The kernel system call faccessat() does not have any flags arguments,
so passing flags to the kernel is currently ignored.
Fix the kernel system call so that no flags argument is passed in.
Ensure that we don't support AT_SYMLINK_NOFOLLOW. This non-POSIX
(http://pubs.opengroup.org/onlinepubs/9699919799/functions/access.html)
flag is a glibc extension, and has non-intuitive, error prone behavior.
For example, consider the following code:
symlink("foo.is.dangling", "foo");
if (faccessat(AT_FDCWD, "foo", R_OK, AT_SYMLINK_NOFOLLOW) == 0) {
int fd = openat(AT_FDCWD, "foo", O_RDONLY | O_NOFOLLOW);
}
The faccessat() call in glibc will return true, but an attempt to
open the dangling symlink will end up failing. GLIBC documents this
as returning the access mode of the symlink itself, which will
always return true for any symlink on Linux.
Some further discussions of this are at:
* http://lists.landley.net/pipermail/toybox-landley.net/2014-September/003617.html
* http://permalink.gmane.org/gmane.linux.lib.musl.general/6952
AT_SYMLINK_NOFOLLOW seems broken by design. I suspect this is why this
function was never added to POSIX. (note that "access" is pretty much
broken by design too, since it introduces a race condition between
check and action). We shouldn't support this until it's clearly
documented by POSIX or we can have it produce intuitive results.
Don't support AT_EACCESS for now. Implementing it is complicated, and
pretty much useless on Android, since we don't have setuid binaries.
See http://git.musl-libc.org/cgit/musl/commit/?id=0a05eace163cee9b08571d2ff9d90f5e82d9c228
for how an implementation might look.
Bug: 18867827
Change-Id: I25b86c5020f3152ffa3ac3047f6c4152908d0e04
The overflow's actually in the generic C implementation of memchr.
While I'm here, let's switch our generic memrchr to the OpenBSD version too.
Bug: https://code.google.com/p/android/issues/detail?id=147048
Change-Id: I296ae06a1ee196d2c77c95a22f11ee4d658962da
Include full 16-byte Mips sigset_t signal mask within jump buffer.
Call sigprocmask instead of sigblockmask/sigsetmask to get/set full signal mask.
Include sigsetjmp's savesigs arg inside jmp_buf, instead of following it.
Reserve room for future extensions.
Preserve historically-large mips32 _JBLEN size.
Eliminate redundancy: code setjmp and _setjmp as tail calls into sigsetjmp,
and make longjmp and _longjmp aliases of siglongjmp.
Change-Id: Ie79137cf059228c1a51344ebb20d3a9a40b4a252
* changes:
Use LOCAL_LDFLAGS_64 instead of enumerating 64-bit architectures
Fix typo in cpu variant makefile depenendency for arm64
Remove libc_static_common_src_files
Share LP32 makefile settings between arches
Add <var>_32 to patch-up-arch-specific-flags, and move the LP32
cruft varaibles from the 32-bit arch specific makefiles into the
top level Android.mk.
Change-Id: Id3fcf6805d4af048c2524c94b1295416ebe7d057
In https://android-review.googlesource.com/#/c/127908/5/libc/SYSCALLS.TXT@116
Elliott said:
for LP64 these will be hidden. for LP32 we were cowards and left
them all public for compatibility (though i don't think we ever
dremeled to see whether it was needed). we don't have an easy
way to recognize additions, though, so we can't prevent adding
new turds.
Add a mechanism to prevent the adding of new turds, and use that
mechanism on the fchmod/fchmodat system calls.
Bug: 19233951
Change-Id: I98f98345970b631a379f348df57858f9fc3d57c0
Many libc functions have an option to not follow symbolic
links. This is useful to avoid security sensitive code
from inadvertantly following attacker supplied symlinks
and taking inappropriate action on files it shouldn't.
For example, open() has O_NOFOLLOW, chown() has
lchown(), stat() has lstat(), etc.
There is no such equivalent function for chmod(), such as lchmod().
To address this, POSIX introduced fchmodat(AT_SYMLINK_NOFOLLOW),
which is intended to provide a way to perform a chmod operation
which doesn't follow symlinks.
Currently, the Linux kernel doesn't implement AT_SYMLINK_NOFOLLOW.
In GLIBC, attempting to use the AT_SYMLINK_NOFOLLOW flag causes
fchmodat to return ENOTSUP. Details are in "man fchmodat".
Bionic currently differs from GLIBC in that AT_SYMLINK_NOFOLLOW
is silently ignored and treated as if the flag wasn't present.
This patch provides a userspace implementation of
AT_SYMLINK_NOFOLLOW for bionic. Using open(O_PATH | O_NOFOLLOW),
we can provide a way to atomically change the permissions on
files without worrying about race conditions.
As part of this change, we add support for fchmod on O_PATH
file descriptors, because it's relatively straight forward
and could be useful in the future.
The basic idea behind this implementation comes from
https://sourceware.org/bugzilla/show_bug.cgi?id=14578 , specifically
comment #10.
Change-Id: I1eba0cdb2c509d9193ceecf28f13118188a3cfa7
Move various mips-only things into the arch-mips directory. As soon as mips
writes assembler replacements, we can remove these.
