These functions can potentially take some time, so allow other OCaml code to proceed meanwhile (if any).
Also raise a Unix_error based on `errno` if `mmap` fails, instead of just calling failwith (which would lose the error reason). Signed-off-by: Edwin Török <edvin.to...@citrix.com> --- Changes since v2: * repost of lost patch from 2020 (posted to ML on 2021 https://patchwork.kernel.org/project/xen-devel/patch/294a60be29027d33b0a1d154b7d576237c7dd420.1620755942.git.edvin.to...@citrix.com/) --- tools/ocaml/libs/mmap/xenmmap_stubs.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/tools/ocaml/libs/mmap/xenmmap_stubs.c b/tools/ocaml/libs/mmap/xenmmap_stubs.c index bf864a7c32..5b8c240ef9 100644 --- a/tools/ocaml/libs/mmap/xenmmap_stubs.c +++ b/tools/ocaml/libs/mmap/xenmmap_stubs.c @@ -27,6 +27,8 @@ #include <caml/custom.h> #include <caml/fail.h> #include <caml/callback.h> +#include <caml/unixsupport.h> +#include <caml/signals.h> #define Intf_val(a) ((struct mmap_interface *) Data_abstract_val(a)) @@ -35,7 +37,9 @@ static int mmap_interface_init(struct mmap_interface *intf, int len, int offset) { intf->len = len; + caml_enter_blocking_section(); intf->addr = mmap(NULL, len, pflag, mflag, fd, offset); + caml_leave_blocking_section(); return (intf->addr == MAP_FAILED) ? errno : 0; } @@ -64,17 +68,22 @@ CAMLprim value stub_mmap_init(value fd, value pflag, value mflag, if (mmap_interface_init(Intf_val(result), Int_val(fd), c_pflag, c_mflag, Int_val(len), Int_val(offset))) - caml_failwith("mmap"); + uerror("mmap", Nothing); CAMLreturn(result); } CAMLprim value stub_mmap_final(value intf) { CAMLparam1(intf); + struct mmap_interface interface = *Intf_val(intf); - if (Intf_val(intf)->addr != MAP_FAILED) - munmap(Intf_val(intf)->addr, Intf_val(intf)->len); + /* mark it as freed, in case munmap below fails, so we don't retry it */ Intf_val(intf)->addr = MAP_FAILED; + if (interface.addr != MAP_FAILED) { + caml_enter_blocking_section(); + munmap(interface.addr, interface.len); + caml_leave_blocking_section(); + } CAMLreturn(Val_unit); } -- 2.34.1
