From patchwork Wed Aug 26 21:02:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 40328 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id DC354386F813; Wed, 26 Aug 2020 21:03:01 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DC354386F813 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1598475781; bh=pc+8IhkARfSJiUyfBQcIjhzqV65Bo9WXlTWW1+MhxZg=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=hiqnCrezkkd7l2PNVidlSyP94HLHa7wL2iVOISExlMOm8nQoc7LdwpvHEUlJ3ix8G NPzRSXvxoRIFY6wW4ukuxf2juZtRbua32zrFoLwlGX4izfdNaHhIrktJ9ZVmAx28A7 xF1299a8DDaVuTM57t96/rTTq5MjcmEFNMdBI1u8= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-qk1-x743.google.com (mail-qk1-x743.google.com [IPv6:2607:f8b0:4864:20::743]) by sourceware.org (Postfix) with ESMTPS id 99617384605A for ; Wed, 26 Aug 2020 21:02:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 99617384605A Received: by mail-qk1-x743.google.com with SMTP id g26so3739256qka.3 for ; Wed, 26 Aug 2020 14:02:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=pc+8IhkARfSJiUyfBQcIjhzqV65Bo9WXlTWW1+MhxZg=; b=pMYWGXIsn9bluUn8fLOFlXvtUnVq4UPzwb0pcfowPy3iiUGgjRmDGWHnCwsDURVjts xGZ0zMBKEfJATzQoxmMOb3GspXG/j3ULQOKJrhEJfb+d0sB3SM38DxtCGpGzNfWr3W6J 5K8ht6b5iLKZopr/E0yFBE8a1MCZw8Z6AbEhleOf6P+kctowTtRlCNZY18BIW07GKSeJ 5LWhUKhJzfF8gUYmv70jpcuavBOlv5yZGd4bcaL0/SKeEhzwdQqbOPxezIoZTUufnmn1 R1i9qXCqteoJL5LvBUG/BVh5RtEsOQP+eYVeqwJgYMT0fSpzVXcWrsimn/Gq7yj4gt0k T3NA== X-Gm-Message-State: AOAM530M76k/0i8rzf1h7tuwigW2RF5jeG2FnE2Cx2VXMNFqxNHajewT RHBRcG/oQXeeby8AOcZruv/qfxShK/ms9JPX X-Google-Smtp-Source: ABdhPJyyz0W+e8r//OPvlij/fHQXe/cVfKpSfIvABRcVEm1pNq6vj9Uzpuj/DO97s/G2+xI0Krs8OA== X-Received: by 2002:a37:bdc4:: with SMTP id n187mr16198130qkf.192.1598475771197; Wed, 26 Aug 2020 14:02:51 -0700 (PDT) Received: from localhost.localdomain ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id k5sm153837qtu.2.2020.08.26.14.02.50 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Aug 2020 14:02:50 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH 1/4] Sync getcwd with gnulib Date: Wed, 26 Aug 2020 18:02:43 -0300 Message-Id: <20200826210246.2830973-1-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-13.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Reply-To: Adhemerval Zanella Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" It sync with gnulib version d4c637e57. The main changes are: - It defines HAVE_OPENAT to 1, D_INO_IN_DIRENT to 1, HAVE_MSVC_INVALID_PARAMETER_HANDLER to 0, and HAVE_MINIMALLY_WORKING_GETCWD to 0 for _LIBC. - It does not include pathmax.h header (glibc does not provide it). - It defines and used __close_nocancel_nostatus, stat64, __fstat64, __fstatat64, __lstat64, __fdopendir, __openat, __rewinddir, __openat64 for !LIBC to enable internal LFS calls. This requires glibc changes should integrate seamlessly on gnulib. Checked on x86_64-linux-gnu and i686-linux-gnu. --- sysdeps/posix/getcwd.c | 782 +++++++++++++++++++---------------------- 1 file changed, 369 insertions(+), 413 deletions(-) diff --git a/sysdeps/posix/getcwd.c b/sysdeps/posix/getcwd.c index f00b337a13..3876e1a641 100644 --- a/sysdeps/posix/getcwd.c +++ b/sysdeps/posix/getcwd.c @@ -15,518 +15,474 @@ License along with the GNU C Library; if not, see . */ -/* Wants: - AC_STDC_HEADERS - AC_DIR_HEADER - AC_UNISTD_H - AC_MEMORY_H - AC_CONST - AC_ALLOCA - */ - -/* AIX requires this to be the first thing in the file. */ -#if defined _AIX && !defined __GNUC__ - #pragma alloca -#endif - -#ifdef HAVE_CONFIG_H -# include "config.h" +#if !