58 lines
992 B
C
58 lines
992 B
C
/*
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* mesg -- set current tty to accept or
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* forbid write permission.
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*
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* mesg [y] [n]
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* y allow messages
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* n forbid messages
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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struct stat sbuf;
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char *tty;
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char *ttyname();
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main(argc, argv)
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char *argv[];
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{
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int r=0;
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tty = ttyname(2);
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if (tty == 0)
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exit(13);
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if(stat(tty, &sbuf) < 0) error("cannot stat");
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if(argc < 2) {
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if(sbuf.st_mode & 020)
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fprintf(stderr,"is y\n");
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else { r=1;
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fprintf(stderr,"is n\n");
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}
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} else switch(*argv[1]) {
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case 'y':
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newmode(sbuf.st_mode|020); break;
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case 'n':
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newmode(sbuf.st_mode&~020); r=1; break;
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default:
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error("usage: mesg [y] [n]");
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}
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exit(r);
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}
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error(s)
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char *s;
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{
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fprintf(stderr,"mesg: %s\n",s);
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exit(-1);
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}
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newmode(m)
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{
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if(chmod(tty,m)<0)
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error("cannot change mode");
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}
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