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am d80ec661: Merge "Add fchmodat(AT_SYMLINK_NOFOLLOW) and fchmod O_PATH support"

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* commit 'd80ec66121b5af96c6b3d07ba34353b3d517f5b3':
  Add fchmodat(AT_SYMLINK_NOFOLLOW) and fchmod O_PATH support
This commit is contained in:
Nick Kralevich 2015-02-02 22:07:35 +00:00 committed by Android Git Automerger
commit 0cb8abc620
17 changed files with 300 additions and 35 deletions
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2
libc/Android.mk
View file

@ -116,6 +116,8 @@ libc_bionic_src_files := \
bionic/error.cpp \
bionic/eventfd_read.cpp \
bionic/eventfd_write.cpp \
bionic/fchmod.cpp \
bionic/fchmodat.cpp \
bionic/ffs.cpp \
bionic/flockfile.cpp \
bionic/fork.cpp \

4
libc/SYSCALLS.TXT
View file

@ -113,7 +113,7 @@ int writev(int, const struct iovec*, int) all
int __fcntl64:fcntl64(int, int, void*) arm,mips,x86
int fcntl(int, int, void*) arm64,mips64,x86_64
int flock(int, int) all
int fchmod(int, mode_t) all
int __fchmod:fchmod(int, mode_t) all
int dup(int) all
int pipe2(int*, int) all
int dup3(int, int, int) all
@ -131,7 +131,7 @@ int __getdents64:getdents64(unsigned int, struct dirent*, unsigned int) arm,ar
int __openat:openat(int, const char*, int, mode_t) all
int faccessat(int, const char*, int, int) all
int fchmodat(int, const char*, mode_t, int) all
int __fchmodat:fchmodat(int, const char*, mode_t) all
int fchownat(int, const char*, uid_t, gid_t, int) all
int fstatat64|fstatat:fstatat64(int, const char*, struct stat*, int) arm,mips,x86
int fstatat64|fstatat:newfstatat(int, const char*, struct stat*, int) arm64,x86_64

4
libc/arch-arm/syscalls/fchmod.S → libc/arch-arm/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
mov ip, r7
ldr r7, =__NR_fchmod
swi #0
@ -11,4 +11,4 @@ ENTRY(fchmod)
bxls lr
neg r0, r0
b __set_errno_internal
END(fchmod)
END(__fchmod)

4
libc/arch-arm/syscalls/fchmodat.S → libc/arch-arm/syscalls/__fchmodat.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
ENTRY(__fchmodat)
mov ip, r7
ldr r7, =__NR_fchmodat
swi #0
@ -11,4 +11,4 @@ ENTRY(fchmodat)
bxls lr
neg r0, r0
b __set_errno_internal
END(fchmodat)
END(__fchmodat)

5
libc/arch-arm64/syscalls/fchmod.S → libc/arch-arm64/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
mov x8, __NR_fchmod
svc #0
@ -11,4 +11,5 @@ ENTRY(fchmod)
b.hi __set_errno_internal
ret
END(fchmod)
END(__fchmod)
.hidden __fchmod

5
libc/arch-arm64/syscalls/fchmodat.S → libc/arch-arm64/syscalls/__fchmodat.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
ENTRY(__fchmodat)
mov x8, __NR_fchmodat
svc #0
@ -11,4 +11,5 @@ ENTRY(fchmodat)
b.hi __set_errno_internal
ret
END(fchmodat)
END(__fchmodat)
.hidden __fchmodat

4
libc/arch-mips/syscalls/fchmod.S → libc/arch-mips/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
.set noreorder
.cpload t9
li v0, __NR_fchmod
@ -16,4 +16,4 @@ ENTRY(fchmod)
j t9
nop
.set reorder
END(fchmod)
END(__fchmod)

4
libc/arch-mips/syscalls/fchmodat.S → libc/arch-mips/syscalls/__fchmodat.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
ENTRY(__fchmodat)
.set noreorder
.cpload t9
li v0, __NR_fchmodat
@ -16,4 +16,4 @@ ENTRY(fchmodat)
j t9
nop
.set reorder
END(fchmodat)
END(__fchmodat)

5
libc/arch-mips64/syscalls/fchmod.S → libc/arch-mips64/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
.set push
.set noreorder
li v0, __NR_fchmod
@ -22,4 +22,5 @@ ENTRY(fchmod)
j t9
move ra, t0
.set pop
END(fchmod)
END(__fchmod)
.hidden __fchmod

5
libc/arch-mips64/syscalls/fchmodat.S → libc/arch-mips64/syscalls/__fchmodat.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
ENTRY(__fchmodat)
.set push
.set noreorder
li v0, __NR_fchmodat
@ -22,4 +22,5 @@ ENTRY(fchmodat)
j t9
move ra, t0
.set pop
END(fchmodat)
END(__fchmodat)
.hidden __fchmodat

