53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
/* ttyname.c POSIX 4.7.2
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* char *ttyname(int fildes);
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*
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* Determines name of a terminal device.
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*/
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#include <lib.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <stddef.h>
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#include <string.h>
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#include <unistd.h>
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PRIVATE char base[] = "/dev";
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PRIVATE char path[sizeof(base) + 1 + NAME_MAX]; /* extra 1 for '/' */
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PUBLIC char *ttyname(fildes)
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int fildes;
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{
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DIR *devices;
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struct dirent *entry;
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struct stat tty_stat;
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struct stat dev_stat;
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/* Simple first test: file descriptor must be a character device */
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if (fstat(fildes, &tty_stat) < 0 || !S_ISCHR(tty_stat.st_mode))
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return (char *) NULL;
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/* Open device directory for reading */
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if ((devices = opendir(base)) == (DIR *) NULL)
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return (char *) NULL;
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/* Scan the entries for one that matches perfectly */
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while ((entry = readdir(devices)) != (struct dirent *) NULL) {
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if (tty_stat.st_ino != entry->d_ino)
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continue;
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strcpy(path, base);
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strcat(path, "/");
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strcat(path, entry->d_name);
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if (stat(path, &dev_stat) < 0 || !S_ISCHR(dev_stat.st_mode))
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continue;
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if (tty_stat.st_ino == dev_stat.st_ino &&
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tty_stat.st_dev == dev_stat.st_dev &&
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tty_stat.st_rdev == dev_stat.st_rdev) {
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closedir(devices);
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return path;
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}
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}
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closedir(devices);
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return (char *) NULL;
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}
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