/*
 * linux/fs/binfmt_som.c
 *
 * These are the functions used to load SOM format executables as used
 * by HP-UX.  
 *
 * Copyright 1999 Matthew Wilcox <willy@bofh.ai>
 * based on binfmt_elf which is
 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 */

#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/a.out.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(long signr, struct pt_regs * regs);
#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;
        down_write(&current->mm->mmap_sem);
        retval = do_mmap(file, code_start, code_size, prot,
                        flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
        up_write(&current->mm->mmap_sem);
        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;
        down_write(&current->mm->mmap_sem);
        retval = do_mmap(file, data_start, data_size,
                        prot | PROT_WRITE, flags,
                        SOM_PAGESTART(hpuxhdr->exec_dfile));
        up_write(&current->mm->mmap_sem);
        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;
        down_write(&current->mm->mmap_sem);
        retval = do_mmap(NULL, bss_start, som_brk - bss_start,
                        prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
        up_write(&current->mm->mmap_sem);
        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 som_exec_fileno;
        int retval;
        unsigned int size;
        unsigned long som_entry;
        struct som_hdr *som_ex;
        struct som_exec_auxhdr *hpuxhdr;
        struct files_struct *files;

        /* 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;
        }

        files = current->files; /* Refcounted so ok */
        retval = unshare_files();
        if (retval < 0)
                goto out_free;
        if (files == current->files) {
                put_files_struct(files);
                files = NULL;
        }

        retval = get_unused_fd();
        if (retval < 0)
                goto out_free;
        get_file(bprm->file);
        fd_install(som_exec_fileno = retval, bprm->file);

        /* 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->flags &= ~PF_FORKNOEXEC;
        current->personality = PER_HPUX;

        /* 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);
        compute_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);
        if (current->ptrace & PT_PTRACED)
                send_sig(SIGTRAP, current, 0);
        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)
{
        return register_binfmt(&som_format);
}

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);