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Annotation of src/lib/libc/gen/getcwd.c, Revision 1.34

1.34    ! simonb      1: /*     $NetBSD: getcwd.c,v 1.33 2005/01/06 00:07:41 christos Exp $     */
1.4       cgd         2:
1.1       cgd         3: /*
1.8       perry       4:  * Copyright (c) 1989, 1991, 1993, 1995
1.4       cgd         5:  *     The Regents of the University of California.  All rights reserved.
1.1       cgd         6:  *
1.8       perry       7:  * This code is derived from software contributed to Berkeley by
                      8:  * Jan-Simon Pendry.
                      9:  *
1.1       cgd        10:  * Redistribution and use in source and binary forms, with or without
                     11:  * modification, are permitted provided that the following conditions
                     12:  * are met:
                     13:  * 1. Redistributions of source code must retain the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer.
                     15:  * 2. Redistributions in binary form must reproduce the above copyright
                     16:  *    notice, this list of conditions and the following disclaimer in the
                     17:  *    documentation and/or other materials provided with the distribution.
1.32      agc        18:  * 3. Neither the name of the University nor the names of its contributors
1.1       cgd        19:  *    may be used to endorse or promote products derived from this software
                     20:  *    without specific prior written permission.
                     21:  *
                     22:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     23:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     24:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     25:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     26:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     27:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     28:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     29:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     30:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     31:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     32:  * SUCH DAMAGE.
                     33:  */
                     34:
1.6       christos   35: #include <sys/cdefs.h>
1.1       cgd        36: #if defined(LIBC_SCCS) && !defined(lint)
1.4       cgd        37: #if 0
1.8       perry      38: static char sccsid[] = "@(#)getcwd.c   8.5 (Berkeley) 2/7/95";
1.4       cgd        39: #else
1.34    ! simonb     40: __RCSID("$NetBSD: getcwd.c,v 1.33 2005/01/06 00:07:41 christos Exp $");
1.4       cgd        41: #endif
1.1       cgd        42: #endif /* LIBC_SCCS and not lint */
                     43:
1.7       jtc        44: #include "namespace.h"
1.1       cgd        45: #include <sys/param.h>
                     46: #include <sys/stat.h>
1.8       perry      47:
1.22      lukem      48: #include <assert.h>
1.8       perry      49: #include <dirent.h>
1.1       cgd        50: #include <errno.h>
1.8       perry      51: #include <fcntl.h>
1.1       cgd        52: #include <stdio.h>
                     53: #include <stdlib.h>
                     54: #include <string.h>
                     55: #include <unistd.h>
1.17      sommerfe   56:
                     57: #include "extern.h"
1.7       jtc        58:
                     59: #ifdef __weak_alias
1.24      mycroft    60: __weak_alias(getcwd,_getcwd)
                     61: __weak_alias(realpath,_realpath)
1.7       jtc        62: #endif
1.1       cgd        63:
                     64: #define        ISDOT(dp) \
                     65:        (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
1.6       christos   66:            (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
1.1       cgd        67:
1.8       perry      68:
1.15      christos   69: #if defined(__SVR4) || defined(__svr4__)
                     70: #define d_fileno d_ino
                     71: #endif
                     72:
1.8       perry      73: /*
                     74:  * char *realpath(const char *path, char resolved_path[MAXPATHLEN]);
                     75:  *
                     76:  * Find the real name of path, by removing all ".", ".." and symlink
                     77:  * components.  Returns (resolved) on success, or (NULL) on failure,
                     78:  * in which case the path which caused trouble is left in (resolved).
                     79:  */
                     80: char *
                     81: realpath(path, resolved)
                     82:        const char *path;
                     83:        char *resolved;
                     84: {
                     85:        struct stat sb;
1.21      fvdl       86:        int fd, n, rootd, serrno, nlnk = 0;
1.8       perry      87:        char *p, *q, wbuf[MAXPATHLEN];
1.22      lukem      88:
                     89:        _DIAGASSERT(path != NULL);
                     90:        _DIAGASSERT(resolved != NULL);
1.8       perry      91:
                     92:        /* Save the starting point. */
                     93:        if ((fd = open(".", O_RDONLY)) < 0) {
1.28      itojun     94:                (void)strlcpy(resolved, ".", MAXPATHLEN);
1.8       perry      95:                return (NULL);
                     96:        }
                     97:
                     98:        /*
                     99:         * Find the dirname and basename from the path to be resolved.
                    100:         * Change directory to the dirname component.
                    101:         * lstat the basename part.
                    102:         *     if it is a symlink, read in the value and loop.
                    103:         *     if it is a directory, then change to that directory.
                    104:         * get the current directory name and append the basename.
