| Message ID | 1520017165-15830-1-git-send-email-adhemerval.zanella@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [1/7] Assume O_DIRECTORY for opendir | expand |
On 02/03/2018 15:59, Adhemerval Zanella wrote: > This patch assumes O_DIRECTORY works as defined by POSIX on opendir > implementation (aligning with other glibc code, for instance pwd). This > allows remove both the fallback code to handle system with missing or > broken O_DIRECTORY along with the Linux specific opendir.c which just > advertise the working flag. > > Checked on aarch64-linux-gnu, x86_64-linux-gnu, i686-linux-gnu, > sparcv9-linux-gnu, sparc64-linux-gnu, powerpc-linux-gnu, and > powerpc64le-linux-gnu. > > * sysdeps/posix/opendir.c (o_directory_works, tryopen_o_directory): > Remove definitions. > (opendir_oflags): Use O_DIRECTORY regardless. > (__opendir, __opendirat): Remove need_isdir_precheck usage. > * sysdeps/unix/sysv/linux/opendir.c: Remove file. If no one opposes it I will commit this shortly. > --- > ChangeLog | 8 +++ > sysdeps/posix/opendir.c | 108 ++------------------------------------ > sysdeps/unix/sysv/linux/opendir.c | 20 ------- > 3 files changed, 13 insertions(+), 123 deletions(-) > delete mode 100644 sysdeps/unix/sysv/linux/opendir.c > > diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c > index d925804..dea23b2 100644 > --- a/sysdeps/posix/opendir.c > +++ b/sysdeps/posix/opendir.c > @@ -15,24 +15,13 @@ > License along with the GNU C Library; if not, see > <http://www.gnu.org/licenses/>. */ > > -#include <assert.h> > -#include <errno.h> > -#include <limits.h> > -#include <stdbool.h> > -#include <stddef.h> > -#include <stdlib.h> > #include <dirent.h> > #include <fcntl.h> > -#include <sys/param.h> > -#include <sys/types.h> > -#include <sys/stat.h> > -#include <unistd.h> > -#include <stdio.h> > -#include <string.h> > - > -#include <dirstream.h> > +#include <errno.h> > +#include <stdio.h> /* For BUFSIZ. */ > +#include <sys/param.h> /* For MIN and MAX. */ > + > #include <not-cancel.h> > -#include <kernel-features.h> > > /* The st_blksize value of the directory is used as a hint for the > size of the buffer which receives struct dirent values from the > @@ -40,49 +29,8 @@ > file system provides a bogus value. */ > #define MAX_DIR_BUFFER_SIZE 1048576U > > -/* opendir() must not accidentally open something other than a directory. > - Some OS's have kernel support for that, some don't. In the worst > - case we have to stat() before the open() AND fstat() after. > - > - We have to test at runtime for kernel support since libc may have > - been compiled with different headers to the kernel it's running on. > - This test can't be done reliably in the general case. We'll use > - /dev/null, which if it's not a device lots of stuff will break, as > - a guinea pig. It may be missing in chroot environments, so we > - make sure to fail safe. */ > -#ifdef O_DIRECTORY > -# ifdef O_DIRECTORY_WORKS > -# define o_directory_works 1 > -# define tryopen_o_directory() while (1) /* This must not be called. */ > -# else > -static int o_directory_works; > - > -static void > -tryopen_o_directory (void) > -{ > - int serrno = errno; > - int x = __open_nocancel ("/dev/null", O_RDONLY|O_NDELAY|O_DIRECTORY); > - > - if (x >= 0) > - { > - __close_nocancel_nostatus (x); > - o_directory_works = -1; > - } > - else if (errno != ENOTDIR) > - o_directory_works = -1; > - else > - o_directory_works = 1; > - > - __set_errno (serrno); > -} > -# endif > -# define EXTRA_FLAGS O_DIRECTORY > -#else > -# define EXTRA_FLAGS 0 > -#endif > - > enum { > - opendir_oflags = O_RDONLY|O_NDELAY|EXTRA_FLAGS|O_LARGEFILE|O_CLOEXEC > + opendir_oflags = O_RDONLY|O_NDELAY|O_DIRECTORY|O_LARGEFILE|O_CLOEXEC > }; > > static bool > @@ -98,21 +46,6 @@ invalid_name (const char *name) > return false; > } > > - > -static bool > -need_isdir_precheck (void) > -{ > -#ifdef O_DIRECTORY > - /* Test whether O_DIRECTORY works. */ > - if (o_directory_works == 0) > - tryopen_o_directory (); > - > - /* We can skip the expensive `stat' call if O_DIRECTORY works. */ > - return o_directory_works < 0; > -#endif > - return true; > -} > - > static DIR * > opendir_tail (int fd) > { > @@ -144,22 +77,6 @@ __opendirat (int dfd, const char *name) > if (__glibc_unlikely (invalid_name (name))) > return NULL; > > - if (need_isdir_precheck ()) > - { > - /* We first have to check whether the name is for a directory. We > - cannot do this after the open() call since the open/close operation > - performed on, say, a tape device might have undesirable effects. */ > - struct stat64 statbuf; > - if (__glibc_unlikely (__fxstatat64 (_STAT_VER, dfd, name, > - &statbuf, 0) < 0)) > - return NULL; > - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) > - { > - __set_errno (ENOTDIR); > - return NULL; > - } > - } > - > return opendir_tail (__openat_nocancel (dfd, name, opendir_oflags)); > } > #endif > @@ -172,21 +89,6 @@ __opendir (const char *name) > if (__glibc_unlikely (invalid_name (name))) > return NULL; > > - if (need_isdir_precheck ()) > - { > - /* We first have to check whether the name is for a directory. We > - cannot do this after the open() call since the open/close operation > - performed on, say, a tape device might have undesirable effects. */ > - struct stat64 statbuf; > - if (__glibc_unlikely (__xstat64 (_STAT_VER, name, &statbuf) < 0)) > - return NULL; > - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) > - { > - __set_errno (ENOTDIR); > - return NULL; > - } > - } > - > return opendir_tail (__open_nocancel (name, opendir_oflags)); > } > weak_alias (__opendir, opendir) > diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c > deleted file mode 100644 > index 2677253..0000000 > --- a/sysdeps/unix/sysv/linux/opendir.c > +++ /dev/null > @@ -1,20 +0,0 @@ > -/* Copyright (C) 2000-2018 Free Software Foundation, Inc. > - This file is part of the GNU C Library. > - > - The GNU C Library is free software; you can redistribute it and/or > - modify it under the terms of the GNU Lesser General Public > - License as published by the Free Software Foundation; either > - version 2.1 of the License, or (at your option) any later version. > - > - The GNU C Library is distributed in the hope that it will be useful, > - but WITHOUT ANY WARRANTY; without even the implied warranty of > - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > - Lesser General Public License for more details. > - > - You should have received a copy of the GNU Lesser General Public > - License along with the GNU C Library; if not, see > - <http://www.gnu.org/licenses/>. */ > - > -#define O_DIRECTORY_WORKS 1 > - > -#include <sysdeps/posix/opendir.c> >
diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c index d925804..dea23b2 100644 --- a/sysdeps/posix/opendir.c +++ b/sysdeps/posix/opendir.c @@ -15,24 +15,13 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ -#include <assert.h> -#include <errno.h> -#include <limits.h> -#include <stdbool.h> -#include <stddef.h> -#include <stdlib.h> #include <dirent.h> #include <fcntl.h> -#include <sys/param.