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tglsfdctglsfdc
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Plug several holes in backend's ability to cope with
unexpected loss of connection to frontend.
1 parent 991b82e commit 2aa64f7

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3 files changed

+84
-48
lines changed

3 files changed

+84
-48
lines changed

‎src/backend/commands/copy.c

Lines changed: 28 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
*
77
*
88
* IDENTIFICATION
9-
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.85 1999/07/17 20:16:51 momjian Exp $
9+
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.86 1999/07/22 02:40:06 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -54,15 +54,19 @@ static void GetIndexRelations(Oid main_relation_oid,
5454
#ifdef COPY_PATCH
5555
static void CopyReadNewline(FILE *fp, int *newline);
5656
static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim, int *newline);
57-
5857
#else
5958
static char *CopyReadAttribute(FILE *fp, bool *isnull, char *delim);
60-
6159
#endif
60+
6261
static void CopyAttributeOut(FILE *fp, char *string, char *delim, int is_array);
6362
static int CountTuples(Relation relation);
6463

64+
/*
65+
* Static communication variables ... pretty grotty, but COPY has
66+
* never been reentrant...
67+
*/
6568
static int lineno;
69+
static bool fe_eof;
6670

6771
/*
6872
* Internal communications functions
@@ -90,7 +94,10 @@ static void
9094
CopySendData(void *databuf, int datasize, FILE *fp)
9195
{
9296
if (!fp)
93-
pq_putbytes((char *) databuf, datasize);
97+
{
98+
if (pq_putbytes((char *) databuf, datasize))
99+
fe_eof = true;
100+
}
94101
else
95102
fwrite(databuf, datasize, 1, fp);
96103
}
@@ -121,7 +128,10 @@ static void
121128
CopyGetData(void *databuf, int datasize, FILE *fp)
122129
{
123130
if (!fp)
124-
pq_getbytes((char *) databuf, datasize);
131+
{
132+
if (pq_getbytes((char *) databuf, datasize))
133+
fe_eof = true;
134+
}
125135
else
126136
fread(databuf, datasize, 1, fp);
127137
}
@@ -134,7 +144,10 @@ CopyGetChar(FILE *fp)
134144
unsigned char ch;
135145

136146
if (pq_getbytes((char *) &ch, 1))
147+
{
148+
fe_eof = true;
137149
return EOF;
150+
}
138151
return ch;
139152
}
140153
else
@@ -145,24 +158,28 @@ static int
145158
CopyGetEof(FILE *fp)
146159
{
147160
if (!fp)
148-
return 0; /* Never return EOF when talking to
149-
* frontend ? */
161+
return fe_eof;
150162
else
151163
return feof(fp);
152164
}
153165

154166
/*
155167
* CopyPeekChar reads a byte in "peekable" mode.
156168
* after each call to CopyPeekChar, a call to CopyDonePeek _must_
157-
* follow.
169+
* follow, unless EOF was returned.
158170
* CopyDonePeek will either take the peeked char off the steam
159171
* (if pickup is != 0) or leave it on the stream (if pickup == 0)
160172
*/
161173
static int
162174
CopyPeekChar(FILE *fp)
163175
{
164176
if (!fp)
165-
return pq_peekbyte();
177+
{
178+
int ch = pq_peekbyte();
179+
if (ch == EOF)
180+
fe_eof = true;
181+
return ch;
182+
}
166183
else
167184
return getc(fp);
168185
}
@@ -668,6 +685,8 @@ CopyFrom(Relation rel, bool binary, bool oids, FILE *fp, char *delim)
668685
}
669686

670687
lineno = 0;
688+
fe_eof = false;
689+
671690
while (!done)
672691
{
673692
if (!binary)
@@ -1193,10 +1212,7 @@ CopyReadAttribute(FILE *fp, bool *isnull, char *delim)
11931212
else
11941213
{
11951214
if (CopyGetEof(fp))
1196-
{
1197-
CopyDonePeek(fp, c, 1); /* pick up */
11981215
return NULL;
1199-
}
12001216
CopyDonePeek(fp, c, 0); /* Return to stream! */
12011217
}
12021218
}

