35778253a5
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
15 lines
326 B
ArmAsm
15 lines
326 B
ArmAsm
/* Generated by gensyscalls.py. Do not edit. */
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#include <private/bionic_asm.h>
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ENTRY(___faccessat)
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mov ip, r7
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ldr r7, =__NR_faccessat
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swi #0
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mov r7, ip
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cmn r0, #(MAX_ERRNO + 1)
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bxls lr
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neg r0, r0
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b __set_errno_internal
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END(___faccessat)
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.hidden ___faccessat
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