[Qemu-devel] [PATCH] linux-user: rlimit conversion between host and target.

[takasi-y]

rlim_t conversion between host and target added.
Otherwise there are some incorrect case like
- RLIM_INFINITY on 32bit target -> 64bit host. 
- RLIM_INFINITY on 64bit host -> mips and sparc target ?
- Big value(for 32bit target) on 64bit host -> 32bit target.

One is added into getrlimit, setrlimit, and ugetrlimit. It converts both
RLIM_INFINITY and value bigger than target can hold(>31bit) to RLIM_INFINITY.

Another one is added to guest_stack_size calculation introduced by
703e0e89. The rule is mostly same except the result on the case is keeping
the value of guest_stack_size.

Slightly tested for SH4, and x86_64 -linux-user on x86_64-pc-linux host.

Signed-off-by: Takashi YOSHII <address@hidden>
---
 linux-user/main.c         |    3 ++-
 linux-user/syscall.c      |   30 ++++++++++++++++++++++--------
 linux-user/syscall_defs.h |    8 ++++++++
 3 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index b394c00..60eea3a 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2645,7 +2645,8 @@ int main(int argc, char **argv, char **envp)
     {
         struct rlimit lim;
         if (getrlimit(RLIMIT_STACK, &lim) == 0
-            && lim.rlim_cur != RLIM_INFINITY) {
+            && lim.rlim_cur != RLIM_INFINITY
+            && lim.rlim_cur == (target_long)lim.rlim_cur) {
             guest_stack_size = lim.rlim_cur;
         }
     }
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a03e432..cfc91d1 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -831,6 +831,22 @@ static inline abi_long host_to_target_rusage(abi_ulong 
target_addr,
     return 0;
 }
 
+static inline rlim_t target_to_host_rlim(target_ulong target_rlim)
+{
+    if (target_rlim == TARGET_RLIM_INFINITY)
+        return RLIM_INFINITY;
+    else
+        return tswapl(target_rlim);
+}
+
+static inline target_ulong host_to_target_rlim(rlim_t rlim)
+{
+    if (rlim == RLIM_INFINITY || rlim != (target_long)rlim)
+        return TARGET_RLIM_INFINITY;
+    else
+        return tswapl(rlim);
+}
+
 static inline abi_long copy_from_user_timeval(struct timeval *tv,
                                               abi_ulong target_tv_addr)
 {
@@ -5124,21 +5140,19 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
arg1,
         break;
     case TARGET_NR_setrlimit:
         {
-            /* XXX: convert resource ? */
             int resource = arg1;
             struct target_rlimit *target_rlim;
             struct rlimit rlim;
             if (!lock_user_struct(VERIFY_READ, target_rlim, arg2, 1))
                 goto efault;
-            rlim.rlim_cur = tswapl(target_rlim->rlim_cur);
-            rlim.rlim_max = tswapl(target_rlim->rlim_max);
+            rlim.rlim_cur = target_to_host_rlim(target_rlim->rlim_cur);
+            rlim.rlim_max = target_to_host_rlim(target_rlim->rlim_max);
             unlock_user_struct(target_rlim, arg2, 0);
             ret = get_errno(setrlimit(resource, &rlim));
         }
         break;
     case TARGET_NR_getrlimit:
         {
-            /* XXX: convert resource ? */
             int resource = arg1;
             struct target_rlimit *target_rlim;
             struct rlimit rlim;
@@ -5147,8 +5161,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
             if (!is_error(ret)) {
                 if (!lock_user_struct(VERIFY_WRITE, target_rlim, arg2, 0))
                     goto efault;
-                target_rlim->rlim_cur = tswapl(rlim.rlim_cur);
-                target_rlim->rlim_max = tswapl(rlim.rlim_max);
+                target_rlim->rlim_cur = host_to_target_rlim(rlim.rlim_cur);
+                target_rlim->rlim_max = host_to_target_rlim(rlim.rlim_max);
                 unlock_user_struct(target_rlim, arg2, 1);
             }
         }
@@ -6233,8 +6247,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
            struct target_rlimit *target_rlim;
             if (!lock_user_struct(VERIFY_WRITE, target_rlim, arg2, 0))
                 goto efault;
-           target_rlim->rlim_cur = tswapl(rlim.rlim_cur);
-           target_rlim->rlim_max = tswapl(rlim.rlim_max);
+           target_rlim->rlim_cur = host_to_target_rlim(rlim.rlim_cur);
+           target_rlim->rlim_max = host_to_target_rlim(rlim.rlim_max);
             unlock_user_struct(target_rlim, arg2, 1);
        }
        break;
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 63c2bc3..255e89c 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -669,6 +669,14 @@ struct target_rlimit {
         abi_ulong   rlim_max;
 };
 
+#if defined(TARGET_ALPHA)
+#define TARGET_RLIM_INFINITY   0x7ffffffffffffffful
+#elif defined(TARGET_MIPS) || defined(TARGET_SPARC)
+#define TARGET_RLIM_INFINITY   0x7fffffffUL
+#else
+#define TARGET_RLIM_INFINITY   ((target_ulong)~0UL)
+#endif
+
 struct target_pollfd {
     int fd;           /* file descriptor */
     short events;     /* requested events */
-- 
1.6.5