Change-Id: Ia7308559bc361f5c8df3e1d456b381865e060b93
Interestingly, this mostly involves cleaning up our implementation of
various <string.h> functions.
Change-Id: Ifaef49b5cb997134f7bc0cc31bdac844bdb9e089
Position Independent Executables cannot communicate with GDB using DT_MIPS_RLD_TAG.
Hence a new tag DT_MIPS_RLD_MAP2 got introduced to fix the issue.
Change-Id: I77ce3faf1ef2e121003b804ecd291abb25cfbb56
Signed-off-by: Nikola Veljkovic<Nikola.Veljkovic@imgtec.com>
They'd drifted slightly which led to a compilation error in toybox,
which was assuming pid_t was defined. arm and arm64 were picking it
up via <endian.h> but x86 wasn't.
Change-Id: I58401e6c0066959dfc3b305b020876aaf7074bbf
This is a MIPS-only header, and should not be part of the common
headers. See http://b.android.com/79841 for context.
Change-Id: I610bc3ff626b57e7854dad15a4a2f67e1e5ded75
Add the missing prototypes, fix the existing prototypes to use clockid_t
rather than int, fix clock_nanosleep's failure behavior, and add simple
tests.
Bug: 17644443
Bug: https://code.google.com/p/android/issues/detail?id=77372
Change-Id: I03fba369939403918abcabae9551a7123953d780
Signed-off-by: Haruki Hasegawa <h6a.h4i.0@gmail.com>
The use of the .hidden directive to avoid going via the PLT for
__set_errno had the side-effect of actually making __set_errno
hidden (which is odd because assembler directives don't usually
affect symbols defined in a different file --- you can't even
create a weak reference to a symbol that's defined in a different
file).
This change switches the system call stubs over to a new always-hidden
__set_errno_internal and has a visible __set_errno on LP32 just for
binary compatibility with old NDK apps.
(cherry-pick of 7efad83d430f4d824f2aaa75edea5106f6ff8aae.)
Bug: 17423135
Change-Id: I6b6d7a05dda85f923d22e5ffd169a91e23499b7b
On most architectures the kernel subtracts a random offset to the stack
pointer in create_elf_tables by calling arch_align_stack before writing
the auxval table and so on. On all but x86 this doesn't cause a problem
because the random offset is less than a page, but on x86 it's up to two
pages. This means that our old technique of rounding the stack pointer
doesn't work. (Our old implementation of that technique was wrong too.)
It's also incorrect to assume that the main thread's stack base and size
are constant. Likewise to assume that the main thread has a guard page.
The main thread is not like other threads.
This patch switches to reading /proc/self/maps (and checking RLIMIT_STACK)
whenever we're asked.
Bug: 17111575
Signed-off-by: Fengwei Yin <fengwei.yin@intel.com>
Change-Id: I1d4dbffe7bc7bda1d353c3a295dbf68d29f63158
Save and restore floating point registers via 64-bit
load/stores when possible. Use assembler's builtin macro
ops to generate pairs of 32-bit load/stores on Mips I cpus.
Some cpus or FR modes have only 16 even-numbered dp fp regs.
This is exposed by _MIPS_FPSET, defined by existing compilers.
Change-Id: I7f617a3ffea8da41c402ef3a68ab32c91d3d7622
Explicitly tell 32-bit links that they are doing 32-bit links.
This is needed when using united 32-bit and 64-bit toolchains.
This is harmless when using older separate 32-only toolchains.
Change-Id: I70cbd3f5867e59b1f6f829793444242fb0894aa6
In practice, with this implementation we never need to make a system call.
We get the main thread's tid (which is the same as our pid) back from
the set_tid_address system call we have to make during initialization.
A new pthread will have the same pid as its parent, and a fork child's
main (and only) thread will have a pid equal to its tid, which we get for
free from the kernel before clone returns.
The only time we'd actually have to make a getpid system call now is if
we take a signal during fork and the signal handler calls getpid. (That,
or we call getpid in the dynamic linker while it's still dealing with its
own relocations and hasn't even set up the main thread yet.)
Bug: 15387103
Change-Id: I6d4718ed0a5c912fc75b5f738c49a023dbed5189
The C library didn't export the 'index' symbol, but its C++ name-mangling
instead, which broke the ABI and prevented some applications from loading
properly.
The main reason was that the implementation under bionic/index.cpp relied
on the declaration to specify that the function has C linkage.
However, the declaration for index() was removed from both <string.h>
and <strings.h> in a recent patch, which made the compiler think it was
ok to compile the function with C++ linkage instead!
This patch does the following:
- Move index() definition to bionic/ndk_cruft.cpp and ensure it uses
C linkage.
Note that this removes index() from the 64-bit library entirely, this
is intentional and will break source compatibility. Simply replacing
an index() call with the equivalent strchr() should be enough to fix
this in third-party code.
- Remove bionic/index.cpp from the tree and build files.
- Remove x86 assembly implementation from arch-x86/ to avoid conflict
with the one in ndk_cruft.cpp
BUG=15606653
Change-Id: I816b589f69c8f8a6511f6be6195d20cf1c4e8123
