am e93bc6bb: am d91ded81: Merge "Fix "faccessat ignores flags""

* commit 'e93bc6bbe8ce180187e3914d0a7494cfe84f6255':
  Fix "faccessat ignores flags"

libc/Android.mk

@@ -116,6 +116,7 @@ libc_bionic_ndk_src_files := \
     bionic/error.cpp \
     bionic/eventfd_read.cpp \
     bionic/eventfd_write.cpp \
+    bionic/faccessat.cpp \
     bionic/fchmod.cpp \
     bionic/fchmodat.cpp \
     bionic/ffs.cpp \

libc/SYSCALLS.TXT

@@ -130,7 +130,7 @@ int         fremovexattr(int, const char*) all
 int __getdents64:getdents64(unsigned int, struct dirent*, unsigned int)   arm,arm64,mips,mips64,x86,x86_64
 
 int __openat:openat(int, const char*, int, mode_t) all
-int faccessat(int, const char*, int, int)  all
+int ___faccessat:faccessat(int, const char*, 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

libc/arch-arm/syscalls/___faccessat.S

@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(faccessat)
+ENTRY(___faccessat)
     mov     ip, r7
     ldr     r7, =__NR_faccessat
     swi     #0
@@ -11,4 +11,5 @@ ENTRY(faccessat)
     bxls    lr
     neg     r0, r0
     b       __set_errno_internal
-END(faccessat)
+END(___faccessat)
+.hidden ___faccessat

libc/arch-arm64/syscalls/___faccessat.S

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

libc/arch-mips/syscalls/___faccessat.S

@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(faccessat)
+ENTRY(___faccessat)
     .set noreorder
     .cpload t9
     li v0, __NR_faccessat
@@ -16,4 +16,5 @@ ENTRY(faccessat)
     j t9
     nop
     .set reorder
-END(faccessat)
+END(___faccessat)
+.hidden ___faccessat

libc/arch-mips64/syscalls/___faccessat.S

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

libc/arch-x86/syscalls/___faccessat.S

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

libc/arch-x86_64/syscalls/___faccessat.S

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

libc/bionic/faccessat.cpp

@@ -0,0 +1,59 @@
+/*
+ * 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 <unistd.h>
+#include <errno.h>
+
+extern "C" int ___faccessat(int, const char*, int);
+
+int faccessat(int dirfd, const char* pathname, int mode, int flags) {
+  // "The mode specifies the accessibility check(s) to be performed,
+  // and is either the value F_OK, or a mask consisting of the
+  // bitwise OR of one or more of R_OK, W_OK, and X_OK."
+  if ((mode != F_OK) && ((mode & ~(R_OK | W_OK | X_OK)) != 0) &&
+      ((mode & (R_OK | W_OK | X_OK)) == 0)) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  if (flags != 0) {
+    // We deliberately don't support AT_SYMLINK_NOFOLLOW, a glibc
+    // only feature which is error prone and dangerous.
+    //
+    // AT_EACCESS isn't supported either. Android doesn't have setuid
+    // programs, and never runs code with euid!=uid. It could be
+    // implemented in an expensive way, following the model at
+    // https://gitlab.com/bminor/musl/commit/0a05eace163cee9b08571d2ff9d90f5e82d9c228
+    // but not worth it.
+    errno = EINVAL;
+    return -1;
+  }
+
+  return ___faccessat(dirfd, pathname, mode);
+}

tests/sys_stat_test.cpp

@@ -219,3 +219,43 @@ TEST(sys_stat, fchmodat_AT_SYMLINK_NOFOLLOW_with_dangling_symlink) {
   ASSERT_EQ(ENOTSUP, errno);
   unlink(linkname);
 }
+
+TEST(sys_stat, faccessat_EINVAL) {
+  ASSERT_EQ(-1, faccessat(AT_FDCWD, "/dev/null", F_OK, ~AT_SYMLINK_NOFOLLOW));
+  ASSERT_EQ(EINVAL, errno);
+#if defined(__BIONIC__)
+  ASSERT_EQ(-1, faccessat(AT_FDCWD, "/dev/null", ~(R_OK | W_OK | X_OK), 0));
+  ASSERT_EQ(EINVAL, errno);
+#else
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", ~(R_OK | W_OK | X_OK), AT_SYMLINK_NOFOLLOW));
+  ASSERT_EQ(-1, faccessat(AT_FDCWD, "/dev/null", ~(R_OK | W_OK | X_OK), 0));
+  ASSERT_EQ(EINVAL, errno);
+#endif
+}
+
+TEST(sys_stat, faccessat_AT_SYMLINK_NOFOLLOW_EINVAL) {
+#if defined(__BIONIC__)
+  // Android doesn't support AT_SYMLINK_NOFOLLOW
+  ASSERT_EQ(-1, faccessat(AT_FDCWD, "/dev/null", F_OK, AT_SYMLINK_NOFOLLOW));
+  ASSERT_EQ(EINVAL, errno);
+#else
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", F_OK, AT_SYMLINK_NOFOLLOW));
+#endif
+}
+
+TEST(sys_stat, faccessat_dev_null) {
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", F_OK, 0));
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", R_OK, 0));
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", W_OK, 0));
+  ASSERT_EQ(0, faccessat(AT_FDCWD, "/dev/null", R_OK|W_OK, 0));
+}
+
+TEST(sys_stat, faccessat_nonexistant) {
+  ASSERT_EQ(-1, faccessat(AT_FDCWD, "/blah", F_OK, AT_SYMLINK_NOFOLLOW));
+#if defined(__BIONIC__)
+  // Android doesn't support AT_SYMLINK_NOFOLLOW
+  ASSERT_EQ(EINVAL, errno);
+#else
+  ASSERT_EQ(ENOENT, errno);
+#endif
+}