[PATCH] linux-user: open_self_stat: Implement num_threads

["Fabio D'Urso" <fdurso@google.com>]

The num_threads field reports the total number of threads in the
process. In QEMU, this is equal to the number of CPU instances.

Signed-off-by: Fabio D'Urso <fdurso@google.com>
---
 linux-user/syscall.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index b9b5a387b3..a47b2eeb65 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8171,6 +8171,16 @@ static int open_self_stat(CPUArchState *cpu_env, int fd)
         } else if (i == 3) {
             /* ppid */
             g_string_printf(buf, FMT_pid " ", getppid());
+        } else if (i == 19) {
+            /* num_threads */
+            int cpus = 0;
+            WITH_RCU_READ_LOCK_GUARD() {
+                CPUState *cpu_iter;
+                CPU_FOREACH(cpu_iter) {
+                    cpus++;
+                }
+            }
+            g_string_printf(buf, "%d ", cpus);
         } else if (i == 21) {
             /* starttime */
             g_string_printf(buf, "%" PRIu64 " ", ts->start_boottime);
-- 
2.45.2.627.g7a2c4fd464-goog