Make nonfatal override GAWK_SOCK_RETRIES. Document it.

4 files changed, 51 insertions, 16 deletions

diff --git a/ChangeLog b/ChangeLog
index 62777ab3..cc15ccbf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2015-03-08         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* io.c (devopen): Change the logic such that if nonfatal is true
+	for the socket, don't do retries.  Also clean up the formatting
+	some.  At strictopen, check if errno is ENOENT and if so, propagate
+	the error from getaddrinfo() up to the caller. Add explanatory
+	comments.
+
 2015-02-28         Andrew J. Schorr     <aschorr@telemetry-investments.com>
 
 	* io.c (pty_vs_pipe): Remove check for NULL PROCINFO_node, since
diff --git a/doc/ChangeLog b/doc/ChangeLog
index d8c42cb4..b58699a4 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,9 @@
+2015-03-08         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* gawktexi.in: Briefly describe that nonfatal I/O overrides
+	GAWK_SOCK_RETRIES, in the env var part and in the nonfatal I/O
+	part.
+
 2015-03-01         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* gawktexi.in: Change quotes to @dfn for pseudorandom.
diff --git a/doc/gawktexi.in b/doc/gawktexi.in
index 1b99b5bc..8612876e 100644
--- a/doc/gawktexi.in
+++ b/doc/gawktexi.in
@@ -4461,6 +4461,8 @@ wait for input before returning with an error.
 Controls the number of times @command{gawk} attempts to
 retry a two-way TCP/IP (socket) connection before giving up.
 @xref{TCP/IP Networking}.
+Note that when nonfatal I/O is enabled (@pxref{Nonfatal}),
+@command{gawk} only tries to open a TCP/IP socket once.
 
 @item POSIXLY_CORRECT
 Causes @command{gawk} to switch to POSIX-compatibility
@@ -9996,6 +9998,14 @@ For standard output, you may use @code{PROCINFO["-", "NONFATAL"]}
 or @code{PROCINFO["/dev/stdout", "NONFATAL"]}.  For standard error, use
 @code{PROCINFO["/dev/stderr", "NONFATAL"]}.
 
+When attempting to open a TCP/IP socket (@pxref{TCP/IP Networking}),
+@command{gawk} tries multiple times. The @env{GAWK_SOCK_RETRIES}
+environment variable (@pxref{Other Environment Variables}) allows you to
+override @command{gawk}'s builtin default number of attempts.  However,
+once nonfatal I/O is enabled for a given socket, @command{gawk} only
+retries once, relying on @command{awk}-level code to notice that there
+was a problem.
+
 @node Output Summary
 @section Summary
 
diff --git a/io.c b/io.c
index 162fb4e8..55c5d3a5 100644
--- a/io.c
+++ b/io.c
@@ -1661,20 +1661,20 @@ devopen(const char *name, const char *mode)
 		goto strictopen;
 	} else if (inetfile(name, & isi)) {
 #ifdef HAVE_SOCKETS
-		cp = (char *) name;
-
-		/* socketopen requires NUL-terminated strings */
-		cp[isi.localport.offset+isi.localport.len] = '\0';
-		cp[isi.remotehost.offset+isi.remotehost.len] = '\0';
-		/* remoteport comes last, so already NUL-terminated */
-
-		{
 #define DEFAULT_RETRIES 20
 		static unsigned long def_retries = DEFAULT_RETRIES;
 		static bool first_time = true;
 		unsigned long retries = 0;
 		static long msleep = 1000;
 		bool hard_error = false;
+		bool non_fatal = is_non_fatal_redirect(name);
+
+		cp = (char *) name;
+
+		/* socketopen requires NUL-terminated strings */
+		cp[isi.localport.offset+isi.localport.len] = '\0';
+		cp[isi.remotehost.offset+isi.remotehost.len] = '\0';
+		/* remoteport comes last, so already NUL-terminated */
 
 		if (first_time) {
 			char *cp, *end;
@@ -1701,28 +1701,39 @@ devopen(const char *name, const char *mode)
 					msleep *= 1000;
 			}
 		}
-		retries = def_retries;
+		/*
+		 * PROCINFO["NONFATAL"] or PROCINFO[name, "NONFATAL"] overrrides
+		 * GAWK_SOCK_RETRIES.  The explicit code in the program carries
+		 * a bigger stick than the environment variable does.
+		 */
+		retries = non_fatal ? 1 : def_retries;
 
 		errno = 0;
 		do {
-			openfd = socketopen(isi.family, isi.protocol, name+isi.localport.offset, name+isi.remoteport.offset, name+isi.remotehost.offset, & hard_error);
+			openfd = socketopen(isi.family, isi.protocol, name+isi.localport.offset,
+					name+isi.remoteport.offset, name+isi.remotehost.offset,
+					& hard_error);
 			retries--;
 		} while (openfd == INVALID_HANDLE && ! hard_error && retries > 0 && usleep(msleep) == 0);
 		save_errno = errno;
-	}
 
-	/* restore original name string */
-	cp[isi.localport.offset+isi.localport.len] = '/';
-	cp[isi.remotehost.offset+isi.remotehost.len] = '/';
+		/* restore original name string */
+		cp[isi.localport.offset+isi.localport.len] = '/';
+		cp[isi.remotehost.offset+isi.remotehost.len] = '/';
 #else /* ! HAVE_SOCKETS */
-	fatal(_("TCP/IP communications are not supported"));
+		fatal(_("TCP/IP communications are not supported"));
 #endif /* HAVE_SOCKETS */
 	}
 
 strictopen:
 	if (openfd == INVALID_HANDLE) {
 		openfd = open(name, flag, 0666);
-		if (openfd == INVALID_HANDLE && save_errno)
+		/*
+		 * ENOENT means there is no such name in the filesystem.
+		 * Therefore it's ok to propagate up the error from
+		 * getaddrinfo() that's in save_errno.
+		 */
+		if (openfd == INVALID_HANDLE && errno == ENOENT && save_errno)
 			errno = save_errno;
 	}
 #if defined(__EMX__) || defined(__MINGW32__)