Re: lib/59198: Reject negative input in strtou(3), reporting ERANGE

["Alejandro Colomar via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR lib/59198; it has been noted by GNATS.

From: Alejandro Colomar <alx%kernel.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: Bruno Haible <bruno%clisp.org@localhost>
Subject: Re: lib/59198: Reject negative input in strtou(3), reporting ERANGE
Date: Fri, 21 Mar 2025 21:25:36 +0100

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 From: Alejandro Colomar <alx%kernel.org@localhost>
 To: gnats-bugs%netbsd.org@localhost
 Cc: Bruno Haible <bruno%clisp.org@localhost>
 Subject: Re: lib/59198: Reject negative input in strtou(3), reporting ERANGE
 References: <pr-misc-59198%gnats.netbsd.org@localhost>
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 Hi,
 
 Actually, considering the name strtou(3), which is about **unsigned**
 integers, maybe negative numbers should not trigger an ERANGE error, but
 actually an ECANCELED error.  The sign, even a positive sign, should not
 be part of an unsigned number.
 
 Here are some example implementations for this:
 
 	unsigned long
 	strtoul_nn(const char *restrict s, char **restrict endp, int base)
 	{
 		while (isspace((unsigned char) *s))
 			s++;
 		if (!isdigit((unsigned char) *s))
 			return 0;
 
 		return strtoul(s, endp, base);
 	}
 
 	uintmax_t
 	strtou_nn(const char *restrict s, char **restrict endp, int base,
 	    uintmax_t min, uintmax_t max, int *status)
 	{
 		while (isspace((unsigned char) *s))
 			s++;
 		if (!isdigit((unsigned char) *s)) {
 			if (status)
 				*status =3D ECANCELED;
 			return min;
 		}
 
 		return strtou(s, endp, base, min, max, status);
 	}
 
 I'm going to expand the BUGS section in the strtoul(3) Linux manual
 page, and mention the strtoul_nn() example as a workaround for this bug
 in the standard strtoul(3).
 
 The strtou_nn() should be the ideal behavior of strtou(3).
 
 (I hope this arrives at the bug ticket.)
 
 
 Cheers,
 Alex
 
 --=20
 <https://www.alejandro-colomar.es/>
 
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