Patch pgcopydb and fix another segfault

[Bodobolero]

Problem

Found another pgcopydb segfault in error handling

2025-02-06 15:30:40.112 51299 ERROR  pgsql.c:2330              [TARGET -738302813] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.112 51298 ERROR  pgsql.c:2330              [TARGET -1407749748] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.112 51297 ERROR  pgsql.c:2330              [TARGET -2073308066] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.112 51300 ERROR  pgsql.c:2330              [TARGET 1220908650] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.432 51300 ERROR  pgsql.c:2536              [Postgres] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.513 51290 ERROR  copydb.c:773              Sub-process 51300 exited with code 0 and signal Segmentation fault
2025-02-06 15:30:40.578 51299 ERROR  pgsql.c:2536              [Postgres] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:40.613 51290 ERROR  copydb.c:773              Sub-process 51299 exited with code 0 and signal Segmentation fault
2025-02-06 15:30:41.253 51298 ERROR  pgsql.c:2536              [Postgres] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:41.314 51290 ERROR  copydb.c:773              Sub-process 51298 exited with code 0 and signal Segmentation fault
2025-02-06 15:30:43.133 51297 ERROR  pgsql.c:2536              [Postgres] FATAL:  terminating connection due to administrator command
2025-02-06 15:30:43.215 51290 ERROR  copydb.c:773              Sub-process 51297 exited with code 0 and signal Segmentation fault
2025-02-06 15:30:43.215 51290 ERROR  indexes.c:123             Some INDEX worker process(es) have exited with error, see above for details
2025-02-06 15:30:43.215 51290 ERROR  indexes.c:59              Failed to create indexes, see above for details
2025-02-06 15:30:43.232 51271 ERROR  copydb.c:768              Sub-process 51290 exited with code 12

admin@ip-172-31-38-164:~/pgcopydb$ gdb /usr/local/pgsql/bin/pgcopydb core
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Reading symbols from /usr/local/pgsql/bin/pgcopydb...
[New LWP 51297]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1".
Core was generated by `pgcopydb: create index …            '.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000aaaac3a4b030 in splitLines (lbuf=lbuf@entry=0xffffd8b86930, buffer=<optimized out>) at string_utils.c:630
630				*newLinePtr = '\0';
(gdb) bt
#0  0x0000aaaac3a4b030 in splitLines (lbuf=lbuf@entry=0xffffd8b86930, buffer=<optimized out>) at string_utils.c:630
#1  0x0000aaaac3a3a678 in pgsql_execute_log_error (pgsql=pgsql@entry=0xffffd8b87040, result=result@entry=0x0, 
    sql=sql@entry=0xffff81fe9be0 "CREATE UNIQUE INDEX IF NOT EXISTS … ON … USING btree (id, transaction_id);", 
    debugParameters=debugParameters@entry=0xaaaaec5f92f0, context=context@entry=0x0) at pgsql.c:2322
#2  0x0000aaaac3a3bbec in pgsql_execute_with_params (pgsql=pgsql@entry=0xffffd8b87040, 
    sql=0xffff81fe9be0 "CREATE UNIQUE INDEX IF NOT EXISTS … ON … USING btree (id, transaction_id);", paramCount=paramCount@entry=0, 
    paramTypes=paramTypes@entry=0x0, paramValues=paramValues@entry=0x0, context=context@entry=0x0, parseFun=parseFun@entry=0x0) at pgsql.c:1649
#3  0x0000aaaac3a3c468 in pgsql_execute (pgsql=pgsql@entry=0xffffd8b87040, sql=<optimized out>) at pgsql.c:1522
#4  0x0000aaaac3a245f4 in copydb_create_index (specs=specs@entry=0xffffd8b8ec98, dst=dst@entry=0xffffd8b87040, index=index@entry=0xffff81f71800, ifNotExists=<optimized out>) at indexes.c:846
#5  0x0000aaaac3a24ca8 in copydb_create_index_by_oid (specs=specs@entry=0xffffd8b8ec98, dst=dst@entry=0xffffd8b87040, indexOid=<optimized out>) at indexes.c:410
#6  0x0000aaaac3a25040 in copydb_index_worker (specs=specs@entry=0xffffd8b8ec98) at indexes.c:297
#7  0x0000aaaac3a25238 in copydb_start_index_workers (specs=specs@entry=0xffffd8b8ec98) at indexes.c:209
#8  0x0000aaaac3a252f4 in copydb_index_supervisor (specs=specs@entry=0xffffd8b8ec98) at indexes.c:112
#9  0x0000aaaac3a253f4 in copydb_start_index_supervisor (specs=0xffffd8b8ec98) at indexes.c:57
#10 copydb_start_index_supervisor (specs=specs@entry=0xffffd8b8ec98) at indexes.c:34
#11 0x0000aaaac3a51ff4 in copydb_process_table_data (specs=specs@entry=0xffffd8b8ec98) at table-data.c:146
#12 0x0000aaaac3a520dc in copydb_copy_all_table_data (specs=specs@entry=0xffffd8b8ec98) at table-data.c:69
#13 0x0000aaaac3a0ccd8 in cloneDB (copySpecs=copySpecs@entry=0xffffd8b8ec98) at cli_clone_follow.c:602
#14 0x0000aaaac3a0d2cc in start_clone_process (pid=0xffffd8b743d8, copySpecs=0xffffd8b8ec98) at cli_clone_follow.c:502
#15 start_clone_process (copySpecs=copySpecs@entry=0xffffd8b8ec98, pid=pid@entry=0xffffd8b89788) at cli_clone_follow.c:482
#16 0x0000aaaac3a0d52c in cli_clone (argc=<optimized out>, argv=<optimized out>) at cli_clone_follow.c:164
#17 0x0000aaaac3a53850 in commandline_run (command=command@entry=0xffffd8b9eb88, argc=0, argc@entry=22, argv=0xffffd8b9edf8, argv@entry=0xffffd8b9ed48) at /home/admin/pgcopydb/src/bin/pgcopydb/../lib/subcommands.c/commandline.c:71
#18 0x0000aaaac3a01464 in main (argc=22, argv=0xffffd8b9ed48) at main.c:140
(gdb) 

The problem is most likely that the following call returned a message in a read-only memory segment where we cannot replace \n with \0 in string_utils.c splitLines() function

char *message = PQerrorMessage(pgsql->connection);

Summary of changes

modified the patch to also address this problem

[github-actions]

7425 tests run: 7073 passed, 0 failed, 352 skipped (full report)

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Flaky tests (3)

Postgres 17

• test_deletion_queue_recovery[no-validate-lose]: release-x86-64-without-lfc
• test_pg_regress[4]: release-arm64-with-lfc
• test_scrubber_physical_gc_ancestors[2]: release-arm64-with-lfc

Code coverage* (full report)

• functions: 33.3% (8587 of 25819 functions)
• lines: 49.1% (72264 of 147242 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
e4c0f1f at 2025-02-06T18:57:17.540Z :recycle:}

[fedordikarev]

looks good to me and I just checked C standard that free(NULL) is not a problem