[CRIU] [PATCH v2 1/2] util: xatol() and xatoi() helpers introduced

[Andrei Vagin]

On Mon, Sep 25, 2017 at 11:07:11AM +0200, Stanislav Kinsburskiy wrote:
> 
> 
> 23.09.2017 00:30, Andrei Vagin пишет:
> > On Wed, Sep 13, 2017 at 04:48:50PM +0300, Stanislav Kinsburskiy wrote:
> >> These helpers are safe versions of atol() and atoi() respectively.
> >> And they check for overflow and NAN errors
> >>
> >> Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
> >> ---
> >>  criu/include/util.h |    3 +++
> >>  criu/util.c         |   38 ++++++++++++++++++++++++++++++++++++++
> >>  2 files changed, 41 insertions(+)
> >>
> >> diff --git a/criu/include/util.h b/criu/include/util.h
> >> index 1fc20db..20684cc 100644
> >> --- a/criu/include/util.h
> >> +++ b/criu/include/util.h
> >> @@ -280,6 +280,9 @@ void tcp_cork(int sk, bool on);
> >>  
> >>  const char *ns_to_string(unsigned int ns);
> >>  
> >> +int xatol(const char *string, long *number);
> >> +int xatoi(const char *string, int *number);
> >> +
> >>  char *xstrcat(char *str, const char *fmt, ...)
> >>  	__attribute__ ((__format__ (__printf__, 2, 3)));
> >>  char *xsprintf(const char *fmt, ...)
> >> diff --git a/criu/util.c b/criu/util.c
> >> index b5a161f..7d60617 100644
> >> --- a/criu/util.c
> >> +++ b/criu/util.c
> >> @@ -58,6 +58,44 @@
> >>  
> >>  #define VMA_OPT_LEN	128
> >>  
> >> +static int xatol_base(const char *string, long *number, int base)
> >> +{
> >> +	char *endptr;
> >> +	long nr;
> >> +
> >> +	errno = 0;
> >> +	nr = strtol(string, &endptr, base);
> >> +	if ((errno == ERANGE && (nr == LONG_MAX || nr == LONG_MIN))
> >> +			|| (errno != 0 && nr == 0)) {
> >> +		pr_perror("failed to convert string");
> > 
> > It is better to print this string in a error message
> > 
> 
> 
> Well,on the other hand how we can distinguish between this error case above and EINVAL, returned below, when string is not a number?

I am not sure that I understand what you mean. Error messages are
different, is it not enough?

> 
> 
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	if ((endptr == string) || (*endptr != '\0')) {
> >> +		pr_err("String is not a number: '%s'\n", string);
> >> +		return -EINVAL;
> >> +	}
> >> +	*number = nr;
> >> +	return 0;
> >> +}
> >> +
> >> +int xatol(const char *string, long *number)
> >> +{
> >> +	return xatol_base(string, number, 10);
> >> +}
> >> +
> >> +
> >> +int xatoi(const char *string, int *number)
> >> +{
> >> +	long tmp;
> >> +	int err;
> >> +
> >> +	err = xatol(string, &tmp);
> > 
> > Should we check that tmp is in [INT_MIN, INT_MAX]?
> 
> 
> Well, looks like we shouldn't. Atoi will return interger even if string contains long.

So why do we need to check that a value is in [LONG_MIN, LONG_MAX] for
xatol? Why do we need these hellpers?

> 
> 
> >> +	if (!err)
> >> +		*number = (int)tmp;
> >> +	return err;
> >> +}
> >> +
> >>  /*
> >>   * This function reallocates passed str pointer.
> >>   * It means:
> >>
> >> _______________________________________________
> >> CRIU mailing list
> >> CRIU at openvz.org
> >> https://lists.openvz.org/mailman/listinfo/criu