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binfmt_elf_fdpic.c

/* binfmt_elf_fdpic.c: FDPIC ELF binary format
 *
 * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Derived from binfmt_elf.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#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/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/init.h>
#include <linux/elf.h>
#include <linux/elf-fdpic.h>
#include <linux/elfcore.h>

#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/pgalloc.h>

typedef char *elf_caddr_t;

#if 0
#define kdebug(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdebug(fmt, ...) do {} while(0)
#endif

#if 0
#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdcore(fmt, ...) do {} while(0)
#endif

MODULE_LICENSE("GPL");

static int load_elf_fdpic_binary(struct linux_binprm *, struct pt_regs *);
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *, struct file *);
static int elf_fdpic_map_file(struct elf_fdpic_params *, struct file *,
                        struct mm_struct *, const char *);

static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
                           struct elf_fdpic_params *,
                           struct elf_fdpic_params *);

#ifndef CONFIG_MMU
static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *,
                                  unsigned long *);
static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
                                       struct file *,
                                       struct mm_struct *);
#endif

static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
                                   struct file *, struct mm_struct *);

#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *, unsigned long limit);
#endif

static struct linux_binfmt elf_fdpic_format = {
      .module           = THIS_MODULE,
      .load_binary      = load_elf_fdpic_binary,
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
      .core_dump  = elf_fdpic_core_dump,
#endif
      .min_coredump     = ELF_EXEC_PAGESIZE,
};

static int __init init_elf_fdpic_binfmt(void)
{
      return register_binfmt(&elf_fdpic_format);
}

static void __exit exit_elf_fdpic_binfmt(void)
{
      unregister_binfmt(&elf_fdpic_format);
}

core_initcall(init_elf_fdpic_binfmt);
module_exit(exit_elf_fdpic_binfmt);

static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
{
      if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0)
            return 0;
      if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN)
            return 0;
      if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr))
            return 0;
      if (!file->f_op || !file->f_op->mmap)
            return 0;
      return 1;
}

/*****************************************************************************/
/*
 * read the program headers table into memory
 */
static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params,
                         struct file *file)
{
      struct elf32_phdr *phdr;
      unsigned long size;
      int retval, loop;

      if (params->hdr.e_phentsize != sizeof(struct elf_phdr))
            return -ENOMEM;
      if (params->hdr.e_phnum > 65536U / sizeof(struct elf_phdr))
            return -ENOMEM;

      size = params->hdr.e_phnum * sizeof(struct elf_phdr);
      params->phdrs = kmalloc(size, GFP_KERNEL);
      if (!params->phdrs)
            return -ENOMEM;

      retval = kernel_read(file, params->hdr.e_phoff,
                       (char *) params->phdrs, size);
      if (retval < 0)
            return retval;

      /* determine stack size for this binary */
      phdr = params->phdrs;
      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            if (phdr->p_type != PT_GNU_STACK)
                  continue;

            if (phdr->p_flags & PF_X)
                  params->flags |= ELF_FDPIC_FLAG_EXEC_STACK;
            else
                  params->flags |= ELF_FDPIC_FLAG_NOEXEC_STACK;

            params->stack_size = phdr->p_memsz;
            break;
      }

      return 0;
}

/*****************************************************************************/
/*
 * load an fdpic binary into various bits of memory
 */
static int load_elf_fdpic_binary(struct linux_binprm *bprm,
                         struct pt_regs *regs)
{
      struct elf_fdpic_params exec_params, interp_params;
      struct elf_phdr *phdr;
      unsigned long stack_size, entryaddr;
#ifndef CONFIG_MMU
      unsigned long fullsize;
#endif
#ifdef ELF_FDPIC_PLAT_INIT
      unsigned long dynaddr;
#endif
      struct file *interpreter = NULL; /* to shut gcc up */
      char *interpreter_name = NULL;
      int executable_stack;
      int retval, i;

      kdebug("____ LOAD %d ____", current->pid);

      memset(&exec_params, 0, sizeof(exec_params));
      memset(&interp_params, 0, sizeof(interp_params));

      exec_params.hdr = *(struct elfhdr *) bprm->buf;
      exec_params.flags = ELF_FDPIC_FLAG_PRESENT | ELF_FDPIC_FLAG_EXECUTABLE;

      /* check that this is a binary we know how to deal with */
      retval = -ENOEXEC;
      if (!is_elf_fdpic(&exec_params.hdr, bprm->file))
            goto error;

      /* read the program header table */
      retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file);
      if (retval < 0)
            goto error;

      /* scan for a program header that specifies an interpreter */
      phdr = exec_params.phdrs;

      for (i = 0; i < exec_params.hdr.e_phnum; i++, phdr++) {
            switch (phdr->p_type) {
            case PT_INTERP:
                  retval = -ENOMEM;
                  if (phdr->p_filesz > PATH_MAX)
                        goto error;
                  retval = -ENOENT;
                  if (phdr->p_filesz < 2)
                        goto error;

                  /* read the name of the interpreter into memory */
                  interpreter_name = kmalloc(phdr->p_filesz, GFP_KERNEL);
                  if (!interpreter_name)
                        goto error;

                  retval = kernel_read(bprm->file,
                                   phdr->p_offset,
                                   interpreter_name,
                                   phdr->p_filesz);
                  if (retval < 0)
                        goto error;

                  retval = -ENOENT;
                  if (interpreter_name[phdr->p_filesz - 1] != '\0')
                        goto error;

                  kdebug("Using ELF interpreter %s", interpreter_name);

                  /* replace the program with the interpreter */
                  interpreter = open_exec(interpreter_name);
                  retval = PTR_ERR(interpreter);
                  if (IS_ERR(interpreter)) {
                        interpreter = NULL;
                        goto error;
                  }

                  /*
                   * If the binary is not readable then enforce
                   * mm->dumpable = 0 regardless of the interpreter's
                   * permissions.
                   */
                  if (file_permission(interpreter, MAY_READ) < 0)
                        bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;

                  retval = kernel_read(interpreter, 0, bprm->buf,
                                   BINPRM_BUF_SIZE);
                  if (retval < 0)
                        goto error;

                  interp_params.hdr = *((struct elfhdr *) bprm->buf);
                  break;

            case PT_LOAD:
#ifdef CONFIG_MMU
                  if (exec_params.load_addr == 0)
                        exec_params.load_addr = phdr->p_vaddr;
#endif
                  break;
            }

