modechange.c (Feature added) - Binary mode support. (original) (raw)

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Hi,
I found some questions on the internet wondering whether chmod tool does support binary numbers as input.
Even though it doesn't support I downloaded core-utils source and got started reading chmode code.

Let's to the point: I added binary input support by making changes into the /lib/modechanges.c file.
PS: (b) prefix is not case sensitive.

Tests:
./chmod b10111 t
stat t (0027/-----w-rwx)
./chmod b t (Error)
./chmod: invalid mode: `b'
./chmod b111111 t
stat t (0077/----rwxrwx)

Octal mode fulfills its goal very well, though Binary mode may be an interesting feature.

Follows the changes:
--- modechange.c~ 2012-11-24 00:03:36.000000000 -0200
+++ modechange.c 2012-11-23 23:54:45.000000000 -0200
@@ -137,6 +137,31 @@
struct mode_change *mc;
size_t used = 0;

+ if (*mode_string == 'b' || *mode_string == 'B')
+ {
+ unsigned int binary_mode = 0;
+ mode_t mode;
+ mode_t mentioned;

• + // Jumps the b character
  + mode_string++;
  + do
  + {
  + binary_mode = (binary_mode << 1) + *mode_string++ - '0';
  + if (ALLM < binary_mode)
  + return NULL;
  + }
  + while ('0' <= *mode_string && *mode_string <= '1');
• + if (*mode_string)
  + return NULL;
  +
  + // Octal_to_mode function will fit the binary mode.
  + mode = octal_to_mode (binary_mode);
  + mentioned = (mode & (S_ISUID | S_ISGID)) | S_ISVTX | S_IRWXUGO;
  + return make_node_op_equals (mode, mentioned);
  + }
  +
  if ('0' <= *mode_string && *mode_string < '8')
  {
  unsigned int octal_mode = 0;

I would like to receive any feedback on the matter.

Regards,Raphael S.Carvalho
Blog: http://raphaelscarvalho.blogspot.com.br/
Github: https://github.com/raphaelsc

• modechange.c (Feature added) - Binary mode support.,Raphael S Carvalho <=

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