builtin/gc: correct total_ram calculation with HAVE_BSD_SYSCTL

The calls to sysctl() assume a 64-bit memory size for the variable holding the value, but the actual size depends on the key name and platform, at least for HW_PHYSMEM. Detect any mismatched reads, and retry with a shorter variable when needed. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Carlo Marcelo Arenas Belón committed Jul 7, 2025 at 09:45 UTC 781c1cf5712f1768278f7f926f39ebad3be4aae0
1 file changed +10 -3
builtin/gc.c
+10 -3
@@ -517,7 +517,7 @@ static uint64_t total_ram(void)
517 return total;
518 }
519 #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM) || defined(HW_PHYSMEM64))
520 - int64_t physical_memory;
520 + uint64_t physical_memory;
521 int mib[2];
522 size_t length;
523
@@ -529,9 +529,16 @@ static uint64_t total_ram(void)
529 # else
530 mib[1] = HW_PHYSMEM;
531 # endif
532 - length = sizeof(int64_t);
533 - if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
532 + length = sizeof(physical_memory);
533 + if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0)) {
534 + if (length == 4) {
535 + uint32_t mem;
536 +
537 + if (!sysctl(mib, 2, &mem, &length, NULL, 0))
538 + physical_memory = mem;
539 + }
540 return physical_memory;
541 + }
542 #elif defined(GIT_WINDOWS_NATIVE)
543 MEMORYSTATUSEX memInfo;
544