root/kernel/exec_domain.c

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DEFINITIONS

This source file includes following definitions.
  1. no_lcall7
  2. lookup_exec_domain
  3. register_exec_domain
  4. unregister_exec_domain
  5. sys_personality

   1 #include <linux/personality.h>
   2 #include <linux/ptrace.h>
   3 #include <linux/sched.h>
   4 
   5 
   6 static asmlinkage void no_lcall7(struct pt_regs * regs);
   7 
   8 
   9 static unsigned long ident_map[32] = {
  10         0,      1,      2,      3,      4,      5,      6,      7,
  11         8,      9,      10,     11,     12,     13,     14,     15,
  12         16,     17,     18,     19,     20,     21,     22,     23,
  13         24,     25,     26,     27,     28,     29,     30,     31
  14 };
  15 
  16 struct exec_domain default_exec_domain = {
  17         "Linux",        /* name */
  18         no_lcall7,      /* lcall7 causes a seg fault. */
  19         0, 0xff,        /* All personalities. */
  20         ident_map,      /* Identiy map signals. */
  21         ident_map,      /*  - both ways. */
  22         NULL,           /* No usage counter. */
  23         NULL            /* Nothing after this in the list. */
  24 };
  25 
  26 static struct exec_domain *exec_domains = &default_exec_domain;
  27 
  28 
  29 static asmlinkage void no_lcall7(struct pt_regs * regs)
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  30 {
  31         send_sig(SIGSEGV, current, 1);
  32 }
  33 
  34 struct exec_domain *lookup_exec_domain(unsigned long personality)
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  35 {
  36         unsigned long pers = personality & PER_MASK;
  37         struct exec_domain *it;
  38 
  39         for (it=exec_domains; it; it=it->next)
  40                 if (pers >= it->pers_low
  41                 && pers <= it->pers_high)
  42                         return it;
  43 
  44         /* Should never get this far. */
  45         printk(KERN_ERR "No execution domain for personality 0x%02lx\n", pers);
  46         return NULL;
  47 }
  48 
  49 int register_exec_domain(struct exec_domain *it)
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  50 {
  51         struct exec_domain *tmp;
  52 
  53         if (!it)
  54                 return -EINVAL;
  55         if (it->next)
  56                 return -EBUSY;
  57         for (tmp=exec_domains; tmp; tmp=tmp->next)
  58                 if (tmp == it)
  59                         return -EBUSY;
  60         it->next = exec_domains;
  61         exec_domains = it;
  62         return 0;
  63 }
  64 
  65 int unregister_exec_domain(struct exec_domain *it)
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  66 {
  67         struct exec_domain ** tmp;
  68 
  69         tmp = &exec_domains;
  70         while (*tmp) {
  71                 if (it == *tmp) {
  72                         *tmp = it->next;
  73                         it->next = NULL;
  74                         return 0;
  75                 }
  76                 tmp = &(*tmp)->next;
  77         }
  78         return -EINVAL;
  79 }
  80 
  81 asmlinkage int sys_personality(unsigned long personality)
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  82 {
  83         struct exec_domain *it;
  84         unsigned long old_personality;
  85 
  86         if (personality == 0xffffffff)
  87                 return current->personality;
  88 
  89         it = lookup_exec_domain(personality);
  90         if (!it)
  91                 return -EINVAL;
  92 
  93         old_personality = current->personality;
  94         if (current->exec_domain && current->exec_domain->use_count)
  95                 (*current->exec_domain->use_count)--;
  96         current->personality = personality;
  97         current->exec_domain = it;
  98         if (current->exec_domain->use_count)
  99                 (*current->exec_domain->use_count)++;
 100 
 101         return old_personality;
 102 }

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