fs/binfmt_som.c

   1 /*
   2  * linux/fs/binfmt_som.c
   3  *
   4  * These are the functions used to load SOM format executables as used
   5  * by HP-UX.
   6  *
   7  * Copyright 1999 Matthew Wilcox <willy@bofh.ai>
   8  * based on binfmt_elf which is
   9  * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
  10  */
  11
  12 #include <linux/module.h>
  13
  14 #include <linux/fs.h>
  15 #include <linux/stat.h>
  16 #include <linux/sched.h>
  17 #include <linux/mm.h>
  18 #include <linux/mman.h>
  19 #include <linux/errno.h>
  20 #include <linux/signal.h>
  21 #include <linux/binfmts.h>
  22 #include <linux/som.h>
  23 #include <linux/string.h>
  24 #include <linux/file.h>
  25 #include <linux/fcntl.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/slab.h>
  28 #include <linux/shm.h>
  29 #include <linux/personality.h>
  30 #include <linux/init.h>
  31
  32 #include <asm/uaccess.h>
  33 #include <asm/pgtable.h>
  34
  35 #include <linux/config.h>
  36
  37 #include <linux/elf.h>
  38
  39 static int load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs);
  40 static int load_som_library(struct file *);
  41
  42 /*
  43  * If we don't support core dumping, then supply a NULL so we
  44  * don't even try.
  45  */
  46 #if 0
  47 static int som_core_dump(long signr, struct pt_regs * regs);
  48 #else
  49 #define som_core_dump   NULL
  50 #endif
  51
  52 #define SOM_PAGESTART(_v) ((_v) & ~(unsigned long)(SOM_PAGESIZE-1))
  53 #define SOM_PAGEOFFSET(_v) ((_v) & (SOM_PAGESIZE-1))
  54 #define SOM_PAGEALIGN(_v) (((_v) + SOM_PAGESIZE - 1) & ~(SOM_PAGESIZE - 1))
  55
  56 static struct linux_binfmt som_format = {
  57         .module         = THIS_MODULE,
  58         .load_binary    = load_som_binary,
  59         .load_shlib     = load_som_library,
  60         .core_dump      = som_core_dump,
  61         .min_coredump   = SOM_PAGESIZE
  62 };
  63
  64 /*
  65  * create_som_tables() parses the env- and arg-strings in new user
  66  * memory and creates the pointer tables from them, and puts their
  67  * addresses on the "stack", returning the new stack pointer value.
  68  */
  69 static void create_som_tables(struct linux_binprm *bprm)
  70 {
  71         char **argv, **envp;
  72         int argc = bprm->argc;
  73         int envc = bprm->envc;
  74         unsigned long p;
  75         unsigned long *sp;
  76
  77         /* Word-align the stack pointer */
  78         sp = (unsigned long *)((bprm->p + 3) & ~3);
  79
  80         envp = (char **) sp;
  81         sp += envc + 1;
  82         argv = (char **) sp;
  83         sp += argc + 1;
  84
  85         __put_user((unsigned long) envp,++sp);
  86         __put_user((unsigned long) argv,++sp);
  87
  88         __put_user(argc, ++sp);
  89
  90         bprm->p = (unsigned long) sp;
  91
  92         p = current->mm->arg_start;
  93         while (argc-- > 0) {
  94                 __put_user((char *)p,argv++);
  95                 p += strlen_user((char *)p);
  96         }
  97         __put_user(NULL, argv);
  98         current->mm->arg_end = current->mm->env_start = p;
  99         while (envc-- > 0) {
 100                 __put_user((char *)p,envp++);
 101                 p += strlen_user((char *)p);
 102         }
 103         __put_user(NULL, envp);
 104         current->mm->env_end = p;
 105 }
 106
 107 static int check_som_header(struct som_hdr *som_ex)
 108 {
 109         int *buf = (int *)som_ex;
 110         int i, ck;
 111
 112         if (som_ex->system_id != SOM_SID_PARISC_1_0 &&
 113             som_ex->system_id != SOM_SID_PARISC_1_1 &&
 114             som_ex->system_id != SOM_SID_PARISC_2_0)
 115                 return -ENOEXEC;
 116
 117         if (som_ex->a_magic != SOM_EXEC_NONSHARE &&
 118             som_ex->a_magic != SOM_EXEC_SHARE &&
 119             som_ex->a_magic != SOM_EXEC_DEMAND)
 120                 return -ENOEXEC;
 121
 122         if (som_ex->version_id != SOM_ID_OLD &&
 123             som_ex->version_id != SOM_ID_NEW)
 124                 return -ENOEXEC;
 125
 126         ck = 0;
 127         for (i=0; i<32; i++)
 128                 ck ^= buf[i];
 129         if (ck != 0)
 130                 return -ENOEXEC;
 131
 132         return 0;
 133 }
 134
 135 static int map_som_binary(struct file *file,
 136                 const struct som_exec_auxhdr *hpuxhdr)
 137 {
 138         unsigned long code_start, code_size, data_start, data_size;
 139         unsigned long bss_start, som_brk;
 140         int retval;
 141         int prot = PROT_READ | PROT_EXEC;
 142         int flags = MAP_FIXED|MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;
 143
 144         mm_segment_t old_fs = get_fs();
 145         set_fs(get_ds());
 146
 147         code_start = SOM_PAGESTART(hpuxhdr->exec_tmem);
 148         code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
 149         current->mm->start_code = code_start;
 150         current->mm->end_code = code_start + code_size;
 151         down_write(&current->mm->mmap_sem);
 152         retval = do_mmap(file, code_start, code_size, prot,
 153                         flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
 154         up_write(&current->mm->mmap_sem);
 155         if (retval < 0 && retval > -1024)
 156                 goto out;
 157
 158         data_start = SOM_PAGESTART(hpuxhdr->exec_dmem);
 159         data_size = SOM_PAGEALIGN(hpuxhdr->exec_dsize);
 160         current->mm->start_data = data_start;
 161         current->mm->end_data = bss_start = data_start + data_size;
 162         down_write(&current->mm->mmap_sem);
 163         retval = do_mmap(file, data_start, data_size,
 164                         prot | PROT_WRITE, flags,
 165                         SOM_PAGESTART(hpuxhdr->exec_dfile));
 166         up_write(&current->mm->mmap_sem);
 167         if (retval < 0 && retval > -1024)
 168                 goto out;
 169
 170         som_brk = bss_start + SOM_PAGEALIGN(hpuxhdr->exec_bsize);
 171         current->mm->start_brk = current->mm->brk = som_brk;
 172         down_write(&current->mm->mmap_sem);
 173         retval = do_mmap(NULL, bss_start, som_brk - bss_start,
 174                         prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
 175         up_write(&current->mm->mmap_sem);
 176         if (retval > 0 || retval < -1024)
 177                 retval = 0;
 178 out:
 179         set_fs(old_fs);
 180         return retval;
 181 }
 182
 183
 184 /*
 185  * These are the functions used to load SOM executables and shared
 186  * libraries.  There is no binary dependent code anywhere else.