      }

      if (elf_check_const_displacement(&exec_params.hdr))
            exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;

      /* perform insanity checks on the interpreter */
      if (interpreter_name) {
            retval = -ELIBBAD;
            if (!is_elf_fdpic(&interp_params.hdr, interpreter))
                  goto error;

            interp_params.flags = ELF_FDPIC_FLAG_PRESENT;

            /* read the interpreter's program header table */
            retval = elf_fdpic_fetch_phdrs(&interp_params, interpreter);
            if (retval < 0)
                  goto error;
      }

      stack_size = exec_params.stack_size;
      if (stack_size < interp_params.stack_size)
            stack_size = interp_params.stack_size;

      if (exec_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
            executable_stack = EXSTACK_ENABLE_X;
      else if (exec_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
            executable_stack = EXSTACK_DISABLE_X;
      else if (interp_params.flags & ELF_FDPIC_FLAG_EXEC_STACK)
            executable_stack = EXSTACK_ENABLE_X;
      else if (interp_params.flags & ELF_FDPIC_FLAG_NOEXEC_STACK)
            executable_stack = EXSTACK_DISABLE_X;
      else
            executable_stack = EXSTACK_DEFAULT;

      retval = -ENOEXEC;
      if (stack_size == 0)
            goto error;

      if (elf_check_const_displacement(&interp_params.hdr))
            interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP;

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

      /* there's now no turning back... the old userspace image is dead,
       * defunct, deceased, etc. after this point we have to exit via
       * error_kill */
      set_personality(PER_LINUX_FDPIC);
      set_binfmt(&elf_fdpic_format);

      current->mm->start_code = 0;
      current->mm->end_code = 0;
      current->mm->start_stack = 0;
      current->mm->start_data = 0;
      current->mm->end_data = 0;
      current->mm->context.exec_fdpic_loadmap = 0;
      current->mm->context.interp_fdpic_loadmap = 0;

      current->flags &= ~PF_FORKNOEXEC;

#ifdef CONFIG_MMU
      elf_fdpic_arch_lay_out_mm(&exec_params,
                          &interp_params,
                          &current->mm->start_stack,
                          &current->mm->start_brk);

      retval = setup_arg_pages(bprm, current->mm->start_stack,
                         executable_stack);
      if (retval < 0) {
            send_sig(SIGKILL, current, 0);
            goto error_kill;
      }
#endif

      /* load the executable and interpreter into memory */
      retval = elf_fdpic_map_file(&exec_params, bprm->file, current->mm,
                            "executable");
      if (retval < 0)
            goto error_kill;

      if (interpreter_name) {
            retval = elf_fdpic_map_file(&interp_params, interpreter,
                                  current->mm, "interpreter");
            if (retval < 0) {
                  printk(KERN_ERR "Unable to load interpreter\n");
                  goto error_kill;
            }

            allow_write_access(interpreter);
            fput(interpreter);
            interpreter = NULL;
      }

#ifdef CONFIG_MMU
      if (!current->mm->start_brk)
            current->mm->start_brk = current->mm->end_data;

      current->mm->brk = current->mm->start_brk =
            PAGE_ALIGN(current->mm->start_brk);

#else
      /* create a stack and brk area big enough for everyone
       * - the brk heap starts at the bottom and works up
       * - the stack starts at the top and works down
       */
      stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK;
      if (stack_size < PAGE_SIZE * 2)
            stack_size = PAGE_SIZE * 2;

      down_write(&current->mm->mmap_sem);
      current->mm->start_brk = do_mmap(NULL, 0, stack_size,
                               PROT_READ | PROT_WRITE | PROT_EXEC,
                               MAP_PRIVATE | MAP_ANONYMOUS | MAP_GROWSDOWN,
                               0);

      if (IS_ERR_VALUE(current->mm->start_brk)) {
            up_write(&current->mm->mmap_sem);
            retval = current->mm->start_brk;
            current->mm->start_brk = 0;
            goto error_kill;
      }

      /* expand the stack mapping to use up the entire allocation granule */
      fullsize = ksize((char *) current->mm->start_brk);
      if (!IS_ERR_VALUE(do_mremap(current->mm->start_brk, stack_size,
                            fullsize, 0, 0)))
            stack_size = fullsize;
      up_write(&current->mm->mmap_sem);

      current->mm->brk = current->mm->start_brk;
      current->mm->context.end_brk = current->mm->start_brk;
      current->mm->context.end_brk +=
            (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0;
      current->mm->start_stack = current->mm->start_brk + stack_size;
#endif

      compute_creds(bprm);
      current->flags &= ~PF_FORKNOEXEC;
      if (create_elf_fdpic_tables(bprm, current->mm,
                            &exec_params, &interp_params) < 0)
            goto error_kill;

      kdebug("- start_code  %lx", current->mm->start_code);
      kdebug("- end_code    %lx", current->mm->end_code);
      kdebug("- start_data  %lx", current->mm->start_data);
      kdebug("- end_data    %lx", current->mm->end_data);
      kdebug("- start_brk   %lx", current->mm->start_brk);
      kdebug("- brk         %lx", current->mm->brk);
      kdebug("- start_stack %lx", current->mm->start_stack);

#ifdef ELF_FDPIC_PLAT_INIT
      /*
       * The ABI may specify that certain registers be set up in special
       * ways (on i386 %edx is the address of a DT_FINI function, for
       * example.  This macro performs whatever initialization to
       * the regs structure is required.
       */
      dynaddr = interp_params.dynamic_addr ?: exec_params.dynamic_addr;
      ELF_FDPIC_PLAT_INIT(regs, exec_params.map_addr, interp_params.map_addr,
                      dynaddr);
#endif

      /* everything is now ready... get the userspace context ready to roll */
      entryaddr = interp_params.entry_addr ?: exec_params.entry_addr;
      start_thread(regs, entryaddr, current->mm->start_stack);

      if (unlikely(current->ptrace & PT_PTRACED)) {
            if (current->ptrace & PT_TRACE_EXEC)
                  ptrace_notify((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
            else
                  send_sig(SIGTRAP, current, 0);
      }

      retval = 0;

error:
      if (interpreter) {
            allow_write_access(interpreter);
            fput(interpreter);
      }
      kfree(interpreter_name);
      kfree(exec_params.phdrs);
      kfree(exec_params.loadmap);
      kfree(interp_params.phdrs);
      kfree(interp_params.loadmap);
      return retval;

