ibmi: read memory and CPU usage info

PR-URL: https://github.com/libuv/libuv/pull/2261
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

src/unix/ibmi.c

@@ -55,19 +55,150 @@
 #include <strings.h>
 #include <sys/vnode.h>
 
+#include <as400_protos.h>
+
+
+typedef struct {
+  int bytes_available;
+  int bytes_returned;
+  char current_date_and_time[8];
+  char system_name[8];
+  char elapsed_time[6];
+  char restricted_state_flag;
+  char reserved;
+  int percent_processing_unit_used;
+  int jobs_in_system;
+  int percent_permanent_addresses;
+  int percent_temporary_addresses;
+  int system_asp;
+  int percent_system_asp_used;
+  int total_auxiliary_storage;
+  int current_unprotected_storage_used;
+  int maximum_unprotected_storage_used;
+  int percent_db_capability;
+  int main_storage_size;
+  int number_of_partitions;
+  int partition_identifier;
+  int reserved1;
+  int current_processing_capacity;
+  char processor_sharing_attribute;
+  char reserved2[3];
+  int number_of_processors;
+  int active_jobs_in_system;
+  int active_threads_in_system;
+  int maximum_jobs_in_system;
+  int percent_temporary_256mb_segments_used;
+  int percent_temporary_4gb_segments_used;
+  int percent_permanent_256mb_segments_used;
+  int percent_permanent_4gb_segments_used;
+  int percent_current_interactive_performance;
+  int percent_uncapped_cpu_capacity_used;
+  int percent_shared_processor_pool_used;
+  long main_storage_size_long;
+} SSTS0200;
+
+
+static int get_ibmi_system_status(SSTS0200* rcvr) {
+  /* rcvrlen is input parameter 2 to QWCRSSTS */
+  unsigned int rcvrlen = sizeof(*rcvr);
+
+  /* format is input parameter 3 to QWCRSSTS ("SSTS0200" in EBCDIC) */
+  unsigned char format[] = {0xE2, 0xE2, 0xE3, 0xE2, 0xF0, 0xF2, 0xF0, 0xF0};
+
+  /* reset_status is input parameter 4 to QWCRSSTS ("*NO       " in EBCDIC) */
+  unsigned char reset_status[] = {
+    0x5C, 0xD5, 0xD6, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40
+  };
+
+  /* errcode is input parameter 5 to QWCRSSTS */
+  struct _errcode {
+    int bytes_provided;
+    int bytes_available;
+    char msgid[7];
+  } errcode;
+
+  /* qwcrssts_pointer is the 16-byte tagged system pointer to QWCRSSTS */
+  ILEpointer __attribute__((aligned(16))) qwcrssts_pointer;
+
+  /* qwcrssts_argv is the array of argument pointers to QWCRSSTS */
+  void* qwcrssts_argv[6];
+
+  /* Set the IBM i pointer to the QSYS/QWCRSSTS *PGM object */
+  int rc = _RSLOBJ2(&qwcrssts_pointer, RSLOBJ_TS_PGM, "QWCRSSTS", "QSYS");
+
+  if (rc != 0)
+    return rc;
+
+  /* initialize the QWCRSSTS returned info structure */
+  memset(rcvr, 0, sizeof(*rcvr));
+
+  /* initialize the QWCRSSTS error code structure */
+  memset(&errcode, 0, sizeof(errcode));
+  errcode.bytes_provided = sizeof(errcode);
+
+  /* initialize the array of argument pointers for the QWCRSSTS API */
+  qwcrssts_argv[0] = rcvr;
+  qwcrssts_argv[1] = &rcvrlen;
+  qwcrssts_argv[2] = &format;
+  qwcrssts_argv[3] = &reset_status;
+  qwcrssts_argv[4] = &errcode;
+  qwcrssts_argv[5] = NULL;
+
+  /* Call the IBM i QWCRSSTS API from PASE */
+  rc = _PGMCALL(&qwcrssts_pointer, (void**)&qwcrssts_argv, 0);
+
+  return rc;
+}
+
+
 uint64_t uv_get_free_memory(void) {
-  return (uint64_t) sysconf(_SC_PAGESIZE) * sysconf(_SC_AVPHYS_PAGES);
+  SSTS0200 rcvr;
+
+  if (get_ibmi_system_status(&rcvr))
+    return 0;
+
+  /* The amount of main storage, in kilobytes, in the system. */
+  uint64_t main_storage_size = rcvr.main_storage_size;
+
+  /* The current amount of storage in use for temporary objects.
+   * in millions (M) of bytes.
+   */
+  uint64_t current_unprotected_storage_used =
+    rcvr.current_unprotected_storage_used * 1024ULL;
+
+  uint64_t free_storage_size =
+    (main_storage_size - current_unprotected_storage_used) * 1024ULL;
+
+  return free_storage_size < 0 ? 0 : free_storage_size;
 }
 
 
 uint64_t uv_get_total_memory(void) {
-  return (uint64_t) sysconf(_SC_PAGESIZE) * sysconf(_SC_PHYS_PAGES);
+  SSTS0200 rcvr;
+
+  if (get_ibmi_system_status(&rcvr))
+    return 0;
+
+  return (uint64_t)rcvr.main_storage_size * 1024ULL;
 }
 
 
 void uv_loadavg(double avg[3]) {
+  SSTS0200 rcvr;
+
+  if (get_ibmi_system_status(&rcvr)) {
     avg[0] = avg[1] = avg[2] = 0;
     return;
+  }
+
+  /* The average (in tenths) of the elapsed time during which the processing
+   * units were in use. For example, a value of 411 in binary would be 41.1%.
+   * This percentage could be greater than 100% for an uncapped partition.
+   */
+  double processing_unit_used_percent =
+    rcvr.percent_processing_unit_used / 1000.0;
+
+  avg[0] = avg[1] = avg[2] = processing_unit_used_percent;
 }
 
 
@@ -110,4 +241,4 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
   *count = numcpus;
 
   return 0;
-}
+}