 187  */
 188
 189 static int
 190 load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 191 {
 192         int som_exec_fileno;
 193         int retval;
 194         unsigned int size;
 195         unsigned long som_entry;
 196         struct som_hdr *som_ex;
 197         struct som_exec_auxhdr *hpuxhdr;
 198
 199         /* Get the exec-header */
 200         som_ex = (struct som_hdr *) bprm->buf;
 201
 202         retval = check_som_header(som_ex);
 203         if (retval != 0)
 204                 goto out;
 205
 206         /* Now read in the auxiliary header information */
 207
 208         retval = -ENOMEM;
 209         size = som_ex->aux_header_size;
 210         if (size > SOM_PAGESIZE)
 211                 goto out;
 212         hpuxhdr = (struct som_exec_auxhdr *) kmalloc(size, GFP_KERNEL);
 213         if (!hpuxhdr)
 214                 goto out;
 215
 216         retval = kernel_read(bprm->file, som_ex->aux_header_location,
 217                         (char *) hpuxhdr, size);
 218         if (retval < 0)
 219                 goto out_free;
 220 #error "Fix security hole before enabling me"
 221         retval = get_unused_fd();
 222         if (retval < 0)
 223                 goto out_free;
 224         get_file(bprm->file);
 225         fd_install(som_exec_fileno = retval, bprm->file);
 226
 227         /* Flush all traces of the currently running executable */
 228         retval = flush_old_exec(bprm);
 229         if (retval)
 230                 goto out_free;
 231
 232         /* OK, This is the point of no return */
 233         current->flags &= ~PF_FORKNOEXEC;
 234         current->personality = PER_HPUX;
 235
 236         /* Set the task size for HP-UX processes such that
 237          * the gateway page is outside the address space.
 238          * This can be fixed later, but for now, this is much
 239          * easier.
 240          */
 241
 242         current->thread.task_size = 0xc0000000;
 243
 244         /* Set map base to allow enough room for hp-ux heap growth */
 245
 246         current->thread.map_base = 0x80000000;
 247
 248         retval = map_som_binary(bprm->file, hpuxhdr);
 249         if (retval < 0)
 250                 goto out_free;
 251
 252         som_entry = hpuxhdr->exec_entry;
 253         kfree(hpuxhdr);
 254
 255         set_binfmt(&som_format);
 256         compute_creds(bprm);
 257         setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
 258
 259         create_som_tables(bprm);
 260
 261         current->mm->start_stack = bprm->p;
 262         set_mm_counter(current->mm, rss, 0);
 263
 264 #if 0
 265         printk("(start_brk) %08lx\n" , (unsigned long) current->mm->start_brk);
 266         printk("(end_code) %08lx\n" , (unsigned long) current->mm->end_code);
 267         printk("(start_code) %08lx\n" , (unsigned long) current->mm->start_code);
 268         printk("(end_data) %08lx\n" , (unsigned long) current->mm->end_data);
 269         printk("(start_stack) %08lx\n" , (unsigned long) current->mm->start_stack);
 270         printk("(brk) %08lx\n" , (unsigned long) current->mm->brk);
 271 #endif
 272
 273         map_hpux_gateway_page(current,current->mm);
 274
 275         start_thread_som(regs, som_entry, bprm->p);
 276         if (current->ptrace & PT_PTRACED)
 277                 send_sig(SIGTRAP, current, 0);
 278         return 0;
 279
 280         /* error cleanup */
 281 out_free:
 282         kfree(hpuxhdr);
 283 out:
 284         return retval;
 285 }
 286
 287 static int load_som_library(struct file *f)
 288 {
 289 /* No lib support in SOM yet.  gizza chance.. */
 290         return -ENOEXEC;
 291 }
 292         /* Install the SOM loader.
 293          * N.B. We *rely* on the table being the right size with the
 294          * right number of free slots...
 295          */
 296
 297 static int __init init_som_binfmt(void)
 298 {
 299         return register_binfmt(&som_format);
 300 }
 301
 302 static void __exit exit_som_binfmt(void)
 303 {
 304         /* Remove the SOM loader. */
 305         unregister_binfmt(&som_format);
 306 }
 307
 308 core_initcall(init_som_binfmt);
 309 module_exit(exit_som_binfmt);