      /* unrecoverable error - kill the process */
error_kill:
      send_sig(SIGSEGV, current, 0);
      goto error;

}

/*****************************************************************************/
/*
 * present useful information to the program
 */
static int create_elf_fdpic_tables(struct linux_binprm *bprm,
                           struct mm_struct *mm,
                           struct elf_fdpic_params *exec_params,
                           struct elf_fdpic_params *interp_params)
{
      unsigned long sp, csp, nitems;
      elf_caddr_t __user *argv, *envp;
      size_t platform_len = 0, len;
      char *k_platform;
      char __user *u_platform, *p;
      long hwcap;
      int loop;

      /* we're going to shovel a whole load of stuff onto the stack */
#ifdef CONFIG_MMU
      sp = bprm->p;
#else
      sp = mm->start_stack;

      /* stack the program arguments and environment */
      if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
            return -EFAULT;
#endif

      /* get hold of platform and hardware capabilities masks for the machine
       * we are running on.  In some cases (Sparc), this info is impossible
       * to get, in others (i386) it is merely difficult.
       */
      hwcap = ELF_HWCAP;
      k_platform = ELF_PLATFORM;
      u_platform = NULL;

      if (k_platform) {
            platform_len = strlen(k_platform) + 1;
            sp -= platform_len;
            u_platform = (char __user *) sp;
            if (__copy_to_user(u_platform, k_platform, platform_len) != 0)
                  return -EFAULT;
      }

#if defined(__i386__) && defined(CONFIG_SMP)
      /* in some cases (e.g. Hyper-Threading), we want to avoid L1 evictions
       * by the processes running on the same package. One thing we can do is
       * to shuffle the initial stack for them.
       *
       * the conditionals here are unneeded, but kept in to make the code
       * behaviour the same as pre change unless we have hyperthreaded
       * processors. This keeps Mr Marcelo Person happier but should be
       * removed for 2.5
       */
      if (smp_num_siblings > 1)
            sp = sp - ((current->pid % 64) << 7);
#endif

      sp &= ~7UL;

      /* stack the load map(s) */
      len = sizeof(struct elf32_fdpic_loadmap);
      len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs;
      sp = (sp - len) & ~7UL;
      exec_params->map_addr = sp;

      if (copy_to_user((void __user *) sp, exec_params->loadmap, len) != 0)
            return -EFAULT;

      current->mm->context.exec_fdpic_loadmap = (unsigned long) sp;

      if (interp_params->loadmap) {
            len = sizeof(struct elf32_fdpic_loadmap);
            len += sizeof(struct elf32_fdpic_loadseg) *
                  interp_params->loadmap->nsegs;
            sp = (sp - len) & ~7UL;
            interp_params->map_addr = sp;

            if (copy_to_user((void __user *) sp, interp_params->loadmap,
                         len) != 0)
                  return -EFAULT;

            current->mm->context.interp_fdpic_loadmap = (unsigned long) sp;
      }

      /* force 16 byte _final_ alignment here for generality */
#define DLINFO_ITEMS 13

      nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0);
#ifdef DLINFO_ARCH_ITEMS
      nitems += DLINFO_ARCH_ITEMS;
#endif

      csp = sp;
      sp -= nitems * 2 * sizeof(unsigned long);
      sp -= (bprm->envc + 1) * sizeof(char *);  /* envv[] */
      sp -= (bprm->argc + 1) * sizeof(char *);  /* argv[] */
      sp -= 1 * sizeof(unsigned long);          /* argc */

      csp -= sp & 15UL;
      sp -= sp & 15UL;

      /* put the ELF interpreter info on the stack */
#define NEW_AUX_ENT(nr, id, val)                            \
      do {                                            \
            struct { unsigned long _id, _val; } __user *ent;      \
                                                      \
            ent = (void __user *) csp;                      \
            __put_user((id), &ent[nr]._id);                       \
            __put_user((val), &ent[nr]._val);               \
      } while (0)

      csp -= 2 * sizeof(unsigned long);
      NEW_AUX_ENT(0, AT_NULL, 0);
      if (k_platform) {
            csp -= 2 * sizeof(unsigned long);
            NEW_AUX_ENT(0, AT_PLATFORM,
                      (elf_addr_t) (unsigned long) u_platform);
      }

      csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
      NEW_AUX_ENT( 0, AT_HWCAP,     hwcap);
      NEW_AUX_ENT( 1, AT_PAGESZ,    PAGE_SIZE);
      NEW_AUX_ENT( 2, AT_CLKTCK,    CLOCKS_PER_SEC);
      NEW_AUX_ENT( 3, AT_PHDR,      exec_params->ph_addr);
      NEW_AUX_ENT( 4, AT_PHENT,     sizeof(struct elf_phdr));
      NEW_AUX_ENT( 5, AT_PHNUM,     exec_params->hdr.e_phnum);
      NEW_AUX_ENT( 6,   AT_BASE,    interp_params->elfhdr_addr);
      NEW_AUX_ENT( 7, AT_FLAGS,     0);
      NEW_AUX_ENT( 8, AT_ENTRY,     exec_params->entry_addr);
      NEW_AUX_ENT( 9, AT_UID,       (elf_addr_t) current->uid);
      NEW_AUX_ENT(10, AT_EUID,      (elf_addr_t) current->euid);
      NEW_AUX_ENT(11, AT_GID,       (elf_addr_t) current->gid);
      NEW_AUX_ENT(12, AT_EGID,      (elf_addr_t) current->egid);

#ifdef ARCH_DLINFO
      /* ARCH_DLINFO must come last so platform specific code can enforce
       * special alignment requirements on the AUXV if necessary (eg. PPC).
       */
      ARCH_DLINFO;
#endif
#undef NEW_AUX_ENT

      /* allocate room for argv[] and envv[] */
      csp -= (bprm->envc + 1) * sizeof(elf_caddr_t);
      envp = (elf_caddr_t __user *) csp;
      csp -= (bprm->argc + 1) * sizeof(elf_caddr_t);
      argv = (elf_caddr_t __user *) csp;

      /* stack argc */
      csp -= sizeof(unsigned long);
      __put_user(bprm->argc, (unsigned long __user *) csp);

      BUG_ON(csp != sp);

