[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging-4.13] tools/ocaml: libxb: Avoid to use String_val() when value is bytes
commit 23f3adaa37f85c2863633e76f9ccce6447b5571c Author: Julien Grall <jgrall@xxxxxxxxxx> AuthorDate: Mon Mar 30 18:50:08 2020 +0100 Commit: Ian Jackson <iwj@xxxxxxxxxxxxxx> CommitDate: Fri Mar 19 13:41:10 2021 +0000 tools/ocaml: libxb: Avoid to use String_val() when value is bytes Commit ec7d54dd1a "ocaml/libs/xb: Use bytes in place of strings for mutable buffers" switch mutable buffers from string to bytes. However the C code were still using String_Val() to access them. While the underlying structure is the same between string and bytes, a string is meant to be immutable. OCaml 4.06.1 and later will enforce it. Therefore, it will not be possible to build the OCaml libs when using -safe-string. This is because String_val() will return a const value. To avoid plain cast in the code, the code is now switched to use Bytes_val(). As the macro is not defined in older OCaml version, we need to provide a stub. Take the opportunity to switch to const the buffer in ml_interface_write() as it should not be modified. Reported-by: Dario Faggioli <dfaggioli@xxxxxxxx> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> Acked-by: Christian Lindig <christian.lindig@xxxxxxxxxx> (cherry picked from commit 78686437e949a85a207ae1a0d637efe2d3778bbe) --- tools/ocaml/libs/xb/xs_ring_stubs.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/ocaml/libs/xb/xs_ring_stubs.c b/tools/ocaml/libs/xb/xs_ring_stubs.c index 473787064a..7537a23949 100644 --- a/tools/ocaml/libs/xb/xs_ring_stubs.c +++ b/tools/ocaml/libs/xb/xs_ring_stubs.c @@ -36,6 +36,14 @@ #define GET_C_STRUCT(a) ((struct mmap_interface *) a) +/* + * Bytes_val has been introduced by Ocaml 4.06.1. So define our own version + * if needed. + */ +#ifndef Bytes_val +#define Bytes_val(x) ((unsigned char *) Bp_val(x)) +#endif + CAMLprim value ml_interface_read(value ml_interface, value ml_buffer, value ml_len) @@ -44,7 +52,7 @@ CAMLprim value ml_interface_read(value ml_interface, CAMLlocal1(ml_result); struct mmap_interface *interface = GET_C_STRUCT(ml_interface); - char *buffer = String_val(ml_buffer); + unsigned char *buffer = Bytes_val(ml_buffer); int len = Int_val(ml_len); int result; @@ -103,7 +111,7 @@ CAMLprim value ml_interface_write(value ml_interface, CAMLlocal1(ml_result); struct mmap_interface *interface = GET_C_STRUCT(ml_interface); - char *buffer = String_val(ml_buffer); + const unsigned char *buffer = Bytes_val(ml_buffer); int len = Int_val(ml_len); int result; -- generated by git-patchbot for /home/xen/git/xen.git#staging-4.13
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