wrapper: add function to compare strings with different NUL termination

When parsing capabilities for the pack protocol, there are times we'll
want to compare the value of a capability to a NUL-terminated string.
Since the data we're reading will be space-terminated, not
NUL-terminated, we need a function that compares the two strings, but
also checks that they're the same length.  Otherwise, if we used strncmp
to compare these strings, we might accidentally accept a parameter that
was a prefix of the expected value.

Add a function, xstrncmpz, that takes a NUL-terminated string and a
non-NUL-terminated string, plus a length, and compares them, ensuring
that they are the same length.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
brian m. carlson 2020-05-25 19:58:50 +00:00 committed by Junio C Hamano
parent 92315e50b2
commit 14570dc67d
2 changed files with 14 additions and 0 deletions

View File

@ -868,6 +868,12 @@ char *xgetcwd(void);
FILE *fopen_for_writing(const char *path);
FILE *fopen_or_warn(const char *path, const char *mode);
/*
* Like strncmp, but only return zero if s is NUL-terminated and exactly len
* characters long. If it is not, consider it greater than t.
*/
int xstrncmpz(const char *s, const char *t, size_t len);
/*
* FREE_AND_NULL(ptr) is like free(ptr) followed by ptr = NULL. Note
* that ptr is used twice, so don't pass e.g. ptr++.

View File

@ -105,6 +105,14 @@ char *xstrndup(const char *str, size_t len)
return xmemdupz(str, p ? p - str : len);
}
int xstrncmpz(const char *s, const char *t, size_t len)
{
int res = strncmp(s, t, len);
if (res)
return res;
return s[len] == '\0' ? 0 : 1;
}
void *xrealloc(void *ptr, size_t size)
{
void *ret;