load_addr, interp_load_addr, regs, elf_ephdr);
      current->mm->start_brk = current->mm->brk = elf_brk;
      current->mm->end_code = end_code;
      current->mm->start_code = start_code;
      current->mm->end_data = end_data;
      current->mm->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);

      /*
       * IRIX maps a page at 0x200000 which holds some system
       * information.  Programs depend on this.
       */
      irix_map_prda_page();

      padzero(elf_bss);

      pr_debug("(start_brk) %lx\n" , (long) current->mm->start_brk);
      pr_debug("(end_code) %lx\n" , (long) current->mm->end_code);
      pr_debug("(start_code) %lx\n" , (long) current->mm->start_code);
      pr_debug("(end_data) %lx\n" , (long) current->mm->end_data);
      pr_debug("(start_stack) %lx\n" , (long) current->mm->start_stack);
      pr_debug("(brk) %lx\n" , (long) current->mm->brk);

#if 0 /* XXX No fucking way dude... */
      /* 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.
       */
      down_write(&current->mm->mmap_sem);
      (void) do_mmap(NULL, 0, 4096, PROT_READ | PROT_EXEC,
                   MAP_FIXED | MAP_PRIVATE, 0);
      up_write(&current->mm->mmap_sem);
#endif

      start_thread(regs, elf_entry, bprm->p);
      if (current->ptrace & PT_PTRACED)
            send_sig(SIGTRAP, current, 0);
      return 0;
out:
      return retval;

out_free_dentry:
      allow_write_access(interpreter);
      fput(interpreter);
out_free_interp:
      kfree(elf_interpreter);
out_free_file:
out_free_ph:
      kfree(elf_phdata);
      goto out;
}

/* This is really simpleminded and specialized - we are loading an
 * a.out library that is given an ELF header.
 */
static int load_irix_library(struct file *file)
{
      struct elfhdr elf_ex;
      struct elf_phdr *elf_phdata  =  NULL;
      unsigned int len = 0;
      int elf_bss = 0;
      int retval;
      unsigned int bss;
      int error;
      int i, j, k;

      error = kernel_read(file, 0, (char *) &elf_ex, sizeof(elf_ex));
      if (error != sizeof(elf_ex))
            return -ENOEXEC;

      if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
            return -ENOEXEC;

      /* First of all, some simple consistency checks. */
      if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
         !file->f_op->mmap)
            return -ENOEXEC;

      /* Now read in all of the header information. */
      if (sizeof(struct elf_phdr) * elf_ex.e_phnum > PAGE_SIZE)
            return -ENOEXEC;

      elf_phdata = kmalloc(sizeof(struct elf_phdr) * elf_ex.e_phnum, GFP_KERNEL);
      if (elf_phdata == NULL)
            return -ENOMEM;

      retval = kernel_read(file, elf_ex.e_phoff, (char *) elf_phdata,
                     sizeof(struct elf_phdr) * elf_ex.e_phnum);

      j = 0;
      for (i=0; i<elf_ex.e_phnum; i++)
            if ((elf_phdata + i)->p_type == PT_LOAD) j++;

      if (j != 1)  {
            kfree(elf_phdata);
            return -ENOEXEC;
      }

      while (elf_phdata->p_type != PT_LOAD) elf_phdata++;

      /* Now use mmap to map the library into memory. */
      down_write(&current->mm->mmap_sem);
      error = do_mmap(file,
                  elf_phdata->p_vaddr & 0xfffff000,
                  elf_phdata->p_filesz + (elf_phdata->p_vaddr & 0xfff),
                  PROT_READ | PROT_WRITE | PROT_EXEC,
                  MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
                  elf_phdata->p_offset & 0xfffff000);
      up_write(&current->mm->mmap_sem);

      k = elf_phdata->p_vaddr + elf_phdata->p_filesz;
      if (k > elf_bss) elf_bss = k;

      if (error != (elf_phdata->p_vaddr & 0xfffff000)) {
            kfree(elf_phdata);
            return error;
      }

      padzero(elf_bss);

      len = (elf_phdata->p_filesz + elf_phdata->p_vaddr+ 0xfff) & 0xfffff000;
      bss = elf_phdata->p_memsz + elf_phdata->p_vaddr;
      if (bss > len) {
        down_write(&current->mm->mmap_sem);
        do_brk(len, bss-len);
        up_write(&current->mm->mmap_sem);
      }
      kfree(elf_phdata);
      return 0;
}

