6262#ifdef HAVE_SYSLOG
6363#include <syslog.h>
6464#endif
65+ #ifdef HAVE_EXECINFO_H
66+ #include <execinfo.h>
67+ #endif
6568
6669#include "access/transam.h"
6770#include "access/xact.h"
@@ -167,6 +170,7 @@ static char formatted_log_time[FORMATTED_TS_LEN];
167170
168171
169172static const char * err_gettext (const char * str ) pg_attribute_format_arg (1 );
173+ static pg_noinline void set_backtrace (ErrorData * edata , int num_skip );
170174static void set_errdata_field (MemoryContextData * cxt , char * * ptr , const char * str );
171175static void write_console (const char * line , int len );
172176static void setup_formatted_log_time (void );
@@ -398,6 +402,32 @@ errstart(int elevel, const char *filename, int lineno,
398402 return true;
399403}
400404
405+ /*
406+ * Checks whether the given funcname matches backtrace_functions; see
407+ * check_backtrace_functions.
408+ */
409+ static bool
410+ matches_backtrace_functions (const char * funcname )
411+ {
412+ char * p ;
413+
414+ if (!backtrace_symbol_list || funcname == NULL || funcname [0 ] == '\0' )
415+ return false;
416+
417+ p = backtrace_symbol_list ;
418+ for (;;)
419+ {
420+ if (* p == '\0' ) /* end of backtrace_symbol_list */
421+ break ;
422+
423+ if (strcmp (funcname , p ) == 0 )
424+ return true;
425+ p += strlen (p ) + 1 ;
426+ }
427+
428+ return false;
429+ }
430+
401431/*
402432 * errfinish --- end an error-reporting cycle
403433 *
@@ -424,6 +454,12 @@ errfinish(int dummy,...)
424454 */
425455 oldcontext = MemoryContextSwitchTo (ErrorContext );
426456
457+ if (!edata -> backtrace &&
458+ edata -> funcname &&
459+ backtrace_functions &&
460+ matches_backtrace_functions (edata -> funcname ))
461+ set_backtrace (edata , 2 );
462+
427463 /*
428464 * Call any context callback functions. Errors occurring in callback
429465 * functions will be treated as recursive errors --- this ensures we will
@@ -488,6 +524,8 @@ errfinish(int dummy,...)
488524 pfree (edata -> hint );
489525 if (edata -> context )
490526 pfree (edata -> context );
527+ if (edata -> backtrace )
528+ pfree (edata -> backtrace );
491529 if (edata -> schema_name )
492530 pfree (edata -> schema_name );
493531 if (edata -> table_name )
@@ -798,6 +836,65 @@ errmsg(const char *fmt,...)
798836 return 0 ; /* return value does not matter */
799837}
800838
839+ /*
840+ * Add a backtrace to the containing ereport() call. This is intended to be
841+ * added temporarily during debugging.
842+ */
843+ int
844+ errbacktrace (void )
845+ {
846+ ErrorData * edata = & errordata [errordata_stack_depth ];
847+ MemoryContext oldcontext ;
848+
849+ Assert (false);
850+
851+ recursion_depth ++ ;
852+ CHECK_STACK_DEPTH ();
853+ oldcontext = MemoryContextSwitchTo (edata -> assoc_context );
854+
855+ set_backtrace (edata , 1 );
856+
857+ MemoryContextSwitchTo (oldcontext );
858+ recursion_depth -- ;
859+
860+ return 0 ;
861+ }
862+
863+ /*
864+ * Compute backtrace data and add it to the supplied ErrorData. num_skip
865+ * specifies how many inner frames to skip. Use this to avoid showing the
866+ * internal backtrace support functions in the backtrace. This requires that
867+ * this and related functions are not inlined.
