PostgreSQL Source Code: src/bin/psql/large_obj.c Source File

PostgreSQL Source Code git master
large_obj.c
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1/*
2 * psql - the PostgreSQL interactive terminal
3 *
4 * Copyright (c) 2000-2025, PostgreSQL Global Development Group
5 *
6 * src/bin/psql/large_obj.c
7 */
8#include "postgres_fe.h"
9
10#include "common.h"
11#include "common/logging.h"
12#include "fe_utils/cancel.h"
13#include "large_obj.h"
14#include "settings.h"
15
16static void print_lo_result(const char *fmt,...) pg_attribute_printf(1, 2);
17
18static void
19 print_lo_result(const char *fmt,...)
20{
21 va_list ap;
22
23 if (!pset.quiet)
24 {
25 if (pset.popt.topt.format == PRINT_HTML)
26 fputs("<p>", pset.queryFout);
27
28 va_start(ap, fmt);
29 vfprintf(pset.queryFout, fmt, ap);
30 va_end(ap);
31
32 if (pset.popt.topt.format == PRINT_HTML)
33 fputs("</p>\n", pset.queryFout);
34 else
35 fputs("\n", pset.queryFout);
36 }
37
38 if (pset.logfile)
39 {
40 va_start(ap, fmt);
41 vfprintf(pset.logfile, fmt, ap);
42 va_end(ap);
43 fputs("\n", pset.logfile);
44 }
45}
46
47
48/*
49 * Prepare to do a large-object operation. We *must* be inside a transaction
50 * block for all these operations, so start one if needed.
51 *
52 * Returns true if okay, false if failed. *own_transaction is set to indicate
53 * if we started our own transaction or not.
54 */
55static bool
56 start_lo_xact(const char *operation, bool *own_transaction)
57{
58 PGTransactionStatusType tstatus;
59 PGresult *res;
60
61 *own_transaction = false;
62
63 if (!pset.db)
64 {
65 pg_log_error("%s: not connected to a database", operation);
66 return false;
67 }
68
69 tstatus = PQtransactionStatus(pset.db);
70
71 switch (tstatus)
72 {
73 case PQTRANS_IDLE:
74 /* need to start our own xact */
75 if (!(res = PSQLexec("BEGIN")))
76 return false;
77 PQclear(res);
78 *own_transaction = true;
79 break;
80 case PQTRANS_INTRANS:
81 /* use the existing xact */
82 break;
83 case PQTRANS_INERROR:
84 pg_log_error("%s: current transaction is aborted", operation);
85 return false;
86 default:
87 pg_log_error("%s: unknown transaction status", operation);
88 return false;
89 }
90
91 return true;
92}
93
94/*
95 * Clean up after a successful LO operation
96 */
97static bool
98 finish_lo_xact(const char *operation, bool own_transaction)
99{
100 PGresult *res;
101
102 if (own_transaction && pset.autocommit)
103 {
104 /* close out our own xact */
105 if (!(res = PSQLexec("COMMIT")))
106 {
107 res = PSQLexec("ROLLBACK");
108 PQclear(res);
109 return false;
110 }
111 PQclear(res);
112 }
113
114 return true;
115}
116
117/*
118 * Clean up after a failed LO operation
119 */
120static bool
121 fail_lo_xact(const char *operation, bool own_transaction)
122{
123 PGresult *res;
124
125 if (own_transaction && pset.autocommit)
126 {
127 /* close out our own xact */
128 res = PSQLexec("ROLLBACK");
129 PQclear(res);
130 }
131
132 return false; /* always */
133}
134
135
136/*
137 * do_lo_export()
138 *
139 * Write a large object to a file
140 */
141bool
142 do_lo_export(const char *loid_arg, const char *filename_arg)
143{
144 int status;
145 bool own_transaction;
146
147 if (!start_lo_xact("\\lo_export", &own_transaction))
148 return false;
149
150 SetCancelConn(NULL);
151 status = lo_export(pset.db, atooid(loid_arg), filename_arg);
152 ResetCancelConn();
153
154 /* of course this status is documented nowhere :( */
155 if (status != 1)
156 {
157 pg_log_info("%s", PQerrorMessage(pset.db));
158 return fail_lo_xact("\\lo_export", own_transaction);
159 }
160
161 if (!finish_lo_xact("\\lo_export", own_transaction))
162 return false;
163
164 print_lo_result("lo_export");
165
166 return true;
167}
168
169
170/*
171 * do_lo_import()
172 *
173 * Copy large object from file to database
174 */
175bool
176 do_lo_import(const char *filename_arg, const char *comment_arg)
177{
178 PGresult *res;
179 Oid loid;
180 char oidbuf[32];
181 bool own_transaction;
182
183 if (!start_lo_xact("\\lo_import", &own_transaction))
184 return false;
185
186 SetCancelConn(NULL);
187 loid = lo_import(pset.db, filename_arg);
188 ResetCancelConn();
189
190 if (loid == InvalidOid)
191 {
192 pg_log_info("%s", PQerrorMessage(pset.db));
193 return fail_lo_xact("\\lo_import", own_transaction);
194 }
195
196 /* insert description if given */
