Per the man page forstrncpy:

If the array pointed to by s2 is a string that is shorter than n
bytes, NUL characters shall be appended to the copy in the array
pointed to by s1, until n bytes in all are written.

This will copy unnecessary NUL characters ifsrc is shorter thansizeof(buffer) - 1
If we look atstrncat:

This function appends at most ssize non-null bytes from the array
pointed to by src, followed by a null character, to the end of the
string pointed to by dst.

strncat will not copy unnecessary NUL characters.

Per the Stack Overflow link below, the fix could look like:

dst[0] = '\0';strncat( dst, src, sizeof(buffer - 1) );

Butdst is already appropriately set a few lines up:

*dst = 0;

So the final fix would look like:

strncat( dst, src, sizeof(buffer - 1) );

Nevertheless, the current change does address the issue 😄

strncpy
strncat
Copying using strncat

Per the man page forstrncpy:

If the array pointed to by s2 is a string that is shorter than n
bytes, NUL characters shall be appended to the copy in the array
pointed to by s1, until n bytes in all are written.

This will copy unnecessary NUL characters ifsrc is shorter thansizeof(buffer) - 1 If we look atstrncat:

This function appends at most ssize non-null bytes from the array
pointed to by src, followed by a null character, to the end of the
string pointed to by dst.

strncat will not copy unnecessary NUL characters.

Per the Stack Overflow link below, the fix could look like:

dst[0] = '\0';strncat( dst, src, sizeof(buffer - 1) );

Butdst is already appropriately set a few lines up:

*dst = 0;

So the final fix would look like:

strncat( dst, src, sizeof(buffer - 1) );

Nevertheless, the current change does address the issue 😄

strncpystrncatCopying using strncat

Good point about strncat — makes total sense and yeah, definitely cleaner than strncpy in this case. I’ve updated the patch to use that instead. Appreciate the suggestion!