4
libc/arch-x86/syscalls/fchmod.S → libc/arch-x86/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
pushl %ebx
.cfi_def_cfa_offset 8
.cfi_rel_offset ebx, 0
@ -23,4 +23,4 @@ ENTRY(fchmod)
popl %ecx
popl %ebx
ret
END(fchmod)
END(__fchmod)

15
libc/arch-x86/syscalls/fchmodat.S → libc/arch-x86/syscalls/__fchmodat.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
ENTRY(__fchmodat)
pushl %ebx
.cfi_def_cfa_offset 8
.cfi_rel_offset ebx, 0
@ -12,13 +12,9 @@ ENTRY(fchmodat)
pushl %edx
.cfi_adjust_cfa_offset 4
.cfi_rel_offset edx, 0
pushl %esi
.cfi_adjust_cfa_offset 4
.cfi_rel_offset esi, 0
mov 20(%esp), %ebx
mov 24(%esp), %ecx
mov 28(%esp), %edx
mov 32(%esp), %esi
mov 16(%esp), %ebx
mov 20(%esp), %ecx
mov 24(%esp), %edx
movl $__NR_fchmodat, %eax
int $0x80
cmpl $-MAX_ERRNO, %eax
@ -28,9 +24,8 @@ ENTRY(fchmodat)
call __set_errno_internal
addl $4, %esp
1:
popl %esi
popl %edx
popl %ecx
popl %ebx
ret
END(fchmodat)
END(__fchmodat)

5
libc/arch-x86_64/syscalls/fchmod.S → libc/arch-x86_64/syscalls/__fchmod.S
View file

@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmod)
ENTRY(__fchmod)
movl $__NR_fchmod, %eax
syscall
cmpq $-MAX_ERRNO, %rax
@ -12,4 +12,5 @@ ENTRY(fchmod)
call __set_errno_internal
1:
ret
END(fchmod)
END(__fchmod)
.hidden __fchmod

6
libc/arch-x86_64/syscalls/fchmodat.S → libc/arch-x86_64/syscalls/__fchmodat.S
View file

@ -2,8 +2,7 @@
#include <private/bionic_asm.h>
ENTRY(fchmodat)
movq %rcx, %r10
ENTRY(__fchmodat)
movl $__NR_fchmodat, %eax
syscall
cmpq $-MAX_ERRNO, %rax
@ -13,4 +12,5 @@ ENTRY(fchmodat)
call __set_errno_internal
1:
ret
END(fchmodat)
END(__fchmodat)
.hidden __fchmodat

72
libc/bionic/fchmod.cpp Normal file
View file

@ -0,0 +1,72 @@
/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
extern "C" int __fchmod(int, mode_t);
int fchmod(int fd, mode_t mode) {
int saved_errno = errno;
int result = __fchmod(fd, mode);
if ((result == 0) || (errno != EBADF)) {
return result;
}
// fd could be an O_PATH file descriptor, and the kernel
// may not directly support fchmod() on such a file descriptor.
// Use /proc/self/fd instead to emulate this support.
// https://sourceware.org/bugzilla/show_bug.cgi?id=14578
//
// As of February 2015, there are no kernels which support fchmod
// on an O_PATH file descriptor, and "man open" documents fchmod
// on O_PATH file descriptors as returning EBADF.
int fd_flag = fcntl(fd, F_GETFL);
if ((fd_flag == -1) || ((fd_flag & O_PATH) == 0)) {
errno = EBADF;
return -1;
}
char buf[40];
snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd);
errno = saved_errno;
result = chmod(buf, mode);
if ((result == -1) && (errno == ELOOP)) {
// Linux does not support changing the mode of a symlink.
// For fchmodat(AT_SYMLINK_NOFOLLOW), POSIX requires a return
// value of ENOTSUP. Assume that's true here too.
errno = ENOTSUP;
}
return result;
}

67
libc/bionic/fchmodat.cpp Normal file
View file

@ -0,0 +1,67 @@
/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include "private/ErrnoRestorer.h"
extern "C" int __fchmodat(int, const char*, mode_t);
int fchmodat(int dirfd, const char* pathname, mode_t mode, int flags) {
if ((flags & ~AT_SYMLINK_NOFOLLOW) != 0) {
errno = EINVAL;
return -1;
}
if (flags & AT_SYMLINK_NOFOLLOW) {
// Emulate AT_SYMLINK_NOFOLLOW using the mechanism described
// at https://sourceware.org/bugzilla/show_bug.cgi?id=14578
// comment #10
int fd = openat(dirfd, pathname, O_PATH | O_NOFOLLOW | O_CLOEXEC);
if (fd == -1) {
return -1; // returns errno from openat
}
// POSIX requires that ENOTSUP be returned when the system
// doesn't support setting the mode of a symbolic link.
// This is true for all Linux kernels.
// We rely on the O_PATH compatibility layer added in the
// fchmod() function to get errno correct.
int result = fchmod(fd, mode);
ErrnoRestorer errno_restorer; // don't let close() clobber errno
close(fd);
return result;
}
return __fchmodat(dirfd, pathname, mode);
}

