On 07/06/18 08:49, Ian Lepore wrote: > On Fri, 2018-07-06 at 13:22 +0000, Sean Bruno wrote: >> Author: sbruno >> Date: Fri Jul 6 13:22:44 2018 >> New Revision: 336031 >> URL: https://svnweb.freebsd.org/changeset/base/336031 >> >> Log: >> r336028 changed next_msg to a char * from char [] of fixed size. Change >> 2nd argument of vsnprintf() to get the strlen of next_msg so that the >> appropriate size is used. >> >> Found with gcc. >> >> /usr.bin/top/display.c: In function 'new_message': >> /usr.bin/top/display.c:963:31: error: >> argument to 'sizeof' in 'vsnprintf' call is the same expression as the >> destination; did you mean to provide an explicit length? >> [-Werror=sizeof-pointer-memaccess] >> vsnprintf(next_msg, sizeof(next_msg), msgfmt, args); >> >> Reviewed by: daichi >> >> Modified: >> head/usr.bin/top/display.c >> >> Modified: head/usr.bin/top/display.c >> ============================================================================== >> --- head/usr.bin/top/display.c Fri Jul 6 12:44:48 2018 >> (r336030) >> +++ head/usr.bin/top/display.c Fri Jul 6 13:22:44 2018 >> (r336031) >> @@ -960,7 +960,7 @@ new_message(int type, const char *msgfmt, ...) >> va_start(args, msgfmt); >> >> /* first, format the message */ >> - vsnprintf(next_msg, sizeof(next_msg), msgfmt, args); >> + vsnprintf(next_msg, strlen(next_msg), msgfmt, args); >> >> va_end(args); >> >> > > This fix is incorrect. The original commit that changed next_msg to a > pointer is probably flawed enough to revert and redevelop rather than > try a rolling set of bandaid fixes. > > Whenever setup_buffer() creates a new buffer it will need to store the > size it allocated for use in this vsnprintf() call (and maybe other > places that write directly into next_msg without calling setup_buffer > to reallocate it first, I didn't look). The setup_buffer_bufsiz > variable isn't quite right as-is, because it doesn't include the > 'addlen' value passed to setup_buffer(). > > -- Ian > >
Yeah, this isn't going well. I've been poking around in it and I can't see an quick way to do this correctly. sean
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