ifstat, nstat: fix daemon mode

Since the relevant code (and it's bugs) is identical in both files, fix
them in one go. This patch fixes multiple issues:

* Using 'int' for the 'tdiff' variable does not suffice on 64bit
  systems, the assigned initial time difference makes it wrap and
  contain a negative value afterwards. Instead use the more appropriate
  'time_t' type.

* As far as I understood the code, poll() is supposed to time out just
  at the right time to trigger update_db() in the configured interval.
  Therefore it's timeout must be set to the desired interval *minus* the
  time that has already passed since then.

* With the last change to the algorithm in place, it does not make sense
  to call update_db() before returning data to the connected client.
  Actually, it never does otherwise we could skip the periodic updates
  in the first place.

Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/misc/ifstat.c b/misc/ifstat.c
index ac5c29c89184ab9dbd3029e6bf0c9414e77c7635..694d9839d2bd0d474d02eacb288dc22dff7fec0d 100644 (file)
--- a/misc/ifstat.c
+++ b/misc/ifstat.c
@@ -589,7 +589,7 @@ static void server_loop(int fd)
 
        for (;;) {
                int status;
-               int tdiff;
+               time_t tdiff;
                struct timeval now;
 
                gettimeofday(&now, NULL);
@@ -600,7 +600,7 @@ static void server_loop(int fd)
                        tdiff = 0;
                }
 
-               if (poll(&p, 1, tdiff + scan_interval) > 0
+               if (poll(&p, 1, scan_interval - tdiff) > 0
                    && (p.revents&POLLIN)) {
                        int clnt = accept(fd, NULL, NULL);
                        if (clnt >= 0) {
@@ -613,11 +613,8 @@ static void server_loop(int fd)
                                        close(clnt);
                                } else {
                                        FILE *fp = fdopen(clnt, "w");
-                                       if (fp) {
-                                               if (tdiff > 0)
-                                                       update_db(tdiff);
+                                       if (fp)
                                                dump_raw_db(fp, 0);
-                                       }
                                        exit(0);
                                }
                        }

diff --git a/misc/nstat.c b/misc/nstat.c
index 99705286d279cb47d2a12a78fac23851a5f0082e..22b27eba7c8f600a0824f86a018f28a41de686aa 100644 (file)
--- a/misc/nstat.c
+++ b/misc/nstat.c
@@ -433,7 +433,7 @@ static void server_loop(int fd)
 
        for (;;) {
                int status;
-               int tdiff;
+               time_t tdiff;
                struct timeval now;
                gettimeofday(&now, NULL);
                tdiff = T_DIFF(now, snaptime);
@@ -442,7 +442,7 @@ static void server_loop(int fd)
                        snaptime = now;
                        tdiff = 0;
                }
-               if (poll(&p, 1, tdiff + scan_interval) > 0
+               if (poll(&p, 1, scan_interval - tdiff) > 0
                    && (p.revents&POLLIN)) {
                        int clnt = accept(fd, NULL, NULL);
                        if (clnt >= 0) {
@@ -455,11 +455,8 @@ static void server_loop(int fd)
                                        close(clnt);
                                } else {
                                        FILE *fp = fdopen(clnt, "w");
-                                       if (fp) {
-                                               if (tdiff > 0)
-                                                       update_db(tdiff);
+                                       if (fp)
                                                dump_kern_db(fp, 0);
-                                       }
                                        exit(0);
                                }
                        }