      /* fill in the argv[] array */
#ifdef CONFIG_MMU
      current->mm->arg_start = bprm->p;
#else
      current->mm->arg_start = current->mm->start_stack -
            (MAX_ARG_PAGES * PAGE_SIZE - bprm->p);
#endif

      p = (char __user *) current->mm->arg_start;
      for (loop = bprm->argc; loop > 0; loop--) {
            __put_user((elf_caddr_t) p, argv++);
            len = strnlen_user(p, MAX_ARG_STRLEN);
            if (!len || len > MAX_ARG_STRLEN)
                  return -EINVAL;
            p += len;
      }
      __put_user(NULL, argv);
      current->mm->arg_end = (unsigned long) p;

      /* fill in the envv[] array */
      current->mm->env_start = (unsigned long) p;
      for (loop = bprm->envc; loop > 0; loop--) {
            __put_user((elf_caddr_t)(unsigned long) p, envp++);
            len = strnlen_user(p, MAX_ARG_STRLEN);
            if (!len || len > MAX_ARG_STRLEN)
                  return -EINVAL;
            p += len;
      }
      __put_user(NULL, envp);
      current->mm->env_end = (unsigned long) p;

      mm->start_stack = (unsigned long) sp;
      return 0;
}

/*****************************************************************************/
/*
 * transfer the program arguments and environment from the holding pages onto
 * the stack
 */
#ifndef CONFIG_MMU
static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm,
                                  unsigned long *_sp)
{
      unsigned long index, stop, sp;
      char *src;
      int ret = 0;

      stop = bprm->p >> PAGE_SHIFT;
      sp = *_sp;

      for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
            src = kmap(bprm->page[index]);
            sp -= PAGE_SIZE;
            if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
                  ret = -EFAULT;
            kunmap(bprm->page[index]);
            if (ret < 0)
                  goto out;
      }

      *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;

out:
      return ret;
}
#endif

/*****************************************************************************/
/*
 * load the appropriate binary image (executable or interpreter) into memory
 * - we assume no MMU is available
 * - if no other PIC bits are set in params->hdr->e_flags
 *   - we assume that the LOADable segments in the binary are independently relocatable
 *   - we assume R/O executable segments are shareable
 * - else
 *   - we assume the loadable parts of the image to require fixed displacement
 *   - the image is not shareable
 */
static int elf_fdpic_map_file(struct elf_fdpic_params *params,
                        struct file *file,
                        struct mm_struct *mm,
                        const char *what)
{
      struct elf32_fdpic_loadmap *loadmap;
#ifdef CONFIG_MMU
      struct elf32_fdpic_loadseg *mseg;
#endif
      struct elf32_fdpic_loadseg *seg;
      struct elf32_phdr *phdr;
      unsigned long load_addr, stop;
      unsigned nloads, tmp;
      size_t size;
      int loop, ret;

      /* allocate a load map table */
      nloads = 0;
      for (loop = 0; loop < params->hdr.e_phnum; loop++)
            if (params->phdrs[loop].p_type == PT_LOAD)
                  nloads++;

      if (nloads == 0)
            return -ELIBBAD;

      size = sizeof(*loadmap) + nloads * sizeof(*seg);
      loadmap = kzalloc(size, GFP_KERNEL);
      if (!loadmap)
            return -ENOMEM;

      params->loadmap = loadmap;

      loadmap->version = ELF32_FDPIC_LOADMAP_VERSION;
      loadmap->nsegs = nloads;

      load_addr = params->load_addr;
      seg = loadmap->segs;

      /* map the requested LOADs into the memory space */
      switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
      case ELF_FDPIC_FLAG_CONSTDISP:
      case ELF_FDPIC_FLAG_CONTIGUOUS:
#ifndef CONFIG_MMU
            ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm);
            if (ret < 0)
                  return ret;
            break;
#endif
      default:
            ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm);
            if (ret < 0)
                  return ret;
            break;
      }

      /* map the entry point */
      if (params->hdr.e_entry) {
            seg = loadmap->segs;
            for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
                  if (params->hdr.e_entry >= seg->p_vaddr &&
                      params->hdr.e_entry < seg->p_vaddr + seg->p_memsz) {
                        params->entry_addr =
                              (params->hdr.e_entry - seg->p_vaddr) +
                              seg->addr;
                        break;
                  }
            }
      }

      /* determine where the program header table has wound up if mapped */
      stop = params->hdr.e_phoff;
      stop += params->hdr.e_phnum * sizeof (struct elf_phdr);
      phdr = params->phdrs;

      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            if (phdr->p_type != PT_LOAD)
                  continue;

            if (phdr->p_offset > params->hdr.e_phoff ||
                phdr->p_offset + phdr->p_filesz < stop)
                  continue;

            seg = loadmap->segs;
            for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
                  if (phdr->p_vaddr >= seg->p_vaddr &&
                      phdr->p_vaddr + phdr->p_filesz <=
                      seg->p_vaddr + seg->p_memsz) {
                        params->ph_addr =
                              (phdr->p_vaddr - seg->p_vaddr) +
                              seg->addr +
                              params->hdr.e_phoff - phdr->p_offset;
                        break;
                  }
            }
            break;
      }

      /* determine where the dynamic section has wound up if there is one */
      phdr = params->phdrs;
      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            if (phdr->p_type != PT_DYNAMIC)
                  continue;

            seg = loadmap->segs;
            for (loop = loadmap->nsegs; loop > 0; loop--, seg++) {
                  if (phdr->p_vaddr >= seg->p_vaddr &&
                      phdr->p_vaddr + phdr->p_memsz <=
                      seg->p_vaddr + seg->p_memsz) {
                        params->dynamic_addr =
                              (phdr->p_vaddr - seg->p_vaddr) +
                              seg->addr;

                        /* check the dynamic section contains at least
                         * one item, and that the last item is a NULL
                         * entry */
                        if (phdr->p_memsz == 0 ||
                            phdr->p_memsz % sizeof(Elf32_Dyn) != 0)
                              goto dynamic_error;

                        tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
                        if (((Elf32_Dyn *)
                             params->dynamic_addr)[tmp - 1].d_tag != 0)
                              goto dynamic_error;
                        break;
                  }
            }
            break;
      }