868+ */
869+ static void
870+ set_backtrace (ErrorData * edata , int num_skip )
871+ {
872+ StringInfoData errtrace ;
873+
874+ initStringInfo (& errtrace );
875+
876+ #ifdef HAVE_BACKTRACE_SYMBOLS
877+ {
878+ void * buf [100 ];
879+ int nframes ;
880+ char * * strfrms ;
881+
882+ nframes = backtrace (buf , lengthof (buf ));
883+ strfrms = backtrace_symbols (buf , nframes );
884+ if (strfrms == NULL )
885+ return ;
886+
887+ for (int i = num_skip ; i < nframes ; i ++ )
888+ appendStringInfo (& errtrace , "\n%s" , strfrms [i ]);
889+ free (strfrms );
890+ }
891+ #else
892+ appendStringInfoString (& errtrace ,
893+ "backtrace generation is not supported by this installation" );
894+ #endif
895+
896+ edata -> backtrace = errtrace .data ;
897+ }
801898
802899/*
803900 * errmsg_internal --- add a primary error message text to the current error
@@ -1353,6 +1450,11 @@ elog_finish(int elevel, const char *fmt,...)
13531450 recursion_depth ++ ;
13541451 oldcontext = MemoryContextSwitchTo (edata -> assoc_context );
13551452
1453+ if (!edata -> backtrace &&
1454+ edata -> funcname &&
1455+ matches_backtrace_functions (edata -> funcname ))
1456+ set_backtrace (edata , 2 );
1457+
13561458 edata -> message_id = fmt ;
13571459 EVALUATE_MESSAGE (edata -> domain , message , false, false);
13581460
@@ -1509,6 +1611,8 @@ CopyErrorData(void)
15091611 newedata -> hint = pstrdup (newedata -> hint );
15101612 if (newedata -> context )
15111613 newedata -> context = pstrdup (newedata -> context );
1614+ if (newedata -> backtrace )
1615+ newedata -> backtrace = pstrdup (newedata -> backtrace );
15121616 if (newedata -> schema_name )
15131617 newedata -> schema_name = pstrdup (newedata -> schema_name );
15141618 if (newedata -> table_name )
@@ -1547,6 +1651,8 @@ FreeErrorData(ErrorData *edata)
15471651 pfree (edata -> hint );
15481652 if (edata -> context )
15491653 pfree (edata -> context );
1654+ if (edata -> backtrace )
1655+ pfree (edata -> backtrace );
15501656 if (edata -> schema_name )
15511657 pfree (edata -> schema_name );
15521658 if (edata -> table_name )
@@ -1622,6 +1728,8 @@ ThrowErrorData(ErrorData *edata)
16221728 newedata -> hint = pstrdup (edata -> hint );
16231729 if (edata -> context )
16241730 newedata -> context = pstrdup (edata -> context );
1731+ if (edata -> backtrace )
1732+ newedata -> backtrace = pstrdup (edata -> backtrace );
16251733 /* assume message_id is not available */
16261734 if (edata -> schema_name )
16271735 newedata -> schema_name = pstrdup (edata -> schema_name );
@@ -1689,6 +1797,8 @@ ReThrowError(ErrorData *edata)
16891797 newedata -> hint = pstrdup (newedata -> hint );
16901798 if (newedata -> context )
16911799 newedata -> context = pstrdup (newedata -> context );
1800+ if (newedata -> backtrace )
1801+ newedata -> backtrace = pstrdup (newedata -> backtrace );
16921802 if (newedata -> schema_name )
16931803 newedata -> schema_name = pstrdup (newedata -> schema_name );
16941804 if (newedata -> table_name )
@@ -2914,6 +3024,13 @@ send_message_to_server_log(ErrorData *edata)
29143024 append_with_tabs (& buf , edata -> context );
29153025 appendStringInfoChar (& buf , '\n' );
29163026 }
3027+ if (edata -> backtrace )
3028+ {
3029+ log_line_prefix (& buf , edata );
3030+ appendStringInfoString (& buf , _ ("BACKTRACE: " ));
3031+ append_with_tabs (& buf , edata -> backtrace );
3032+ appendStringInfoChar (& buf , '\n' );
3033+ }
29173034 if (Log_error_verbosity >= PGERROR_VERBOSE )
29183035 {
29193036 /* assume no newlines in funcname or filename... */
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