/* Called through irix_syssgi() to map an elf image given an FD,
 * a phdr ptr USER_PHDRP in userspace, and a count CNT telling how many
 * phdrs there are in the USER_PHDRP array.  We return the vaddr the
 * first phdr was successfully mapped to.
 */
unsigned long irix_mapelf(int fd, struct elf_phdr __user *user_phdrp, int cnt)
{
      unsigned long type, vaddr, filesz, offset, flags;
      struct elf_phdr __user *hp;
      struct file *filp;
      int i, retval;

      pr_debug("irix_mapelf: fd[%d] user_phdrp[%p] cnt[%d]\n",
               fd, user_phdrp, cnt);

      /* First get the verification out of the way. */
      hp = user_phdrp;
      if (!access_ok(VERIFY_READ, hp, (sizeof(struct elf_phdr) * cnt))) {
            pr_debug("irix_mapelf: bad pointer to ELF PHDR!\n");

            return -EFAULT;
      }

      dump_phdrs(user_phdrp, cnt);

      for (i = 0; i < cnt; i++, hp++) {
            if (__get_user(type, &hp->p_type))
                  return -EFAULT;
            if (type != PT_LOAD) {
                  printk("irix_mapelf: One section is not PT_LOAD!\n");
                  return -ENOEXEC;
            }
      }

      filp = fget(fd);
      if (!filp)
            return -EACCES;
      if (!filp->f_op) {
            printk("irix_mapelf: Bogon filp!\n");
            fput(filp);
            return -EACCES;
      }

      hp = user_phdrp;
      for (i = 0; i < cnt; i++, hp++) {
            int prot;

            retval = __get_user(vaddr, &hp->p_vaddr);
            retval |= __get_user(filesz, &hp->p_filesz);
            retval |= __get_user(offset, &hp->p_offset);
            retval |= __get_user(flags, &hp->p_flags);
            if (retval)
                  return retval;

            prot  = (flags & PF_R) ? PROT_READ : 0;
            prot |= (flags & PF_W) ? PROT_WRITE : 0;
            prot |= (flags & PF_X) ? PROT_EXEC : 0;

            down_write(&current->mm->mmap_sem);
            retval = do_mmap(filp, (vaddr & 0xfffff000),
                         (filesz + (vaddr & 0xfff)),
                         prot, (MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE),
                         (offset & 0xfffff000));
            up_write(&current->mm->mmap_sem);

            if (retval != (vaddr & 0xfffff000)) {
                  printk("irix_mapelf: do_mmap fails with %d!\n", retval);
                  fput(filp);
                  return retval;
            }
      }

      pr_debug("irix_mapelf: Success, returning %08lx\n",
             (unsigned long) user_phdrp->p_vaddr);

      fput(filp);

      if (__get_user(vaddr, &user_phdrp->p_vaddr))
            return -EFAULT;

      return vaddr;
}

/*
 * ELF core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 */

/* These are the only things you should do on a core-file: use only these
 * functions to write out all the necessary info.
 */
static int dump_write(struct file *file, const void __user *addr, int nr)
{
      return file->f_op->write(file, (const char __user *) addr, nr, &file->f_pos) == nr;
}

static int dump_seek(struct file *file, off_t off)
{
      if (file->f_op->llseek) {
            if (file->f_op->llseek(file, off, 0) != off)
                  return 0;
      } else
            file->f_pos = off;
      return 1;
}