_LIBC +# include +# include +#else +# define HAVE_OPENAT 1 +# define D_INO_IN_DIRENT 1 +# define HAVE_MSVC_INVALID_PARAMETER_HANDLER 0 +# define HAVE_MINIMALLY_WORKING_GETCWD 0 #endif #include -#include #include #include +#include +#include -#ifdef STDC_HEADERS -# include -#endif +#include /* For AT_FDCWD on Solaris 9. */ -#if !defined __GNU_LIBRARY__ && !defined STDC_HEADERS -extern int errno; +/* If this host provides the openat function or if we're using the + gnulib replacement function with a native fdopendir, then enable + code below to make getcwd more efficient and robust. */ +#if defined HAVE_OPENAT || (defined GNULIB_OPENAT && defined HAVE_FDOPENDIR) +# define HAVE_OPENAT_SUPPORT 1 +#else +# define HAVE_OPENAT_SUPPORT 0 #endif + #ifndef __set_errno -# define __set_errno(val) errno = (val) +# define __set_errno(val) (errno = (val)) #endif -#ifndef NULL -# define NULL 0 +#include +#ifndef _D_EXACT_NAMLEN +# define _D_EXACT_NAMLEN(d) strlen ((d)->d_name) #endif - -#if defined USGr3 && !defined DIRENT -# define DIRENT -#endif /* USGr3 */ -#if defined Xenix && !defined SYSNDIR -# define SYSNDIR -#endif /* Xenix */ - -#if defined POSIX || defined DIRENT || defined __GNU_LIBRARY__ -# include -# ifndef __GNU_LIBRARY__ -# define D_NAMLEN(d) strlen((d)->d_name) -# else -# define HAVE_D_NAMLEN -# define D_NAMLEN(d) ((d)->d_namlen) -# endif -#else /* not POSIX or DIRENT */ -# define dirent direct -# define D_NAMLEN(d) ((d)->d_namlen) -# define HAVE_D_NAMLEN -# if defined USG && !defined sgi -# if defined SYSNDIR -# include -# else /* Not SYSNDIR */ -# include "ndir.h" -# endif /* SYSNDIR */ -# else /* not USG */ -# include -# endif /* USG */ -#endif /* POSIX or DIRENT or __GNU_LIBRARY__ */ - -#if defined HAVE_UNISTD_H || defined __GNU_LIBRARY__ -# include +#ifndef _D_ALLOC_NAMLEN +# define _D_ALLOC_NAMLEN(d) (_D_EXACT_NAMLEN (d) + 1) #endif -#if defined STDC_HEADERS || defined __GNU_LIBRARY__ || defined POSIX -# include -# include -# define ANSI_STRING -#else /* No standard headers. */ - -# ifdef USG - -# include -# ifdef NEED_MEMORY_H -# include -# endif -# define ANSI_STRING - -# else /* Not USG. */ - -# ifdef NeXT - -# include - -# else /* Not NeXT. */ - -# include - -# ifndef bcmp -extern int bcmp (); -# endif -# ifndef bzero -extern void bzero (); -# endif -# ifndef bcopy -extern void bcopy (); -# endif - -# endif /* NeXT. */ - -# endif /* USG. */ - -extern char *malloc (), *realloc (); -extern void free (); - -#endif /* Standard headers. */ +#include +#include +#include -#ifndef ANSI_STRING -# define memcpy(d, s, n) bcopy((s), (d), (n)) -# define memmove memcpy -#endif /* Not ANSI_STRING. */ - -#ifndef MAX -# define MAX(a, b) ((a) < (b) ? (b) : (a)) -#endif - -#ifdef _LIBC +#if _LIBC # ifndef mempcpy # define mempcpy __mempcpy # endif -# define HAVE_MEMPCPY 1 #endif -#if !defined __alloca && !defined __GNU_LIBRARY__ - -# ifdef __GNUC__ -# undef alloca -# define alloca(n) __builtin_alloca (n) -# else /* Not GCC. */ -# if defined sparc || defined HAVE_ALLOCA_H -# include -# else /* Not sparc or HAVE_ALLOCA_H. */ -# ifndef _AIX -extern char *alloca (); -# endif /* Not _AIX. */ -# endif /* sparc or HAVE_ALLOCA_H. */ -# endif /* GCC. */ - -# define __alloca alloca - +#ifndef MAX +# define MAX(a, b) ((a) < (b) ? (b) : (a)) +#endif +#ifndef MIN +# define