6164445cce
I found quite a lot of bugs, so I ended up pretty much rewriting as I
followed the spec¹.
Now, it works as follows:
- Determine a mask (who) of bits that can be modified for the subsequent
operations. If none are specified, select all file mode bits.
- In a loop, determine which operation (+, -, =) to apply.
- If the next character is a permcopy (u, g, o), set the new permissions
(perm) corresponding to the bits set in the user, group or other parts
of the existing mode.
- Otherwise, set the new permissions by looping through the next r, w,
x, s, t characters.
- Now, the set of bits we want to add or remove is (who & perm). Set or
remove these bits according the the operation (first clearing the
appropriate bits if the operation is =).
- Continue from the top if the next character is a comma, otherwise,
process the next operation.
I tested this on some made up inputs, and I believe it is working
correctly now:
parsemode("g+w", 0644, 0), before: 0606, now: 0664, fixed
parsemode("u+rx", 0222, 0), before: 0077, now: 0722, fixed
parsemode("+x", 0644, 023), before: 0754, now: 0754, still works
parsemode("+w", 0444, 022), before: 0644, now: 0644, still works
parsemode("+w", 0444, 0), before: 0666, now: 0666, still works
parsemode("+s", 0755, 0), before: 0755, now: 6755, fixed
parsemode("u+s", 0755, 0), before: 0055, now: 4755, fixed
parsemode("g+s", 0755, 0), before: 0705, now: 2755, fixed
parsemode("g=u", 0700, 0), before: 0000, now: 0770, fixed
parsemode("go=u-w", 0700, 0), before: 0000, now: 0755, fixed
parsemode("o+u-g", 0641, 0), before: 0000, now: 0643, fixed
parsemode("u=rx,o+w,g-r", 0654, 0) before: error, now: 0516, fixed
parsemode(",", 0654, 0), before: error, now: error, still works
¹ http://pubs.opengroup.org/onlinepubs/9699919799/utilities/chmod.html
sbase - suckless unix tools =========================== sbase is a collection of unix tools that are inherently portable across UNIX and UNIX-like systems. The following programs are currently implemented: basename cal cat chgrp chmod chown chroot cksum cmp col cols comm cp csplit cut date dirname du echo env expand expr false fold grep head hostname kill link ln logname ls md5sum mkdir mkfifo mktemp mv nice nl nohup paste printenv printf pwd readlink renice rm rmdir sleep setsid sort split sponge strings sync tail tar tee test touch tr true tty uudecode uuencode uname unexpand uniq unlink seq sha1sum sha256sum sha512sum wc xargs yes The complement of sbase is ubase[1] which is Linux-specific and provides all the non-portable tools. Together they are intended to form a base system similar to busybox but much smaller and suckless. Building -------- To build sbase, simply type make. You may have to fiddle with config.mk depending on your system. You can also build sbase-box, which generates a single binary containing all the required tools. You can then symlink the individual tools to sbase-box. Ideally you will want to statically link sbase. If you are on Linux we recommend using musl-libc[2]. Portability ----------- sbase has been compiled on a variety of different operating systems, including Linux, *BSD, OSX, Haiku, Solaris, SCO OpenServer and others. sbase also compiles and runs on minix3 with slight modifications. They do not provide mmap()/munmap() so you need to use minix_mmap() and minix_munmap() respectively. Various combinations of operating systems and architectures have also been built. You can build sbase with gcc, clang, tcc, nwcc and pcc. [1] http://git.suckless.org/ubase/ [2] http://www.musl-libc.org/