diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml index 82a440531b..c10957f1ee 100644 --- a/doc/src/sgml/libpq.sgml +++ b/doc/src/sgml/libpq.sgml @@ -964,49 +964,41 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname host - Name of host to connect to.host name - If a host name begins with a slash, it specifies Unix-domain - communication rather than TCP/IP communication; the value is the - name of the directory in which the socket file is stored. + Comma-separated list of hosts to connect to.host name + Each specified host will be tried in turn in the order given. + See for details. + Each item may be a host name that will be resolved with a look-up, + a numeric IP address (IPv4 in the standard format, e.g., + 172.28.40.9, or IPv6 if supported by your machine) + that will be used directly, or + the name of a directory which contains the socket file for Unix-domain + communication rather than TCP/IP communication + (the specification must then begin with a slash); + + + The default behavior when host is - not specified, or is empty, is to connect to a Unix-domain + not specified, or an item is empty, is to connect to a Unix-domain socketUnix domain socket in /tmp (or whatever socket directory was specified - when PostgreSQL was built). On machines without - Unix-domain sockets, the default is to connect to localhost. + when PostgreSQL was built). + On machines without Unix-domain sockets, the default is to connect to + localhost. - - A comma-separated list of host names is also accepted, in which case - each host name in the list is tried in order; an empty item in the - list selects the default behavior as explained above. See - for details. - - - - - hostaddr - - Numeric IP address of host to connect to. This should be in the - standard IPv4 address format, e.g., 172.28.40.9. If - your machine supports IPv6, you can also use those addresses. - TCP/IP communication is - always used when a nonempty string is specified for this parameter. + To shortcut host name lookups, see parameter + . - Using hostaddr instead of host allows the - application to avoid a host name look-up, which might be important - in applications with time constraints. However, a host name is - required for GSSAPI or SSPI authentication - methods, as well as for verify-full SSL - certificate verification. The following rules are used: + When connecting, the following rules apply: - If host is specified - without hostaddr, a host name lookup occurs. + If a host name item in host has a + corresponding empty item in hostaddr, a host name + lookup occurs, and the resulting set of IPs will be tried in turn. (When using PQconnectPoll, the lookup occurs when PQconnectPoll first considers this host name, and it may cause PQconnectPoll to block @@ -1015,45 +1007,69 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname - If hostaddr is specified without host, - the value for hostaddr gives the server network address. - The connection attempt will fail if the authentication - method requires a host name. + If a host name item in host has a + corresponding non-empty item in hostaddr, the + later network address is used and the host name may be used for + authentication purposes. - If both host and hostaddr are specified, - the value for hostaddr gives the server network address. - The value for host is ignored unless the - authentication method requires it, in which case it will be - used as the host name. + If an item in host is either an IP or a + Unix-domain socket, the corresponding hostaddr + must be empty, and the connection uses the provided data. - Note that authentication is likely to fail if host + + + + + + hostaddr + + + Comma-separated numeric IP addresses corresponding one-to-one to + host, to avoid a host name look-up when non empty. + This may be desirable for testing, to work around NAT settings, or for + better performance. + + + + Parameter hostaddr must be either empty or a + list of the same length as host. + A non empty item in hostaddr can only be provided + for corresponding host name items in host, but not + for IP addresses or Unix-domain sockets. + + + + If a host name is required for GSSAPI or SSPI authentication + methods, for verify-full SSL certificate + verification, or to identify the connection in + a password file (see ), + the corresponding host name provided by host is used. + + + + When both host and hostaddr parameters + are set, note that authentication is likely to fail if host is not the name of the server at network address hostaddr. - Also, when both host and hostaddr - are specified, host - is used to identify the connection in a password file (see - ). - - A comma-separated list of hostaddr values is also - accepted, in which case each host in the list is tried in order. - An empty item in the list causes the corresponding host name to be - used, or the default host name if that is empty as well. See - for details. - - - Without either a host name or host address, - libpq will connect using a - local Unix-domain socket; or on machines without Unix-domain - sockets, it will attempt to connect to