/* Decide whether a segment is worth dumping; default is yes to be
 * sure (missing info is worse than too much; etc).
 * Personally I'd include everything, and use the coredump limit...
 *
 * I think we should skip something. But I am not sure how. H.J.
 */
static inline int maydump(struct vm_area_struct *vma)
{
      if (!(vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC)))
            return 0;
#if 1
      if (vma->vm_flags & (VM_WRITE|VM_GROWSUP|VM_GROWSDOWN))
            return 1;
      if (vma->vm_flags & (VM_READ|VM_EXEC|VM_EXECUTABLE|VM_SHARED))
            return 0;
#endif
      return 1;
}

/* An ELF note in memory. */
struct memelfnote
{
      const char *name;
      int type;
      unsigned int datasz;
      void *data;
};

static int notesize(struct memelfnote *en)
{
      int sz;

      sz = sizeof(struct elf_note);
      sz += roundup(strlen(en->name) + 1, 4);
      sz += roundup(en->datasz, 4);

      return sz;
}

#define DUMP_WRITE(addr, nr)  \
      if (!dump_write(file, (addr), (nr))) \
            goto end_coredump;
#define DUMP_SEEK(off)  \
      if (!dump_seek(file, (off))) \
            goto end_coredump;

static int writenote(struct memelfnote *men, struct file *file)
{
      struct elf_note en;

      en.n_namesz = strlen(men->name) + 1;
      en.n_descsz = men->datasz;
      en.n_type = men->type;

      DUMP_WRITE(&en, sizeof(en));
      DUMP_WRITE(men->name, en.n_namesz);
      /* XXX - cast from long long to long to avoid need for libgcc.a */
      DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));    /* XXX */
      DUMP_WRITE(men->data, men->datasz);
      DUMP_SEEK(roundup((unsigned long)file->f_pos, 4));    /* XXX */

      return 1;

end_coredump:
      return 0;
}
#undef DUMP_WRITE
#undef DUMP_SEEK

#define DUMP_WRITE(addr, nr)  \
      if (!dump_write(file, (addr), (nr))) \
            goto end_coredump;
#define DUMP_SEEK(off)  \
      if (!dump_seek(file, (off))) \
            goto end_coredump;

/* Actual dumper.
 *
 * This is a two-pass process; first we find the offsets of the bits,
 * and then they are actually written out.  If we run out of core limit
 * we just truncate.
 */
static int irix_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
{
      int has_dumped = 0;
      mm_segment_t fs;
      int segs;
      int i;
      size_t size;
      struct vm_area_struct *vma;
      struct elfhdr elf;
      off_t offset = 0, dataoff;
      int numnote = 3;
      struct memelfnote notes[3];
      struct elf_prstatus prstatus; /* NT_PRSTATUS */
      elf_fpregset_t fpu;           /* NT_PRFPREG */
      struct elf_prpsinfo psinfo;   /* NT_PRPSINFO */

      /* Count what's needed to dump, up to the limit of coredump size. */
      segs = 0;
      size = 0;
      for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
            if (maydump(vma))
            {
                  int sz = vma->vm_end-vma->vm_start;

                  if (size+sz >= limit)
                        break;
                  else
                        size += sz;
            }

            segs++;
      }
      pr_debug("irix_core_dump: %d segs taking %d bytes\n", segs, size);

      /* Set up header. */
      memcpy(elf.e_ident, ELFMAG, SELFMAG);
      elf.e_ident[EI_CLASS] = ELFCLASS32;
      elf.e_ident[EI_DATA] = ELFDATA2LSB;
      elf.e_ident[EI_VERSION] = EV_CURRENT;
      elf.e_ident[EI_OSABI] = ELF_OSABI;
      memset(elf.e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);

      elf.e_type = ET_CORE;
      elf.e_machine = ELF_ARCH;
      elf.e_version = EV_CURRENT;
      elf.e_entry = 0;
      elf.e_phoff = sizeof(elf);
      elf.e_shoff = 0;
      elf.e_flags = 0;
      elf.e_ehsize = sizeof(elf);
      elf.e_phentsize = sizeof(struct elf_phdr);
      elf.e_phnum = segs+1;         /* Include notes. */
      elf.e_shentsize = 0;
      elf.e_shnum = 0;
      elf.e_shstrndx = 0;

      fs = get_fs();
      set_fs(KERNEL_DS);

      has_dumped = 1;
      current->flags |= PF_DUMPCORE;

