binfmt_elf_fdpic.c

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/* binfmt_elf_fdpic.c: FDPIC ELF binary format
 *
 * Copyright (C) 2003, 2004, 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 * 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/security.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 <linux/coredump.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 *);

#ifdef CONFIG_ELF_CORE
static int elf_fdpic_core_dump(struct coredump_params *cprm);
#endif

static struct linux_binfmt elf_fdpic_format = {
    .module     = THIS_MODULE,
    .load_binary    = load_elf_fdpic_binary,
#ifdef CONFIG_ELF_CORE
    .core_dump  = elf_fdpic_core_dump,
#endif
    .min_coredump   = ELF_EXEC_PAGESIZE,
};

static int __init init_elf_fdpic_binfmt(void)
{
    register_binfmt(&elf_fdpic_format);
    return 0;
}

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 (unlikely(retval != size))
        return retval < 0 ? retval : -ENOEXEC;

    /* 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;
#ifdef ELF_FDPIC_PLAT_INIT
    unsigned long dynaddr;
#endif
#ifndef CONFIG_MMU
    unsigned long stack_prot;
#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 (unlikely(retval != phdr->p_filesz)) {
                if (retval >= 0)
                    retval = -ENOEXEC;
                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.
             */
            would_dump(bprm, interpreter);

            retval = kernel_read(interpreter, 0, bprm->buf,
                         BINPRM_BUF_SIZE);
            if (unlikely(retval != BINPRM_BUF_SIZE)) {
                if (retval >= 0)
                    retval = -ENOEXEC;
                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 (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
        executable_stack = EXSTACK_DEFAULT;

    if (stack_size == 0) {
        stack_size = interp_params.stack_size;
        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);
    if (elf_read_implies_exec(&exec_params.hdr, executable_stack))
        current->personality |= READ_IMPLIES_EXEC;

    setup_new_exec(bprm);

    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;

#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;

    stack_prot = PROT_READ | PROT_WRITE;
    if (executable_stack == EXSTACK_ENABLE_X ||
        (executable_stack == EXSTACK_DEFAULT && VM_STACK_FLAGS & VM_EXEC))
        stack_prot |= PROT_EXEC;

    current->mm->start_brk = vm_mmap(NULL, 0, stack_size, stack_prot,
                     MAP_PRIVATE | MAP_ANONYMOUS |
                     MAP_UNINITIALIZED | MAP_GROWSDOWN,
                     0);

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

    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

    install_exec_creds(bprm);
    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);

    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;

}

/*****************************************************************************/

#ifndef ELF_BASE_PLATFORM
/*
 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 * will be copied to the user stack in the same manner as AT_PLATFORM.
 */
#define ELF_BASE_PLATFORM NULL
#endif

/*
 * present useful information to the program by shovelling it onto the new
 * process's stack
 */
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)
{
    const struct cred *cred = current_cred();
    unsigned long sp, csp, nitems;
    elf_caddr_t __user *argv, *envp;
    size_t platform_len = 0, len;
    char *k_platform, *k_base_platform;
    char __user *u_platform, *u_base_platform, *p;
    long hwcap;
    int loop;
    int nr; /* reset for each csp adjustment */

#ifdef CONFIG_MMU
    /* 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, so we give the architecture
     * an opportunity to do so here.
     */
    sp = arch_align_stack(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

    hwcap = ELF_HWCAP;

    /*
     * If this architecture has a platform capability string, copy it
     * to userspace.  In some cases (Sparc), this info is impossible
     * for userspace to get any other way, in others (i386) it is
     * merely difficult.
     */
    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 this architecture has a "base" platform capability
     * string, copy it to userspace.
     */
    k_base_platform = ELF_BASE_PLATFORM;
    u_base_platform = NULL;

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

    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 15

    nitems = 1 + DLINFO_ITEMS + (k_platform ? 1 : 0) +
        (k_base_platform ? 1 : 0) + AT_VECTOR_SIZE_ARCH;

    if (bprm->interp_flags & BINPRM_FLAGS_EXECFD)
        nitems++;

    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(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);           \
        nr++;                           \
    } while (0)

