redfishpower: support setstatuspollinginterval

Problem: The wait until on/off polling interval in redfishpower
is currently hard coded to 1 second.  On some slow systems, it has
been observed that on/off can take upwards of a minute.  On that
hardware, a 1 second retry delay can lead to an excess amount of
traffic on the network.

Support a prompt command that will allow change of the status polling
interval.  Document new command in redfishpower(8).  Update redfishpower
test helper to parse setstatuspollinginterval.

man/redfishpower.8.in

@@ -63,6 +63,10 @@ Set path and optional post data to turn off node.
 .I "settimeout <seconds>"
 Set command timeout in seconds.
 .TP
+.I "setstatuspollinginterval <seconds>"
+Set status polling interval in seconds. This is the polling interval
+to determine an on/off command has completed.
+.TP
 .I "stat [nodes]"
 Get power status of all nodes or specified subset of nodes.
 .TP

src/redfishpower/redfishpower.c

@@ -22,6 +22,7 @@
 #include <sys/select.h>
 #include <limits.h>
 #include <sys/time.h>
+#include <limits.h>
 #include <ctype.h>
 #include <errno.h>
 #include <assert.h>
@@ -64,11 +65,13 @@ static zhashx_t *test_power_status;
 
 /* in usec
  *
- * status polling interval of 1 second may seem long, but testing
- * shows wait ranges from a few seconds to 20 seconds
+ * status polling interval of 1 second may seem long, but testing shows wait ranges
+ * from a few seconds to almost a minute. Device files should adjust
+ * to longer times for really bad systems.
  */
-#define STATUS_POLLING_INTERVAL 1000000
+#define STATUS_POLLING_INTERVAL_DEFAULT 1000000
 
+#define USEC_IN_SEC 1000000
 #define MS_IN_SEC 1000
 
 #define CMD_STAT "stat"
@@ -138,6 +141,10 @@ static struct option longopts[] = {
 };
 
 static time_t cmd_timeout = CMD_TIMEOUT_DEFAULT;
+/* typically is of type suseconds_t, but has questionable portability,
+ * so use 'long int' instead
+ */
+static long int status_polling_interval = STATUS_POLLING_INTERVAL_DEFAULT;
 
 void help(void)
 {
@@ -148,6 +155,7 @@ void help(void)
  printf(" setonpath path [postdata]\n");
  printf(" setoffpath path [postdata]\n");
  printf(" settimeout seconds\n");
+ printf(" setstatuspollinginterval seconds\n");
  printf(" stat [nodes]\n");
  printf(" on [nodes]\n");
  printf(" off [nodes]\n");
@@ -569,7 +577,7 @@ static void send_status_poll(struct powermsg *pm)
  statpath,
  NULL,
  &pm->start,
- STATUS_POLLING_INTERVAL,
+ status_polling_interval,
  STATE_WAIT_UNTIL_ON_OFF);
  if (!(nextpm->handle = zlistx_add_end(delayedcmds, nextpm)))
  err_exit(true, "zlistx_add_end");
@@ -749,6 +757,23 @@ static void settimeout(char **av)
  }
 }
 
+static void setstatuspollinginterval(char **av)
+{
+ if (av[0]) {
+ char *endptr;
+ long tmp;
+
+ errno = 0;
+ tmp = strtol (av[0], &endptr, 10);
+ if (errno
+ || endptr[0] != '\0'
+ || tmp <= 0
+ || (tmp > (LONG_MAX / USEC_IN_SEC)))
+ printf("invalid status polling interval specified\n");
+ status_polling_interval = tmp * USEC_IN_SEC;
+ }
+}
+
 static void process_cmd(CURLM *mh, char **av, int *exitflag)
 {
  if (av[0] != NULL) {
@@ -768,6 +793,8 @@ static void process_cmd(CURLM *mh, char **av, int *exitflag)
  setpowerpath(av + 1, &offpath, &offpostdata);
  else if (strcmp(av[0], "settimeout") == 0)
  settimeout(av + 1);
+ else if (strcmp(av[0], "setstatuspollinginterval") == 0)
+ setstatuspollinginterval(av + 1);
  else if (strcmp(av[0], CMD_STAT) == 0)
  stat_cmd(mh, av + 1);
  else if (strcmp(av[0], CMD_ON) == 0)