[3.15] backport #10333 (#10431)

* test: demonstrate overflow with sendfile (#10334) See #10333 Signed-off-by: Etienne Millon <[email protected]> * fix: use `Long_val` for sendfile() parameters to fix file copying in docker (#10333) * fix: sendfile() in docker Signed-off-by: Haoxiang Fei <[email protected]> * use ssize_t for return value Co-authored-by: Etienne Millon <[email protected]> Signed-off-by: Haoxiang Fei <[email protected]> * update test Signed-off-by: Etienne Millon <[email protected]> * Add changelog Signed-off-by: Etienne Millon <[email protected]> --------- Signed-off-by: Haoxiang Fei <[email protected]> Signed-off-by: Haoxiang Fei <[email protected]> Signed-off-by: Etienne Millon <[email protected]> Co-authored-by: Etienne Millon <[email protected]> Co-authored-by: Etienne Millon <[email protected]> * fix formatting (#10356) Signed-off-by: Etienne Millon <[email protected]> * move changelog entry to the right place (#10375) Signed-off-by: Etienne Millon <[email protected]> --------- Signed-off-by: Etienne Millon <[email protected]> Signed-off-by: Haoxiang Fei <[email protected]> Signed-off-by: Haoxiang Fei <[email protected]> Co-authored-by: Haoxiang Fei <[email protected]>
ocaml · Apr 17, 2024 · f434ff8 · f434ff8
1 parent 95f208c
commit f434ff8
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diff --git a/doc/changes/10333.md b/doc/changes/10333.md
@@ -0,0 +1,2 @@
+- fix overflow in sendfile stubs (copy of large files could fail or end with
+  truncated files) (#10333, @tonyfettes)
diff --git a/otherlibs/stdune/src/copyfile_stubs.c b/otherlibs/stdune/src/copyfile_stubs.c
@@ -73,8 +73,8 @@ CAMLprim value stdune_copyfile(value v_from, value v_to) {
   caml_failwith("copyfile: only on macos");
 }
 
-static int dune_sendfile(int in, int out, int length) {
-  int ret;
+static int dune_sendfile(int in, int out, size_t length) {
+  ssize_t ret;
   while (length > 0) {
     ret = sendfile(out, in, NULL, length);
     if (ret < 0) {
@@ -90,7 +90,7 @@ CAMLprim value stdune_sendfile(value v_in, value v_out, value v_size) {
   caml_release_runtime_system();
   /* TODO Use copy_file_range once we have a good mechanism to test for its
    * existence */
-  int ret = dune_sendfile(FD_val(v_in), FD_val(v_out), Int_val(v_size));
+  int ret = dune_sendfile(FD_val(v_in), FD_val(v_out), Long_val(v_size));
   caml_acquire_runtime_system();
   if (ret < 0) {
     uerror("sendfile", Nothing);

diff --git a/test/blackbox-tests/test-cases/dune b/test/blackbox-tests/test-cases/dune
@@ -43,6 +43,14 @@
  (applies_to fdo)
  (enabled_if false))
 
+; This test copies a large file, which is too slow to be enabled all the time.
+; The source file is actually sparse, but sendfile seems to do a full copy
+; nevertheless.
+
+(cram
+ (applies_to sendfile-large-file)
+ (enabled_if false))
+
 ; This test is flaky
 
 (cram

diff --git a/test/blackbox-tests/test-cases/sendfile-large-file.t b/test/blackbox-tests/test-cases/sendfile-large-file.t
@@ -0,0 +1,22 @@
+We create a large file and check that it is copied completely.
+
+  $ cat > dune-project << EOF
+  > (lang dune 1.0)
+  > EOF
+
+  $ cat > create.ml << EOF
+  > let () = Unix.truncate "file.dat" 0x1_00_00_00_03
+  > EOF
+  $ touch file.dat
+  $ ocaml unix.cma create.ml
+  $ rm create.ml
+
+  $ dune build file.dat
+
+  $ dune_cmd stat size file.dat
+  4294967299
+
+  $ dune_cmd stat size _build/default/file.dat
+  4294967299
+
+(3 indicates that the file size is taken modulo 2**32)
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		- fix overflow in sendfile stubs (copy of large files could fail or end with
		truncated files) (#10333, @tonyfettes)