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Annotation of src/lib/libc/gen/getcwd.c, Revision 1.35

1.35    ! enami       1: /*     $NetBSD: getcwd.c,v 1.34 2005/01/06 23:43:32 simonb 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
1.35    ! enami      40: __RCSID("$NetBSD: getcwd.c,v 1.34 2005/01/06 23:43:32 simonb 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:
1.8       perry      64: /*
                     65:  * char *realpath(const char *path, char resolved_path[MAXPATHLEN]);
                     66:  *
                     67:  * Find the real name of path, by removing all ".", ".." and symlink
                     68:  * components.  Returns (resolved) on success, or (NULL) on failure,
                     69:  * in which case the path which caused trouble is left in (resolved).
                     70:  */
                     71: char *
                     72: realpath(path, resolved)
                     73:        const char *path;
                     74:        char *resolved;
                     75: {
                     76:        struct stat sb;
1.21      fvdl       77:        int fd, n, rootd, serrno, nlnk = 0;
1.8       perry      78:        char *p, *q, wbuf[MAXPATHLEN];
1.22      lukem      79:
                     80:        _DIAGASSERT(path != NULL);
                     81:        _DIAGASSERT(resolved != NULL);
1.8       perry      82:
                     83:        /* Save the starting point. */
                     84:        if ((fd = open(".", O_RDONLY)) < 0) {
1.28      itojun     85:                (void)strlcpy(resolved, ".", MAXPATHLEN);
1.8       perry      86:                return (NULL);
                     87:        }
                     88:
                     89:        /*
                     90:         * Find the dirname and basename from the path to be resolved.
                     91:         * Change directory to the dirname component.
                     92:         * lstat the basename part.
                     93:         *     if it is a symlink, read in the value and loop.
                     94:         *     if it is a directory, then change to that directory.
                     95:         * get the current directory name and append the basename.
                     96:         */
1.31      itojun     97:        if (strlcpy(resolved, path, MAXPATHLEN) >= MAXPATHLEN) {
                     98:                errno = ENAMETOOLONG;
                     99:                goto err1;
                    100:        }
1.8       perry     101: loop:
                    102:        q = strrchr(resolved, '/');
                    103:        if (q != NULL) {
                    104:                p = q + 1;
                    105:                if (q == resolved)
                    106:                        q = "/";
                    107:                else {
                    108:                        do {
                    109:                                --q;
                    110:                        } while (q > resolved && *q == '/');
                    111:                        q[1] = '\0';
                    112:                        q = resolved;
                    113:                }
                    114:                if (chdir(q) < 0)
                    115:                        goto err1;
                    116:        } else
                    117:                p = resolved;
                    118:
                    119:        /* Deal with the last component. */
                    120:        if (lstat(p, &sb) == 0) {
                    121:                if (S_ISLNK(sb.st_mode)) {
1.21      fvdl      122:                        if (nlnk++ >= MAXSYMLINKS) {
                    123:                                errno = ELOOP;
                    124:                                goto err1;
                    125:                        }
1.26      provos    126:                        n = readlink(p, resolved, MAXPATHLEN-1);
1.8       perry     127:                        if (n < 0)
                    128:                                goto err1;
                    129:                        resolved[n] = '\0';
                    130:                        goto loop;
                    131:                }
                    132:                if (S_ISDIR(sb.st_mode)) {
                    133:                        if (chdir(p) < 0)
                    134:                                goto err1;
                    135:                        p = "";
                    136:                }
                    137:        }
                    138:
                    139:        /*
                    140:         * Save the last component name and get the full pathname of
                    141:         * the current directory.
                    142:         */
1.31      itojun    143:        if (strlcpy(wbuf, p, sizeof(wbuf)) >= sizeof(wbuf)) {
                    144:                errno = ENAMETOOLONG;
                    145:                goto err1;
                    146:        }
1.8       perry     147:
                    148:        /*
                    149:         * Call the inernal internal version of getcwd which
                    150:         * does a physical search rather than using the $PWD short-cut
                    151:         */
1.12      lukem     152:        if (getcwd(resolved, MAXPATHLEN) == 0)
1.8       perry     153:                goto err1;
                    154:
                    155:        /*
                    156:         * Join the two strings together, ensuring that the right thing
                    157:         * happens if the last component is empty, or the dirname is root.
                    158:         */
                    159:        if (resolved[0] == '/' && resolved[1] == '\0')
                    160:                rootd = 1;
                    161:        else
                    162:                rootd = 0;
                    163:
                    164:        if (*wbuf) {
1.29      itojun    165:                if (strlen(resolved) + strlen(wbuf) + (rootd ? 0 : 1) + 1 >
                    166:                    MAXPATHLEN) {
1.8       perry     167:                        errno = ENAMETOOLONG;
                    168:                        goto err1;
                    169:                }
                    170:                if (rootd == 0)
1.31      itojun    171:                        if (strlcat(resolved, "/", MAXPATHLEN) >= MAXPATHLEN) {
                    172:                                errno = ENAMETOOLONG;
                    173:                                goto err1;
                    174:                        }
                    175:                if (strlcat(resolved, wbuf, MAXPATHLEN) >= MAXPATHLEN) {
                    176:                        errno = ENAMETOOLONG;
                    177:                        goto err1;
                    178:                }
1.8       perry     179:        }
                    180:
                    181:        /* Go back to where we came from. */
                    182:        if (fchdir(fd) < 0) {
                    183:                serrno = errno;
                    184:                goto err2;
                    185:        }
                    186:
                    187:        /* It's okay if the close fails, what's an fd more or less? */
                    188:        (void)close(fd);
                    189:        return (resolved);
                    190:
                    191: err1:  serrno = errno;
                    192:        (void)fchdir(fd);
                    193: err2:  (void)close(fd);
                    194:        errno = serrno;
                    195:        return (NULL);
                    196: }
                    197:
1.16      sommerfe  198: char *
1.35    ! enami     199: getcwd(char *pt, size_t size)
1.16      sommerfe  200: {
1.35    ! enami     201:        char *npt;
        !           202:
1.16      sommerfe  203:        /*
1.35    ! enami     204:         * If a buffer is specified, the size has to be non-zero.
1.16      sommerfe  205:         */
1.35    ! enami     206:        if (pt != NULL) {
        !           207:                if (size == 0) {
        !           208:                        /* __getcwd(pt, 0) results ERANGE. */
1.16      sommerfe  209:                        errno = EINVAL;
                    210:                        return (NULL);
                    211:                }
1.35    ! enami     212:                if (__getcwd(pt, size) >= 0)
        !           213:                        return (pt);
        !           214:                return (NULL);
1.16      sommerfe  215:        }
1.35    ! enami     216:
        !           217:        /*
        !           218:         * If no buffer specified by the user, allocate one as necessary.
        !           219:         */
        !           220:        size = 1024 >> 1;
        !           221:        do {
        !           222:                if ((npt = realloc(pt, size <<= 1)) == NULL)
        !           223:                        break;
        !           224:                pt = npt;
        !           225:                if (__getcwd(pt, size) >= 0)
        !           226:                        return (pt);
        !           227:        } while (size <= MAXPATHLEN * 4 && errno == ERANGE);
        !           228:
        !           229:        free(pt);
        !           230:        return (NULL);
1.16      sommerfe  231: }

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