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Annotation of 43BSDReno/lib/libc/gen/getwd.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that: (1) source distributions retain this entire copyright
                      7:  * notice and comment, and (2) distributions including binaries display
                      8:  * the following acknowledgement:  ``This product includes software
                      9:  * developed by the University of California, Berkeley and its contributors''
                     10:  * in the documentation or other materials provided with the distribution
                     11:  * and in all advertising materials mentioning features or use of this
                     12:  * software. Neither the name of the University nor the names of its
                     13:  * contributors may be used to endorse or promote products derived
                     14:  * from this software without specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)getwd.c    5.8 (Berkeley) 6/1/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: #include <sys/param.h>
                     25: #include <sys/stat.h>
                     26: #include <dirent.h>
                     27: #include <string.h>
                     28: 
                     29: #define        ISDOT(dp) \
                     30:        (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
                     31:            dp->d_name[1] == '.' && dp->d_name[2] == '\0'))
                     32: 
                     33: char *
                     34: getwd(store)
                     35:        char *store;
                     36: {
                     37:        extern int errno;
                     38:        register struct dirent *dp;
                     39:        register DIR *dir;
                     40:        register ino_t ino;
                     41:        register char *pp, *pu;
                     42:        register int first;
                     43:        struct stat s;
                     44:        dev_t root_dev, dev;
                     45:        ino_t root_ino;
                     46:        int save_errno, found;
                     47:        char path[MAXPATHLEN], up[MAXPATHLEN], *file;
                     48: 
                     49:        /* save root values */
                     50:        if (stat("/", &s)) {
                     51:                file = "/";
                     52:                goto err;
                     53:        }
                     54:        root_dev = s.st_dev;
                     55:        root_ino = s.st_ino;
                     56: 
                     57:        /* init path pointer; built from the end of the buffer */
                     58:        pp = path + sizeof(path) - 1;
                     59:        *pp = '\0';
                     60: 
                     61:        /* special case first stat, it's ".", not ".." */
                     62:        up[0] = '.';
                     63:        up[1] = '\0';
                     64: 
                     65:        for (pu = up, first = 1;; first = 0) {
                     66:                /* stat current level */
                     67:                if (lstat(up, &s)) {
                     68:                        file = up;
                     69:                        goto err;
                     70:                }
                     71: 
                     72:                /* save current node values */
                     73:                ino = s.st_ino;
                     74:                dev = s.st_dev;
                     75: 
                     76:                /* check for root */
                     77:                if (root_dev == dev && root_ino == ino) {
                     78:                        *store = '/';
                     79:                        (void) strcpy(store + 1, pp);
                     80:                        return (store);
                     81:                }
                     82: 
                     83:                *pu++ = '.';
                     84:                *pu++ = '.';
                     85:                *pu = '\0';
                     86: 
                     87:                /* open and stat parent */
                     88:                if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) {
                     89:                        file = up;
                     90:                        goto err;
                     91:                }
                     92:                found = save_errno = 0;
                     93: 
                     94:                *pu++ = '/';
                     95: 
                     96:                /*
                     97:                 * if it's a mount point you have to stat each element because
                     98:                 * the inode number in the directory is for the entry in the
                     99:                 * parent directory, not the inode number of the mounted file.
                    100:                 */
                    101:                if (s.st_dev == dev) {
                    102:                        while (dp = readdir(dir))
                    103:                                if (dp->d_fileno == ino)
                    104:                                        goto hit;
                    105:                } else {
                    106:                        while (dp = readdir(dir)) {
                    107:                                if (ISDOT(dp))
                    108:                                        continue;
                    109:                                bcopy(dp->d_name, pu, dp->d_namlen + 1);
                    110:                                if (lstat(up, &s)) {
                    111:                                        file = dp->d_name;
                    112:                                        save_errno = errno;
                    113:                                        errno = 0;
                    114:                                        continue;
                    115:                                }
                    116:                                if (s.st_dev == dev && s.st_ino == ino) {
                    117: hit:                                   if (!first)
                    118:                                                *--pp = '/';
                    119:                                        pp -= dp->d_namlen;
                    120:                                        bcopy(dp->d_name, pp, dp->d_namlen);
                    121:                                        found = 1;
                    122:                                        break;
                    123:                                }
                    124:                        }
                    125:                        if (errno) {
                    126:                                file = up;
                    127:                                save_errno = errno;
                    128:                        }
                    129:                }
                    130:                (void) closedir(dir);
                    131: 
                    132:                *pu = '\0';
                    133: 
                    134:                if (!found) {
                    135:                        /*
                    136:                         * We didn't find the current level in its parent
                    137:                         * directory; figure out what to complain about.
                    138:                         */
                    139:                        if (save_errno) {
                    140:                                errno = save_errno;
                    141:                                goto err;
                    142:                        }
                    143:                        (void) sprintf(store, "%s not found in %s?\n",
                    144:                                first ? "." : pp, up);
                    145:                        return ((char *)NULL);
                    146:                }
                    147:        }
                    148: err:
                    149:        (void) sprintf(store, "getwd: %s: %s", file, strerror(errno));
                    150:        return ((char *)NULL);
                    151: }

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