kernel/exec_domain.c

   1 #include <linux/mm.h>
   2 #include <linux/smp_lock.h>
   3 #include <linux/module.h>
   4
   5 static asmlinkage void no_lcall7(int segment, struct pt_regs * regs);
   6
   7
   8 static unsigned long ident_map[32] = {
   9         0,      1,      2,      3,      4,      5,      6,      7,
  10         8,      9,      10,     11,     12,     13,     14,     15,
  11         16,     17,     18,     19,     20,     21,     22,     23,
  12         24,     25,     26,     27,     28,     29,     30,     31
  13 };
  14
  15 struct exec_domain default_exec_domain = {
  16         "Linux",        /* name */
  17         no_lcall7,      /* lcall7 causes a seg fault. */
  18         0, 0xff,        /* All personalities. */
  19         ident_map,      /* Identity map signals. */
  20         ident_map,      /*  - both ways. */
  21         NULL,           /* No usage counter. */
  22         NULL            /* Nothing after this in the list. */
  23 };
  24
  25 static struct exec_domain *exec_domains = &default_exec_domain;
  26
  27
  28 static asmlinkage void no_lcall7(int segment, struct pt_regs * regs)
  29 {
  30   /*
  31    * This may have been a static linked SVr4 binary, so we would have the
  32    * personality set incorrectly.  Check to see whether SVr4 is available,
  33    * and use it, otherwise give the user a SEGV.
  34    */
  35         if (current->exec_domain && current->exec_domain->module)
  36                 __MOD_DEC_USE_COUNT(current->exec_domain->module);
  37
  38         current->personality = PER_SVR4;
  39         current->exec_domain = lookup_exec_domain(current->personality);
  40
  41         if (current->exec_domain && current->exec_domain->module)
  42                 __MOD_INC_USE_COUNT(current->exec_domain->module);
  43
  44         if (current->exec_domain && current->exec_domain->handler
  45         && current->exec_domain->handler != no_lcall7) {
  46                 current->exec_domain->handler(segment, regs);
  47                 return;
  48         }
  49
  50         send_sig(SIGSEGV, current, 1);
  51 }
  52
  53 struct exec_domain *lookup_exec_domain(unsigned long personality)
  54 {
  55         unsigned long pers = personality & PER_MASK;
  56         struct exec_domain *it;
  57
  58         for (it=exec_domains; it; it=it->next)
  59                 if (pers >= it->pers_low
  60                 && pers <= it->pers_high)
  61                         return it;
  62
  63         /* Should never get this far. */
  64         printk(KERN_ERR "No execution domain for personality 0x%02lx\n", pers);
  65         return NULL;
  66 }
  67
  68 int register_exec_domain(struct exec_domain *it)
  69 {
  70         struct exec_domain *tmp;
  71
  72         if (!it)
  73                 return -EINVAL;
  74         if (it->next)
  75                 return -EBUSY;
  76         for (tmp=exec_domains; tmp; tmp=tmp->next)
  77                 if (tmp == it)
  78                         return -EBUSY;
  79         it->next = exec_domains;
  80         exec_domains = it;
  81         return 0;
  82 }
  83
  84 int unregister_exec_domain(struct exec_domain *it)
  85 {
  86         struct exec_domain ** tmp;
  87
  88         tmp = &exec_domains;
  89         while (*tmp) {
  90                 if (it == *tmp) {
  91                         *tmp = it->next;
  92                         it->next = NULL;
  93                         return 0;
  94                 }
  95                 tmp = &(*tmp)->next;
  96         }
  97         return -EINVAL;
  98 }
  99
 100 asmlinkage long sys_personality(unsigned long personality)
 101 {
 102         struct exec_domain *it;
 103         unsigned long old_personality;
 104         int ret;
 105
 106         lock_kernel();
 107         ret = current->personality;
 108         if (personality == 0xffffffff)
 109                 goto out;
 110
 111         ret = -EINVAL;
 112         it = lookup_exec_domain(personality);
 113         if (!it)
 114                 goto out;
 115
 116         old_personality = current->personality;
 117         if (current->exec_domain && current->exec_domain->module)
 118                 __MOD_DEC_USE_COUNT(current->exec_domain->module);
 119         current->personality = personality;
 120         current->exec_domain = it;
 121         if (current->exec_domain->module)
 122                 __MOD_INC_USE_COUNT(current->exec_domain->module);
 123         ret = old_personality;
 124 out:
 125         unlock_kernel();
 126         return ret;
 127 }
 128
 129 int get_exec_domain_list(char * page)
 130 {
 131         int len = 0;
 132         struct exec_domain * e;
 133
 134         for (e=exec_domains; e && len < PAGE_SIZE - 80; e=e->next)
 135                 len += sprintf(page+len, "%d-%d\t%-16s\t[%s]\n",
 136                         e->pers_low, e->pers_high, e->name,
 137                         e->module ? e->module->name : "kernel");
 138         return len;
 139 }