cmd_ipc4: retry sendmsg on ENOBUFS/ENOMEM/ETOOMANYREFS

[public-inbox.git] / lib / PublicInbox / Spawn.pm

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index e940d3c9d7f44710e86b8b1118f921cf8cea562e..6ca1ca2a0be3538b3cb9dc663422698b6b94952b 100644 (file)
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -34,6 +34,9 @@ BEGIN {
 #include <unistd.h>
 #include <stdlib.h>
 #include <errno.h>
+#include <time.h>
+#include <stdio.h>
+#include <string.h>
 
 /* some platforms need alloca.h, but some don't */
 #if defined(__GNUC__) && !defined(alloca)
@@ -162,6 +165,22 @@ int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref,
        return (int)pid;
 }
 
+static int sleep_wait(unsigned *try, int err)
+{
+       const struct timespec req = { 0, 100000000 }; /* 100ms */
+       switch (err) {
+       case ENOBUFS: case ENOMEM: case ETOOMANYREFS:
+               if (++*try < 50) {
+                       fprintf(stderr, "sleeping on sendmsg: %s (#%u)\n",
+                               strerror(err), *try);
+                       nanosleep(&req, NULL);
+                       return 1;
+               }
+       default:
+               return 0;
+       }
+}
+
 #if defined(CMSG_SPACE) && defined(CMSG_LEN)
 #define SEND_FD_CAPA 10
 #define SEND_FD_SPACE (SEND_FD_CAPA * sizeof(int))
@@ -180,6 +199,7 @@ SV *send_cmd4(PerlIO *s, SV *svfds, SV *data, int flags)
        AV *fds = (AV *)SvRV(svfds);
        I32 i, nfds = av_len(fds) + 1;
        int *fdp;
+       unsigned try = 0;
 
        if (SvOK(data)) {
                iov.iov_base = SvPV(data, dlen);
@@ -207,7 +227,9 @@ SV *send_cmd4(PerlIO *s, SV *svfds, SV *data, int flags)
                        *fdp++ = SvIV(*fd);
                }
        }
-       sent = sendmsg(PerlIO_fileno(s), &msg, flags);
+       do {
+               sent = sendmsg(PerlIO_fileno(s), &msg, flags);
+       } while (sent < 0 && sleep_wait(&try, errno));
        return sent >= 0 ? newSViv(sent) : &PL_sv_undef;
 }
 
@@ -258,9 +280,6 @@ ALL_LIBC
 #include <linux/magic.h>
 #include <linux/fs.h>
 #include <dirent.h>
-#include <errno.h>
-#include <stdio.h>
-#include <string.h>
 
 void nodatacow_fd(int fd)
 {