libc: Add O_PATH support for fgetxattr / fsetxattr
Support O_PATH file descriptors when handling fgetxattr and fsetxattr.
This avoids requiring file read access to pull extended attributes.
This is needed to support O_PATH file descriptors when calling
SELinux's fgetfilecon() call. In particular, this allows the querying
and setting of SELinux file context by using something like the following
code:
int dirfd = open("/path/to/dir", O_DIRECTORY);
int fd = openat(dirfd, "file", O_PATH | O_NOFOLLOW);
char *context;
fgetfilecon(fd, &context);
This change was motivated by a comment in
https://android-review.googlesource.com/#/c/152680/1/toys/posix/ls.c
Change-Id: Ic0cdf9f9dd0e35a63b44a4c4a08400020041eddf
diff --git a/libc/Android.mk b/libc/Android.mk
index d6274dd..4dd1086 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -129,8 +129,10 @@
bionic/fchmod.cpp \
bionic/fchmodat.cpp \
bionic/ffs.cpp \
+ bionic/fgetxattr.cpp \
bionic/flockfile.cpp \
bionic/fpclassify.cpp \
+ bionic/fsetxattr.cpp \
bionic/ftruncate.cpp \
bionic/futimens.cpp \
bionic/getcwd.cpp \