      /* now elide adjacent segments in the load map on MMU linux
       * - on uClinux the holes between may actually be filled with system
       *   stuff or stuff from other processes
       */
#ifdef CONFIG_MMU
      nloads = loadmap->nsegs;
      mseg = loadmap->segs;
      seg = mseg + 1;
      for (loop = 1; loop < nloads; loop++) {
            /* see if we have a candidate for merging */
            if (seg->p_vaddr - mseg->p_vaddr == seg->addr - mseg->addr) {
                  load_addr = PAGE_ALIGN(mseg->addr + mseg->p_memsz);
                  if (load_addr == (seg->addr & PAGE_MASK)) {
                        mseg->p_memsz +=
                              load_addr -
                              (mseg->addr + mseg->p_memsz);
                        mseg->p_memsz += seg->addr & ~PAGE_MASK;
                        mseg->p_memsz += seg->p_memsz;
                        loadmap->nsegs--;
                        continue;
                  }
            }

            mseg++;
            if (mseg != seg)
                  *mseg = *seg;
      }
#endif

      kdebug("Mapped Object [%s]:", what);
      kdebug("- elfhdr   : %lx", params->elfhdr_addr);
      kdebug("- entry    : %lx", params->entry_addr);
      kdebug("- PHDR[]   : %lx", params->ph_addr);
      kdebug("- DYNAMIC[]: %lx", params->dynamic_addr);
      seg = loadmap->segs;
      for (loop = 0; loop < loadmap->nsegs; loop++, seg++)
            kdebug("- LOAD[%d] : %08x-%08x [va=%x ms=%x]",
                   loop,
                   seg->addr, seg->addr + seg->p_memsz - 1,
                   seg->p_vaddr, seg->p_memsz);

      return 0;

dynamic_error:
      printk("ELF FDPIC %s with invalid DYNAMIC section (inode=%lu)\n",
             what, file->f_path.dentry->d_inode->i_ino);
      return -ELIBBAD;
}

/*****************************************************************************/
/*
 * map a file with constant displacement under uClinux
 */
#ifndef CONFIG_MMU
static int elf_fdpic_map_file_constdisp_on_uclinux(
      struct elf_fdpic_params *params,
      struct file *file,
      struct mm_struct *mm)
{
      struct elf32_fdpic_loadseg *seg;
      struct elf32_phdr *phdr;
      unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0, mflags;
      loff_t fpos;
      int loop, ret;

      load_addr = params->load_addr;
      seg = params->loadmap->segs;

      /* determine the bounds of the contiguous overall allocation we must
       * make */
      phdr = params->phdrs;
      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            if (params->phdrs[loop].p_type != PT_LOAD)
                  continue;

            if (base > phdr->p_vaddr)
                  base = phdr->p_vaddr;
            if (top < phdr->p_vaddr + phdr->p_memsz)
                  top = phdr->p_vaddr + phdr->p_memsz;
      }

      /* allocate one big anon block for everything */
      mflags = MAP_PRIVATE;
      if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
            mflags |= MAP_EXECUTABLE;

      down_write(&mm->mmap_sem);
      maddr = do_mmap(NULL, load_addr, top - base,
                  PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
      up_write(&mm->mmap_sem);
      if (IS_ERR_VALUE(maddr))
            return (int) maddr;

      if (load_addr != 0)
            load_addr += PAGE_ALIGN(top - base);

      /* and then load the file segments into it */
      phdr = params->phdrs;
      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            if (params->phdrs[loop].p_type != PT_LOAD)
                  continue;

            fpos = phdr->p_offset;

            seg->addr = maddr + (phdr->p_vaddr - base);
            seg->p_vaddr = phdr->p_vaddr;
            seg->p_memsz = phdr->p_memsz;

            ret = file->f_op->read(file, (void *) seg->addr,
                               phdr->p_filesz, &fpos);
            if (ret < 0)
                  return ret;

            /* map the ELF header address if in this segment */
            if (phdr->p_offset == 0)
                  params->elfhdr_addr = seg->addr;

            /* clear any space allocated but not loaded */
            if (phdr->p_filesz < phdr->p_memsz)
                  clear_user((void *) (seg->addr + phdr->p_filesz),
                           phdr->p_memsz - phdr->p_filesz);

            if (mm) {
                  if (phdr->p_flags & PF_X) {
                        if (!mm->start_code) {
                              mm->start_code = seg->addr;
                              mm->end_code = seg->addr +
                                    phdr->p_memsz;
                        }
                  } else if (!mm->start_data) {
                        mm->start_data = seg->addr;
#ifndef CONFIG_MMU
                        mm->end_data = seg->addr + phdr->p_memsz;
#endif
                  }

#ifdef CONFIG_MMU
                  if (seg->addr + phdr->p_memsz > mm->end_data)
                        mm->end_data = seg->addr + phdr->p_memsz;
#endif
            }

            seg++;
      }

      return 0;
}
#endif

/*****************************************************************************/
/*
 * map a binary by direct mmap() of the individual PT_LOAD segments
 */
static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
                                   struct file *file,
                                   struct mm_struct *mm)
{
      struct elf32_fdpic_loadseg *seg;
      struct elf32_phdr *phdr;
      unsigned long load_addr, delta_vaddr;
      int loop, dvset;

      load_addr = params->load_addr;
      delta_vaddr = 0;
      dvset = 0;

      seg = params->loadmap->segs;

      /* deal with each load segment separately */
      phdr = params->phdrs;
      for (loop = 0; loop < params->hdr.e_phnum; loop++, phdr++) {
            unsigned long maddr, disp, excess, excess1;
            int prot = 0, flags;

            if (phdr->p_type != PT_LOAD)
                  continue;

            kdebug("[LOAD] va=%lx of=%lx fs=%lx ms=%lx",
                   (unsigned long) phdr->p_vaddr,
                   (unsigned long) phdr->p_offset,
                   (unsigned long) phdr->p_filesz,
                   (unsigned long) phdr->p_memsz);

            /* determine the mapping parameters */
            if (phdr->p_flags & PF_R) prot |= PROT_READ;
            if (phdr->p_flags & PF_W) prot |= PROT_WRITE;
            if (phdr->p_flags & PF_X) prot |= PROT_EXEC;

            flags = MAP_PRIVATE | MAP_DENYWRITE;
            if (params->flags & ELF_FDPIC_FLAG_EXECUTABLE)
                  flags |= MAP_EXECUTABLE;

            maddr = 0;

            switch (params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) {
            case ELF_FDPIC_FLAG_INDEPENDENT:
                  /* PT_LOADs are independently locatable */
                  break;

            case ELF_FDPIC_FLAG_HONOURVADDR:
                  /* the specified virtual address must be honoured */
                  maddr = phdr->p_vaddr;
                  flags |= MAP_FIXED;
                  break;

            case ELF_FDPIC_FLAG_CONSTDISP:
                  /* constant displacement
                   * - can be mapped anywhere, but must be mapped as a
                   *   unit
                   */
                  if (!dvset) {
                        maddr = load_addr;
                        delta_vaddr = phdr->p_vaddr;
                        dvset = 1;
                  } else {
                        maddr = load_addr + phdr->p_vaddr - delta_vaddr;
                        flags |= MAP_FIXED;
                  }
                  break;

            case ELF_FDPIC_FLAG_CONTIGUOUS:
                  /* contiguity handled later */
                  break;

            default:
                  BUG();
            }

            maddr &= PAGE_MASK;

