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
  36 #include <linux/elf.h>
  37
  38 static int load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs);
  39 static int load_som_library(struct file *);
  40
  41 /*
  42  * If we don't support core dumping, then supply a NULL so we
  43  * don't even try.
  44  */
  45 #if 0
  46 static int som_core_dump(long signr, struct pt_regs *regs, unsigned long limit);
  47 #else
  48 #define som_core_dump   NULL
  49 #endif
  50
  51 #define SOM_PAGESTART(_v) ((_v) & ~(unsigned long)(SOM_PAGESIZE-1))
  52 #define SOM_PAGEOFFSET(_v) ((_v) & (SOM_PAGESIZE-1))
  53 #define SOM_PAGEALIGN(_v) (((_v) + SOM_PAGESIZE - 1) & ~(SOM_PAGESIZE - 1))
  54
  55 static struct linux_binfmt som_format = {
  56         .module         = THIS_MODULE,
  57         .load_binary    = load_som_binary,
  58         .load_shlib     = load_som_library,
  59         .core_dump      = som_core_dump,
  60         .min_coredump   = SOM_PAGESIZE
  61 };
  62
  63 /*
  64  * create_som_tables() parses the env- and arg-strings in new user
  65  * memory and creates the pointer tables from them, and puts their
  66  * addresses on the "stack", returning the new stack pointer value.
  67  */
  68 static void create_som_tables(struct linux_binprm *bprm)
  69 {
  70         char **argv, **envp;
  71         int argc = bprm->argc;
  72         int envc = bprm->envc;
  73         unsigned long p;
  74         unsigned long *sp;
  75
  76         /* Word-align the stack pointer */
  77         sp = (unsigned long *)((bprm->p + 3) & ~3);
  78
  79         envp = (char **) sp;
  80         sp += envc + 1;
  81         argv = (char **) sp;
  82         sp += argc + 1;
  83
  84         __put_user((unsigned long) envp,++sp);
  85         __put_user((unsigned long) argv,++sp);
  86
  87         __put_user(argc, ++sp);
  88
  89         bprm->p = (unsigned long) sp;
  90
  91         p = current->mm->arg_start;
  92         while (argc-- > 0) {
  93                 __put_user((char *)p,argv++);
  94                 p += strlen_user((char *)p);
  95         }
  96         __put_user(NULL, argv);
  97         current->mm->arg_end = current->mm->env_start = p;
  98         while (envc-- > 0) {
  99                 __put_user((char *)p,envp++);
 100                 p += strlen_user((char *)p);
 101         }
 102         __put_user(NULL, envp);
 103         current->mm->env_end = p;
 104 }
 105
 106 static int check_som_header(struct som_hdr *som_ex)
 107 {
 108         int *buf = (int *)som_ex;
 109         int i, ck;
 110
 111         if (som_ex->system_id != SOM_SID_PARISC_1_0 &&
 112             som_ex->system_id != SOM_SID_PARISC_1_1 &&
 113             som_ex->system_id != SOM_SID_PARISC_2_0)
 114                 return -ENOEXEC;
 115
 116         if (som_ex->a_magic != SOM_EXEC_NONSHARE &&
 117             som_ex->a_magic != SOM_EXEC_SHARE &&
 118             som_ex->a_magic != SOM_EXEC_DEMAND)
 119                 return -ENOEXEC;
 120
 121         if (som_ex->version_id != SOM_ID_OLD &&
 122             som_ex->version_id != SOM_ID_NEW)
 123                 return -ENOEXEC;
 124
 125         ck = 0;
 126         for (i=0; i<32; i++)
 127                 ck ^= buf[i];
 128         if (ck != 0)
 129                 return -ENOEXEC;
 130
 131         return 0;
 132 }
 133
 134 static int map_som_binary(struct file *file,
 135                 const struct som_exec_auxhdr *hpuxhdr)
 136 {
 137         unsigned long code_start, code_size, data_start, data_size;
 138         unsigned long bss_start, som_brk;
 139         int retval;
 140         int prot = PROT_READ | PROT_EXEC;
 141         int flags = MAP_FIXED|MAP_PRIVATE|MAP_DENYWRITE|MAP_EXECUTABLE;
 142
 143         mm_segment_t old_fs = get_fs();
 144         set_fs(get_ds());
 145
 146         code_start = SOM_PAGESTART(hpuxhdr->exec_tmem);
 147         code_size = SOM_PAGEALIGN(hpuxhdr->exec_tsize);
 148         current->mm->start_code = code_start;
 149         current->mm->end_code = code_start + code_size;
 150         down_write(&current->mm->mmap_sem);
 151         retval = do_mmap(file, code_start, code_size, prot,
 152                         flags, SOM_PAGESTART(hpuxhdr->exec_tfile));
 153         up_write(&current->mm->mmap_sem);
 154         if (retval < 0 && retval > -1024)
 155                 goto out;
 156
 157         data_start = SOM_PAGESTART(hpuxhdr->exec_dmem);
 158         data_size = SOM_PAGEALIGN(hpuxhdr->exec_dsize);
 159         current->mm->start_data = data_start;
 160         current->mm->end_data = bss_start = data_start + data_size;
 161         down_write(&current->mm->mmap_sem);
 162         retval = do_mmap(file, data_start, data_size,
 163                         prot | PROT_WRITE, flags,
 164                         SOM_PAGESTART(hpuxhdr->exec_dfile));
 165         up_write(&current->mm->mmap_sem);
 166         if (retval < 0 && retval > -1024)
 167                 goto out;
 168
 169         som_brk = bss_start + SOM_PAGEALIGN(hpuxhdr->exec_bsize);
 170         current->mm->start_brk = current->mm->brk = som_brk;
 171         down_write(&current->mm->mmap_sem);
 172         retval = do_mmap(NULL, bss_start, som_brk - bss_start,
 173                         prot | PROT_WRITE, MAP_FIXED | MAP_PRIVATE, 0);
 174         up_write(&current->mm->mmap_sem);
 175         if (retval > 0 || retval < -1024)
 176                 retval = 0;
 177 out:
 178         set_fs(old_fs);
 179         return retval;
 180 }
 181
 182
 183 /*
 184  * These are the functions used to load SOM executables and shared
 185  * libraries.  There is no binary dependent code anywhere else.