‎src/backend/tcop/fastpath.c

Lines changed: 25 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/tcop/fastpath.c,v 1.29 1999/07/17 20:17:50 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/tcop/fastpath.c,v 1.30 1999/07/22 02:40:07 tgl Exp $
1111
*
1212
* NOTES
1313
* This cruft is the server side of PQfn.
@@ -265,8 +265,11 @@ update_fp_info(Oid func_id, struct fp_info * fip)
265265
* This corresponds to the libpq protocol symbol "F".
266266
*
267267
* RETURNS:
268-
* nothing of significance.
269-
* All errors result in elog(ERROR,...).
268+
* 0 if successful completion, EOF if frontend connection lost.
269+
*
270+
* Note: All ordinary errors result in elog(ERROR,...). However,
271+
* if we lose the frontend connection there is no one to elog to,
272+
* and no use in proceeding...
270273
*/
271274
int
272275
HandleFunctionRequest()
@@ -282,9 +285,11 @@ HandleFunctionRequest()
282285
char *p;
283286
struct fp_info *fip;
284287

285-
pq_getint(&tmp, 4); /* function oid */
288+
if (pq_getint(&tmp, 4)) /* function oid */
289+
return EOF;
286290
fid = (Oid) tmp;
287-
pq_getint(&nargs, 4); /* # of arguments */
291+
if (pq_getint(&nargs, 4)) /* # of arguments */
292+
return EOF;
288293

289294
/*
290295
* This is where the one-back caching is done. If you want to save
@@ -294,6 +299,13 @@ HandleFunctionRequest()
294299
if (!valid_fp_info(fid, fip))
295300
update_fp_info(fid, fip);
296301

302+
/*
303+
* XXX FIXME: elog() here means we lose sync with the frontend,
304+
* since we have not swallowed all of its input message. What
305+
* should happen is we absorb all of the input message per protocol
306+
* syntax, and *then* do error checking and elog if appropriate.
307+
*/
308+
297309
if (fip->nargs != nargs)
298310
{
299311
elog(ERROR, "HandleFunctionRequest: actual arguments (%d) != registered arguments (%d)",
@@ -311,13 +323,15 @@ HandleFunctionRequest()
311323
arg[i] = (char *) NULL;
312324
else
313325
{
314-
pq_getint(&argsize, 4);
326+
if (pq_getint(&argsize, 4))
327+
return EOF;
315328

316329
Assert(argsize > 0);
317330
if (fip->argbyval[i])
318331
{ /* by-value */
319332
Assert(argsize <= 4);
320-
pq_getint(&tmp, argsize);
333+
if (pq_getint(&tmp, argsize))
334+
return EOF;
321335
arg[i] = (char *) tmp;
322336
}
323337
else
@@ -329,14 +343,16 @@ HandleFunctionRequest()
329343
* 98 Jan 6 */
330344
elog(ERROR, "HandleFunctionRequest: palloc failed");
331345
VARSIZE(p) = argsize + VARHDRSZ;
332-
pq_getbytes(VARDATA(p), argsize);
346+
if (pq_getbytes(VARDATA(p), argsize))
347+
return EOF;
333348
}
334349
else
335350
{ /* ... fixed */
336351
/* XXX cross our fingers and trust "argsize" */
337352
if (!(p = palloc(argsize + 1)))
338353
elog(ERROR, "HandleFunctionRequest: palloc failed");
339-
pq_getbytes(p, argsize);
354+
if (pq_getbytes(p, argsize))
355+
return EOF;
340356
}
341357
palloced |= (1 << i);
342358
arg[i] = p;
@@ -374,7 +390,5 @@ HandleFunctionRequest()
374390
if (!fip->retbyval)
375391
pfree(retval);
376392

377-
378-
379393
return 0;
380394
}

‎src/backend/tcop/postgres.c

Lines changed: 31 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.126 1999/07/19 02:27:06 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.127 1999/07/22 02:40:07 tgl Exp $
1111
*
1212
* NOTES
1313
* this is the "main" module of the postgres backend and
@@ -158,9 +158,9 @@ int _exec_repeat_ = 1;
158158
* decls for routines only used in this file
159159
* ----------------------------------------------------------------
160160
*/
161-
static char InteractiveBackend(char *inBuf);
162-
static char SocketBackend(char *inBuf);
163-
static char ReadCommand(char *inBuf);
161+
static int InteractiveBackend(char *inBuf);
162+
static int SocketBackend(char *inBuf);
163+
static int ReadCommand(char *inBuf);
164164
static void pg_exec_query(char *query_string);
165165

166166

@@ -172,10 +172,12 @@ static void pg_exec_query(char *query_string);
172172
/* ----------------
173173
* InteractiveBackend() is called for user interactive connections
174174
* the string entered by the user is placed in its parameter inBuf.
175+
*
176+
* EOF is returned if end-of-file input is seen; time to shut down.
175177
* ----------------
176178
*/
177179

