https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=2ecaa3c1769ce1bf2e42d30304903ac8c9a5fbc8
commit 2ecaa3c1769ce1bf2e42d30304903ac8c9a5fbc8 Author: Corinna Vinschen <[email protected]> Date: Fri Jun 26 20:41:54 2015 +0200 Fix values returned by getrlimit(RLIMIT_STACK) * resource.cc (getrlimit): Fix values returned by RLIMIT_STACK. Explain why this had to be changed. Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/ChangeLog | 5 +++++ winsup/cygwin/resource.cc | 36 ++++++++++++++++++++++++++---------- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog index 3b492e4..060eb80 100644 --- a/winsup/cygwin/ChangeLog +++ b/winsup/cygwin/ChangeLog @@ -1,3 +1,8 @@ +2015-06-26 Corinna Vinschen <[email protected]> + + * resource.cc (getrlimit): Fix values returned by RLIMIT_STACK. + Explain why this had to be changed. + 2015-06-23 Ken Brown <[email protected]> * include/cygwin/signal.h (SIGEV_*): Add macros. diff --git a/winsup/cygwin/resource.cc b/winsup/cygwin/resource.cc index 27ba4d4..895ba7f 100644 --- a/winsup/cygwin/resource.cc +++ b/winsup/cygwin/resource.cc @@ -114,8 +114,6 @@ getrusage (int intwho, struct rusage *rusage_in) extern "C" int getrlimit (int resource, struct rlimit *rlp) { - MEMORY_BASIC_INFORMATION m; - __try { rlp->rlim_cur = RLIM_INFINITY; @@ -129,14 +127,32 @@ getrlimit (int resource, struct rlimit *rlp) case RLIMIT_AS: break; case RLIMIT_STACK: - if (!VirtualQuery ((LPCVOID) &m, &m, sizeof m)) - debug_printf ("couldn't get stack info, returning def.values. %E"); - else - { - rlp->rlim_cur = (rlim_t) &m - (rlim_t) m.AllocationBase; - rlp->rlim_max = (rlim_t) m.BaseAddress + m.RegionSize - - (rlim_t) m.AllocationBase; - } + PTEB teb; + /* 2015-06-26: Originally rlim_cur returned the size of the still + available stack area on the current stack, rlim_max the total size + of the current stack. Two problems: + + - Per POSIX, RLIMIT_STACK returns "the maximum size of the initial + thread's stack, in bytes. The implementation does not + automatically grow the stack beyond this limit". + + - With the implementation of sigaltstack, the current stack is not + necessarily the "initial thread's stack" anymore. Rather, when + called from a signal handler running on the alternate stack, + RLIMIT_STACK should return the size of the original stack. + + rlim_cur is now the size of the stack. For system-provided stacks + it's the size between DeallocationStack and StackBase. For + application-provided stacks (via pthread_attr_setstack), + DeallocationStack is NULL, but StackLimit points to the bottom + of the stack. + + rlim_max is set to RLIM_INFINITY since there's no hard limit + for stack sizes on Windows. */ + teb = NtCurrentTeb (); + rlp->rlim_cur = (rlim_t) teb->Tib.StackBase + - (rlim_t) (teb->DeallocationStack + ?: teb->Tib.StackLimit); break; case RLIMIT_NOFILE: rlp->rlim_cur = getdtablesize ();