MIN(a, b) ((a) < (b) ? (a) : (b)) #endif -#if defined HAVE_LIMITS_H || defined STDC_HEADERS || defined __GNU_LIBRARY__ -# include -#else -# include +/* In this file, PATH_MAX only serves as a threshold for choosing among two + algorithms. */ +#ifndef PATH_MAX +# define PATH_MAX 8192 #endif -#if defined _LIBC -# include -# include +#if D_INO_IN_DIRENT +# define MATCHING_INO(dp, ino) ((dp)->d_ino == (ino)) #else -# define __openat64_nocancel(dfd, name, mode) openat64 (dfd, name, mode) -# define __close_nocancel_nostatus(fd) close (fd) +# define MATCHING_INO(dp, ino) true #endif -#ifndef PATH_MAX -# ifdef MAXPATHLEN -# define PATH_MAX MAXPATHLEN -# else -# define PATH_MAX 1024 -# endif +#if HAVE_MSVC_INVALID_PARAMETER_HANDLER +# include "msvc-inval.h" #endif -#if !defined STDC_HEADERS && !defined __GNU_LIBRARY__ -# undef size_t -# define size_t unsigned int +#if !_LIBC +# define __close_nocancel_nostatus close +# define __getcwd rpl_getcwd +# define stat64 stat +# define __fstat64 fstat +# define __fstatat64 fstatat +# define __lstat64 lstat +# define __closedir closedir +# define __opendir opendir +# define __readdir readdir +# define __fdopendir fdopendir +# define __openat openat +# define __rewinddir rewinddir +# define __openat64 openat +#else +# include #endif -#ifndef __GNU_LIBRARY__ -# define __lstat64 stat64 +/* The results of opendir() in this file are not used with dirfd and fchdir, + and we do not leak fds to any single-threaded code that could use stdio, + therefore save some unnecessary recursion in fchdir.c. + FIXME - if the kernel ever adds support for multi-thread safety for + avoiding standard fds, then we should use opendir_safer and + openat_safer. */ +#ifdef GNULIB_defined_opendir +# undef opendir #endif - -#ifndef _LIBC -# define __rewinddir rewinddir +#ifdef GNULIB_defined_closedir +# undef closedir #endif -#ifndef _LIBC -# define __getcwd getcwd -#endif +#if defined _WIN32 && !defined __CYGWIN__ +# if HAVE_MSVC_INVALID_PARAMETER_HANDLER +static char * +getcwd_nothrow (char *buf, size_t size) +{ + char *result; -#ifndef GETCWD_RETURN_TYPE -# define GETCWD_RETURN_TYPE char * -#endif + TRY_MSVC_INVAL + { + result = _getcwd (buf, size); + } + CATCH_MSVC_INVAL + { + result = NULL; + errno = ERANGE; + } + DONE_MSVC_INVAL; -#ifdef __ASSUME_ATFCTS -# define __have_atfcts 1 -#elif IS_IN (rtld) -static int __rtld_have_atfcts; -# define __have_atfcts __rtld_have_atfcts + return result; +} +# else +# define getcwd_nothrow _getcwd +# endif +# define getcwd_system getcwd_nothrow +#else +# define getcwd_system getcwd #endif -/* Get the pathname of the current working directory, and put it in SIZE - bytes of BUF. Returns NULL if the directory couldn't be determined or - SIZE was too small. If successful, returns BUF. In GNU, if BUF is - NULL, an array is allocated with `malloc'; the array is SIZE bytes long, - unless SIZE == 0, in which case it is as big as necessary. */ +/* Get the name of the current working directory, and put it in SIZE + bytes of BUF. Returns NULL with errno set if the directory couldn't be + determined or SIZE was too small. If successful, returns BUF. In GNU, + if BUF is NULL, an array is allocated with 'malloc'; the array is SIZE + bytes long, unless SIZE == 0, in which case it is as big as necessary. */ -GETCWD_RETURN_TYPE +char * __getcwd (char *buf, size_t size) { -#ifndef __ASSUME_ATFCTS - static const char dots[] - = "../../../../../../../../../../../../../../../../../../../../../../../\ -../../../../../../../../../../../../../../../../../../../../../../../../../../\ -../../../../../../../../../../../../../../../../../../../../../../../../../.."; - const char *dotp = &dots[sizeof (dots)]; - const char *dotlist = dots; - size_t dotsize = sizeof (dots) - 1; + /* Lengths of big file name components and entire file names, and a + deep level of file name nesting. These numbers are not upper + bounds; they are merely large values suitable for initial + allocations, designed to be large enough for most real-world + uses. */ + enum + { + BIG_FILE_NAME_COMPONENT_LENGTH = 255, + BIG_FILE_NAME_LENGTH = MIN (4095, PATH_MAX - 1), + DEEP_NESTING = 100 + }; + +#if HAVE_OPENAT_SUPPORT + int fd = AT_FDCWD; + bool fd_needs_closing = false; +#else + char dots[DEEP_NESTING * sizeof ".." + BIG_FILE_NAME_COMPONENT_LENGTH + 1]; + char *dotlist = dots; + size_t dotsize = sizeof dots; + size_t dotlen = 0; #endif - int prev_errno = errno; DIR *dirstream = NULL; - bool fd_needs_closing = false; - int fd = AT_FDCWD; - - char *path; -#ifndef NO_ALLOCATION + dev_t rootdev, thisdev; + ino_t rootino, thisino; + char *dir; + register char *dirp; + struct stat64 st; size_t allocated = size; + size_t used; + +#if HAVE_MINIMALLY_WORKING_GETCWD + /* If AT_FDCWD is not defined, the algorithm below is O(N**2) and + this is much slower than the system getcwd (at least on + GNU/Linux). So trust the system getcwd's results unless they + look suspicious. + + Use the system getcwd even if we have openat support, since the + system getcwd works even when a parent is unreadable, while the + openat-based approach does not. + + But on AIX 5.1..7.1, the system getcwd is not even minimally + working: If the current directory name is slightly longer than + PATH_MAX, it omits the first directory component and returns + this wrong result with errno = 0. */ + +# undef getcwd + dir = getcwd_system (buf, size); + if (dir || (size && errno == ERANGE)) + return dir; + + /* Solaris getcwd (NULL, 0) fails with errno == EINVAL, but it has + internal magic that lets it work even if an ancestor directory is + inaccessible, which is better in many cases. So in this case try + again with a buffer that's almost always big enough. */ + if (errno == EINVAL && buf == NULL && size == 0) + { + char big_buffer[BIG_FILE_NAME_LENGTH + 1]; + dir = getcwd_system (big_buffer, sizeof big_buffer); + if (dir) + return strdup (dir); + } + +# if HAVE_PARTLY_WORKING_GETCWD + /* The system getcwd works, except it sometimes fails when it + shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT. */ + if (errno != ERANGE && errno != ENAMETOOLONG && errno != ENOENT) + return NULL; +# endif +#endif if (size == 0) { if (buf != NULL) - { - __set_errno (EINVAL); - return NULL; - } + { + __set_errno (EINVAL); + return NULL; + } - allocated = PATH_MAX + 1; + allocated = BIG_FILE_NAME_LENGTH + 1; } if (buf == NULL) { - path = malloc (allocated); - if (path == NULL) - return NULL; + dir = malloc (allocated); + if (dir == NULL) + return NULL; } else -#else -# define allocated size -#endif - path = buf; + dir = buf; - char *pathp = path + allocated; - *--pathp = '\0'; + dirp = dir + allocated; + *--dirp = '\0'; - struct stat64 st; if (__lstat64 (".", &st) < 0) goto lose; - dev_t thisdev = st.st_dev; - ino_t thisino = st.st_ino; + thisdev = st.st_dev; + thisino = st.st_ino; if (__lstat64 ("/", &st) < 0) goto lose; - dev_t rootdev = st.st_dev; - ino_t rootino = st.st_ino; + rootdev = st.st_dev; + rootino = st.st_ino; while (!