ipc: lower-level send_cmd/recv_cmd handle EINTR directly

This ensures script/lei $send_cmd usage is EINTR-safe (since
I prefer to avoid loading PublicInbox::IPC for startup time).
Overall, it saves us some code, too.

1 files changed, 23 insertions, 18 deletions

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index bb2abe28..4c7e0f80 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -173,19 +173,20 @@ int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref,
         return (int)pid;
 }
 
-static int sleep_wait(unsigned *tries, int err)
+static int sendmsg_retry(unsigned *tries)
 {
         const struct timespec req = { 0, 100000000 }; /* 100ms */
+        int err = errno;
         switch (err) {
+        case EINTR: PERL_ASYNC_CHECK(); return 1;
         case ENOBUFS: case ENOMEM: case ETOOMANYREFS:
-                if (++*tries < 50) {
-                        fprintf(stderr, "# sleeping on sendmsg: %s (#%u)\n",
-                                strerror(err), *tries);
-                        nanosleep(&req, NULL);
-                        return 1;
-                }
-        default:
-                return 0;
+                if (++*tries >= 50) return 0;
+                fprintf(stderr, "# sleeping on sendmsg: %s (#%u)\n",
+                        strerror(err), *tries);
+                nanosleep(&req, NULL);
+                PERL_ASYNC_CHECK();
+                return 1;
+        default: return 0;
         }
 }
 
@@ -237,7 +238,7 @@ SV *send_cmd4(PerlIO *s, SV *svfds, SV *data, int flags)
         }
         do {
                 sent = sendmsg(PerlIO_fileno(s), &msg, flags);
-        } while (sent < 0 && sleep_wait(&tries, errno));
+        } while (sent < 0 && sendmsg_retry(&tries));
         return sent >= 0 ? newSViv(sent) : &PL_sv_undef;
 }
 
@@ -259,20 +260,24 @@ void recv_cmd4(PerlIO *s, SV *buf, STRLEN n)
         msg.msg_control = &cmsg.hdr;
         msg.msg_controllen = CMSG_SPACE(SEND_FD_SPACE);
 
-        i = recvmsg(PerlIO_fileno(s), &msg, 0);
+        for (;;) {
+                i = recvmsg(PerlIO_fileno(s), &msg, 0);
+                if (i >= 0 || errno != EINTR) break;
+                PERL_ASYNC_CHECK();
+        }
         if (i >= 0) {
                 SvCUR_set(buf, i);
+                if (cmsg.hdr.cmsg_level == SOL_SOCKET &&
+                                cmsg.hdr.cmsg_type == SCM_RIGHTS) {
+                        size_t len = cmsg.hdr.cmsg_len;
+                        int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
+                        for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= len; i++)
+                                Inline_Stack_Push(sv_2mortal(newSViv(*fdp++)));
+                }
         } else {
                 Inline_Stack_Push(&PL_sv_undef);
                 SvCUR_set(buf, 0);
         }
-        if (i > 0 && cmsg.hdr.cmsg_level == SOL_SOCKET &&
-                        cmsg.hdr.cmsg_type == SCM_RIGHTS) {
-                size_t len = cmsg.hdr.cmsg_len;
-                int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
-                for (i = 0; CMSG_LEN((i + 1) * sizeof(int)) <= len; i++)
-                        Inline_Stack_Push(sv_2mortal(newSViv(*fdp++)));
-        }
         Inline_Stack_Done;
 }
 #endif /* defined(CMSG_SPACE) && defined(CMSG_LEN) */