binfmt_som.c

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/*
 * linux/fs/binfmt_som.c
 *
 * These are the functions used to load SOM format executables as used
 * by HP-UX.  
 *
 * Copyright 1999 Matthew Wilcox <[email protected]>
 * based on binfmt_elf which is
 * Copyright 1993, 1994: Eric Youngdale ([email protected]).
 */

#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/som.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/init.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>


#include <linux/elf.h>

static int load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs);
static int load_som_library(struct file *);

/*
 * If we don't support core dumping, then supply a NULL so we
 * don't even try.
 */
#if 0
static int som_core_dump(struct coredump_params *cprm);
#else
#define som_core_dump   NULL
#endif

#define SOM_PAGESTART(_v) ((_v) & ~(unsigned long)(SOM_PAGESIZE-1))
#define SOM_PAGEOFFSET(_v) ((_v) & (SOM_PAGESIZE-1))
#define SOM_PAGEALIGN(_v) (((_v) + SOM_PAGESIZE - 1) & ~(SOM_PAGESIZE - 1))

static struct linux_binfmt som_format = {
    .module     = THIS_MODULE,
    .load_binary    = load_som_binary,
    .load_shlib = load_som_library,
    .core_dump  = som_core_dump,
    .min_coredump   = SOM_PAGESIZE
};

/*
 * create_som_tables() parses the env- and arg-strings in new user
 * memory and creates the pointer tables from them, and puts their
 * addresses on the "stack", returning the new stack pointer value.
 */
static void create_som_tables(struct linux_binprm *bprm)
{
    char **argv, **envp;
    int argc = bprm->argc;
    int envc = bprm->envc;
    unsigned long p;
    unsigned long *sp;

    /* Word-align the stack pointer */
    sp = (unsigned long *)((bprm->p + 3) & ~3);

    envp = (char **) sp;
    sp += envc + 1;
    argv = (char **) sp;
    sp += argc + 1;

    __put_user((unsigned long) envp,++sp);
    __put_user((unsigned long) argv,++sp);

    __put_user(argc, ++sp);

    bprm->p = (unsigned long) sp;

    p = current->mm->arg_start;
    while (argc-- > 0) {
        __put_user((char *)p,argv++);
        p += strlen_user((char *)p);
    }
    __put_user(NULL, argv);
    current->mm->arg_end = current->mm->env_start = p;
    while (envc-- > 0) {
        __put_user((char *)p,envp++);
        p += strlen_user((char *)p);
    }
    __put_user(NULL, envp);
    current->mm->env_end = p;
}

static int check_som_header(struct som_hdr *som_ex)
{
    int *buf = (int *)som_ex;
    int i, ck;

    if (som_ex->system_id != SOM_SID_PARISC_1_0 &&
        som_ex->system_id != SOM_SID_PARISC_1_1 &&
        som_ex->system_id != SOM_SID_PARISC_2_0)
        return -ENOEXEC;

    if (som_ex->a_magic != SOM_EXEC_NONSHARE &&
        som_ex->a_magic != SOM_EXEC_SHARE &&
        som_ex->a_magic != SOM_EXEC_DEMAND)
        return -ENOEXEC;

    if (som_ex->version_id != SOM_ID_OLD &&
        som_ex->version_id != SOM_ID_NEW)
        return -ENOEXEC;

    ck = 0;
    for (i=0; i<32; i++)
        ck ^= buf[i];
    if (ck != 0)
        return -ENOEXEC;

    return 0;
}

static int map_som_binary(struct file *file,
        const struct som_exec_auxhdr *hpuxhdr)
{
    unsigned long code_start, code_size, data_start, data_size;
    unsigned long bss_start, som_brk;
    int retval;
    int prot = PROT_READ | PROT_EXEC;
    int flags = MAP_FIXED|MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;

    mm_segment_t old_fs = get_fs();
    set_fs(get_ds());

    code_start = SOM_PAGESTART(hpuxhdr->exec_tmem);
    code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
    current->mm->start_code = code_start;
    current->mm->end_code = code_start + code_size;
    retval = vm_mmap(file, code_start, code_size, prot,
            flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
    if (retval < 0 && retval > -1024)
        goto out;