      DUMP_WRITE(&elf, sizeof(elf));
      offset += sizeof(elf);                    /* Elf header. */
      offset += (segs+1) * sizeof(struct elf_phdr);   /* Program headers. */

      /* Set up the notes in similar form to SVR4 core dumps made
       * with info from their /proc.
       */
      memset(&psinfo, 0, sizeof(psinfo));
      memset(&prstatus, 0, sizeof(prstatus));

      notes[0].name = "CORE";
      notes[0].type = NT_PRSTATUS;
      notes[0].datasz = sizeof(prstatus);
      notes[0].data = &prstatus;
      prstatus.pr_info.si_signo = prstatus.pr_cursig = signr;
      prstatus.pr_sigpend = current->pending.signal.sig[0];
      prstatus.pr_sighold = current->blocked.sig[0];
      psinfo.pr_pid = prstatus.pr_pid = current->pid;
      psinfo.pr_ppid = prstatus.pr_ppid = current->parent->pid;
      psinfo.pr_pgrp = prstatus.pr_pgrp = task_pgrp_nr(current);
      psinfo.pr_sid = prstatus.pr_sid = task_session_nr(current);
      if (current->pid == current->tgid) {
            /*
             * This is the record for the group leader.  Add in the
             * cumulative times of previous dead threads.  This total
             * won't include the time of each live thread whose state
             * is included in the core dump.  The final total reported
             * to our parent process when it calls wait4 will include
             * those sums as well as the little bit more time it takes
             * this and each other thread to finish dying after the
             * core dump synchronization phase.
             */
            jiffies_to_timeval(current->utime + current->signal->utime,
                               &prstatus.pr_utime);
            jiffies_to_timeval(current->stime + current->signal->stime,
                               &prstatus.pr_stime);
      } else {
            jiffies_to_timeval(current->utime, &prstatus.pr_utime);
            jiffies_to_timeval(current->stime, &prstatus.pr_stime);
      }
      jiffies_to_timeval(current->signal->cutime, &prstatus.pr_cutime);
      jiffies_to_timeval(current->signal->cstime, &prstatus.pr_cstime);

      if (sizeof(elf_gregset_t) != sizeof(struct pt_regs)) {
            printk("sizeof(elf_gregset_t) (%d) != sizeof(struct pt_regs) "
                   "(%d)\n", sizeof(elf_gregset_t), sizeof(struct pt_regs));
      } else {
            *(struct pt_regs *)&prstatus.pr_reg = *regs;
      }

      notes[1].name = "CORE";
      notes[1].type = NT_PRPSINFO;
      notes[1].datasz = sizeof(psinfo);
      notes[1].data = &psinfo;
      i = current->state ? ffz(~current->state) + 1 : 0;
      psinfo.pr_state = i;
      psinfo.pr_sname = (i < 0 || i > 5) ? '.' : "RSDZTD"[i];
      psinfo.pr_zomb = psinfo.pr_sname == 'Z';
      psinfo.pr_nice = task_nice(current);
      psinfo.pr_flag = current->flags;
      psinfo.pr_uid = current->uid;
      psinfo.pr_gid = current->gid;
      {
            int i, len;

            set_fs(fs);

            len = current->mm->arg_end - current->mm->arg_start;
            len = len >= ELF_PRARGSZ ? ELF_PRARGSZ : len;
            (void *) copy_from_user(&psinfo.pr_psargs,
                         (const char __user *)current->mm->arg_start, len);
            for (i = 0; i < len; i++)
                  if (psinfo.pr_psargs[i] == 0)
                        psinfo.pr_psargs[i] = ' ';
            psinfo.pr_psargs[len] = 0;

            set_fs(KERNEL_DS);
      }
      strlcpy(psinfo.pr_fname, current->comm, sizeof(psinfo.pr_fname));

