Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * Facilities for frontend code to connect to and disconnect from databases.
4 : *
5 : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
6 : * Portions Copyright (c) 1994, Regents of the University of California
7 : *
8 : * src/fe_utils/connect_utils.c
9 : *
10 : *-------------------------------------------------------------------------
11 : */
12 : #include "postgres_fe.h"
13 :
14 : #include "common/connect.h"
15 : #include "common/logging.h"
16 : #include "common/string.h"
17 : #include "fe_utils/connect_utils.h"
18 : #include "fe_utils/query_utils.h"
19 :
20 : /*
21 : * Make a database connection with the given parameters.
22 : *
23 : * An interactive password prompt is automatically issued if needed and
24 : * allowed by cparams->prompt_password.
25 : *
26 : * If allow_password_reuse is true, we will try to re-use any password
27 : * given during previous calls to this routine. (Callers should not pass
28 : * allow_password_reuse=true unless reconnecting to the same host+port+user
29 : * as before, else we might create password exposure hazards.)
30 : */
31 : PGconn *
32 0 : connectDatabase(const ConnParams *cparams, const char *progname,
33 : bool echo, bool fail_ok, bool allow_password_reuse)
34 : {
35 0 : PGconn *conn;
36 0 : bool new_pass;
37 : static char *password = NULL;
38 :
39 : /* Callers must supply at least dbname; other params can be NULL */
40 0 : Assert(cparams->dbname);
41 :
42 0 : if (!allow_password_reuse && password)
43 : {
44 0 : free(password);
45 0 : password = NULL;
46 0 : }
47 :
48 0 : if (cparams->prompt_password == TRI_YES && password == NULL)
49 0 : password = simple_prompt("Password: ", false);
50 :
51 : /*
52 : * Start the connection. Loop until we have a password if requested by
53 : * backend.
54 : */
55 0 : do
56 : {
57 0 : const char *keywords[8];
58 0 : const char *values[8];
59 0 : int i = 0;
60 :
61 : /*
62 : * If dbname is a connstring, its entries can override the other
63 : * values obtained from cparams; but in turn, override_dbname can
64 : * override the dbname component of it.
65 : */
66 0 : keywords[i] = "host";
67 0 : values[i++] = cparams->pghost;
68 0 : keywords[i] = "port";
69 0 : values[i++] = cparams->pgport;
70 0 : keywords[i] = "user";
71 0 : values[i++] = cparams->pguser;
72 0 : keywords[i] = "password";
73 0 : values[i++] = password;
74 0 : keywords[i] = "dbname";
75 0 : values[i++] = cparams->dbname;
76 0 : if (cparams->override_dbname)
77 : {
78 0 : keywords[i] = "dbname";
79 0 : values[i++] = cparams->override_dbname;
80 0 : }
81 0 : keywords[i] = "fallback_application_name";
82 0 : values[i++] = progname;
83 0 : keywords[i] = NULL;
84 0 : values[i++] = NULL;
85 0 : Assert(i <= lengthof(keywords));
86 :
87 0 : new_pass = false;
88 0 : conn = PQconnectdbParams(keywords, values, true);
89 :
90 0 : if (!conn)
91 0 : pg_fatal("could not connect to database %s: out of memory",
92 : cparams->dbname);
93 :
94 : /*
95 : * No luck? Trying asking (again) for a password.
96 : */
97 0 : if (PQstatus(conn) == CONNECTION_BAD &&
98 0 : PQconnectionNeedsPassword(conn) &&
99 0 : cparams->prompt_password != TRI_NO)
100 : {
101 0 : PQfinish(conn);
102 0 : free(password);
103 0 : password = simple_prompt("Password: ", false);
104 0 : new_pass = true;
105 0 : }
106 0 : } while (new_pass);
107 :
108 : /* check to see that the backend connection was successfully made */
109 0 : if (PQstatus(conn) == CONNECTION_BAD)
110 : {
111 0 : if (fail_ok)
112 : {
113 0 : PQfinish(conn);
114 0 : return NULL;
115 : }
116 0 : pg_fatal("%s", PQerrorMessage(conn));
117 0 : }
118 :
119 : /* Start strict; callers may override this. */
120 0 : PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
121 :
122 0 : return conn;
123 0 : }
124 :
125 : /*
126 : * Try to connect to the appropriate maintenance database.
127 : *
128 : * This differs from connectDatabase only in that it has a rule for
129 : * inserting a default "dbname" if none was given (which is why cparams
130 : * is not const). Note that cparams->dbname should typically come from
131 : * a --maintenance-db command line parameter.
132 : */
133 : PGconn *
134 0 : connectMaintenanceDatabase(ConnParams *cparams,
135 : const char *progname, bool echo)
136 : {
137 0 : PGconn *conn;
138 :
139 : /* If a maintenance database name was specified, just connect to it. */
140 0 : if (cparams->dbname)
141 0 : return connectDatabase(cparams, progname, echo, false, false);
142 :
143 : /* Otherwise, try postgres first and then template1. */
144 0 : cparams->dbname = "postgres";
145 0 : conn = connectDatabase(cparams, progname, echo, true, false);
146 0 : if (!conn)
147 : {
148 0 : cparams->dbname = "template1";
149 0 : conn = connectDatabase(cparams, progname, echo, false, false);
150 0 : }
151 0 : return conn;
152 0 : }
153 :
154 : /*
155 : * Disconnect the given connection, canceling any statement if one is active.
156 : */
157 : void
158 0 : disconnectDatabase(PGconn *conn)
159 : {
160 0 : Assert(conn != NULL);
161 :
162 0 : if (PQtransactionStatus(conn) == PQTRANS_ACTIVE)
163 : {
164 0 : PGcancelConn *cancelConn = PQcancelCreate(conn);
165 :
166 0 : (void) PQcancelBlocking(cancelConn);
167 0 : PQcancelFinish(cancelConn);
168 0 : }
169 :
170 0 : PQfinish(conn);
171 0 : }
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