runsvdir: conditionalize "log in argiment" (mis)feature. By Vladimir.

 with:
runsv                                                139     141      +2
runsvdir_main                                       1583    1513     -70

 without:
warn2_cannot                                          14      27     +13
runsv                                                139     141      +2
warnx                                                 28      16     -12
warn3x                                                23       -     -23
runsvdir_main                                       1583    1125    -458

2 files changed, 88 insertions, 64 deletions

diff --git a/runit/Config.in b/runit/Config.in
index 8a7deea72..beff1e7e2 100644
--- a/runit/Config.in
+++ b/runit/Config.in
@@ -20,6 +20,15 @@ config RUNSVDIR
           a directory, in the services directory dir, up to a limit of 1000
           subdirectories, and restarts a runsv process if it terminates.
 
+config FEATURE_RUNSVDIR_LOG
+        bool "Enable scrolling argument log"
+        depends on RUNSVDIR
+        default n
+        help
+          Enable feature where second parameter of runsvdir holds last error
+          message (viewable via top/ps). Otherwise (feature is off
+          or no parameter), error messages go to stderr only.
+
 config SV
         bool "sv"
         default n
diff --git a/runit/runsvdir.c b/runit/runsvdir.c
index 0dedd5c77..8099ebf5c 100644
--- a/runit/runsvdir.c
+++ b/runit/runsvdir.c
@@ -35,8 +35,13 @@ ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #define MAXSERVICES 1000
 
+/* Should be not needed - all dirs are on same FS, right? */
+#define CHECK_DEVNO_TOO 0
+
 struct service {
+#if CHECK_DEVNO_TOO
         dev_t dev;
+#endif
         ino_t ino;
         pid_t pid;
         smallint isgone;
@@ -45,28 +50,30 @@ struct service {
 struct globals {
         struct service *sv;
         char *svdir;
-        char *rplog;
         int svnum;
+#if ENABLE_FEATURE_RUNSVDIR_LOG
+        char *rplog;
         int rploglen;
         struct fd_pair logpipe;
         struct pollfd pfd[1];
         unsigned stamplog;
-        smallint check; /* = 1; */
+#endif
+        smallint need_rescan; /* = 1; */
         smallint set_pgrp;
 };
 #define G (*(struct globals*)&bb_common_bufsiz1)
-#define sv        (G.sv        )
-#define svdir     (G.svdir     )
-#define rplog     (G.rplog     )
-#define svnum     (G.svnum     )
-#define rploglen  (G.rploglen  )
-#define logpipe   (G.logpipe   )
-#define pfd       (G.pfd       )
-#define stamplog  (G.stamplog  )
-#define check     (G.check     )
-#define set_pgrp  (G.set_pgrp  )
+#define sv          (G.sv          )
+#define svdir       (G.svdir       )
+#define svnum       (G.svnum       )
+#define rplog       (G.rplog       )
+#define rploglen    (G.rploglen    )
+#define logpipe     (G.logpipe     )
+#define pfd         (G.pfd         )
+#define stamplog    (G.stamplog    )
+#define need_rescan (G.need_rescan )
+#define set_pgrp    (G.set_pgrp    )
 #define INIT_G() do { \
-        check = 1; \
+        need_rescan = 1; \
 } while (0)
 
 static void fatal2_cannot(const char *m1, const char *m2)
@@ -82,10 +89,12 @@ static void warn2_cannot(const char *m1, const char *m2)
 {
         warn3x("cannot ", m1, m2);
 }
+#if ENABLE_FEATURE_RUNSVDIR_LOG
 static void warnx(const char *m1)
 {
         warn3x(m1, "", "");
 }
+#endif
 
 static void runsv(int no, const char *name)
 {
@@ -116,7 +125,7 @@ static void runsv(int no, const char *name)
         sv[no].pid = pid;
 }
 
-static void runsvdir(void)
+static void do_rescan(void)
 {
         DIR *dir;
         direntry *d;
@@ -140,13 +149,16 @@ static void runsvdir(void)
                         continue;
                 if (stat(d->d_name, &s) == -1) {
                         warn2_cannot("stat ", d->d_name);
-                        errno = 0;
                         continue;
                 }
                 if (!S_ISDIR(s.st_mode))
                         continue;
                 for (i = 0; i < svnum; i++) {
-                        if ((sv[i].ino == s.st_ino) && (sv[i].dev == s.st_dev)) {
+                        if ((sv[i].ino == s.st_ino)
+#if CHECK_DEVNO_TOO
+                         && (sv[i].dev == s.st_dev)
+#endif
+                        ) {
                                 sv[i].isgone = 0;
                                 if (!sv[i].pid)
                                         runsv(i, d->d_name);
@@ -157,66 +169,43 @@ static void runsvdir(void)
                         /* new service */
                         struct service *svnew = realloc(sv, (i+1) * sizeof(*sv));
                         if (!svnew) {
-                                warn3x("cannot start runsv ", d->d_name,
-                                                " too many services");
+                                warn2_cannot("start runsv ", d->d_name);
                                 continue;
                         }
                         sv = svnew;
                         svnum++;
                         memset(&sv[i], 0, sizeof(sv[i]));
                         sv[i].ino = s.st_ino;
+#if CHECK_DEVNO_TOO
                         sv[i].dev = s.st_dev;
+#endif
                         /*sv[i].pid = 0;*/
                         /*sv[i].isgone = 0;*/
                         runsv(i, d->d_name);
-                        check = 1;
+                        need_rescan = 1;
                 }
         }
-        if (errno) {
+        i = errno;
+        closedir(dir);
+        if (i) {
                 warn2_cannot("read directory ", svdir);
-                closedir(dir);
-                check = 1;
+                need_rescan = 1;
                 return;
         }
-        closedir(dir);
 