      /* Try to dump the FPU. */
      prstatus.pr_fpvalid = dump_fpu(regs, &fpu);
      if (!prstatus.pr_fpvalid) {
            numnote--;
      } else {
            notes[2].name = "CORE";
            notes[2].type = NT_PRFPREG;
            notes[2].datasz = sizeof(fpu);
            notes[2].data = &fpu;
      }

      /* Write notes phdr entry. */
      {
            struct elf_phdr phdr;
            int sz = 0;

            for (i = 0; i < numnote; i++)
                  sz += notesize(&notes[i]);

            phdr.p_type = PT_NOTE;
            phdr.p_offset = offset;
            phdr.p_vaddr = 0;
            phdr.p_paddr = 0;
            phdr.p_filesz = sz;
            phdr.p_memsz = 0;
            phdr.p_flags = 0;
            phdr.p_align = 0;

            offset += phdr.p_filesz;
            DUMP_WRITE(&phdr, sizeof(phdr));
      }

      /* Page-align dumped data. */
      dataoff = offset = roundup(offset, PAGE_SIZE);

      /* Write program headers for segments dump. */
      for (vma = current->mm->mmap, i = 0;
            i < segs && vma != NULL; vma = vma->vm_next) {
            struct elf_phdr phdr;
            size_t sz;

            i++;

            sz = vma->vm_end - vma->vm_start;

            phdr.p_type = PT_LOAD;
            phdr.p_offset = offset;
            phdr.p_vaddr = vma->vm_start;
            phdr.p_paddr = 0;
            phdr.p_filesz = maydump(vma) ? sz : 0;
            phdr.p_memsz = sz;
            offset += phdr.p_filesz;
            phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
            if (vma->vm_flags & VM_WRITE)
                  phdr.p_flags |= PF_W;
            if (vma->vm_flags & VM_EXEC)
                  phdr.p_flags |= PF_X;
            phdr.p_align = PAGE_SIZE;

            DUMP_WRITE(&phdr, sizeof(phdr));
      }

      for (i = 0; i < numnote; i++)
            if (!writenote(&notes[i], file))
                  goto end_coredump;

      set_fs(fs);

      DUMP_SEEK(dataoff);

      for (i = 0, vma = current->mm->mmap;
          i < segs && vma != NULL;
          vma = vma->vm_next) {
            unsigned long addr = vma->vm_start;
            unsigned long len = vma->vm_end - vma->vm_start;

            if (!maydump(vma))
                  continue;
            i++;
            pr_debug("elf_core_dump: writing %08lx %lx\n", addr, len);
            DUMP_WRITE((void __user *)addr, len);
      }

      if ((off_t) file->f_pos != offset) {
            /* Sanity check. */
            printk("elf_core_dump: file->f_pos (%ld) != offset (%ld)\n",
                   (off_t) file->f_pos, offset);
      }

end_coredump:
      set_fs(fs);
      return has_dumped;
}

static int __init init_irix_binfmt(void)
{
      extern int init_inventory(void);
      extern asmlinkage unsigned long sys_call_table;
      extern asmlinkage unsigned long sys_call_table_irix5;

      init_inventory();

      /*
       * Copy the IRIX5 syscall table (8000 bytes) into the main syscall
       * table. The IRIX5 calls are located by an offset of 8000 bytes
       * from the beginning of the main table.
       */
      memcpy((void *) ((unsigned long) &sys_call_table + 8000),
            &sys_call_table_irix5, 8000);

      return register_binfmt(&irix_format);
}

static void __exit exit_irix_binfmt(void)
{
      /*
       * Remove the Irix ELF loader.
       */
      unregister_binfmt(&irix_format);
}

module_init(init_irix_binfmt)
module_exit(exit_irix_binfmt)

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