            /* create the mapping */
            disp = phdr->p_vaddr & ~PAGE_MASK;
            down_write(&mm->mmap_sem);
            maddr = do_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
                        phdr->p_offset - disp);
            up_write(&mm->mmap_sem);

            kdebug("mmap[%d] <file> sz=%lx pr=%x fl=%x of=%lx --> %08lx",
                   loop, phdr->p_memsz + disp, prot, flags,
                   phdr->p_offset - disp, maddr);

            if (IS_ERR_VALUE(maddr))
                  return (int) maddr;

            if ((params->flags & ELF_FDPIC_FLAG_ARRANGEMENT) ==
                ELF_FDPIC_FLAG_CONTIGUOUS)
                  load_addr += PAGE_ALIGN(phdr->p_memsz + disp);

            seg->addr = maddr + disp;
            seg->p_vaddr = phdr->p_vaddr;
            seg->p_memsz = phdr->p_memsz;

            /* map the ELF header address if in this segment */
            if (phdr->p_offset == 0)
                  params->elfhdr_addr = seg->addr;

            /* clear the bit between beginning of mapping and beginning of
             * PT_LOAD */
            if (prot & PROT_WRITE && disp > 0) {
                  kdebug("clear[%d] ad=%lx sz=%lx", loop, maddr, disp);
                  clear_user((void __user *) maddr, disp);
                  maddr += disp;
            }

            /* clear any space allocated but not loaded
             * - on uClinux we can just clear the lot
             * - on MMU linux we'll get a SIGBUS beyond the last page
             *   extant in the file
             */
            excess = phdr->p_memsz - phdr->p_filesz;
            excess1 = PAGE_SIZE - ((maddr + phdr->p_filesz) & ~PAGE_MASK);

#ifdef CONFIG_MMU
            if (excess > excess1) {
                  unsigned long xaddr = maddr + phdr->p_filesz + excess1;
                  unsigned long xmaddr;

                  flags |= MAP_FIXED | MAP_ANONYMOUS;
                  down_write(&mm->mmap_sem);
                  xmaddr = do_mmap(NULL, xaddr, excess - excess1,
                               prot, flags, 0);
                  up_write(&mm->mmap_sem);

                  kdebug("mmap[%d] <anon>"
                         " ad=%lx sz=%lx pr=%x fl=%x of=0 --> %08lx",
                         loop, xaddr, excess - excess1, prot, flags,
                         xmaddr);

                  if (xmaddr != xaddr)
                        return -ENOMEM;
            }

            if (prot & PROT_WRITE && excess1 > 0) {
                  kdebug("clear[%d] ad=%lx sz=%lx",
                         loop, maddr + phdr->p_filesz, excess1);
                  clear_user((void __user *) maddr + phdr->p_filesz,
                           excess1);
            }

#else
            if (excess > 0) {
                  kdebug("clear[%d] ad=%lx sz=%lx",
                         loop, maddr + phdr->p_filesz, excess);
                  clear_user((void *) maddr + phdr->p_filesz, excess);
            }
#endif

            if (mm) {
                  if (phdr->p_flags & PF_X) {
                        if (!mm->start_code) {
                              mm->start_code = maddr;
                              mm->end_code = maddr + phdr->p_memsz;
                        }
                  } else if (!mm->start_data) {
                        mm->start_data = maddr;
                        mm->end_data = maddr + phdr->p_memsz;
                  }
            }

            seg++;
      }

      return 0;
}

/*****************************************************************************/
/*
 * ELF-FDPIC core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 *
 * Modelled on fs/binfmt_elf.c core dumper
 */
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)

/*
 * 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 *addr, int nr)
{
      return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}

static int dump_seek(struct file *file, loff_t off)
{
      if (file->f_op->llseek) {
            if (file->f_op->llseek(file, off, SEEK_SET) != 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 int maydump(struct vm_area_struct *vma, unsigned long mm_flags)
{
      int dump_ok;

      /* Do not dump I/O mapped devices or special mappings */
      if (vma->vm_flags & (VM_IO | VM_RESERVED)) {
            kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
            return 0;
      }

      /* If we may not read the contents, don't allow us to dump
       * them either. "dump_write()" can't handle it anyway.
       */
      if (!(vma->vm_flags & VM_READ)) {
            kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
            return 0;
      }

      /* By default, dump shared memory if mapped from an anonymous file. */
      if (vma->vm_flags & VM_SHARED) {
            if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0) {
                  dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags);
                  kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
                         vma->vm_flags, dump_ok ? "yes" : "no");
                  return dump_ok;
            }

            dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags);
            kdcore("%08lx: %08lx: %s (share)", vma->vm_start,
                   vma->vm_flags, dump_ok ? "yes" : "no");
            return dump_ok;
      }

#ifdef CONFIG_MMU
      /* By default, if it hasn't been written to, don't write it out */
      if (!vma->anon_vma) {
            dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags);
            kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start,
                   vma->vm_flags, dump_ok ? "yes" : "no");
            return dump_ok;
      }
#endif

      dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags);
      kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags,
             dump_ok ? "yes" : "no");
      return dump_ok;
}

/* 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 DEBUG */

#define DUMP_WRITE(addr, nr)  \
      do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
#define DUMP_SEEK(off)  \
      do { if (!dump_seek(file, (off))) return 0; } while(0)

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;
}
#undef DUMP_WRITE
#undef DUMP_SEEK

#define DUMP_WRITE(addr, nr)  \
      if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
            goto end_coredump;
#define DUMP_SEEK(off)  \
      if (!dump_seek(file, (off))) \
            goto end_coredump;

static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
{
      memcpy(elf->e_ident, ELFMAG, SELFMAG);
      elf->e_ident[EI_CLASS] = ELF_CLASS;
      elf->e_ident[EI_DATA] = ELF_DATA;
      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(struct elfhdr);
      elf->e_shoff = 0;
      elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
      elf->e_ehsize = sizeof(struct elfhdr);
      elf->e_phentsize = sizeof(struct elf_phdr);
      elf->e_phnum = segs;
      elf->e_shentsize = 0;
      elf->e_shnum = 0;
      elf->e_shstrndx = 0;
      return;
}

static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
{
      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;
      return;
}

static inline void fill_note(struct memelfnote *note, const char *name, int type,
            unsigned int sz, void *data)
{
      note->name = name;
      note->type = type;
      note->datasz = sz;
      note->data = data;
      return;
}

