linux-user: Add support for adjtimex() syscall

This patch implements Qemu user mode adjtimex() syscall support.

Syscall adjtimex() reads and optionally sets parameters for a clock
adjustment algorithm used in network synchonization or similar scenarios.

Its declaration is:

int adjtimex(struct timex *buf);

The correspondent source code in the Linux kernel is at kernel/time.c,
line 206.

The Qemu implementation is based on invocation of host's adjtimex(), and
its key part is in the "TARGET_NR_adjtimex" case segment of the the main
switch statement of the function do_syscall(), in linux-user/syscalls.c. All
necessary conversions of the data structures from target to host and from
host to target are covered. Two new functions, target_to_host_timex() and
host_to_target_timex(), are provided for the purpose of such conversions.
For that purpose, the support for related structure "timex" had tp be added
to the file linux-user/syscall_defs.h, based on its definition in Linux
kernel. Also, the relevant support for "-strace" Qemu option is included
in files linux-user/strace.c and linux-user/strace.list.

This patch also fixes failures of LTP tests adjtimex01 and adjtimex02, if
executed in Qemu user mode.

Signed-off-by: Aleksandar Rikalo <aleksandar.rikalo@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 1e5136098e..f37b386bda 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -577,6 +577,52 @@ print_syscall_ret_newselect(const struct syscallname *name, abi_long ret)
 }
 #endif
 
+/* special meanings of adjtimex()' non-negative return values */
+#define TARGET_TIME_OK       0   /* clock synchronized, no leap second */
+#define TARGET_TIME_INS      1   /* insert leap second */
+#define TARGET_TIME_DEL      2   /* delete leap second */
+#define TARGET_TIME_OOP      3   /* leap second in progress */
+#define TARGET_TIME_WAIT     4   /* leap second has occurred */
+#define TARGET_TIME_ERROR    5   /* clock not synchronized */
+static void
+print_syscall_ret_adjtimex(const struct syscallname *name, abi_long ret)
+{
+    const char *errstr = NULL;
+
+    gemu_log(" = ");
+    if (ret < 0) {
+        gemu_log("-1 errno=%d", errno);
+        errstr = target_strerror(-ret);
+        if (errstr) {
+            gemu_log(" (%s)", errstr);
+        }
+    } else {
+        gemu_log(TARGET_ABI_FMT_ld, ret);
+        switch (ret) {
+        case TARGET_TIME_OK:
+            gemu_log(" TIME_OK (clock synchronized, no leap second)");
+            break;
+        case TARGET_TIME_INS:
+            gemu_log(" TIME_INS (insert leap second)");
+            break;
+        case TARGET_TIME_DEL:
+            gemu_log(" TIME_DEL (delete leap second)");
+            break;
+        case TARGET_TIME_OOP:
+            gemu_log(" TIME_OOP (leap second in progress)");
+            break;
+        case TARGET_TIME_WAIT:
+            gemu_log(" TIME_WAIT (leap second has occurred)");
+            break;
+        case TARGET_TIME_ERROR:
+            gemu_log(" TIME_ERROR (clock not synchronized)");
+            break;
+        }
+    }
+
+    gemu_log("\n");
+}
+
 UNUSED static struct flags access_flags[] = {
     FLAG_GENERIC(F_OK),
     FLAG_GENERIC(R_OK),