linux-user: Special-case ERESTARTSYS in target_strerror()

Since TARGET_ERESTARTSYS and TARGET_ESIGRETURN are internal-to-QEMU
error numbers, handle them specially in target_strerror(), to avoid
confusing strace output like:

9521 rt_sigreturn(14,8,274886297808,8,0,268435456) = -1 errno=513 (Unknown error 513)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 262c645d3c..bd8095c819 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -632,6 +632,13 @@ static inline int is_error(abi_long ret)
 
 const char *target_strerror(int err)
 {
+    if (err == TARGET_ERESTARTSYS) {
+        return "To be restarted";
+    }
+    if (err == TARGET_QEMU_ESIGRETURN) {
+        return "Successful exit from sigreturn";
+    }
+
     if ((err >= ERRNO_TABLE_SIZE) || (err < 0)) {
         return NULL;
     }