Qemu includes the glibc headers for the host defines and target headers are
part of the qemu source themselves. The glibc has the F_GETLK64, F_SETLK64
and F_SETLKW64 defined to 12, 13 and 14 for all archs in
sysdeps/unix/sysv/linux/bits/fcntl-linux.h. The linux kernel generic
definition for F_*LK is 5, 6 & 7 and F_*LK64* is 12,13, and 14 as seen in
include/uapi/asm-generic/fcntl.h. On 64bit machine, by default the kernel
assumes all F_*LK to 64bit calls and doesnt support use of F_*LK64* as
can be seen in include/linux/fcntl.h in linux source.
On x86_64 host, the values for F_*LK64* are set to 5, 6 and 7
explicitly in /usr/include/x86_64-linux-gnu/bits/fcntl.h by the glibc.
Whereas, a PPC64 host doesn't have such a definition in
/usr/include/powerpc64le-linux-gnu/bits/fcntl.h by the glibc. So,
the sources on PPC64 host sees the default value of F_*LK64*
as 12, 13 & 14(fcntl-linux.h).
Since the 64bit kernel doesnt support 12, 13 & 14; the glibc fcntl syscall
implementation(__libc_fcntl*(), __fcntl64_nocancel) does the F_*LK64* value
convertion back to F_*LK* values on PPC64 as seen in
sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h with FCNTL_ADJUST_CMD()
macro. Whereas on x86_64 host the values for F_*LK64* are set to 5, 6 and 7
and no adjustments are needed.
Since qemu doesnt use the glibc fcntl, but makes the safe_syscall* on its
own, the PPC64 qemu is calling the syscall with 12, 13, and 14(without
adjustment) and they all fail. The fcntl calls to F_GETLK/F_SETLK|W all
fail by all pplications run on PPC64 host user emulation.
The fix here could be to see why on PPC64 the glibc is still keeping
F_*LK64* different from F_*LK and why adjusting them to 5, 6 and 7 before
the syscall for PPC only. See if we can make the
/usr/include/powerpc64le-linux-gnu/bits/fcntl.h to have the values
5, 6 & 7 just like x86_64 and remove the adjustment code in glibc. That
way, qemu sources see the kernel supported values in glibc headers.
OR
On PPC64 host, qemu sources see both F_*LK & F_*LK64* as same and set to
12, 13 and 14 because __USE_FILE_OFFSET64 is defined in qemu
sources(also refer sysdeps/unix/sysv/linux/bits/fcntl-linux.h).
Do the value adjustment just like it is done by glibc source by using
F_GETLK value of 5. That way, we make the syscalls with the actual
supported values in Qemu. The patch is taking this approach.
Signed-off-by: Shivaprasad G Bhat <sb...@linux.vnet.ibm.com>
---
Changes from v1:
- Changed the overwrite of F*LK64* with 5, 6 and 7 in using #define
instead using the adjustment code similar to glibc as suggested.
- Dropped __linux__ check for the adjustment code as suggested.
- Moved the adjustment code inside target_to_host_fcntl_cmd to address
all possible|future cases.
linux-user/syscall.c | 73 ++++++++++++++++++++++++++++++++++++--------------
1 file changed, 52 insertions(+), 21 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 643b8833de..38c2f1e90f 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6475,63 +6475,94 @@ static int do_fork(CPUArchState *env, unsigned int
flags, abi_ulong newsp,
/* warning : doesn't handle linux specific flags... */
static int target_to_host_fcntl_cmd(int cmd)
{
+ int ret = -TARGET_EINVAL;
switch(cmd) {
case TARGET_F_DUPFD:
case TARGET_F_GETFD:
case TARGET_F_SETFD:
case TARGET_F_GETFL:
case TARGET_F_SETFL:
- return cmd;
+ ret = cmd;
+ break;
case TARGET_F_GETLK:
- return F_GETLK64;
+ ret = F_GETLK64;
+ break;
case TARGET_F_SETLK:
- return F_SETLK64;
+ ret = F_SETLK64;
+ break;
case TARGET_F_SETLKW:
- return F_SETLKW64;
+ ret = F_SETLKW64;
+ break;
case TARGET_F_GETOWN:
- return F_GETOWN;
+ ret = F_GETOWN;
+ break;
case TARGET_F_SETOWN:
- return F_SETOWN;
+ ret = F_SETOWN;
+ break;
case TARGET_F_GETSIG:
- return F_GETSIG;
+ ret = F_GETSIG;
+ break;
case TARGET_F_SETSIG:
- return F_SETSIG;
+ ret = F_SETSIG;
+ break;
#if TARGET_ABI_BITS == 32
case TARGET_F_GETLK64:
- return F_GETLK64;
+ ret = F_GETLK64;
+ break;
case TARGET_F_SETLK64:
- return F_SETLK64;
+ ret = F_SETLK64;
+ break;
case TARGET_F_SETLKW64:
- return F_SETLKW64;
+ ret = F_SETLKW64;
+ break;
#endif
case TARGET_F_SETLEASE:
- return F_SETLEASE;
+ ret = F_SETLEASE;
+ break;
case TARGET_F_GETLEASE:
- return F_GETLEASE;
+ ret = F_GETLEASE;
+ break;
#ifdef F_DUPFD_CLOEXEC
case TARGET_F_DUPFD_CLOEXEC:
- return F_DUPFD_CLOEXEC;
+ ret = F_DUPFD_CLOEXEC;
+ break;
#endif
case TARGET_F_NOTIFY:
- return F_NOTIFY;
+ ret = F_NOTIFY;
+ break;
#ifdef F_GETOWN_EX
case TARGET_F_GETOWN_EX:
- return F_GETOWN_EX;
+ ret = F_GETOWN_EX;
+ break;
#endif
#ifdef F_SETOWN_EX
case TARGET_F_SETOWN_EX:
- return F_SETOWN_EX;
+ ret = F_SETOWN_EX;
+ break;
#endif
#ifdef F_SETPIPE_SZ
case TARGET_F_SETPIPE_SZ:
- return F_SETPIPE_SZ;
+ ret = F_SETPIPE_SZ;
+ break;
case TARGET_F_GETPIPE_SZ:
- return F_GETPIPE_SZ;
+ ret = F_GETPIPE_SZ;
+ break;
#endif
default:
- return -TARGET_EINVAL;
+ ret = -TARGET_EINVAL;
}
- return -TARGET_EINVAL;
+
+#if defined(__powerpc64__)
+/* On PPC64, glibc headers has the F_*LK* defined to 12, 13 and 14 and
+ * is not supported by kernel. The glibc fcntl call actually adjusts
+ * them to 5, 6 and 7 before making the syscall(). Since we make the
+ * syscall directly, adjust to what is supported by the kernel.
+ */
+ if (ret >= F_GETLK64 && ret <= F_SETLKW64) {
+ ret -= F_GETLK64 - 5;
+#endif
+
+ return ret;
}
#define TRANSTBL_CONVERT(a) { -1, TARGET_##a, -1, a }