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <unistd.h> -#include <stdio.h> -#include <string.h> - -#include <dirstream.h> +#include <errno.h> +#include <stdio.h> /* For BUFSIZ. */ +#include <sys/param.h> /* For MIN and MAX. */ + #include <not-cancel.h> -#include <kernel-features.h> /* The st_blksize value of the directory is used as a hint for the size of the buffer which receives struct dirent values from the @@ -40,49 +29,8 @@ file system provides a bogus value. */ #define MAX_DIR_BUFFER_SIZE 1048576U -/* opendir() must not accidentally open something other than a directory. - Some OS's have kernel support for that, some don't. In the worst - case we have to stat() before the open() AND fstat() after. - - We have to test at runtime for kernel support since libc may have - been compiled with different headers to the kernel it's running on. - This test can't be done reliably in the general case. We'll use - /dev/null, which if it's not a device lots of stuff will break, as - a guinea pig. It may be missing in chroot environments, so we - make sure to fail safe. */ -#ifdef O_DIRECTORY -# ifdef O_DIRECTORY_WORKS -# define o_directory_works 1 -# define tryopen_o_directory() while (1) /* This must not be called. */ -# else -static int o_directory_works; - -static void -tryopen_o_directory (void) -{ - int serrno = errno; - int x = __open_nocancel ("/dev/null", O_RDONLY|O_NDELAY|O_DIRECTORY); - - if (x >= 0) - { - __close_nocancel_nostatus (x); - o_directory_works = -1; - } - else if (errno != ENOTDIR) - o_directory_works = -1; - else - o_directory_works = 1; - - __set_errno (serrno); -} -# endif -# define EXTRA_FLAGS O_DIRECTORY -#else -# define EXTRA_FLAGS 0 -#endif - enum { - opendir_oflags = O_RDONLY|O_NDELAY|EXTRA_FLAGS|O_LARGEFILE|O_CLOEXEC + opendir_oflags = O_RDONLY|O_NDELAY|O_DIRECTORY|O_LARGEFILE|O_CLOEXEC }; static bool @@ -98,21 +46,6 @@ invalid_name (const char *name) return false; } - -static bool -need_isdir_precheck (void) -{ -#ifdef O_DIRECTORY - /* Test whether O_DIRECTORY works. */ - if (o_directory_works == 0) - tryopen_o_directory (); - - /* We can skip the expensive `stat' call if O_DIRECTORY works. */ - return o_directory_works < 0; -#endif - return true; -} - static DIR * opendir_tail (int fd) { @@ -144,22 +77,6 @@ __opendirat (int dfd, const char *name) if (__glibc_unlikely (invalid_name (name))) return NULL; - if (need_isdir_precheck ()) - { - /* We first have to check whether the name is for a directory. We - cannot do this after the open() call since the open/close operation - performed on, say, a tape device might have undesirable effects. */ - struct stat64 statbuf; - if (__glibc_unlikely (__fxstatat64 (_STAT_VER, dfd, name, - &statbuf, 0) < 0)) - return NULL; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) - { - __set_errno (ENOTDIR); - return NULL; - } - } - return opendir_tail (__openat_nocancel (dfd, name, opendir_oflags)); } #endif @@ -172,21 +89,6 @@ __opendir (const char *name) if (__glibc_unlikely (invalid_name (name))) return NULL; - if (need_isdir_precheck ()) - { - /* We first have to check whether the name is for a directory. We - cannot do this after the open() call since the open/close operation - performed on, say, a tape device might have undesirable effects. */ - struct stat64 statbuf; - if (__glibc_unlikely (__xstat64 (_STAT_VER, name, &statbuf) < 0)) - return NULL; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) - { - __set_errno (ENOTDIR); - return NULL; - } - } - return opendir_tail (__open_nocancel (name, opendir_oflags)); } weak_alias (__opendir, opendir) diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c deleted file mode 100644 index 2677253..0000000 --- a/sysdeps/unix/sysv/linux/opendir.c +++ /dev/null @@ -1,20 +0,0 @@ -/* Copyright (C) 2000-2018 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#define O_DIRECTORY_WORKS 1 - -#include <sysdeps/posix/opendir.c>