197 if (comment_arg)
198 {
199 char *cmdbuf;
200 char *bufptr;
201 size_t slen = strlen(comment_arg);
202
203 cmdbuf = pg_malloc_extended(slen * 2 + 256, MCXT_ALLOC_NO_OOM);
204 if (!cmdbuf)
205 return fail_lo_xact("\\lo_import", own_transaction);
206 sprintf(cmdbuf, "COMMENT ON LARGE OBJECT %u IS '", loid);
207 bufptr = cmdbuf + strlen(cmdbuf);
208 bufptr += PQescapeStringConn(pset.db, bufptr, comment_arg, slen, NULL);
209 strcpy(bufptr, "'");
210
211 if (!(res = PSQLexec(cmdbuf)))
212 {
213 free(cmdbuf);
214 return fail_lo_xact("\\lo_import", own_transaction);
215 }
216
217 PQclear(res);
218 free(cmdbuf);
219 }
220
221 if (!finish_lo_xact("\\lo_import", own_transaction))
222 return false;
223
224 print_lo_result("lo_import %u", loid);
225
226 sprintf(oidbuf, "%u", loid);
227 SetVariable(pset.vars, "LASTOID", oidbuf);
228
229 return true;
230}
231
232
233/*
234 * do_lo_unlink()
235 *
236 * removes a large object out of the database
237 */
238bool
239 do_lo_unlink(const char *loid_arg)
240{
241 int status;
242 Oid loid = atooid(loid_arg);
243 bool own_transaction;
244
245 if (!start_lo_xact("\\lo_unlink", &own_transaction))
246 return false;
247
248 SetCancelConn(NULL);
249 status = lo_unlink(pset.db, loid);
250 ResetCancelConn();
251
252 if (status == -1)
253 {
254 pg_log_info("%s", PQerrorMessage(pset.db));
255 return fail_lo_xact("\\lo_unlink", own_transaction);
256 }
257
258 if (!finish_lo_xact("\\lo_unlink", own_transaction))
259 return false;
260
261 print_lo_result("lo_unlink %u", loid);
262
263 return true;
264}
PGresult * PSQLexec(const char *query)
Definition: common.c:655
#define pg_attribute_printf(f, a)
Definition: c.h:232
void ResetCancelConn(void)
Definition: cancel.c:107
void SetCancelConn(PGconn *conn)
Definition: cancel.c:77
PGTransactionStatusType PQtransactionStatus(const PGconn *conn)
Definition: fe-connect.c:7624
char * PQerrorMessage(const PGconn *conn)
Definition: fe-connect.c:7679
size_t PQescapeStringConn(PGconn *conn, char *to, const char *from, size_t length, int *error)
Definition: fe-exec.c:4188
int lo_unlink(PGconn *conn, Oid lobjId)
Definition: fe-lobj.c:589
Oid lo_import(PGconn *conn, const char *filename)
Definition: fe-lobj.c:626
int lo_export(PGconn *conn, Oid lobjId, const char *filename)
Definition: fe-lobj.c:748
void * pg_malloc_extended(size_t size, int flags)
Definition: fe_memutils.c:59
#define MCXT_ALLOC_NO_OOM
Definition: fe_memutils.h:29
@ PRINT_HTML
Definition: print.h:34
#define free(a)
Definition: header.h:65
static bool start_lo_xact(const char *operation, bool *own_transaction)
Definition: large_obj.c:56
bool do_lo_export(const char *loid_arg, const char *filename_arg)
Definition: large_obj.c:142
static bool fail_lo_xact(const char *operation, bool own_transaction)
Definition: large_obj.c:121
static void print_lo_result(const char *fmt,...) pg_attribute_printf(1
Definition: large_obj.c:19
static bool finish_lo_xact(const char *operation, bool own_transaction)
Definition: large_obj.c:98
bool do_lo_import(const char *filename_arg, const char *comment_arg)
Definition: large_obj.c:176
bool do_lo_unlink(const char *loid_arg)
Definition: large_obj.c:239
#define PQclear
Definition: libpq-be-fe.h:245
PGTransactionStatusType
Definition: libpq-fe.h:146
@ PQTRANS_INTRANS
Definition: libpq-fe.h:149
@ PQTRANS_IDLE
Definition: libpq-fe.h:147
@ PQTRANS_INERROR
Definition: libpq-fe.h:150
#define pg_log_error(...)
Definition: logging.h:106
#define pg_log_info(...)
Definition: logging.h:124
#define sprintf
Definition: port.h:241
#define vfprintf
Definition: port.h:242
#define InvalidOid
Definition: postgres_ext.h:37
unsigned int Oid
Definition: postgres_ext.h:32
#define atooid(x)
Definition: postgres_ext.h:43
PsqlSettings pset
Definition: startup.c:32
printQueryOpt popt
Definition: settings.h:112
VariableSpace vars
Definition: settings.h:151
bool quiet
Definition: settings.h:167
FILE * logfile
Definition: settings.h:149
bool autocommit
Definition: settings.h:165
PGconn * db
Definition: settings.h:103
FILE * queryFout
Definition: settings.h:105
Definition: libpq-int.h:165
printTableOpt topt
Definition: print.h:185
enum printFormat format
Definition: print.h:113
bool SetVariable(VariableSpace space, const char *name, const char *value)
Definition: variables.c:281

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