projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| b11ade1b BJ |
1 | /* @(#)ttyname.c 4.1 (Berkeley) %G% */ |
| 2 | /* | |
| 3 | * ttyname(f): return "/dev/ttyXX" which the the name of the | |
| 4 | * tty belonging to file f. | |
| 5 | * NULL if it is not a tty | |
| 6 | */ | |
| 7 | ||
| 8 | #define NULL 0 | |
| 9 | #include <sys/types.h> | |
| 10 | #include <sys/dir.h> | |
| 11 | #include <sys/stat.h> | |
| 12 | ||
| 13 | static char dev[] = "/dev/"; | |
| 14 | char *strcpy(); | |
| 15 | char *strcat(); | |
| 16 | ||
| 17 | char * | |
| 18 | ttyname(f) | |
| 19 | { | |
| 20 | struct stat fsb; | |
| 21 | struct stat tsb; | |
| 22 | struct direct db; | |
| 23 | static char rbuf[32]; | |
| 24 | register df; | |
| 25 | ||
| 26 | if (isatty(f)==0) | |
| 27 | return(NULL); | |
| 28 | if (fstat(f, &fsb) < 0) | |
| 29 | return(NULL); | |
| 30 | if ((fsb.st_mode&S_IFMT) != S_IFCHR) | |
| 31 | return(NULL); | |
| 32 | if ((df = open(dev, 0)) < 0) | |
| 33 | return(NULL); | |
| 34 | while (read(df, (char *)&db, sizeof(db)) == sizeof(db)) { | |
| 35 | if (db.d_ino == 0) | |
| 36 | continue; | |
| 37 | if (db.d_ino != fsb.st_ino) | |
| 38 | continue; | |
| 39 | strcpy(rbuf, dev); | |
| 40 | strcat(rbuf, db.d_name); | |
| 41 | if (stat(rbuf, &tsb) < 0) | |
| 42 | continue; | |
| 43 | if (tsb.st_dev==fsb.st_dev && tsb.st_ino==fsb.st_ino) { | |
| 44 | close(df); | |
| 45 | return(rbuf); | |
| 46 | } | |
| 47 | } | |
| 48 | close(df); | |
| 49 | return(NULL); | |
| 50 | } |