Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>

#define U(x) (x<<6)
#define G(x) (x<<3)
#define O(x) (x)
#define A(x) (U(x)|G(x)|O(x))

#define DMRWE (DMREAD|DMWRITE|DMEXEC)

int parsemode(char *, ulong *, ulong *);

void
main(int argc, char *argv[])
{
        int i;
        Dir *dir, ndir;
        ulong mode, mask;
        char *p;

        if(argc < 3){
                fprint(2, "usage: chmod 0777 file ... or chmod [who]op[rwxalt] file ...\n");
                exits("usage");
        }
        mode = strtol(argv[1], &p, 8);
        if(*p == 0)
                mask = A(DMRWE);
        else if(!parsemode(argv[1], &mask, &mode)){
                fprint(2, "chmod: bad mode: %s\n", argv[1]);
                exits("mode");
        }
        nulldir(&ndir);
        for(i=2; i<argc; i++){
                dir = dirstat(argv[i]);
                if(dir == nil){
                        fprint(2, "chmod: can't stat %s: %r\n", argv[i]);
                        continue;
                }
                ndir.mode = (dir->mode & ~mask) | (mode & mask);
                free(dir);
                if(dirwstat(argv[i], &ndir)==-1){
                        fprint(2, "chmod: can't wstat %s: %r\n", argv[i]);
                        continue;
                }
        }
        exits(0);
}

int
parsemode(char *spec, ulong *pmask, ulong *pmode)
{
        ulong mode, mask;
        int done, op;
        char *s;

        s = spec;
        mask = DMAPPEND | DMEXCL | DMTMP;
        for(done=0; !done; ){
                switch(*s){
                case 'u':
                        mask |= U(DMRWE); break;
                case 'g':
                        mask |= G(DMRWE); break;
                case 'o':
                        mask |= O(DMRWE); break;
                case 'a':
                        mask |= A(DMRWE); break;
                case 0:
                        return 0;
                default:
                        done = 1;
                }
                if(!done)
                        s++;
        }
        if(s == spec)
                mask |= A(DMRWE);
        op = *s++;
        if(op != '+' && op != '-' && op != '=')
                return 0;
        mode = 0;
        for(; *s ; s++){
                switch(*s){
                case 'r':
                        mode |= A(DMREAD); break;
                case 'w':
                        mode |= A(DMWRITE); break;
                case 'x':
                        mode |= A(DMEXEC); break;
                case 'a':
                        mode |= DMAPPEND; break;
                case 'l':
                        mode |= DMEXCL; break;
                case 't':
                        mode |= DMTMP; break;
                default:
                        return 0;
                }
        }
        if(*s != 0)
                return 0;
        if(op == '+' || op == '-')
                mask &= mode;
        if(op == '-')
                mode = ~mode;
        *pmask = mask;
        *pmode = mode;
        return 1;
}