mask signals while using connect(2) in connectto() - sacc - sacc(omys), simple console gopher client
git clone git://bitreich.org/sacc/ git://enlrupgkhuxnvlhsf6lc3fziv5h2hhfrinws65d7roiv6bfj7d652fid.onion/sacc/
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---
commit dba0b8d682e77ac33fbdc6f75dee9ee9f08553f9
parent c7ab5157ebc7e7d502e0970770a7e7be48e61ea2
Author: Hiltjo Posthuma 
Date:   Tue, 25 Dec 2018 20:44:18 +0100

mask signals while using connect(2) in connectto()

This makes sure connect(2) don't return a possible < 0 and errno = EINTR.

POSIX says for connect(2): "
[EINTR]         The connection attempt was interrupted by a signal.
                The attempt will continue asynchronously as if the
                socket was non-blocking."

This was reproducable by launching with st -e sacc bitreich.org . When sacc was
signaled with SIGWINCH while it was connecting the connect(2) would be handled
as a failure and the next interface was tried. This gave a vague message "no
route to host", because the next interfaces could fail.

Diffstat:
  M sacc.c                              |      15 ++++++++++++---

1 file changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/sacc.c b/sacc.c
@@ -454,6 +454,7 @@ sendselector(int sock, const char *selector)
 static int
 connectto(const char *host, const char *port)
 {
+        sigset_t set, oset;
         static const struct addrinfo hints = {
             .ai_family = AF_UNSPEC,
             .ai_socktype = SOCK_STREAM,
@@ -462,10 +463,13 @@ connectto(const char *host, const char *port)
         struct addrinfo *addrs, *addr;
         int sock, r;
 
+        sigfillset(&set);
+        sigprocmask(SIG_BLOCK, &set, &oset);
+
         if (r = getaddrinfo(host, port, &hints, &addrs)) {
                 diag("Can't resolve hostname \"%s\": %s",
                      host, gai_strerror(r));
-                return -1;
+                goto err;
         }
 
         for (addr = addrs; addr; addr = addr->ai_next) {
@@ -483,15 +487,20 @@ connectto(const char *host, const char *port)
 
         if (sock < 0) {
                 diag("Can't open socket: %s", strerror(errno));
-                return -1;
+                goto err;
         }
         if (r < 0) {
                 diag("Can't connect to: %s:%s: %s",
                      host, port, strerror(errno));
-                return -1;
+                goto err;
         }
 
+        sigprocmask(SIG_SETMASK, &oset, NULL);
         return sock;
+
+err:
+        sigprocmask(SIG_SETMASK, &oset, NULL);
+        return -1;
 }
 
 static int