/*
 * fill up all the fields in prstatus from the given task struct, except
 * registers which need to be filled up seperately.
 */
static void fill_prstatus(struct elf_prstatus *prstatus,
                    struct task_struct *p, long signr)
{
      prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
      prstatus->pr_sigpend = p->pending.signal.sig[0];
      prstatus->pr_sighold = p->blocked.sig[0];
      prstatus->pr_pid = task_pid_vnr(p);
      prstatus->pr_ppid = task_pid_vnr(p->parent);
      prstatus->pr_pgrp = task_pgrp_vnr(p);
      prstatus->pr_sid = task_session_vnr(p);
      if (thread_group_leader(p)) {
            /*
             * 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.
             */
            cputime_to_timeval(cputime_add(p->utime, p->signal->utime),
                           &prstatus->pr_utime);
            cputime_to_timeval(cputime_add(p->stime, p->signal->stime),
                           &prstatus->pr_stime);
      } else {
            cputime_to_timeval(p->utime, &prstatus->pr_utime);
            cputime_to_timeval(p->stime, &prstatus->pr_stime);
      }
      cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
      cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);

      prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
      prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
}

static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
                   struct mm_struct *mm)
{
      unsigned int i, len;

      /* first copy the parameters from user space */
      memset(psinfo, 0, sizeof(struct elf_prpsinfo));

      len = mm->arg_end - mm->arg_start;
      if (len >= ELF_PRARGSZ)
            len = ELF_PRARGSZ - 1;
      if (copy_from_user(&psinfo->pr_psargs,
                       (const char __user *) mm->arg_start, len))
            return -EFAULT;
      for (i = 0; i < len; i++)
            if (psinfo->pr_psargs[i] == 0)
                  psinfo->pr_psargs[i] = ' ';
      psinfo->pr_psargs[len] = 0;

      psinfo->pr_pid = task_pid_vnr(p);
      psinfo->pr_ppid = task_pid_vnr(p->parent);
      psinfo->pr_pgrp = task_pgrp_vnr(p);
      psinfo->pr_sid = task_session_vnr(p);

      i = p->state ? ffz(~p->state) + 1 : 0;
      psinfo->pr_state = i;
      psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
      psinfo->pr_zomb = psinfo->pr_sname == 'Z';
      psinfo->pr_nice = task_nice(p);
      psinfo->pr_flag = p->flags;
      SET_UID(psinfo->pr_uid, p->uid);
      SET_GID(psinfo->pr_gid, p->gid);
      strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));

      return 0;
}

/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
      struct list_head list;
      struct elf_prstatus prstatus; /* NT_PRSTATUS */
      elf_fpregset_t fpu;           /* NT_PRFPREG */
      struct task_struct *thread;
#ifdef ELF_CORE_COPY_XFPREGS
      elf_fpxregset_t xfpu;         /* ELF_CORE_XFPREG_TYPE */
#endif
      struct memelfnote notes[3];
      int num_notes;
};

/*
 * In order to add the specific thread information for the elf file format,
 * we need to keep a linked list of every thread's pr_status and then create
 * a single section for them in the final core file.
 */
static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
{
      struct task_struct *p = t->thread;
      int sz = 0;

      t->num_notes = 0;

      fill_prstatus(&t->prstatus, p, signr);
      elf_core_copy_task_regs(p, &t->prstatus.pr_reg);

      fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
              &t->prstatus);
      t->num_notes++;
      sz += notesize(&t->notes[0]);

      t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
      if (t->prstatus.pr_fpvalid) {
            fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
                    &t->fpu);
            t->num_notes++;
            sz += notesize(&t->notes[1]);
      }

#ifdef ELF_CORE_COPY_XFPREGS
      if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
            fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
                    sizeof(t->xfpu), &t->xfpu);
            t->num_notes++;
            sz += notesize(&t->notes[2]);
      }
#endif
      return sz;
}

/*
 * dump the segments for an MMU process
 */
#ifdef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                     unsigned long *limit, unsigned long mm_flags)
{
      struct vm_area_struct *vma;

      for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
            unsigned long addr;

            if (!maydump(vma, mm_flags))
                  continue;

            for (addr = vma->vm_start;
                 addr < vma->vm_end;
                 addr += PAGE_SIZE
                 ) {
                  struct vm_area_struct *vma;
                  struct page *page;

                  if (get_user_pages(current, current->mm, addr, 1, 0, 1,
                                 &page, &vma) <= 0) {
                        DUMP_SEEK(file->f_pos + PAGE_SIZE);
                  }
                  else if (page == ZERO_PAGE(0)) {
                        page_cache_release(page);
                        DUMP_SEEK(file->f_pos + PAGE_SIZE);
                  }
                  else {
                        void *kaddr;

                        flush_cache_page(vma, addr, page_to_pfn(page));
                        kaddr = kmap(page);
                        if ((*size += PAGE_SIZE) > *limit ||
                            !dump_write(file, kaddr, PAGE_SIZE)
                            ) {
                              kunmap(page);
                              page_cache_release(page);
                              return -EIO;
                        }
                        kunmap(page);
                        page_cache_release(page);
                  }
            }
      }

      return 0;

end_coredump:
      return -EFBIG;
}
#endif

/*
 * dump the segments for a NOMMU process
 */
#ifndef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, size_t *size,
                     unsigned long *limit, unsigned long mm_flags)
{
      struct vm_list_struct *vml;

      for (vml = current->mm->context.vmlist; vml; vml = vml->next) {
      struct vm_area_struct *vma = vml->vma;

            if (!maydump(vma, mm_flags))
                  continue;

            if ((*size += PAGE_SIZE) > *limit)
                  return -EFBIG;

            if (!dump_write(file, (void *) vma->vm_start,
                        vma->vm_end - vma->vm_start))
                  return -EIO;
      }

      return 0;
}
#endif

/*
 * 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 elf_fdpic_core_dump(long signr, struct pt_regs *regs,
                         struct file *file, unsigned long limit)
{
#define     NUM_NOTES   6
      int has_dumped = 0;
      mm_segment_t fs;
      int segs;
      size_t size = 0;
      int i;
      struct vm_area_struct *vma;
      struct elfhdr *elf = NULL;
      loff_t offset = 0, dataoff;
      int numnote;
      struct memelfnote *notes = NULL;
      struct elf_prstatus *prstatus = NULL;     /* NT_PRSTATUS */
      struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
      struct task_struct *g, *p;
      LIST_HEAD(thread_list);
      struct list_head *t;
      elf_fpregset_t *fpu = NULL;
#ifdef ELF_CORE_COPY_XFPREGS
      elf_fpxregset_t *xfpu = NULL;
#endif
      int thread_status_size = 0;
#ifndef CONFIG_MMU
      struct vm_list_struct *vml;
#endif
      elf_addr_t *auxv;
      unsigned long mm_flags;

