Set the stack_base_ptr in main(), not in random other places.

Previously we did this in PostmasterMain() and InitPostmasterChild(),
which meant that stack depth checking was disabled in non-postmaster
server processes, for instance in single-user mode.  That seems like
a fairly bad idea, since there's no a-priori restriction on the
complexity of queries we will run in single-user mode.  Moreover, this
led to not having quite the same stack depth limit in all processes,
which likely has no real-world effect but it offends my inner neatnik.
Setting the depth in main() guarantees that check_stack_depth() is
armed and has a consistent interpretation of stack depth in all forms
of server processes.

While at it, move the code associated with checking the stack depth
out of tcop/postgres.c (which was never a great home for it) into
a new file src/backend/utils/misc/stack_depth.c.

Discussion: https://postgr.es/m/2081982.1734393311@sss.pgh.pa.us

1 files changed, 7 insertions, 1 deletions

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 42a2b38cac9..3f97fcef800 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -288,7 +288,12 @@ extern PGDLLIMPORT int VacuumCostBalance;
 extern PGDLLIMPORT bool VacuumCostActive;
 
 
-/* in tcop/postgres.c */
+/* in utils/misc/stack_depth.c */
+
+extern PGDLLIMPORT int max_stack_depth;
+
+/* Required daylight between max_stack_depth and the kernel limit, in bytes */
+#define STACK_DEPTH_SLOP (512 * 1024L)
 
 typedef char *pg_stack_base_t;
 
@@ -296,6 +301,7 @@ extern pg_stack_base_t set_stack_base(void);
 extern void restore_stack_base(pg_stack_base_t base);
 extern void check_stack_depth(void);
 extern bool stack_is_too_deep(void);
+extern long get_stack_depth_rlimit(void);
 
 /* in tcop/utility.c */
 extern void PreventCommandIfReadOnly(const char *cmdname);