(thisdev == rootdev && thisino == rootino)) { - if (__have_atfcts >= 0) - fd = __openat64_nocancel (fd, "..", O_RDONLY | O_CLOEXEC); - else - fd = -1; - if (fd >= 0) - { - fd_needs_closing = true; - if (__fstat64 (fd, &st) < 0) - goto lose; - } -#ifndef __ASSUME_ATFCTS - else if (errno == ENOSYS) - { - __have_atfcts = -1; - - /* Look at the parent directory. */ - if (dotp == dotlist) - { -# ifdef NO_ALLOCATION - __set_errno (ENOMEM); - goto lose; -# else - /* My, what a deep directory tree you have, Grandma. */ - char *new; - if (dotlist == dots) - { - new = malloc (dotsize * 2 + 1); - if (new == NULL) - goto lose; -# ifdef HAVE_MEMPCPY - dotp = mempcpy (new, dots, dotsize); -# else - memcpy (new, dots, dotsize); - dotp = &new[dotsize]; -# endif - } - else - { - new = realloc ((void *) dotlist, dotsize * 2 + 1); - if (new == NULL) - goto lose; - dotp = &new[dotsize]; - } -# ifdef HAVE_MEMPCPY - *((char *) mempcpy ((char *) dotp, new, dotsize)) = '\0'; - dotsize *= 2; -# else - memcpy ((char *) dotp, new, dotsize); - dotsize *= 2; - new[dotsize] = '\0'; -# endif - dotlist = new; -# endif - } - - dotp -= 3; + struct dirent *d; + dev_t dotdev; + ino_t dotino; + bool mount_point; + int parent_status; + size_t dirroom; + size_t namlen; + bool use_d_ino = true; - /* Figure out if this directory is a mount point. */ - if (__lstat64 (dotp, &st) < 0) - goto lose; - } + /* Look at the parent directory. */ +#if HAVE_OPENAT_SUPPORT + fd = __openat64 (fd, "..", O_RDONLY); + if (fd < 0) + goto lose; + fd_needs_closing = true; + parent_status = __fstat64 (fd, &st); +#else + dotlist[dotlen++] = '.'; + dotlist[dotlen++] = '.'; + dotlist[dotlen] = '\0'; + parent_status = __lstat64 (dotlist, &st); #endif - else - goto lose; + if (parent_status != 0) + goto lose; if (dirstream && __closedir (dirstream) != 0) - { - dirstream = NULL; - goto lose; - } + { + dirstream = NULL; + goto lose; + } - dev_t dotdev = st.st_dev; - ino_t dotino = st.st_ino; - bool mount_point = dotdev != thisdev; + /* Figure out if this directory is a mount point. */ + dotdev = st.st_dev; + dotino = st.st_ino; + mount_point = dotdev != thisdev; /* Search for the last directory. */ - if (__have_atfcts >= 0) - dirstream = __fdopendir (fd); -#ifndef __ASSUME_ATFCTS - else - dirstream = __opendir (dotp); -#endif +#if HAVE_OPENAT_SUPPORT + dirstream = __fdopendir (fd); if (dirstream == NULL) - goto lose; + goto lose; fd_needs_closing = false; - - struct dirent *d; - bool use_d_ino = true; - while (1) - { - /* Clear errno to distinguish EOF from error if readdir returns - NULL. */ - __set_errno (0); - d = __readdir (dirstream); - if (d == NULL) - { - if (errno == 0) - { - /* When we've iterated through all directory entries - without finding one with a matching d_ino, rewind the - stream and consider each name again, but this time, using - lstat64. This is necessary in a chroot on at least one - system. */ - if (use_d_ino) - { - use_d_ino = false; - __rewinddir (dirstream); - continue; - } - - /* EOF on dirstream, which means that the current directory - has been removed. */ - __set_errno (ENOENT); - } - goto lose; - } - -#ifdef _DIRENT_HAVE_D_TYPE - if (d->d_type != DT_DIR && d->d_type != DT_UNKNOWN) - continue; -#endif - if (d->d_name[0] == '.' - && (d->d_name[1] == '\0' - || (d->d_name[1] == '.' && d->d_name[2] == '\0'))) - continue; - if (use_d_ino && !mount_point && (ino_t) d->d_ino != thisino) - continue; - - if (__have_atfcts >= 0) - { - /* We don't fail here if we cannot stat64() a directory entry. - This can happen when (network) filesystems fail. If this - entry is in fact the one we are looking for we will find - out soon as we reach the end of the directory without - having found anything. */ - if (__fstatat64 (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) - continue; - } -#ifndef __ASSUME_ATFCTS - else - { - char name[dotlist + dotsize - dotp + 1 + _D_ALLOC_NAMLEN (d)]; -# ifdef HAVE_MEMPCPY - char *tmp = mempcpy (name, dotp, dotlist + dotsize - dotp); - *tmp++ = '/'; - strcpy (tmp, d->d_name); -# else - memcpy (name, dotp, dotlist + dotsize - dotp); - name[dotlist + dotsize - dotp] = '/'; - strcpy (&name[dotlist + dotsize - dotp + 1], d->d_name); -# endif - /* We don't fail here if we cannot stat64() a directory entry. - This can happen when (network) filesystems fail. If this - entry is in fact the one we are looking for we will find - out soon as we reach the end of the directory without - having found anything. */ - if (__lstat64 (name, &st) < 0) - continue; - } +#else + dirstream = __opendir (dotlist); + if (dirstream == NULL) + goto lose; + dotlist[dotlen++] = '/'; #endif - if (S_ISDIR (st.st_mode) - && st.st_dev == thisdev && st.st_ino == thisino) - break; - } - - size_t namlen = _D_EXACT_NAMLEN (d); - - if ((size_t) (pathp - path) <= namlen) - { -#ifndef NO_ALLOCATION - if (size == 0) - { - size_t oldsize = allocated; - - allocated = 2 * MAX (allocated, namlen); - char *tmp = realloc (path, allocated); - if (tmp == NULL) - goto lose; - - /* Move current contents up to the end of the buffer. - This is guaranteed to be non-overlapping. */ - pathp = memcpy (tmp + allocated - (path + oldsize - pathp), - tmp + (pathp - path), - path + oldsize - pathp); - path = tmp; - } - else + for (;;) + { + /* Clear errno to distinguish EOF from error if readdir returns + NULL. */ + __set_errno (0); + d = __readdir (dirstream); + + /* When we've iterated through all directory entries without finding + one with a matching d_ino, rewind the stream and consider each + name again, but this time, using lstat. This is necessary in a + chroot on at least one system (glibc-2.3.6 + linux 2.6.12), where + .., ../.., ../../.., etc. all had the same device number, yet the + d_ino values for entries in / did not match those obtained + via lstat. */ + if (d == NULL && errno == 0 && use_d_ino) + { + use_d_ino = false; + __rewinddir (dirstream); + d = __readdir (dirstream); + } + + if (d == NULL) + { + if (errno == 0) + /* EOF on dirstream, which can mean e.g., that the current + directory has been removed. */ + __set_errno (ENOENT); + goto lose; + } + if (d->d_name[0] == '.' && + (d->d_name[1] == '\0' || + (d->d_name[1] == '.' && d->d_name[2] == '\0'))) + continue; + + if (use_d_ino) + { + bool match = (MATCHING_INO (d, thisino) || mount_point); + if (! match) + continue; + } + + { + int entry_status; +#if HAVE_OPENAT_SUPPORT + entry_status = __fstatat64 (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW); +#else + /* Compute size needed for this file name, or for the file + name ".." in the same directory, whichever is larger. + Room for ".." might be needed the next time through + the outer loop. */ + size_t name_alloc = _D_ALLOC_NAMLEN (d); + size_t filesize = dotlen + MAX (sizeof "..", name_alloc); + + if (filesize < dotlen) + goto memory_exhausted; + + if (dotsize < filesize) + { + /* My, what a deep directory tree you have, Grandma. */ + size_t newsize = MAX (filesize, dotsize * 2); + size_t i; + if (newsize < dotsize) + goto memory_exhausted; + if (dotlist != dots) + free (dotlist); + dotlist = malloc (newsize); + if (dotlist == NULL) + goto lose; + dotsize = newsize; + + i = 0; + do + { + dotlist[i++] = '.'; + dotlist[i++] = '.'; + dotlist[i++] = '/'; + } + while (i < dotlen); + } + + memcpy (dotlist + dotlen, d->d_name, _D_ALLOC_NAMLEN (d)); + entry_status = __lstat64 (dotlist, &st); #endif - { - __set_errno (ERANGE); - goto lose; - } - } - pathp -= namlen; - (void) memcpy (pathp, d->d_name, namlen); - *--pathp = '/'; + /* We don't fail here if we cannot stat() a directory entry. + This can happen when (network) file systems fail. If this + entry is in fact the one we are looking for we will find + out soon as we reach the end of the directory without + having found anything. */ + if (entry_status == 0 && S_ISDIR (st.st_mode) + && st.st_dev == thisdev && st.st_ino == thisino) + break; + } + } + + dirroom = dirp - dir; + namlen = _D_EXACT_NAMLEN (d); + + if (dirroom <= namlen) + { + if (size != 0) + { + __set_errno (ERANGE); + goto lose; + } + else + { + char *tmp; + size_t oldsize = allocated; + + allocated += MAX (allocated, namlen); + if (allocated < oldsize + || ! (tmp = realloc (dir, allocated))) + goto memory_exhausted; + + /* Move current contents up to the end of the buffer. + This is guaranteed to be non-overlapping. */ + dirp = memcpy (tmp + allocated - (oldsize - dirroom), + tmp + dirroom, + oldsize - dirroom); + dir = tmp; + } + } + dirp -= namlen; + memcpy (dirp, d->d_name, namlen); + *--dirp = '/'; thisdev = dotdev; thisino = dotino; } - if (dirstream != NULL && __closedir (dirstream) != 0) + if (dirstream && __closedir (dirstream) != 0) { dirstream = NULL; goto lose; } - if (pathp == &path[allocated - 1]) - *--pathp = '/'; + if (dirp == &dir[allocated - 1]) + *--dirp = '/'; -#ifndef __ASSUME_ATFCTS +#if ! HAVE_OPENAT_SUPPORT if (dotlist != dots) - free ((void *) dotlist); + free (dotlist); #endif - size_t used = path + allocated - pathp; - memmove (path, pathp, used); + used = dir + allocated - dirp; + memmove (dir, dirp, used); if (size == 0) /* Ensure that the buffer is only as large as necessary. */ - buf = realloc (path, used); + buf = (used < allocated ? realloc (dir, used) : dir); if (buf == NULL) - /* Either buf was NULL all along, or `realloc' failed but + /* Either buf was NULL all along, or 'realloc' failed but we still have the original string. */ - buf = path; - - /* Restore errno on successful return. */ - __set_errno (prev_errno); + buf = dir; return buf; - lose:; - int save_errno = errno; -#ifndef __ASSUME_ATFCTS - if (dotlist != dots) - free ((void *) dotlist); -#endif - if (dirstream != NULL) - __closedir (dirstream); - if (fd_needs_closing) - __close_nocancel_nostatus (fd); -#ifndef NO_ALLOCATION - if (buf == NULL) - free (path); + memory_exhausted: + __set_errno (ENOMEM); + lose: + { + int save = errno; + if (dirstream) + __closedir (dirstream); +#if HAVE_OPENAT_SUPPORT + if (fd_needs_closing) + __close_nocancel_nostatus (fd); +#else + if (dotlist != dots) + free (dotlist); #endif - __set_errno (save_errno); + if (buf == NULL) + free (dir); + __set_errno (save); + } return NULL; }