43 lines
795 B
C
43 lines
795 B
C
/*
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* Return the number of the slot in the utmp file
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* corresponding to the current user: try for file 0, 1, 2.
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* Returns -1 if slot not found.
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*/
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#include <sys/types.h>
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#include <utmp.h>
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#define NULL 0
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extern char *ttyname(), *strrchr();
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extern int strncmp(), open(), read(), close();
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int
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ttyslot()
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{
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struct utmp ubuf;
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register char *tp, *p;
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register int s, fd;
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if((tp=ttyname(0)) == NULL && (tp=ttyname(1)) == NULL &&
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(tp=ttyname(2)) == NULL)
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return(-1);
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if((p=strrchr(tp, '/')) == NULL)
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p = tp;
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else
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p++;
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if((fd=open(UTMP_FILE, 0)) < 0)
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return(-1);
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s = 0;
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while(read(fd, (char*)&ubuf, sizeof(ubuf)) == sizeof(ubuf)) {
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if (strncmp(p, ubuf.ut_line, sizeof(ubuf.ut_line)) == 0){
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(void) close(fd);
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return(s);
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}
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s++;
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}
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(void) close(fd);
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return(-1);
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}
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