Differential D31603 Diff 94119 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;			const char *spanp;
	int c, sc;			char *tok;
				char c, sc;

	if (s == NULL && (s = *last) == NULL)			if (__predict_false(s == NULL && (s = *last) == NULL))
				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…
	return (NULL);			return (NULL);

	/*			/*
	* 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 = delim; (sc = *spanp++) != '\0';) {
	if (c == sc)			if (c == sc)
	goto cont;			goto cont;
	}			}

	if (c == 0) { /* no non-delimiter characters */			if (c == '\0') { /* no non-delimiter characters */
	*last = NULL;			*last = NULL;
	return (NULL);			return (NULL);
	}			}
	tok = s - 1;			tok = s - 1;

	/*			/*
	* Scan token (scan for delimiters: s += strcspn(s, delim), sort of).			* Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
	* Note that delim must have one NUL; we stop if we see that, too.			* Note that delim must have one NUL; we stop if we see that, too.
	*/			*/
	for (;;) {			for (;;) {
	c = *s++;			c = *s++;
	spanp = (char *)delim;			spanp = delim;
	do {			do {
	if ((sc = *spanp++) == c) {			if ((sc = *spanp++) == c) {
	if (c == 0)			if (c == '\0')
	s = NULL;			s = NULL;
	else			else
	s[-1] = '\0';			s[-1] = '\0';
	*last = s;			*last = s;
	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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