Splint: new fresh storage from strcpy()?

Question

I'm trying to learn and better understand splint, and I'm wondering about an error that I get from this code:

#include <stddef.h>
#include <stdlib.h>
#include <string.h>

/*@null@*/ /*@only@*/ char *dupStr(const char *str) {
    char *copy;
    size_t len;

    len = strlen(str) + 1U;
    if (!(copy = malloc(len * sizeof *str))) {
        return NULL;
    }
    (void) strncpy(copy, str, len);
    return copy;
}

The error is:

Splint 3.1.2 --- 26 Feb 2013

test.c: (in function dupStr)
test.c:13:9: New fresh storage copy (type void) cast to void (not released):
                (void)strncpy(copy, str, len)
  A memory leak has been detected. Storage allocated locally is not released
  before the last reference to it is lost. (Use -mustfreefresh to inhibit
  warning)

Finished checking --- 1 code warning

Is the correct solution to assign the return value to copy instead of throwing it away (it gets rid of the warning)?

I would have written it as you have, (or nearly so). So I'm not clear what its complaining about. — WhozCraig, Oct 19 '13 at 09:59
Apparently removing the `(void)` negates that warning, Interesting tool. — WhozCraig, Oct 19 '13 at 10:07
Hej, Side note: Instead of `(void) strncpy(copy, str, len);` how about `(void) memcpy(copy, str, len);`? (This is a performance idea, not Splint) — chux - Reinstate Monica, Oct 19 '13 at 21:48

score 0 · Answer 1 · answered Jan 26 '14 at 15:49

0

You don't want to ignore the return value of strncpy, that's why splint complains. You want something like:

if (strncpy(copy, str, len) == NULL)
    return NULL;

answered Jan 26 '14 at 15:49

lbolla

5,387
1
22
35

Splint: new fresh storage from strcpy()?

1 Answers1