| 1 | /* |
| 2 | * Copyright (c) 1980 Regents of the University of California. |
| 3 | * All rights reserved. The Berkeley software License Agreement |
| 4 | * specifies the terms and conditions for redistribution. |
| 5 | */ |
| 6 | |
| 7 | #if defined(LIBC_SCCS) && !defined(lint) |
| 8 | static char sccsid[] = "@(#)getcwd.c 5.3 (Berkeley) %G%"; |
| 9 | #endif LIBC_SCCS and not lint |
| 10 | |
| 11 | /* |
| 12 | * getwd() returns the pathname of the current working directory. On error |
| 13 | * an error message is copied to pathname and null pointer is returned. |
| 14 | */ |
| 15 | #include <sys/param.h> |
| 16 | #include <sys/stat.h> |
| 17 | #include <sys/dir.h> |
| 18 | |
| 19 | #define GETWDERR(s) strcpy(pathname, (s)); |
| 20 | |
| 21 | char *strcpy(); |
| 22 | static int pathsize; /* pathname length */ |
| 23 | |
| 24 | char * |
| 25 | getwd(pathname) |
| 26 | char *pathname; |
| 27 | { |
| 28 | char pathbuf[MAXPATHLEN]; /* temporary pathname buffer */ |
| 29 | char *pnptr = &pathbuf[(sizeof pathbuf)-1]; /* pathname pointer */ |
| 30 | char curdir[MAXPATHLEN]; /* current directory buffer */ |
| 31 | char *dptr = curdir; /* directory pointer */ |
| 32 | char *prepend(); /* prepend dirname to pathname */ |
| 33 | dev_t cdev, rdev; /* current & root device number */ |
| 34 | ino_t cino, rino; /* current & root inode number */ |
| 35 | DIR *dirp; /* directory stream */ |
| 36 | struct direct *dir; /* directory entry struct */ |
| 37 | struct stat d, dd; /* file status struct */ |
| 38 | |
| 39 | pathsize = 0; |
| 40 | *pnptr = '\0'; |
| 41 | if (stat("/", &d) < 0) { |
| 42 | GETWDERR("getwd: can't stat /"); |
| 43 | return (NULL); |
| 44 | } |
| 45 | rdev = d.st_dev; |
| 46 | rino = d.st_ino; |
| 47 | strcpy(dptr, "./"); |
| 48 | dptr += 2; |
| 49 | if (stat(curdir, &d) < 0) { |
| 50 | GETWDERR("getwd: can't stat ."); |
| 51 | return (NULL); |
| 52 | } |
| 53 | for (;;) { |
| 54 | if (d.st_ino == rino && d.st_dev == rdev) |
| 55 | break; /* reached root directory */ |
| 56 | cino = d.st_ino; |
| 57 | cdev = d.st_dev; |
| 58 | strcpy(dptr, "../"); |
| 59 | dptr += 3; |
| 60 | if ((dirp = opendir(curdir)) == NULL) { |
| 61 | GETWDERR("getwd: can't open .."); |
| 62 | return (NULL); |
| 63 | } |
| 64 | fstat(dirp->dd_fd, &d); |
| 65 | if (cdev == d.st_dev) { |
| 66 | if (cino == d.st_ino) { |
| 67 | /* reached root directory */ |
| 68 | closedir(dirp); |
| 69 | break; |
| 70 | } |
| 71 | do { |
| 72 | if ((dir = readdir(dirp)) == NULL) { |
| 73 | closedir(dirp); |
| 74 | GETWDERR("getwd: read error in .."); |
| 75 | return (NULL); |
| 76 | } |
| 77 | } while (dir->d_ino != cino); |
| 78 | } else |
| 79 | do { |
| 80 | if ((dir = readdir(dirp)) == NULL) { |
| 81 | closedir(dirp); |
| 82 | GETWDERR("getwd: read error in .."); |
| 83 | return (NULL); |
| 84 | } |
| 85 | strcpy(dptr, dir->d_name); |
| 86 | lstat(curdir, &dd); |
| 87 | } while(dd.st_ino != cino || dd.st_dev != cdev); |
| 88 | pnptr = prepend("/", prepend(dir->d_name, pnptr)); |
| 89 | closedir(dirp); |
| 90 | } |
| 91 | if (*pnptr == '\0') /* current dir == root dir */ |
| 92 | strcpy(pathname, "/"); |
| 93 | else |
| 94 | strcpy(pathname, pnptr); |
| 95 | return (pathname); |
| 96 | } |
| 97 | |
| 98 | /* |
| 99 | * prepend() tacks a directory name onto the front of a pathname. |
| 100 | */ |
| 101 | static char * |
| 102 | prepend(dirname, pathname) |
| 103 | register char *dirname; |
| 104 | register char *pathname; |
| 105 | { |
| 106 | register int i; /* directory name size counter */ |
| 107 | |
| 108 | for (i = 0; *dirname != '\0'; i++, dirname++) |
| 109 | continue; |
| 110 | if ((pathsize += i) < MAXPATHLEN) |
| 111 | while (i-- > 0) |
| 112 | *--pathname = *--dirname; |
| 113 | return (pathname); |
| 114 | } |