      /*
       * We no longer stop all VM operations.
       *
       * This is because those proceses that could possibly change map_count
       * or the mmap / vma pages are now blocked in do_exit on current
       * finishing this core dump.
       *
       * Only ptrace can touch these memory addresses, but it doesn't change
       * the map_count or the pages allocated. So no possibility of crashing
       * exists while dumping the mm->vm_next areas to the core file.
       */

      /* alloc memory for large data structures: too large to be on stack */
      elf = kmalloc(sizeof(*elf), GFP_KERNEL);
      if (!elf)
            goto cleanup;
      prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
      if (!prstatus)
            goto cleanup;
      psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
      if (!psinfo)
            goto cleanup;
      notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
      if (!notes)
            goto cleanup;
      fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
      if (!fpu)
            goto cleanup;
#ifdef ELF_CORE_COPY_XFPREGS
      xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
      if (!xfpu)
            goto cleanup;
#endif

      if (signr) {
            struct elf_thread_status *tmp;
            rcu_read_lock();
            do_each_thread(g,p)
                  if (current->mm == p->mm && current != p) {
                        tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
                        if (!tmp) {
                              rcu_read_unlock();
                              goto cleanup;
                        }
                        tmp->thread = p;
                        list_add(&tmp->list, &thread_list);
                  }
            while_each_thread(g,p);
            rcu_read_unlock();
            list_for_each(t, &thread_list) {
                  struct elf_thread_status *tmp;
                  int sz;

                  tmp = list_entry(t, struct elf_thread_status, list);
                  sz = elf_dump_thread_status(signr, tmp);
                  thread_status_size += sz;
            }
      }

      /* now collect the dump for the current */
      fill_prstatus(prstatus, current, signr);
      elf_core_copy_regs(&prstatus->pr_reg, regs);

#ifdef CONFIG_MMU
      segs = current->mm->map_count;
#else
      segs = 0;
      for (vml = current->mm->context.vmlist; vml; vml = vml->next)
          segs++;
#endif
#ifdef ELF_CORE_EXTRA_PHDRS
      segs += ELF_CORE_EXTRA_PHDRS;
#endif

      /* Set up header */
      fill_elf_fdpic_header(elf, segs + 1);     /* including notes section */

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

      /*
       * Set up the notes in similar form to SVR4 core dumps made
       * with info from their /proc.
       */

      fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
      fill_psinfo(psinfo, current->group_leader, current->mm);
      fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);

      numnote = 2;

      auxv = (elf_addr_t *) current->mm->saved_auxv;

      i = 0;
      do
            i += 2;
      while (auxv[i - 2] != AT_NULL);
      fill_note(&notes[numnote++], "CORE", NT_AUXV,
              i * sizeof(elf_addr_t), auxv);

      /* Try to dump the FPU. */
      if ((prstatus->pr_fpvalid =
           elf_core_copy_task_fpregs(current, regs, fpu)))
            fill_note(notes + numnote++,
                    "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
#ifdef ELF_CORE_COPY_XFPREGS
      if (elf_core_copy_task_xfpregs(current, xfpu))
            fill_note(notes + numnote++,
                    "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
#endif

      fs = get_fs();
      set_fs(KERNEL_DS);

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

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

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

            sz += thread_status_size;

            fill_elf_note_phdr(&phdr, sz, offset);
            offset += sz;
            DUMP_WRITE(&phdr, sizeof(phdr));
      }

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

      /*
       * We must use the same mm->flags while dumping core to avoid
       * inconsistency between the program headers and bodies, otherwise an
       * unusable core file can be generated.
       */
      mm_flags = current->mm->flags;

      /* write program headers for segments dump */
      for (
#ifdef CONFIG_MMU
            vma = current->mm->mmap; vma; vma = vma->vm_next
#else
                  vml = current->mm->context.vmlist; vml; vml = vml->next
#endif
           ) {
            struct elf_phdr phdr;
            size_t sz;

#ifndef CONFIG_MMU
            vma = vml->vma;
#endif

            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, mm_flags) ? 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 = ELF_EXEC_PAGESIZE;

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

#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
      ELF_CORE_WRITE_EXTRA_PHDRS;
#endif

      /* write out the notes section */
      for (i = 0; i < numnote; i++)
            if (!writenote(notes + i, file))
                  goto end_coredump;

      /* write out the thread status notes section */
      list_for_each(t, &thread_list) {
            struct elf_thread_status *tmp =
                        list_entry(t, struct elf_thread_status, list);

            for (i = 0; i < tmp->num_notes; i++)
                  if (!writenote(&tmp->notes[i], file))
                        goto end_coredump;
      }

      DUMP_SEEK(dataoff);

      if (elf_fdpic_dump_segments(file, &size, &limit, mm_flags) < 0)
            goto end_coredump;

#ifdef ELF_CORE_WRITE_EXTRA_DATA
      ELF_CORE_WRITE_EXTRA_DATA;
#endif

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

end_coredump:
      set_fs(fs);

cleanup:
      while (!list_empty(&thread_list)) {
            struct list_head *tmp = thread_list.next;
            list_del(tmp);
            kfree(list_entry(tmp, struct elf_thread_status, list));
      }

      kfree(elf);
      kfree(prstatus);
      kfree(psinfo);
      kfree(notes);
      kfree(fpu);
#ifdef ELF_CORE_COPY_XFPREGS
      kfree(xfpu);
#endif
      return has_dumped;
#undef NUM_NOTES
}

#endif            /* USE_ELF_CORE_DUMP */

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