124
tests/sys_stat_test.cpp
View file

@ -95,3 +95,127 @@ TEST(sys_stat, stat64_lstat64_fstat64) {
ASSERT_EQ(0, fstat64(fd, &sb));
close(fd);
}
TEST(sys_stat, fchmodat_EFAULT_file) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, (char *) 0x1, 0751, 0));
ASSERT_EQ(EFAULT, errno);
}
TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_EFAULT_file) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, (char *) 0x1, 0751, AT_SYMLINK_NOFOLLOW));
#if defined(__BIONIC__)
ASSERT_EQ(EFAULT, errno);
#else
// glibc 2.19 does not implement AT_SYMLINK_NOFOLLOW and always
// returns ENOTSUP
ASSERT_EQ(ENOTSUP, errno);
#endif
}
TEST(sys_stat, fchmodat_bad_flags) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, "/blah", 0751, ~AT_SYMLINK_NOFOLLOW));
ASSERT_EQ(EINVAL, errno);
}
TEST(sys_stat, fchmodat_bad_flags_ALL) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, "/blah", 0751, ~0));
ASSERT_EQ(EINVAL, errno);
}
TEST(sys_stat, fchmodat_nonexistant_file) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, "/blah", 0751, 0));
ASSERT_EQ(ENOENT, errno);
}
TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_nonexistant_file) {
ASSERT_EQ(-1, fchmodat(AT_FDCWD, "/blah", 0751, AT_SYMLINK_NOFOLLOW));
#if defined(__BIONIC__)
ASSERT_EQ(ENOENT, errno);
#else
// glibc 2.19 does not implement AT_SYMLINK_NOFOLLOW and always
// returns ENOTSUP
ASSERT_EQ(ENOTSUP, errno);
#endif
}
TEST(sys_stat, fchmodat_file) {
TemporaryFile tf;
struct stat sb;
ASSERT_EQ(0, fchmodat(AT_FDCWD, tf.filename, 0751, 0));
ASSERT_EQ(0, fstat(tf.fd, &sb));
ASSERT_TRUE(0751 == (sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)));
}
TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_file) {
TemporaryFile tf;
errno = 0;
int result = fchmodat(AT_FDCWD, tf.filename, 0751, AT_SYMLINK_NOFOLLOW);
#if defined(__BIONIC__)
struct stat sb;
ASSERT_EQ(0, result);
ASSERT_EQ(0, errno);
ASSERT_EQ(0, fstat(tf.fd, &sb));
ASSERT_TRUE(0751 == (sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)));
#else
// glibc 2.19 does not implement AT_SYMLINK_NOFOLLOW and always
// returns ENOTSUP
ASSERT_EQ(-1, result);
ASSERT_EQ(ENOTSUP, errno);
#endif
}
TEST(sys_stat, fchmodat_symlink) {
TemporaryFile tf;
char linkname[255];
struct stat sb;
snprintf(linkname, sizeof(linkname), "%s.link", tf.filename);
ASSERT_EQ(0, symlink(tf.filename, linkname));
ASSERT_EQ(0, fchmodat(AT_FDCWD, linkname, 0751, 0));
ASSERT_EQ(0, fstat(tf.fd, &sb));
ASSERT_TRUE(0751 == (sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)));
unlink(linkname);
}
TEST(sys_stat, fchmodat_dangling_symlink) {
TemporaryFile tf;
char linkname[255];
char target[255];
snprintf(linkname, sizeof(linkname), "%s.link", tf.filename);
snprintf(target, sizeof(target), "%s.doesnotexist", tf.filename);
ASSERT_EQ(0, symlink(target, linkname));
ASSERT_EQ(-1, fchmodat(AT_FDCWD, linkname, 0751, 0));
ASSERT_EQ(ENOENT, errno);
unlink(linkname);
}
TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_with_symlink) {
TemporaryFile tf;
char linkname[255];
snprintf(linkname, sizeof(linkname), "%s.link", tf.filename);
ASSERT_EQ(0, symlink(tf.filename, linkname));
ASSERT_EQ(-1, fchmodat(AT_FDCWD, linkname, 0751, AT_SYMLINK_NOFOLLOW));
ASSERT_EQ(ENOTSUP, errno);
unlink(linkname);
}
TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_with_dangling_symlink) {
TemporaryFile tf;
char linkname[255];
char target[255];
snprintf(linkname, sizeof(linkname), "%s.link", tf.filename);
snprintf(target, sizeof(target), "%s.doesnotexist", tf.filename);
ASSERT_EQ(0, symlink(target, linkname));
ASSERT_EQ(-1, fchmodat(AT_FDCWD, linkname, 0751, AT_SYMLINK_NOFOLLOW));
ASSERT_EQ(ENOTSUP, errno);
unlink(linkname);
}