-        /* SIGTERM removed runsv's */
+        /* Send SIGTERM to runsv whose directories were not found (removed) */
         for (i = 0; i < svnum; i++) {
                 if (!sv[i].isgone)
                         continue;
                 if (sv[i].pid)
                         kill(sv[i].pid, SIGTERM);
-                sv[i] = sv[--svnum];
-/* BUG? we deleted sv[i] by copying over sv[last], but we will not check this newly-copied one! */
-                check = 1;
+                svnum--;
+                sv[i] = sv[svnum];
+                i--; /* so that we don't skip new sv[i] (bug was here!) */
+                need_rescan = 1;
         }
 }
 
-static int setup_log(void)
-{
-        rploglen = strlen(rplog);
-        if (rploglen < 7) {
-                warnx("log must have at least seven characters");
-                return 0;
-        }
-        if (piped_pair(logpipe)) {
-                warnx("cannot create pipe for log");
-                return -1;
-        }
-        close_on_exec_on(logpipe.rd);
-        close_on_exec_on(logpipe.wr);
-        ndelay_on(logpipe.rd);
-        ndelay_on(logpipe.wr);
-        if (dup2(logpipe.wr, 2) == -1) {
-                warnx("cannot set filedescriptor for log");
-                return -1;
-        }
-        pfd[0].fd = logpipe.rd;
-        pfd[0].events = POLLIN;
-        stamplog = monotonic_sec();
-        return 1;
-}
-
 int runsvdir_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int runsvdir_main(int argc UNUSED_PARAM, char **argv)
 {
@@ -230,7 +219,6 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
         unsigned deadline;
         unsigned now;
         unsigned stampcheck;
-        char ch;
         int i;
 
         INIT_G();
@@ -241,13 +229,35 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
 
         bb_signals_recursive((1 << SIGTERM) | (1 << SIGHUP), record_signo);
         svdir = *argv++;
-        if (argv && *argv) {
+
+#if ENABLE_FEATURE_RUNSVDIR_LOG
+        /* setup log */
+        if (*argv) {
                 rplog = *argv;
-                if (setup_log() != 1) {
-                        rplog = 0;
-                        warnx("log service disabled");
+                rploglen = strlen(rplog);
+                if (rploglen < 7) {
+                        warnx("log must have at least seven characters");
+                } else if (piped_pair(logpipe)) {
+                        warnx("cannot create pipe for log");
+                } else {
+                        close_on_exec_on(logpipe.rd);
+                        close_on_exec_on(logpipe.wr);
+                        ndelay_on(logpipe.rd);
+                        ndelay_on(logpipe.wr);
+                        if (dup2(logpipe.wr, 2) == -1) {
+                                warnx("cannot set filedescriptor for log");
+                        } else {
+                                pfd[0].fd = logpipe.rd;
+                                pfd[0].events = POLLIN;
+                                stamplog = monotonic_sec();
+                                goto run;
+                        }
                 }
+                rplog = NULL;
+                warnx("log service disabled");
         }
+run:
+#endif
         curdir = open_read(".");
         if (curdir == -1)
                 fatal2_cannot("open current directory", "");
@@ -265,7 +275,7 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                                 if (pid == sv[i].pid) {
                                         /* runsv has gone */
                                         sv[i].pid = 0;
-                                        check = 1;
+                                        need_rescan = 1;
                                         break;
                                 }
                         }
@@ -277,7 +287,7 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                         stampcheck = now + 1;
 
                         if (stat(svdir, &s) != -1) {
-                                if (check || s.st_mtime != last_mtime
+                                if (need_rescan || s.st_mtime != last_mtime
                                  || s.st_ino != last_ino || s.st_dev != last_dev
                                 ) {
                                         /* svdir modified */
@@ -285,10 +295,10 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                                                 last_mtime = s.st_mtime;
                                                 last_dev = s.st_dev;
                                                 last_ino = s.st_ino;
-                                                check = 0;
+                                                need_rescan = 0;
                                                 //if (now <= mtime)
                                                 //      sleep(1);
-                                                runsvdir();
+                                                do_rescan();
                                                 while (fchdir(curdir) == -1) {
                                                         warn2_cannot("change directory, pausing", "");
                                                         sleep(5);
@@ -300,23 +310,28 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                                 warn2_cannot("stat ", svdir);
                 }
 
+#if ENABLE_FEATURE_RUNSVDIR_LOG
                 if (rplog) {
                         if ((int)(now - stamplog) >= 0) {
                                 write(logpipe.wr, ".", 1);
                                 stamplog = now + 900;
                         }
                 }
-
                 pfd[0].revents = 0;
+#endif
                 sig_block(SIGCHLD);
-                deadline = (check ? 1 : 5);
+                deadline = (need_rescan ? 1 : 5);
+#if ENABLE_FEATURE_RUNSVDIR_LOG
                 if (rplog)
                         poll(pfd, 1, deadline*1000);
                 else
+#endif
                         sleep(deadline);
                 sig_unblock(SIGCHLD);
 
+#if ENABLE_FEATURE_RUNSVDIR_LOG
                 if (pfd[0].revents & POLLIN) {
+                        char ch;
                         while (read(logpipe.rd, &ch, 1) > 0) {
                                 if (ch) {
                                         for (i = 6; i < rploglen; i++)
@@ -325,7 +340,7 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                                 }
                         }
                 }
-
+#endif
                 switch (bb_got_signal) {
                 case SIGHUP:
                         for (i = 0; i < svnum; i++)