On Fri, Apr 5, 2024 at 2:51 AM Daniel Thompson <daniel.thomp...@linaro.org> wrote: > > > len_tmp = strlen(p_tmp); > > - strncpy(cp, p_tmp+len, len_tmp-len + 1); > > + strscpy(cp, p_tmp+len, len_tmp-len + 1); > > Again, I really don't think the third argument provides the number of > characters in the destination buffer. >
Right, the third argument is the length of the "remaining" characters from the completion point. if you type "tes" and press tab then kallsyms_symbol_complete() will populate p_tmp with "test". Prior to rendering to the user, @cp points to "s", we need to catch the user up and print the rest of the symbol name since they've already typed "tes" we only need to print out "t". len_tmp is the length of the entire symbol part as returned by kallsyms_symbol_complete() and len is the length of only the user-typed symbol. Therefore, the amount of remaining characters to print is given by len_tmp-len (and +1 for a NUL-byte). So, yeah, you're right. This isn't the length of the destination but I don't see why we can't use memcpy() (or strscpy()) and have this not be considered "broken". The pointer arithmetic checks out. I tested out strcat and other alternatives and they all seem less readable. > > Daniel.
