270 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			270 lines
		
	
	
		
			8.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* This file contains simplified versions of the standard libary functions for
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 * use with the kernel. This way the kernel sources remain separate from user
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 * sources and can easily be verified. Note that the functionality provided
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 * can be slightly different.  
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 *				                March 2005, Jorrit N. Herder.
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 * Entrypoints into this file:
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 *     katoi:		convert string to integer
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 *     kmemcpy:		copy n bytes from pointer p1 to pointer p2
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 *     kmemset:		set n bytes to c starting at pointer p
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 *     kprintf:		printf for the kernel (see working below) 
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 *     kstrcmp:		lexicographical comparison of two strings
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 *     kstrlen:		get number of non-null characters in string
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 *     kstrncpy:	copy string and pad or copy up to n chars 
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 *     kstrtoulb:	convert string to unsigned long value
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 *
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 * This file contains the routines that take care of kernel messages, i.e.,
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 * diagnostic output within the kernel. Kernel messages are not directly
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 * displayed on the console, because this must be done by the TTY driver. 
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 * Instead, the kernel accumulates characters in a buffer and notifies the
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 * TTY driver when a new message is ready. 
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 */
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#include "kernel.h"
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#include <minix/com.h>		/* need TTY process number */
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#define isdigit(c)	((unsigned) ((c) - '0') <  (unsigned) 10)
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#define END_OF_KMESS 	-1
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FORWARD _PROTOTYPE(void kputc, (int c));
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/*=========================================================================*
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 *				katoi					   *
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 *=========================================================================*/
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PUBLIC int katoi(register const char *s)
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{
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  int value = 0;				/* default value */
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  int sign = 1;					/* assume positive */
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  while(*s == ' ') s++;				/* skip spaces */
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  if (*s == '-') { sign = -1; s++; }		/* detect sign */
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  while(isdigit(*s))				/* get integer */
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      value = value*10 + (*s++) -'0';
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  return(sign * value); 			/* return result */
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}
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/*=========================================================================*
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 *				kmemcpy					   *
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 *=========================================================================*/
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PUBLIC void *kmemcpy(void *s1, const void *s2, register size_t n)
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{
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  register char *p1 = s1;
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  register const char *p2 = s2;
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  while (n-- > 0) 
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      *p1++ = *p2++;
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  return s1;
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}
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/*=========================================================================*
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 *				kmemset		 			   *
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 *=========================================================================*/
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PUBLIC void *kmemset(void *s, register int c, register size_t n)
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{
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  register char *s1 = s;
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  if (n++>0) {			/* optimized for speed */
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      while (--n > 0) 
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          *s1++ = c;
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  }
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  return s;
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}
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/*===========================================================================*
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 *				kprintf					     *
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 *===========================================================================*/
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PUBLIC void kprintf(fmt, arg)
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const char *fmt;		/* format string to be printed */
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karg_t arg;			/* argument for format string */
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{
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  int c;					/* next character in fmt */
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  unsigned long u;				/* hold number argument */
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  int base;					/* base of number arg */
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  int negative = 0;				/* print minus sign */
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  static char x2c[] = "0123456789ABCDEF";	/* nr conversion table */
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  char ascii[8 * sizeof(long) / 3 + 2];		/* string for ascii number */
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  char *s = NULL;				/* string to be printed */
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  while((c=*fmt++) != 0) {
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      if (c == '%') {				/* expect format '%key' */
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          switch(c = *fmt++) {			/* determine what to do */
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          /* Known keys are %d, %u, %x, %s, and %%. This is easily extended 
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           * with number types like %b and %o by providing a different base.
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           * Number type keys don't set a string to 's', but use the general
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           * conversion after the switch statement.
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           */ 
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          case 'd':				/* output decimal */
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              u = arg < 0 ? -arg : arg;
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              if (arg < 0) negative = 1;
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              base = 10;
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              break;
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          case 'u':				/* output unsigned long */
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              u = (unsigned long) arg;
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              base = 10;
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              break;
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          case 'x':				/* output hexadecimal */
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              u = (unsigned long) arg;
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              base = 0x10;
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              break;
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          case 's': 				/* output string */
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              if ((s=(char *)arg) == NULL)
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                  s = "(null)";
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              break;
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          case '%':				/* output percent */
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              s = "%";				 
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              break;			
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          /* Unrecognized key. */
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          default:				/* echo back %key */
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              s = "%?";				
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              s[1] = c;				/* set unknown key */
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          }
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          /* Assume a number if no string is set. Convert to ascii. */
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          if (s == NULL) {
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              s = ascii + sizeof(ascii)-1;
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              *s = 0;			
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              do {  *--s = x2c[(u % base)]; }	/* work backwards */
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              while ((u /= base) > 0); 
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          }
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          /* This is where the actual output for format "%key" is done. */
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          if (negative) kputc('-');  		/* print sign if negative */
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          while(*s != 0) { kputc(*s++); }	/* print string/ number */
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      }
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      else {
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          kputc(c);				/* print and continue */
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      }
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  }
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  kputc(END_OF_KMESS);				/* terminate output */
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}
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/*===========================================================================*
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 *			            kputc				     *
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 *===========================================================================*/
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PRIVATE void kputc(c)
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int c;					/* character to append */
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{
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/* Accumulate a single character for a kernel message. Send a notification
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 * the to TTY driver if the buffer if a END_OF_KMESS is encountered. 
