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[Qemu-devel] [PATCH] linux-user: Fix conversion of sigevent argument to
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH] linux-user: Fix conversion of sigevent argument to timer_create |
Date: |
Sat, 9 Aug 2014 15:42:32 +0100 |
There were a number of bugs in the conversion of the sigevent
argument to timer_create from target to host format:
* signal number not converted from target to host
* thread ID not copied across
* sigev_value not copied across
* we never unlocked the struct when we were done
Between them, these problems meant that SIGEV_THREAD_ID
timers (and the glibc-implemented SIGEV_THREAD timers which
depend on them) didn't work.
Fix these problems and clean up the code a little by pulling
the struct conversion out into its own function, in line with
how we convert various other structs. This allows the test
program in bug LP:1042388 to run.
Signed-off-by: Peter Maydell <address@hidden>
---
Riku: this is going to conflict with and supersede Erik's oneliner
patch which adds the unlock_user_struct() (I'm afraid I forgot about
that when I was writing this and independently re-fixed the bug),
so it might be simplest to drop that from the linux-user queue if
you apply this instead. Otherwise if that patch makes it to master
I'll rebase and resend this one at that point.
linux-user/syscall.c | 38 ++++++++++++++++++++++++++++++--------
1 file changed, 30 insertions(+), 8 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a50229d..4ce7455 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4914,6 +4914,32 @@ static inline abi_long
host_to_target_itimerspec(abi_ulong target_addr,
return 0;
}
+static inline abi_long target_to_host_sigevent(struct sigevent *host_sevp,
+ abi_ulong target_addr)
+{
+ struct target_sigevent *target_sevp;
+
+ if (!lock_user_struct(VERIFY_READ, target_sevp, target_addr, 1)) {
+ return -TARGET_EFAULT;
+ }
+
+ /* This union is awkward on 64 bit systems because it has a 32 bit
+ * integer and a pointer in it; we follow the conversion approach
+ * used for handling sigval types in signal.c so the guest should get
+ * the correct value back even if we did a 64 bit byteswap and it's
+ * using the 32 bit integer.
+ */
+ host_sevp->sigev_value.sival_ptr =
+ (void *)(uintptr_t)tswapal(target_sevp->sigev_value.sival_ptr);
+ host_sevp->sigev_signo =
+ target_to_host_signal(tswap32(target_sevp->sigev_signo));
+ host_sevp->sigev_notify = tswap32(target_sevp->sigev_notify);
+ host_sevp->_sigev_un._tid = tswap32(target_sevp->_sigev_un._tid);
+
+ unlock_user_struct(target_sevp, target_addr, 1);
+ return 0;
+}
+
#if defined(TARGET_NR_stat64) || defined(TARGET_NR_newfstatat)
static inline abi_long host_to_target_stat64(void *cpu_env,
abi_ulong target_addr,
@@ -9413,7 +9439,6 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
/* args: clockid_t clockid, struct sigevent *sevp, timer_t *timerid */
struct sigevent host_sevp = { {0}, }, *phost_sevp = NULL;
- struct target_sigevent *ptarget_sevp;
struct target_timer_t *ptarget_timer;
int clkid = arg1;
@@ -9425,14 +9450,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long
arg1,
timer_t *phtimer = g_posix_timers + timer_index;
if (arg2) {
- if (!lock_user_struct(VERIFY_READ, ptarget_sevp, arg2, 1)) {
- goto efault;
- }
-
- host_sevp.sigev_signo = tswap32(ptarget_sevp->sigev_signo);
- host_sevp.sigev_notify = tswap32(ptarget_sevp->sigev_notify);
-
phost_sevp = &host_sevp;
+ ret = target_to_host_sigevent(phost_sevp, arg2);
+ if (ret != 0) {
+ break;
+ }
}
ret = get_errno(timer_create(clkid, phost_sevp, phtimer));
--
1.9.1
- [Qemu-devel] [PATCH] linux-user: Fix conversion of sigevent argument to timer_create,
Peter Maydell <=