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

    if (k_base_platform) {
        nr = 0;
        csp -= 2 * sizeof(unsigned long);
        NEW_AUX_ENT(AT_BASE_PLATFORM,
                (elf_addr_t) (unsigned long) u_base_platform);
    }

    if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
        nr = 0;
        csp -= 2 * sizeof(unsigned long);
        NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
    }

    nr = 0;
    csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
    NEW_AUX_ENT(AT_HWCAP,   hwcap);
    NEW_AUX_ENT(AT_PAGESZ,  PAGE_SIZE);
    NEW_AUX_ENT(AT_CLKTCK,  CLOCKS_PER_SEC);
    NEW_AUX_ENT(AT_PHDR,    exec_params->ph_addr);
    NEW_AUX_ENT(AT_PHENT,   sizeof(struct elf_phdr));
    NEW_AUX_ENT(AT_PHNUM,   exec_params->hdr.e_phnum);
    NEW_AUX_ENT(AT_BASE,    interp_params->elfhdr_addr);
    NEW_AUX_ENT(AT_FLAGS,   0);
    NEW_AUX_ENT(AT_ENTRY,   exec_params->entry_addr);
    NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid));
    NEW_AUX_ENT(AT_EUID,    (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid));
    NEW_AUX_ENT(AT_GID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->gid));
    NEW_AUX_ENT(AT_EGID,    (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid));
    NEW_AUX_ENT(AT_SECURE,  security_bprm_secureexec(bprm));
    NEW_AUX_ENT(AT_EXECFN,  bprm->exec);

#ifdef ARCH_DLINFO
    nr = 0;
    csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long);

    /* 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;

    maddr = vm_mmap(NULL, load_addr, top - base,
            PROT_READ | PROT_WRITE | PROT_EXEC, mflags, 0);
    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) {
            if (clear_user((void *) (seg->addr + phdr->p_filesz),
                       phdr->p_memsz - phdr->p_filesz))
                return -EFAULT;
        }

        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;
                mm->end_data = seg->addr + phdr->p_memsz;
            }
        }

        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;
        maddr = vm_mmap(file, maddr, phdr->p_memsz + disp, prot, flags,
                phdr->p_offset - disp);

        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);
            if (clear_user((void __user *) maddr, disp))
                return -EFAULT;
            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;
            xmaddr = vm_mmap(NULL, xaddr, excess - excess1,
                     prot, flags, 0);

            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);
            if (clear_user((void __user *) maddr + phdr->p_filesz,
                       excess1))
                return -EFAULT;
        }

#else
        if (excess > 0) {
            kdebug("clear[%d] ad=%lx sz=%lx",
                   loop, maddr + phdr->p_filesz, excess);
            if (clear_user((void *) maddr + phdr->p_filesz, excess))
                return -EFAULT;
        }
#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 <[email protected]>
 *
 * Modelled on fs/binfmt_elf.c core dumper
 */
#ifdef CONFIG_ELF_CORE

/*
 * 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) {
        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, foffset)   \
    do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)

static int alignfile(struct file *file, loff_t *foffset)
{
    static const char buf[4] = { 0, };
    DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
    return 1;
}

static int writenote(struct memelfnote *men, struct file *file,
            loff_t *foffset)
{
    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), foffset);
    DUMP_WRITE(men->name, en.n_namesz, foffset);
    if (!alignfile(file, foffset))
        return 0;
    DUMP_WRITE(men->data, men->datasz, foffset);
    if (!alignfile(file, foffset))
        return 0;

    return 1;
}
#undef DUMP_WRITE

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 separately.
 */
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];
    rcu_read_lock();
    prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
    rcu_read_unlock();
    prstatus->pr_pid = task_pid_vnr(p);
    prstatus->pr_pgrp = task_pgrp_vnr(p);
    prstatus->pr_sid = task_session_vnr(p);
    if (thread_group_leader(p)) {
        struct task_cputime cputime;

        /*
         * This is the record for the group leader.  It shows the
         * group-wide total, not its individual thread total.
         */
        thread_group_cputime(p, &cputime);
        cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
        cputime_to_timeval(cputime.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)
{
    const struct cred *cred;
    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;

    rcu_read_lock();
    psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
    rcu_read_unlock();
    psinfo->pr_pid = task_pid_vnr(p);
    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;
    rcu_read_lock();
    cred = __task_cred(p);
    SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
    SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
    rcu_read_unlock();
    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;
}

static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
                 elf_addr_t e_shoff, int segs)
{
    elf->e_shoff = e_shoff;
    elf->e_shentsize = sizeof(*shdr4extnum);
    elf->e_shnum = 1;
    elf->e_shstrndx = SHN_UNDEF;

    memset(shdr4extnum, 0, sizeof(*shdr4extnum));

    shdr4extnum->sh_type = SHT_NULL;
    shdr4extnum->sh_size = elf->e_shnum;
    shdr4extnum->sh_link = elf->e_shstrndx;
    shdr4extnum->sh_info = segs;
}