 186  */
 187
 188 static int
 189 load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 190 {
 191         int som_exec_fileno;
 192         int retval;
 193         unsigned int size;
 194         unsigned long som_entry;
 195         struct som_hdr *som_ex;
 196         struct som_exec_auxhdr *hpuxhdr;
 197         struct files_struct *files;
 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 = 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 != size) {
 219                 if (retval >= 0)
 220                         retval = -EIO;
 221                 goto out_free;
 222         }
 223
 224         files = current->files; /* Refcounted so ok */
 225         retval = unshare_files();
 226         if (retval < 0)
 227                 goto out_free;
 228         if (files == current->files) {
 229                 put_files_struct(files);
 230                 files = NULL;
 231         }
 232
 233         retval = get_unused_fd();
 234         if (retval < 0)
 235                 goto out_free;
 236         get_file(bprm->file);
 237         fd_install(som_exec_fileno = retval, bprm->file);
 238
 239         /* Flush all traces of the currently running executable */
 240         retval = flush_old_exec(bprm);
 241         if (retval)
 242                 goto out_free;
 243
 244         /* OK, This is the point of no return */
 245         current->flags &= ~PF_FORKNOEXEC;
 246         current->personality = PER_HPUX;
 247
 248         /* Set the task size for HP-UX processes such that
 249          * the gateway page is outside the address space.
 250          * This can be fixed later, but for now, this is much
 251          * easier.
 252          */
 253
 254         current->thread.task_size = 0xc0000000;
 255
 256         /* Set map base to allow enough room for hp-ux heap growth */
 257
 258         current->thread.map_base = 0x80000000;
 259
 260         retval = map_som_binary(bprm->file, hpuxhdr);
 261         if (retval < 0)
 262                 goto out_free;
 263
 264         som_entry = hpuxhdr->exec_entry;
 265         kfree(hpuxhdr);
 266
 267         set_binfmt(&som_format);
 268         compute_creds(bprm);
 269         setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
 270
 271         create_som_tables(bprm);
 272
 273         current->mm->start_stack = bprm->p;
 274
 275 #if 0
 276         printk("(start_brk) %08lx\n" , (unsigned long) current->mm->start_brk);
 277         printk("(end_code) %08lx\n" , (unsigned long) current->mm->end_code);
 278         printk("(start_code) %08lx\n" , (unsigned long) current->mm->start_code);
 279         printk("(end_data) %08lx\n" , (unsigned long) current->mm->end_data);
 280         printk("(start_stack) %08lx\n" , (unsigned long) current->mm->start_stack);
 281         printk("(brk) %08lx\n" , (unsigned long) current->mm->brk);
 282 #endif
 283
 284         map_hpux_gateway_page(current,current->mm);
 285
 286         start_thread_som(regs, som_entry, bprm->p);
 287         if (current->ptrace & PT_PTRACED)
 288                 send_sig(SIGTRAP, current, 0);
 289         return 0;
 290
 291         /* error cleanup */
 292 out_free:
 293         kfree(hpuxhdr);
 294 out:
 295         return retval;
 296 }
 297
 298 static int load_som_library(struct file *f)
 299 {
 300 /* No lib support in SOM yet.  gizza chance.. */
 301         return -ENOEXEC;
 302 }
 303         /* Install the SOM loader.
 304          * N.B. We *rely* on the table being the right size with the
 305          * right number of free slots...
 306          */
 307
 308 static int __init init_som_binfmt(void)
 309 {
 310         return register_binfmt(&som_format);
 311 }
 312
 313 static void __exit exit_som_binfmt(void)
 314 {
 315         /* Remove the SOM loader. */
 316         unregister_binfmt(&som_format);
 317 }
 318
 319 core_initcall(init_som_binfmt);
 320 module_exit(exit_som_binfmt);