1 /* 2 * Copyright (c) 1988 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)ttyname.c 5.8 (Berkeley) 02/23/91"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 #include <sys/stat.h> 14 #include <fcntl.h> 15 #include <dirent.h> 16 #include <sgtty.h> 17 #include <ndbm.h> 18 #include <unistd.h> 19 #include <paths.h> 20 21 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV; 22 23 char * 24 ttyname(fd) 25 int fd; 26 { 27 struct stat sb; 28 struct sgttyb ttyb; 29 DBM *db; 30 datum dp, key; 31 static char *__oldttyname(); 32 33 /* Must be a terminal. */ 34 if (ioctl(fd, TIOCGETP, &ttyb) < 0) 35 return(NULL); 36 /* Must be a character device. */ 37 if (fstat(fd, &sb) || !S_ISCHR(sb.st_mode)) 38 return(NULL); 39 40 if (!(db = dbm_open(_PATH_DEVDB, O_RDONLY, 0))) 41 return(__oldttyname(fd, &sb)); 42 key.dptr = (char *)&sb.st_rdev; 43 key.dsize = sizeof(sb.st_rdev); 44 dp = dbm_fetch(db, key); 45 if (!dp.dptr) 46 return(__oldttyname(fd, &sb)); 47 bcopy(dp.dptr, buf + sizeof(_PATH_DEV) - 1, dp.dsize); 48 return(buf); 49 } 50 51 static char * 52 __oldttyname(fd, sb) 53 int fd; 54 struct stat *sb; 55 { 56 register struct dirent *dirp; 57 register DIR *dp; 58 struct stat dsb; 59 char *rval, *strcpy(); 60 61 if ((dp = opendir(_PATH_DEV)) == NULL) 62 return(NULL); 63 64 for (rval = NULL; dirp = readdir(dp);) { 65 if (dirp->d_fileno != sb->st_ino) 66 continue; 67 bcopy(dirp->d_name, buf + sizeof(_PATH_DEV) - 1, 68 dirp->d_namlen + 1); 69 if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev || 70 sb->st_ino != dsb.st_ino) 71 continue; 72 (void)closedir(dp); 73 rval = buf; 74 break; 75 } 76 (void)closedir(dp); 77 return(rval); 78 } 79