Differential D31603 Diff 93954 lib/libc/string/strtok.c

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lib/libc/string/strtok.c

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__FBSDID("$FreeBSD$");		__FBSDID("$FreeBSD$");

#include <stddef.h>		#include <stddef.h>
#ifdef DEBUG_STRTOK		#ifdef DEBUG_STRTOK
#include <stdio.h>		#include <stdio.h>
#endif		#endif
#include <string.h>		#include <string.h>

char __strtok_r(char , const char , char *);		char __strtok_r(char __restrict, const char * __restrict, char ** __restrict);

__weak_reference(__strtok_r, strtok_r);		__weak_reference(__strtok_r, strtok_r);

char *		char *
__strtok_r(char s, const char delim, char **last)		__strtok_r(char * __restrict s, const char * __restrict delim, char ** __restrict last)
{		{
char spanp, tok;		char spanp, tok;
int c, sc;		int c, sc;

if (s == NULL && (s = *last) == NULL)		if (s == NULL)
return (NULL);		s = *last;
		jrtc27Unsubmitted Done Inline Actions You've lost the return NULL for if s is still NULL jrtc27: You've lost the return NULL for if s is still NULL
		gfunni234_gmail.comAuthorUnsubmitted Done Inline Actions I mean it is undefined to have s and last be null according to the c standard gfunni234_gmail.com: I mean it is undefined to have s and last be null according to the c standard
		jrtc27Unsubmitted Done Inline Actions Not true; `last` is entirely unspecified and up to the implementation. In particular, when our strtok_r returns the final token, it sets last to NULL, but the application needs to call strtok_r one more time to see the NULL return value. This means the final call to strtok_r for an application iterating over the tokens is going to dereference a null pointer. See https://godbolt.org/z/9qEqb34z4 for an example proving the old code works but your new code renders the standard use broken. Also, strtok_r is POSIX not C. jrtc27: Not true; `*last` is entirely unspecified and up to the implementation. In particular, when our…

/*		/*
* Skip (span) leading delimiters (s += strspn(s, delim), sort of).		* Skip (span) leading delimiters (s += strspn(s, delim), sort of).
*/		*/
cont:		cont:
c = *s++;		c = *s++;
for (spanp = (char )delim; (sc = spanp++) != 0;) {		for (spanp = (char )delim; (sc = spanp++) != 0;) {
if (c == sc)		if (c == sc)
Show All 23 Lines	do {
return (tok);		return (tok);
}		}
} while (sc != 0);		} while (sc != 0);
}		}
/* NOTREACHED */		/* NOTREACHED */
}		}

char *		char *
strtok(char s, const char delim)		strtok(char * __restrict s, const char * __restrict delim)
{		{
static char *last;		static char *last;

return (__strtok_r(s, delim, &last));		return (__strtok_r(s, delim, &last));
}		}

#ifdef DEBUG_STRTOK		#ifdef DEBUG_STRTOK
/*		/*
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