178-
static char
180+
static int
179181
InteractiveBackend(char *inBuf)
180182
{
181183
char *stuff = inBuf; /* current place in input buffer */
@@ -244,8 +246,7 @@ InteractiveBackend(char *inBuf)
244246
{
245247
if (Verbose)
246248
puts("EOF");
247-
IsEmptyQuery = true;
248-
proc_exit(0);
249+
return EOF;
249250
}
250251

251252
/* ----------------
@@ -274,11 +275,13 @@ InteractiveBackend(char *inBuf)
274275
*
275276
* If the input is a fastpath function call (case 'F') then
276277
* the function call is processed in HandleFunctionRequest().
277-
* (now called from PostgresMain())
278+
* (now called from PostgresMain()).
279+
*
280+
* EOF is returned if the connection is lost.
278281
* ----------------
279282
*/
280283

281-
static char
284+
static int
282285
SocketBackend(char *inBuf)
283286
{
284287
char qtype;
@@ -290,13 +293,7 @@ SocketBackend(char *inBuf)
290293
*/
291294
qtype = '?';
292295
if (pq_getbytes(&qtype, 1) == EOF)
293-
{
294-
/* ------------
295-
* when front-end applications quits/dies
296-
* ------------
297-
*/
298-
proc_exit(0);
299-
}
296+
return EOF;
300297

301298
switch (qtype)
302299
{
@@ -305,7 +302,8 @@ SocketBackend(char *inBuf)
305302
* ----------------
306303
*/
307304
case 'Q':
308-
pq_getstr(inBuf, MAX_PARSE_BUFFER);
305+
if (pq_getstr(inBuf, MAX_PARSE_BUFFER))
306+
return EOF;
309307
result = 'Q';
310308
break;
311309

@@ -314,8 +312,8 @@ SocketBackend(char *inBuf)
314312
* ----------------
315313
*/
316314
case 'F':
317-
pq_getstr(inBuf, MAX_PARSE_BUFFER); /* ignore the rest of the
318-
* line */
315+
if (pq_getstr(inBuf, MAX_PARSE_BUFFER))
316+
return EOF; /* ignore "string" at start of F message */
319317
result = 'F';
320318
break;
321319

@@ -345,10 +343,10 @@ SocketBackend(char *inBuf)
345343
* ReadCommand reads a command from either the frontend or
346344
* standard input, places it in inBuf, and returns a char
347345
* representing whether the string is a 'Q'uery or a 'F'astpath
348-
* call.
346+
* call. EOF is returned if end of file.
349347
* ----------------
350348
*/
351-
static char
349+
static int
352350
ReadCommand(char *inBuf)
353351
{
354352
if (IsUnderPostmaster)
@@ -890,7 +888,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
890888
bool secure = true;
891889
int errs = 0;
892890

893-
char firstchar;
891+
int firstchar;
894892
char parser_input[MAX_PARSE_BUFFER];
895893
char *userName;
896894

@@ -1494,7 +1492,7 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
14941492
if (!IsUnderPostmaster)
14951493
{
14961494
puts("\nPOSTGRES backend interactive interface ");
1497-
puts("$Revision: 1.126 $ $Date: 1999/07/19 02:27:06 $\n");
1495+
puts("$Revision: 1.127 $ $Date: 1999/07/22 02:40:07 $\n");
14981496
}
14991497

15001498
/* ----------------
@@ -1581,7 +1579,12 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
15811579
TPRINTF(TRACE_VERBOSE, "StartTransactionCommand");
15821580
StartTransactionCommand();
15831581

1584-
HandleFunctionRequest();
1582+
if (HandleFunctionRequest() == EOF)
1583+
{
1584+
/* lost frontend connection during F message input */
1585+
pq_close();
1586+
proc_exit(0);
1587+
}
15851588
break;
15861589

15871590
/* ----------------
@@ -1621,10 +1624,13 @@ PostgresMain(int argc, char *argv[], int real_argc, char *real_argv[])
16211624
break;
16221625

16231626
/* ----------------
1624-
* 'X' means that the frontend is closing down the socket
1627+
* 'X' means that the frontend is closing down the socket.
1628+
* EOF means unexpected loss of frontend connection.
1629+
* Either way, perform normal shutdown.
16251630
* ----------------
16261631
*/
16271632
case 'X':
1633+
case EOF:
16281634
pq_close();
16291635
proc_exit(0);
16301636
break;

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