localhost. - - - + + + From PostgreSQL 12, + hostaddr does not replace host, + but only works as a look-up shortcut. + It can be set only over a host name, but not over an IP address or + a Unix-domain socket. + To connect directly to an IP address, simply use + host=IP. + + + + port @@ -1062,10 +1078,10 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname Port number to connect to at the server host, or socket file name extension for Unix-domain connections.port - If multiple hosts were given in the host or - hostaddr parameters, this parameter may specify a - comma-separated list of ports of the same length as the host list, or - it may specify a single port number to be used for all hosts. + If multiple hosts were given in the host parameter, + this parameter may specify a comma-separated list of ports of the same + length as the host list, or it may specify a single port number to be + used for all hosts. An empty string, or an empty item in a comma-separated list, specifies the default port number established when PostgreSQL was built. diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index d001bc513d..470a47a57b 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -909,14 +909,15 @@ count_comma_separated_elems(const char *input) /* * Parse a simple comma-separated list. * - * On each call, returns a malloc'd copy of the next element, and sets *more - * to indicate whether there are any more elements in the list after this, + * Note: this parsing must be consistent with count_comma_separated_elems. + * + * On each call, returns a malloc'd copy of the next element, * and updates *startptr to point to the next element, if any. * * On out of memory, returns NULL. */ static char * -parse_comma_separated_list(char **startptr, bool *more) +parse_comma_separated_list(char **startptr) { char *p; char *s = *startptr; @@ -930,7 +931,6 @@ parse_comma_separated_list(char **startptr, bool *more) e = s; while (*e != '\0' && *e != ',') ++e; - *more = (*e == ','); len = e - s; p = (char *) malloc(sizeof(char) * (len + 1)); @@ -944,6 +944,22 @@ parse_comma_separated_list(char **startptr, bool *more) return p; } +/* tell whether it is an ipv4 or possibly ipv6 address */ +static bool +look_like_an_ip(const char *str) +{ + int b0, b1, b2, b3; + char garbage; + + if (sscanf(str, "%d.%d.%d.%d%c", &b0, &b1, &b2, &b3, &garbage) == 4 && + 0 <= b0 && b0 < 256 && 0 <= b1 && b1 < 256 && + 0 <= b2 && b2 < 256 && 0 <= b3 && b3 < 256) + return true; + else + /* ":" cannot appear in a host name */ + return strchr(str, ':') != NULL; +} + /* * connectOptions2 * @@ -959,16 +975,27 @@ connectOptions2(PGconn *conn) /* * Allocate memory for details about each host to which we might possibly - * try to connect. For that, count the number of elements in the hostaddr - * or host options. If neither is given, assume one host. + * try to connect. For that, count the number of elements in the host + * options or assume one host if not set. */ conn->whichhost = 0; - if (conn->pghostaddr && conn->pghostaddr[0] != '\0') - conn->nconnhost = count_comma_separated_elems(conn->pghostaddr); - else if (conn->pghost && conn->pghost[0] != '\0') + + if (conn->pghost && conn->pghost[0] != '\0') conn->nconnhost = count_comma_separated_elems(conn->pghost); else conn->nconnhost = 1; + + /* check that hostaddr length is compatible */ + if (conn->pghostaddr && conn->pghostaddr[0] != '\0' && + count_comma_separated_elems(conn->pghostaddr) != conn->nconnhost) + { + conn->status = CONNECTION_BAD; + appendPQExpBuffer(&conn->errorMessage, + libpq_gettext("host and hostaddr list must be of equal length, got %d and %d\n"), + conn->nconnhost, count_comma_separated_elems(conn->pghostaddr)); + return false; + } + conn->connhost = (pg_conn_host *) calloc(conn->nconnhost, sizeof(pg_conn_host)); if (conn->connhost == NULL) @@ -978,82 +1005,86 @@ connectOptions2(PGconn *conn) * We now have one pg_conn_host structure per possible host. Fill in the * host and hostaddr fields for each, by splitting the parameter strings. */ - if (conn->pghostaddr != NULL && conn->pghostaddr[0] != '\0') - { - char *s = conn->pghostaddr; - bool more = true; - - for (i = 0; i < conn->nconnhost && more; i++) - { - conn->connhost[i].hostaddr = parse_comma_separated_list(&s, &more); - if (conn->connhost[i].hostaddr == NULL) - goto oom_error; - } - - /* - * If hostaddr was given, the array was allocated according to the - * number of elements in the hostaddr list, so it really should be the - * right size. - */ - Assert(!more); - Assert(i == conn->nconnhost); - } - if (conn->pghost != NULL && conn->pghost[0] != '\0') { char *s = conn->pghost; - bool more = true; - for (i = 0; i < conn->nconnhost && more; i++) + for (i = 0; i < conn->nconnhost; i++) { - conn->connhost[i].host = parse_comma_separated_list(&s, &more); + conn->connhost[i].host = parse_comma_separated_list(&s); if (conn->connhost[i].host == NULL) goto oom_error; } + } - /* Check for wrong number of host items. */ - if (more || i != conn->nconnhost) + /* we know that the number or host/hostaddr matches. */ + if (conn->pghostaddr != NULL && conn->pghostaddr[0] != '\0') + { + char *s = conn->pghostaddr; + + for (i = 0; i < conn->nconnhost; i++) { - conn->status = CONNECTION_BAD; - printfPQExpBuffer(&conn->errorMessage, - libpq_gettext("could not match %d host names to %d hostaddr values\n"), - count_comma_separated_elems(conn->pghost), conn->nconnhost); - return false; + conn->connhost[i].hostaddr = parse_comma_separated_list(&s); + if (conn->connhost[i].hostaddr == NULL) + goto oom_error; } } /* - * Now, for each host slot, identify the type of address spec, and fill in - * the default address if nothing was given. + * Now, for each host slot, fill in the default address if necessary, + * identify the type of address spec, and make some sanity checks. */ for (i = 0; i < conn->nconnhost; i++) { pg_conn_host *ch = &conn->connhost[i]; - if (ch->hostaddr != NULL && ch->hostaddr[0] != '\0') - ch->type = CHT_HOST_ADDRESS; - else if (ch->host != NULL && ch->host[0] != '\0') - { - ch->type = CHT_HOST_NAME; -#ifdef HAVE_UNIX_SOCKETS - if (is_absolute_path(ch->host)) - ch->type = CHT_UNIX_SOCKET; -#endif - } - else + if (ch->host == NULL || ch->host[0] == '\0') { if (ch->host) free(ch->host); #ifdef HAVE_UNIX_SOCKETS ch->host = strdup(DEFAULT_PGSOCKET_DIR); - ch->type = CHT_UNIX_SOCKET; #else ch->host = strdup(DefaultHost); - ch->type = CHT_HOST_NAME; #endif if (ch->host == NULL) goto oom_error; } + +#ifdef HAVE_UNIX_SOCKETS + if (is_absolute_path(ch->host)) + ch->type = CHT_UNIX_SOCKET; + else +#endif + if (look_like_an_ip(ch->host)) + ch->type = CHT_HOST_ADDRESS; + else + ch->type = CHT_HOST_NAME; + + if (ch->hostaddr != NULL && ch->hostaddr[0] != '\0') + { + /* hostaddr only allowed on host names */ + if (ch->type != CHT_HOST_NAME) + { + conn->status = CONNECTION_BAD; + appendPQExpBuffer(&conn->errorMessage, + libpq_gettext("host \"%s\" cannot have an hostaddr \"%s\"\n"), + ch->host, ch->hostaddr); + return false; + } + + if (!look_like_an_ip(ch->hostaddr)) + { + conn->status = CONNECTION_BAD; + appendPQExpBuffer(&conn->errorMessage, + libpq_gettext("hostaddr \"%s\" is not a numeric IP address\n"), + ch->hostaddr); + return false; + } + + /* hostaddr superseedes name for this connection */ + ch->type = CHT_HOST_ADDRESS; + } } /* @@ -1065,36 +1096,40 @@ connectOptions2(PGconn *conn) */ if (conn->pgport != NULL && conn->pgport[0] != '\0') { - char *s = conn->pgport; - bool more = true; + int count = count_comma_separated_elems(conn->pgport); - for (i = 0; i < conn->nconnhost && more; i++) + if (count > 1) { - conn->connhost[i].port = parse_comma_separated_list(&s, &more); - if (conn->connhost[i].port == NULL) - goto oom_error; - } + char *s = conn->pgport; - /* - * If exactly one port was given, use it for every host. Otherwise, - * there must be exactly as many ports as there were hosts. - */ - if (i == 1 && !more) - { - for (i = 1; i < conn->nconnhost; i++) + /* there must be exactly as many ports as there were hosts. */ + if (count != conn->nconnhost) + { + conn->status = CONNECTION_BAD; + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("could not match %d port numbers to %d hosts\n"), + count, conn->nconnhost); + return false; + } + + for (i = 0; i < conn->nconnhost; i++) { - conn->connhost[i].port = strdup(conn->connhost[0].port); + conn->connhost[i].port = parse_comma_separated_list(&s); if (conn->connhost[i].port == NULL) goto oom_error; } } - else if (more || i != conn->nconnhost) + else { - conn->status = CONNECTION_BAD; - printfPQExpBuffer(&conn->errorMessage, - libpq_gettext("could not match %d port numbers to %d hosts\n"), - count_comma_separated_elems(conn->pgport), conn->nconnhost); - return false; + Assert(count == 1); + + /* If exactly one port was given, use it for every host. */ + for (i = 0; i < conn->nconnhost; i++) + { + conn->connhost[i].port = strdup(conn->pgport); + if (conn->connhost[i].port == NULL) + goto oom_error; + } } } @@ -2120,6 +2155,7 @@ keep_going: /* We will come back to here until there is int thisport; int ret; char portstr[MAXPGPATH]; + char *addr; if (conn->whichhost + 1 >= conn->nconnhost) { @@ -2181,13 +2217,13 @@ keep_going: /* We will come back to here until there is case CHT_HOST_ADDRESS: hint.ai_flags = AI_NUMERICHOST; - ret = pg_getaddrinfo_all(ch->hostaddr, portstr, &hint, - &conn->addrlist); + addr = (ch->hostaddr != NULL && ch->hostaddr[0] != '\0') ? ch->hostaddr : ch->host; + ret = pg_getaddrinfo_all(addr, portstr, &hint, &conn->addrlist); if (ret || !conn->addrlist) { appendPQExpBuffer(&conn->errorMessage, libpq_gettext("could not parse network address \"%s\": %s\n"), - ch->hostaddr, gai_strerror(ret)); + addr, gai_strerror(ret)); goto keep_going; } break; @@ -6161,12 +6197,10 @@ PQhost(const PGconn *conn) if (conn->connhost != NULL) { + /* always true, defaults are filled in by Options2 */ if (conn->connhost[conn->whichhost].host != NULL && conn->connhost[conn->whichhost].host[0] != '\0') return conn->connhost[conn->whichhost].host; - else if (conn->connhost[conn->whichhost].hostaddr != NULL && - conn->connhost[conn->whichhost].hostaddr[0] != '\0') - return conn->connhost[conn->whichhost].hostaddr; } return "";