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 <setjmp.h>
   8 #include <string.h>
   9 #include "user_util.h"
  10 #include "uml_uaccess.h"
  11 #include "task.h"
  12 #include "kern_util.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) return(0);
  26         else return(n - (fault - (unsigned long) from));
  27 }
  28
  29 static void __do_strncpy(void *dst, const void *src, int count)
  30 {
  31         strncpy(dst, src, count);
  32 }
  33
  34 int __do_strncpy_from_user(char *dst, const char *src, unsigned long count,
  35                            void **fault_addr, void **fault_catcher)
  36 {
  37         struct tt_regs save = TASK_REGS(get_current())->tt;
  38         unsigned long fault;
  39         int faulted;
  40
  41         fault = __do_user_copy(dst, src, count, fault_addr, fault_catcher,
  42                                __do_strncpy, &faulted);
  43         TASK_REGS(get_current())->tt = save;
  44
  45         if(!faulted) return(strlen(dst));
  46         else return(-1);
  47 }
  48
  49 static void __do_clear(void *to, const void *from, int n)
  50 {
  51         memset(to, 0, n);
  52 }
  53
  54 int __do_clear_user(void *mem, unsigned long len,
  55                     void **fault_addr, void **fault_catcher)
  56 {
  57         struct tt_regs save = TASK_REGS(get_current())->tt;
  58         unsigned long fault;
  59         int faulted;
  60
  61         fault = __do_user_copy(mem, NULL, len, fault_addr, fault_catcher,
  62                                __do_clear, &faulted);
  63         TASK_REGS(get_current())->tt = save;
  64
  65         if(!faulted) return(0);
  66         else return(len - (fault - (unsigned long) mem));
  67 }
  68
  69 int __do_strnlen_user(const char *str, unsigned long n,
  70                       void **fault_addr, void **fault_catcher)
  71 {
  72         struct tt_regs save = TASK_REGS(get_current())->tt;
  73         int ret;
  74         unsigned long *faddrp = (unsigned long *)fault_addr;
  75         sigjmp_buf jbuf;
  76
  77         *fault_catcher = &jbuf;
  78         if(sigsetjmp(jbuf, 1) == 0)
  79                 ret = strlen(str) + 1;
  80         else ret = *faddrp - (unsigned long) str;
  81
  82         *fault_addr = NULL;
  83         *fault_catcher = NULL;
  84
  85         TASK_REGS(get_current())->tt = save;
  86         return ret;
  87 }
  88
  89 /*
  90  * Overrides for Emacs so that we follow Linus's tabbing style.
  91  * Emacs will notice this stuff at the end of the file and automatically
  92  * adjust the settings for this buffer only.  This must remain at the end
  93  * of the file.
  94  * ---------------------------------------------------------------------------
  95  * Local variables:
  96  * c-file-style: "linux"
  97  * End:
  98  */