/*
 * 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;
    int err = 0;

    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 page *page = get_dump_page(addr);
            if (page) {
                void *kaddr = kmap(page);
                *size += PAGE_SIZE;
                if (*size > *limit)
                    err = -EFBIG;
                else if (!dump_write(file, kaddr, PAGE_SIZE))
                    err = -EIO;
                kunmap(page);
                page_cache_release(page);
            } else if (!dump_seek(file, PAGE_SIZE))
                err = -EFBIG;
            if (err)
                goto out;
        }
    }
out:
    return err;
}
#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_area_struct *vma;

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

static size_t elf_core_vma_data_size(unsigned long mm_flags)
{
    struct vm_area_struct *vma;
    size_t size = 0;

    for (vma = current->mm->mmap; vma; vma = vma->vm_next)
        if (maydump(vma, mm_flags))
            size += vma->vm_end - vma->vm_start;
    return size;
}

/*
 * 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(struct coredump_params *cprm)
{
#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, foffset;
    int numnote;
    struct memelfnote *notes = NULL;
    struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
    struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
    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;
    elf_addr_t *auxv;
    struct elf_phdr *phdr4note = NULL;
    struct elf_shdr *shdr4extnum = NULL;
    Elf_Half e_phnum;
    elf_addr_t e_shoff;

    /*
     * 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 (cprm->siginfo->si_signo) {
        struct core_thread *ct;
        struct elf_thread_status *tmp;

        for (ct = current->mm->core_state->dumper.next;
                        ct; ct = ct->next) {
            tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
            if (!tmp)
                goto cleanup;

            tmp->thread = ct->task;
            list_add(&tmp->list, &thread_list);
        }

        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(cprm->siginfo->si_signo, tmp);
            thread_status_size += sz;
        }
    }

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

    segs = current->mm->map_count;
    segs += elf_core_extra_phdrs();

    /* for notes section */
    segs++;

    /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
     * this, kernel supports extended numbering. Have a look at
     * include/linux/elf.h for further information. */
    e_phnum = segs > PN_XNUM ? PN_XNUM : segs;

    /* Set up header */
    fill_elf_fdpic_header(elf, e_phnum);

    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, cprm->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);

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

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

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

        sz += thread_status_size;

        phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
        if (!phdr4note)
            goto end_coredump;

        fill_elf_note_phdr(phdr4note, sz, offset);
        offset += sz;
    }

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

    offset += elf_core_vma_data_size(cprm->mm_flags);
    offset += elf_core_extra_data_size();
    e_shoff = offset;

    if (e_phnum == PN_XNUM) {
        shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
        if (!shdr4extnum)
            goto end_coredump;
        fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
    }

    offset = dataoff;

    size += sizeof(*elf);
    if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
        goto end_coredump;

    size += sizeof(*phdr4note);
    if (size > cprm->limit
        || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note)))
        goto end_coredump;

    /* write program headers for segments dump */
    for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
        struct elf_phdr phdr;
        size_t sz;

        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, cprm->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;

        size += sizeof(phdr);
        if (size > cprm->limit
            || !dump_write(cprm->file, &phdr, sizeof(phdr)))
            goto end_coredump;
    }

    if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit))
        goto end_coredump;

    /* write out the notes section */
    for (i = 0; i < numnote; i++)
        if (!writenote(notes + i, cprm->file, &foffset))
            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], cprm->file, &foffset))
                goto end_coredump;
    }

    if (!dump_seek(cprm->file, dataoff - foffset))
        goto end_coredump;

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

    if (!elf_core_write_extra_data(cprm->file, &size, cprm->limit))
        goto end_coredump;

    if (e_phnum == PN_XNUM) {
        size += sizeof(*shdr4extnum);
        if (size > cprm->limit
            || !dump_write(cprm->file, shdr4extnum,
                   sizeof(*shdr4extnum)))
            goto end_coredump;
    }

    if (cprm->file->f_pos != offset) {
        /* Sanity check */
        printk(KERN_WARNING
               "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n",
               cprm->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(phdr4note);
    kfree(elf);
    kfree(prstatus);
    kfree(psinfo);
    kfree(notes);
    kfree(fpu);
    kfree(shdr4extnum);
#ifdef ELF_CORE_COPY_XFPREGS
    kfree(xfpu);
#endif
    return has_dumped;
#undef NUM_NOTES
}

#endif      /* CONFIG_ELF_CORE */