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 */
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  message m;
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  if (c != END_OF_KMESS) {
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      kmess.km_buf[kmess.km_next] = c;	/* put normal char in buffer */
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      if (kmess.km_size < KMESS_BUF_SIZE)
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          kmess.km_size += 1;		
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      kmess.km_next = (kmess.km_next + 1) % KMESS_BUF_SIZE;
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  } else {
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      m.NOTIFY_TYPE = NEW_KMESS;
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      lock_notify(TTY, &m);
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  }
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}
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/*=========================================================================*
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 *				kstrlen		 			   *
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 *=========================================================================*/
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PUBLIC size_t kstrlen(const char *org)
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{
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  register const char *s = org;
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  while (*s++)
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	/* EMPTY */ ;
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  return --s - org;
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}
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/*=========================================================================*
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 *				kstrcmp		 			   *
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 *=========================================================================*/
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int kstrcmp(register const char *s1, register const char *s2) 
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{
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  while (*s1 == *s2++) {
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      if (*s1++ == '\0') return 0;
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  }
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  if (*s1 == '\0') return -1;
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  if (*--s2 == '\0') return 1;
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  return (unsigned char) *s1 - (unsigned char) *s2;
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}
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/*=========================================================================*
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 *				kstrncmp		 		   *
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 *=========================================================================*/
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PUBLIC int kstrncmp(register const char *s1, register const char *s2, register size_t n)
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{
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  while (n > 0  &&  *s1 == *s2++) {
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      if (*s1++ == '\0') return 0;
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      n--;
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  } 
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  if (n > 0) {
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      if (*s1 == '\0') return -1;
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      if (*--s2 == '\0') return 1;
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      return (unsigned char) *s1 - (unsigned char) *s2;
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  }
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  return 0;
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}
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/*=========================================================================*
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 *				kstrncpy				   *
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 *=========================================================================*/
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PUBLIC char *kstrncpy(char *ret, register const char *s2, register size_t n)
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{
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  register char *s1 = ret;
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  while((n-- > 0) && (*s1++ = *s2++)) 	/* copy up to n chars */
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      /* EMPTY */ ;
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  while(n-- > 0)   			/* possibly pad target */
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      *s1++ = '\0';
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  return ret;
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}
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/*=========================================================================*
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 *				kstrtoul				   *
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 *=========================================================================*/
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PUBLIC unsigned long kstrtoul(strptr, endptr, base)
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const char *strptr;		/* pointer to string to be parsed */
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char ** const endptr;		/* store pointer to end here */
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int base;
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{
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/* A simplified version of strtoul() for the kernel to prevent including the
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 * one in the ASNI library. No whitespaces are skipped, the numeric value is
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 * expected at the start of 'string'.
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 */
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  register unsigned long val = 0;
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  register int c;
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  register unsigned int v;
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  int overflow = 0;
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  /* Get rid of 0x or 0X for hexidecimal values. */
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  if (base==16 && *strptr=='0' && (*++strptr=='x' || *strptr=='X'))
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  	strptr++;
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  /* Now parse the actual unsigned long number. */
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  for (;;) {
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  	c = *strptr;
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  	if ('0' <= c && c <= '9')	v = c - '0';
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  	else if ('a' <= c && c <= 'z')  v = c - 'a' + 0xa;
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  	else if ('A' <= c && c <= 'Z')  v = c - 'A' + 0xA;
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  	else 		break;		/* end of number */
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  	if (v >= base)	break;		/* end of number */
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  	if (val > (ULONG_MAX - v) / base) overflow = 1;
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  	val = (val*base) + v;
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  	strptr++;
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  }
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  /* Tell caller where parsing ended unless a NULL pointer was passed. */
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  if (endptr) *endptr = (char *) strptr;
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  /* Done, return parsed value or maximum value on overflow. */
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  return (overflow) ? ULONG_MAX : val;
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}
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