    data_start = SOM_PAGESTART(hpuxhdr->exec_dmem);
    data_size = SOM_PAGEALIGN(hpuxhdr->exec_dsize);
    current->mm->start_data = data_start;
    current->mm->end_data = bss_start = data_start + data_size;
    retval = vm_mmap(file, data_start, data_size,
            prot | PROT_WRITE, flags,
            SOM_PAGESTART(hpuxhdr->exec_dfile));
    if (retval < 0 && retval > -1024)
        goto out;

    som_brk = bss_start + SOM_PAGEALIGN(hpuxhdr->exec_bsize);
    current->mm->start_brk = current->mm->brk = som_brk;
    retval = vm_mmap(NULL, bss_start, som_brk - bss_start,
            prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
    if (retval > 0 || retval < -1024)
        retval = 0;
out:
    set_fs(old_fs);
    return retval;
}


/*
 * These are the functions used to load SOM executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */

static int
load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
    int retval;
    unsigned int size;
    unsigned long som_entry;
    struct som_hdr *som_ex;
    struct som_exec_auxhdr *hpuxhdr;

    /* Get the exec-header */
    som_ex = (struct som_hdr *) bprm->buf;

    retval = check_som_header(som_ex);
    if (retval != 0)
        goto out;

    /* Now read in the auxiliary header information */

    retval = -ENOMEM;
    size = som_ex->aux_header_size;
    if (size > SOM_PAGESIZE)
        goto out;
    hpuxhdr = kmalloc(size, GFP_KERNEL);
    if (!hpuxhdr)
        goto out;

    retval = kernel_read(bprm->file, som_ex->aux_header_location,
            (char *) hpuxhdr, size);
    if (retval != size) {
        if (retval >= 0)
            retval = -EIO;
        goto out_free;
    }

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

    /* OK, This is the point of no return */
    current->personality = PER_HPUX;
    setup_new_exec(bprm);

    /* Set the task size for HP-UX processes such that
     * the gateway page is outside the address space.
     * This can be fixed later, but for now, this is much
     * easier.
     */

    current->thread.task_size = 0xc0000000;

    /* Set map base to allow enough room for hp-ux heap growth */

    current->thread.map_base = 0x80000000;

    retval = map_som_binary(bprm->file, hpuxhdr);
    if (retval < 0)
        goto out_free;

    som_entry = hpuxhdr->exec_entry;
    kfree(hpuxhdr);

    set_binfmt(&som_format);
    install_exec_creds(bprm);
    setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);

    create_som_tables(bprm);

    current->mm->start_stack = bprm->p;

#if 0
    printk("(start_brk) %08lx\n" , (unsigned long) current->mm->start_brk);
    printk("(end_code) %08lx\n" , (unsigned long) current->mm->end_code);
    printk("(start_code) %08lx\n" , (unsigned long) current->mm->start_code);
    printk("(end_data) %08lx\n" , (unsigned long) current->mm->end_data);
    printk("(start_stack) %08lx\n" , (unsigned long) current->mm->start_stack);
    printk("(brk) %08lx\n" , (unsigned long) current->mm->brk);
#endif

    map_hpux_gateway_page(current,current->mm);

    start_thread_som(regs, som_entry, bprm->p);
    return 0;

    /* error cleanup */
out_free:
    kfree(hpuxhdr);
out:
    return retval;
}

static int load_som_library(struct file *f)
{
/* No lib support in SOM yet.  gizza chance.. */
    return -ENOEXEC;
}
    /* Install the SOM loader.
     * N.B. We *rely* on the table being the right size with the
     * right number of free slots...
     */

static int __init init_som_binfmt(void)
{
    register_binfmt(&som_format);
    return 0;
}

static void __exit exit_som_binfmt(void)
{
    /* Remove the SOM loader. */
    unregister_binfmt(&som_format);
}

core_initcall(init_som_binfmt);
module_exit(exit_som_binfmt);

MODULE_LICENSE("GPL");