Remove dead code in ECPGconnect(), and improve documentation.

The stanza in ECPGconnect() that intended to allow specification of a
Unix socket directory path in place of a port has never executed since
it was committed, nearly two decades ago; the preceding strrchr()
already found the last colon so there cannot be another one.  The lack
of complaints about that is doubtless related to the fact that no
user-facing documentation suggested it was possible.

Rather than try to fix that up, let's just remove the unreachable
code, and instead document the way that does work to write a socket
directory path, namely specifying it as a "host" option.

In support of that, make another pass at clarifying the syntax
documentation for ECPG connection targets, particularly documenting
which things are parsed as identifiers and where to use double quotes.
Rearrange some things that seemed poorly ordered, and fix a couple of
minor doc errors.

Kyotaro Horiguchi, per gripe from Shenhao Wang
(docs changes mostly by me)

Discussion: https://postgr.es/m/ae52a416bbbf459c96bab30b3038e06c@G08CNEXMBPEKD06.g08.fujitsu.local

1 files changed, 11 insertions, 37 deletions

diff --git a/src/interfaces/ecpg/ecpglib/connect.c b/src/interfaces/ecpg/ecpglib/connect.c
index 6b0a3067e6c..60564b176c9 100644
--- a/src/interfaces/ecpg/ecpglib/connect.c
+++ b/src/interfaces/ecpg/ecpglib/connect.c
@@ -360,8 +360,7 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p
 
 				/*------
 				 * new style:
-				 *	<tcp|unix>:postgresql://server[:port|:/unixsocket/path:]
-				 *	[/db-name][?options]
+				 *	<tcp|unix>:postgresql://server[:port][/db-name][?options]
 				 *------
 				 */
 				offset += strlen("postgresql://");
@@ -385,46 +384,22 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p
 				}
 
 				tmp = strrchr(dbname + offset, ':');
-				if (tmp != NULL)	/* port number or Unix socket path given */
+				if (tmp != NULL)	/* port number given */
 				{
-					char	   *tmp2;
-
 					*tmp = '\0';
-					if ((tmp2 = strchr(tmp + 1, ':')) != NULL)
-					{
-						*tmp2 = '\0';
-						host = ecpg_strdup(tmp + 1, lineno);
-						connect_params++;
-						if (strncmp(dbname, "unix:", 5) != 0)
-						{
-							ecpg_log("ECPGconnect: socketname %s given for TCP connection on line %d\n", host, lineno);
-							ecpg_raise(lineno, ECPG_CONNECT, ECPG_SQLSTATE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION, realname ? realname : ecpg_gettext("<DEFAULT>"));
-							if (host)
-								ecpg_free(host);
-
-							/*
-							 * port not set yet if (port) ecpg_free(port);
-							 */
-							if (options)
-								ecpg_free(options);
-							if (realname)
-								ecpg_free(realname);
-							if (dbname)
-								ecpg_free(dbname);
-							free(this);
-							return false;
-						}
-					}
-					else
-					{
-						port = ecpg_strdup(tmp + 1, lineno);
-						connect_params++;
-					}
+					port = ecpg_strdup(tmp + 1, lineno);
+					connect_params++;
 				}
 
 				if (strncmp(dbname, "unix:", 5) == 0)
 				{
-					if (strcmp(dbname + offset, "localhost") != 0 && strcmp(dbname + offset, "127.0.0.1") != 0)
+					/*
+					 * The alternative of using "127.0.0.1" here is deprecated
+					 * and undocumented; we'll keep it for backward
+					 * compatibility's sake, but not extend it to allow IPv6.
+					 */
+					if (strcmp(dbname + offset, "localhost") != 0 &&
+						strcmp(dbname + offset, "127.0.0.1") != 0)
 					{
 						ecpg_log("ECPGconnect: non-localhost access via sockets on line %d\n", lineno);
 						ecpg_raise(lineno, ECPG_CONNECT, ECPG_SQLSTATE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION, realname ? realname : ecpg_gettext("<DEFAULT>"));
@@ -450,7 +425,6 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p
 						connect_params++;
 					}
 				}
-
 			}
 		}
 		else