[v2,3/3] linux-user: Add support for ustat() syscall

Commit Message

Aleksandar Markovic Sept. 5, 2016, 2 p.m. UTC

From: Aleksandar Markovic <[e-mail]>

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

Syscall ustat() returns information about a mounted filesystem.

The implementation is similar to the implementations of statfs(),
fstatfs() and other related syscalls. It is based on invocation of
host's ustat(), and its key part is in the correspondent case segment
of the main switch statement of the function do_syscall(), in file
linux-user/syscalls.c. All necessary conversions of data structures
from target to host and from host to target are covered. Sufficient
support for "-strace" option for this syscall is already present,
and this patch does not change it.

This patch also fixes failures of LTP tests ustat01, and ustat02, if
executed on Qemu-emulated systems.

Signed-off-by: Aleksandar Markovic <[e-mail]>
---
 linux-user/syscall.c |   25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 38d69f1..b118bd9 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -48,6 +48,7 @@  int __clone2(int (*fn)(void *), void *child_stack_base,
 #include <sys/shm.h>
 #include <sys/sem.h>
 #include <sys/statfs.h>
+#include <ustat.h>
 #include <utime.h>
 #include <sys/sysinfo.h>
 #include <sys/signalfd.h>
@@ -8098,7 +8099,29 @@  abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
         break;
 #ifdef TARGET_NR_ustat
     case TARGET_NR_ustat:
-        goto unimplemented;
+    {
+        struct ustat ust;
+        int cnt;
+        ret = get_errno(ustat(arg1, &ust));
+
+        if (!is_error(ret)) {
+            struct ustat *target_ust;
+
+            if (!lock_user_struct(VERIFY_WRITE, target_ust, arg2, 0)) {
+                goto efault;
+            }
+
+            __put_user(ust.f_tfree, &target_ust->f_tfree);
+            __put_user(ust.f_tinode, &target_ust->f_tinode);
+
+            for (cnt = 0; cnt < 6; cnt++) {
+                __put_user(ust.f_fname[cnt], &target_ust->f_fname[cnt]);
+                __put_user(ust.f_fpack[cnt], &target_ust->f_fpack[cnt]);
+            }
+            unlock_user_struct(target_ust, arg2, 1);
+        }
+        break;
+      }
 #endif
 #ifdef TARGET_NR_dup2
     case TARGET_NR_dup2: