illumos gate

While writing a test suite for ar as part of trying to make #14105 actually work. I noticed that a basic test that should work according to the manual page didn't work on unmodified bits:

$ ar cr t.a ar_test0.o 
$ ar cra ar_test0.o t.a ar_test1.o 
ar: archive t.a not found
$ ls t.a 
t.a

The problem here is the if statement logic that follows:

145         if ((fd == -1) &&
146             (cmd_info->opt_flgs &
147             (d_FLAG | m_FLAG | p_FLAG | t_FLAG | x_FLAG)) ||
148             ((cmd_info->opt_flgs & r_FLAG) &&
149             (cmd_info->opt_flgs & (a_FLAG | b_FLAG)))) {
150                 (void) fprintf(stderr, MSG_INTL(MSG_NOT_FOUND_AR),
151                     cmd_info->arnam);
152                 exit(1);
153         }

If you look at all the parenthesis games, if turns into if ((bad fd && set of flags) || (-r && (-a || -b)). This means that any use of -r and -a and -b would fail. Instead this should have been such that we only entered this case if we had a bad fd. Basically -r is allowed to have a file that doesn't exist, but only if neither -a or -b is passed which suggests updating an existing archive.