                    105:         */
1.31      itojun    106:        if (strlcpy(resolved, path, MAXPATHLEN) >= MAXPATHLEN) {
                    107:                errno = ENAMETOOLONG;
                    108:                goto err1;
                    109:        }
1.8       perry     110: loop:
                    111:        q = strrchr(resolved, '/');
                    112:        if (q != NULL) {
                    113:                p = q + 1;
                    114:                if (q == resolved)
                    115:                        q = "/";
                    116:                else {
                    117:                        do {
                    118:                                --q;
                    119:                        } while (q > resolved && *q == '/');
                    120:                        q[1] = '\0';
                    121:                        q = resolved;
                    122:                }
                    123:                if (chdir(q) < 0)
                    124:                        goto err1;
                    125:        } else
                    126:                p = resolved;
                    127:
                    128:        /* Deal with the last component. */
                    129:        if (lstat(p, &sb) == 0) {
                    130:                if (S_ISLNK(sb.st_mode)) {
1.21      fvdl      131:                        if (nlnk++ >= MAXSYMLINKS) {
                    132:                                errno = ELOOP;
                    133:                                goto err1;
                    134:                        }
1.26      provos    135:                        n = readlink(p, resolved, MAXPATHLEN-1);
1.8       perry     136:                        if (n < 0)
                    137:                                goto err1;
                    138:                        resolved[n] = '\0';
                    139:                        goto loop;
                    140:                }
                    141:                if (S_ISDIR(sb.st_mode)) {
                    142:                        if (chdir(p) < 0)
                    143:                                goto err1;
                    144:                        p = "";
                    145:                }
                    146:        }
                    147:
                    148:        /*
                    149:         * Save the last component name and get the full pathname of
                    150:         * the current directory.
                    151:         */
1.31      itojun    152:        if (strlcpy(wbuf, p, sizeof(wbuf)) >= sizeof(wbuf)) {
                    153:                errno = ENAMETOOLONG;
                    154:                goto err1;
                    155:        }
1.8       perry     156:
                    157:        /*
                    158:         * Call the inernal internal version of getcwd which
                    159:         * does a physical search rather than using the $PWD short-cut
                    160:         */
1.12      lukem     161:        if (getcwd(resolved, MAXPATHLEN) == 0)
1.8       perry     162:                goto err1;
                    163:
                    164:        /*
                    165:         * Join the two strings together, ensuring that the right thing
                    166:         * happens if the last component is empty, or the dirname is root.
                    167:         */
                    168:        if (resolved[0] == '/' && resolved[1] == '\0')
                    169:                rootd = 1;
                    170:        else
                    171:                rootd = 0;
                    172:
                    173:        if (*wbuf) {
1.29      itojun    174:                if (strlen(resolved) + strlen(wbuf) + (rootd ? 0 : 1) + 1 >
                    175:                    MAXPATHLEN) {
1.8       perry     176:                        errno = ENAMETOOLONG;
                    177:                        goto err1;
                    178:                }
                    179:                if (rootd == 0)
1.31      itojun    180:                        if (strlcat(resolved, "/", MAXPATHLEN) >= MAXPATHLEN) {
                    181:                                errno = ENAMETOOLONG;
                    182:                                goto err1;
                    183:                        }
                    184:                if (strlcat(resolved, wbuf, MAXPATHLEN) >= MAXPATHLEN) {
                    185:                        errno = ENAMETOOLONG;
                    186:                        goto err1;
                    187:                }
1.8       perry     188:        }
                    189:
                    190:        /* Go back to where we came from. */
                    191:        if (fchdir(fd) < 0) {
                    192:                serrno = errno;
                    193:                goto err2;
                    194:        }
                    195:
                    196:        /* It's okay if the close fails, what's an fd more or less? */
                    197:        (void)close(fd);
                    198:        return (resolved);
                    199:
                    200: err1:  serrno = errno;
                    201:        (void)fchdir(fd);
                    202: err2:  (void)close(fd);
                    203:        errno = serrno;
                    204:        return (NULL);
                    205: }
                    206:
1.16      sommerfe  207: char *
                    208: getcwd(pt, size)
                    209:        char *pt;
                    210:        size_t size;
                    211: {
1.18      christos  212:        size_t ptsize, bufsize;
                    213:        int len;
1.16      sommerfe  214:
                    215:        /*
                    216:         * If no buffer specified by the user, allocate one as necessary.
                    217:         * If a buffer is specified, the size has to be non-zero.  The path
                    218:         * is built from the end of the buffer backwards.
                    219:         */
                    220:        if (pt) {
                    221:                ptsize = 0;
                    222:                if (!size) {
                    223:                        errno = EINVAL;
                    224:                        return (NULL);
                    225:                }
                    226:                bufsize = size;
                    227:        } else {
                    228:                if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
                    229:                        return (NULL);
                    230:                bufsize = ptsize;
                    231:        }
1.18      christos  232:        for (;;) {
1.16      sommerfe  233:                len = __getcwd(pt, bufsize);
                    234:                if ((len < 0) && (size == 0) && (errno == ERANGE)) {
1.20      sommerfe  235:                        if (ptsize > (MAXPATHLEN*4))
                    236:                                return NULL;
1.16      sommerfe  237:                        if ((pt = realloc(pt, ptsize *= 2)) == NULL)
                    238:                                return NULL;
                    239:                        bufsize = ptsize;
                    240:                        continue;
                    241:                }
1.18      christos  242:                break;
                    243:        }
1.16      sommerfe  244:        if (len < 0)
                    245:                return NULL;
                    246:        else
                    247:                return pt;
                    248: }

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