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