arch/um/kernel/tt/uaccess_user.c

   1 /*
   2  * Copyright (C) 2001 Chris Emerson (cemerson@chiark.greenend.org.uk)
   3  * Copyright (C) 2001 Jeff Dike (jdike@karaya.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include <string.h>
   8 #include "user_util.h"
   9 #include "uml_uaccess.h"
  10 #include "task.h"
  11 #include "kern_util.h"
  12 #include "os.h"
  13 #include "longjmp.h"
  14
  15 int __do_copy_from_user(void *to, const void *from, int n,
  16                         void **fault_addr, void **fault_catcher)
  17 {
  18         struct tt_regs save = TASK_REGS(get_current())->tt;
  19         unsigned long fault;
  20         int faulted;
  21
  22         fault = __do_user_copy(to, from, n, fault_addr, fault_catcher,
  23                                __do_copy, &faulted);
  24         TASK_REGS(get_current())->tt = save;
  25
  26         if(!faulted)
  27                 return 0;
  28         else if (fault)
  29                 return n - (fault - (unsigned long) from);
  30         else
  31                 /* In case of a general protection fault, we don't have the
  32                  * fault address, so NULL is used instead. Pretend we didn't
  33                  * copy anything. */
  34                 return n;
  35 }
  36
  37 static void __do_strncpy(void *dst, const void *src, int count)
  38 {
  39         strncpy(dst, src, count);
  40 }
  41
  42 int __do_strncpy_from_user(char *dst, const char *src, unsigned long count,
  43                            void **fault_addr, void **fault_catcher)
  44 {
  45         struct tt_regs save = TASK_REGS(get_current())->tt;
  46         unsigned long fault;
  47         int faulted;
  48
  49         fault = __do_user_copy(dst, src, count, fault_addr, fault_catcher,
  50                                __do_strncpy, &faulted);
  51         TASK_REGS(get_current())->tt = save;
  52
  53         if(!faulted) return(strlen(dst));
  54         else return(-1);
  55 }
  56
  57 static void __do_clear(void *to, const void *from, int n)
  58 {
  59         memset(to, 0, n);
  60 }
  61
  62 int __do_clear_user(void *mem, unsigned long len,
  63                     void **fault_addr, void **fault_catcher)
  64 {
  65         struct tt_regs save = TASK_REGS(get_current())->tt;
  66         unsigned long fault;
  67         int faulted;
  68
  69         fault = __do_user_copy(mem, NULL, len, fault_addr, fault_catcher,
  70                                __do_clear, &faulted);
  71         TASK_REGS(get_current())->tt = save;
  72
  73         if(!faulted) return(0);
  74         else return(len - (fault - (unsigned long) mem));
  75 }
  76
  77 int __do_strnlen_user(const char *str, unsigned long n,
  78                       void **fault_addr, void **fault_catcher)
  79 {
  80         struct tt_regs save = TASK_REGS(get_current())->tt;
  81         int ret;
  82         unsigned long *faddrp = (unsigned long *)fault_addr;
  83         jmp_buf jbuf;
  84
  85         *fault_catcher = &jbuf;
  86         if(UML_SETJMP(&jbuf) == 0)
  87                 ret = strlen(str) + 1;
  88         else ret = *faddrp - (unsigned long) str;
  89
  90         *fault_addr = NULL;
  91         *fault_catcher = NULL;
  92
  93         TASK_REGS(get_current())->tt = save;
  94         return ret;
  95 }
  96
  97 /*
  98  * Overrides for Emacs so that we follow Linus's tabbing style.
  99  * Emacs will notice this stuff at the end of the file and automatically
 100  * adjust the settings for this buffer only.  This must remain at the end
 101  * of the file.
 102  * ---------------------------------------------------------------------------
 103  * Local variables:
 104  * c-file-style: "linux"
 105  * End:
 106  */