The mremap definition was incorrect (unsigned long instead of int) and
it was missing the optional new_address parameter.
Change-Id: Ib9d0675aaa098c21617cedc9b2b8cf267be3aec4
A continuation of commit 2825f10b7f.
Add O_PATH compatibility support for flistxattr(). This allows
a process to list out all the extended attributes associated with
O_PATH file descriptors.
Change-Id: Ie2285ac7ad2e4eac427ddba6c2d182d41b130f75
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
This doesn't affect code like Chrome that correctly ignores EINTR on
close, makes code that tries TEMP_FAILURE_RETRY work (where before it might
have closed a different fd and appeared to succeed, or had a bogus EBADF),
and makes "goto fail" code work (instead of mistakenly assuming that EINTR
means that the close failed).
Who loses? Anyone actively trying to detect that they caught a signal while
in close(2). I don't think those people exist, and I think they have better
alternatives available.
Bug: https://code.google.com/p/chromium/issues/detail?id=269623
Bug: http://b/20501816
Change-Id: I11e2f66532fe5d1b0082b2433212e24bdda8219b
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
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
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
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
__set_errno returns -1 exactly so that callers don't need to bother.
The other architectures were already taking advantage of this, but
no one had ever fixed x86 and x86_64.
Change-Id: Ie131494be664f6c4a1bbf8c61bbbed58eac56122
System calls can be pretty slow. This is mako, which has one of our
lowest latencies:
iterations ns/op
BM_unistd_getpid 10000000 209
BM_unistd_gettid 200000000 8
Bug: 15297299 (kernel panic from too many gettid calls)
Bug: 15315766 (excessive gettid overhead in liblogd)
Change-Id: I49656c0fc5b5d092390264a59e4f2c0d8a8b1aeb
The problem with the original patch was that using syscall(3) means that
errno can be set, but pthread_create(3) was abusing the TLS errno slot as
a pthread_mutex_t for the thread startup handshake.
There was also a mistake in the check for syscall failures --- it should
have checked against -1 instead of 0 (not just because that's the default
idiom, but also here because futex(2) can legitimately return values > 0).
This patch stops abusing the TLS errno slot and adds a pthread_mutex_t to
pthread_internal_t instead. (Note that for LP64 sizeof(pthread_mutex_t) >
sizeof(uintptr_t), so we could potentially clobber other TLS slots too.)
I've also rewritten the LP32 compatibility stubs to directly reuse the
code from the .h file.
This reverts commit 75c55ff84e.
Bug: 15195455
Change-Id: I6ffb13e5cf6a35d8f59f692d94192aae9ab4593d
This reverts commit ced906c849.
Causes issues on art / dalvik due to a broken return value
check and other undiagnosed issues.
bug: 15195455
Change-Id: I5d6bbb389ecefb0e33a5237421a9d56d32a9317c
glibc doesn't have tkill or tgkill and says "use syscall(3) instead".
I've left tgkill since it's quite widely used, but there's no reason
to have tkill as well.
Bug: 11156955
Change-Id: Ifc0af750320086f829bc9914551c172b501f3b60
This was accidentally added at a time when you couldn't add a constant
to <syscall.h> without generating an assembly stub! (You no longer need
to add the constants at all.)
Bug: 11156955
Change-Id: I053c17879138787976c744a5ecf7d30ee51dc48f
The library exists outside bionic. It is dynamically loaded, to replace selected
standard socket syscalls with versions that talk to netd.
Change connect() to use the library if available.
(cherry picked from commit 3a6b627a14df8111b03e452f2df4b5f4938e0e49)
Change-Id: Ib6198e19dbc306521a26fcecfdf6e8424d163fc9
Also add the corresponding constant, struct, and function declarations
to <sys/socket.h>, and perfunctory tests so we know that the symbols
actually exist.
Signed-off-by: Guillaume Ranquet <guillaumex.ranquet@intel.com>
Change-Id: Ib0d854239d3716be90ad70973c579aff4895a4f7
This gives us:
* <dirent.h>
struct dirent64
readdir64, readdir64_r, alphasort64, scandir64
* <fcntl.h>
creat64, openat64, open64.
* <sys/stat.h>
struct stat64
fstat64, fstatat64, lstat64, stat64.
* <sys/statvfs.h>
struct statvfs64
statvfs64, fstatvfs64.
* <sys/vfs.h>
struct statfs64
statfs64, fstatfs64.
This also removes some of the incorrect #define hacks we've had in the
past (for stat64, for example, which we promised to clean up way back
in bug 8472078).
Bug: 11865851
Bug: 8472078
Change-Id: Ia46443521918519f2dfa64d4621027dfd13ac566
The situation here is a bit confusing. On 64-bit, rlimit and rlimit64 are
the same, and so getrlimit/getrlimit64, setrlimit/setrlimit64,
and prlimit/prlimit64 are all the same. On 32-bit, rlimit and rlimit64 are
different. 32-bit architectures other than MIPS go one step further by having
an even more limited getrlimit system call, so arm and x86 need to use
ugetrlimit instead of getrlimit. Worse, the 32-bit architectures don't have
64-bit getrlimit- and setrlimit-equivalent system calls, and you have to use
prlimit64 instead. There's no 32-bit prlimit system call, so there's no
easy implementation of that --- what should we do if the result of prlimit64
won't fit in a struct rlimit? Since 32-bit survived without prlimit/prlimit64
for this long, I'm not going to bother implementing prlimit for 32-bit.
We need the rlimit64 functions to be able to build strace 4.8 out of the box.
Change-Id: I1903d913b23016a2fc3b9f452885ac730d71e001
This patch switches to using the uapi constants. It also adds the missing
setns system call, fixes sched_getcpu's error behavior, and fixes the
gensyscalls script now ARM is uapi-only too.
Change-Id: I8e16b1693d6d32cd9b8499e46b5d8b0a50bc4f1d
