From 9e4b1beafe587dced744147dfd482eac2779b519 Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Sun, 31 Oct 2021 23:15:13 +0000 Subject: [PATCH 1/6] hash-object: demonstrate a >4GB/LLP64 problem On LLP64 systems, such as Windows, the size of `long`, `int`, etc. is only 32 bits (for backward compatibility). Git's use of `unsigned long` for file memory sizes in many places, rather than size_t, limits the handling of large files on LLP64 systems (commonly given as `>4GB`). Provide a minimum test for handling a >4GB file. The `hash-object` command, with the `--literally` and without `-w` option avoids writing the object, either loose or packed. This avoids the code paths hitting the `bigFileThreshold` config test code, the zlib code, and the pack code. Subsequent patches will walk the test's call chain, converting types to `size_t` (which is larger in LLP64 data models) where appropriate. Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- t/t1007-hash-object.sh | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh index de076293b6..7867fd1dbf 100755 --- a/t/t1007-hash-object.sh +++ b/t/t1007-hash-object.sh @@ -49,6 +49,9 @@ test_expect_success 'setup' ' example sha1:ddd3f836d3e3fbb7ae289aa9ae83536f76956399 example sha256:b44fe1fe65589848253737db859bd490453510719d7424daab03daf0767b85ae + + large5GB sha1:0be2be10a4c8764f32c4bf372a98edc731a4b204 + large5GB sha256:dc18ca621300c8d3cfa505a275641ebab00de189859e022a975056882d313e64 EOF ' @@ -258,4 +261,12 @@ test_expect_success '--stdin outside of repository (uses default hash)' ' test_cmp expect actual ' +test_expect_failure EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ + 'files over 4GB hash literally' ' + test-tool genzeros $((5*1024*1024*1024)) >big && + test_oid large5GB >expect && + git hash-object --stdin --literally actual && + test_cmp expect actual +' + test_done From b9da4f898348670643b79abf73179d686942a53f Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Fri, 12 Nov 2021 21:14:50 +0000 Subject: [PATCH 2/6] object-file.c: use size_t for header lengths Continue walking the code path for the >4GB `hash-object --literally` test. The `hash_object_file_literally()` function internally uses both `hash_object_file()` and `write_object_file_prepare()`. Both function signatures use `unsigned long` rather than `size_t` for the mem buffer sizes. Use `size_t` instead, for LLP64 compatibility. While at it, convert those function's object's header buffer length to `size_t` for consistency. The value is already upcast to `uintmax_t` for print format compatibility. Note: The hash-object test still does not pass. A subsequent commit continues to walk the call tree's lower level hash functions to identify further fixes. Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- object-file.c | 14 +++++++------- object-file.h | 4 ++-- 2 files changed, 9 insertions(+), 9 deletions(-) diff --git a/object-file.c b/object-file.c index 6280e42f34..5615908967 100644 --- a/object-file.c +++ b/object-file.c @@ -509,7 +509,7 @@ cleanup: static void hash_object_body(const struct git_hash_algo *algo, struct git_hash_ctx *c, const void *buf, unsigned long len, struct object_id *oid, - char *hdr, int *hdrlen) + char *hdr, size_t *hdrlen) { algo->init_fn(c); git_hash_update(c, hdr, *hdrlen); @@ -518,9 +518,9 @@ static void hash_object_body(const struct git_hash_algo *algo, struct git_hash_c } static void write_object_file_prepare(const struct git_hash_algo *algo, - const void *buf, unsigned long len, + const void *buf, size_t len, enum object_type type, struct object_id *oid, - char *hdr, int *hdrlen) + char *hdr, size_t *hdrlen) { struct git_hash_ctx c; @@ -663,11 +663,11 @@ out: } void hash_object_file(const struct git_hash_algo *algo, const void *buf, - unsigned long len, enum object_type type, + size_t len, enum object_type type, struct object_id *oid) { char hdr[MAX_HEADER_LEN]; - int hdrlen = sizeof(hdr); + size_t hdrlen = sizeof(hdr); write_object_file_prepare(algo, buf, len, type, oid, hdr, &hdrlen); } @@ -1108,7 +1108,7 @@ cleanup: } int odb_source_loose_write_object(struct odb_source *source, - const void *buf, unsigned long len, + const void *buf, size_t len, enum object_type type, struct object_id *oid, struct object_id *compat_oid_in, unsigned flags) { @@ -1116,7 +1116,7 @@ int odb_source_loose_write_object(struct odb_source *source, const struct git_hash_algo *compat = source->odb->repo->compat_hash_algo; struct object_id compat_oid; char hdr[MAX_HEADER_LEN]; - int hdrlen = sizeof(hdr); + size_t hdrlen = sizeof(hdr); /* Generate compat_oid */ if (compat) { diff --git a/object-file.h b/object-file.h index 1229d5f675..a5b7f9aa5b 100644 --- a/object-file.h +++ b/object-file.h @@ -65,7 +65,7 @@ int odb_source_loose_freshen_object(struct odb_source *source, const struct object_id *oid); int odb_source_loose_write_object(struct odb_source *source, - const void *buf, unsigned long len, + const void *buf, size_t len, enum object_type type, struct object_id *oid, struct object_id *compat_oid_in, unsigned flags); @@ -177,7 +177,7 @@ int finalize_object_file_flags(struct repository *repo, enum finalize_object_file_flags flags); void hash_object_file(const struct git_hash_algo *algo, const void *buf, - unsigned long len, enum object_type type, + size_t len, enum object_type type, struct object_id *oid); /* Helper to check and "touch" a file */ From 840b7e45a49cba7ccff11b720fd853ab8438cd1e Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Fri, 12 Nov 2021 21:16:51 +0000 Subject: [PATCH 3/6] hash algorithms: use size_t for section lengths Continue walking the code path for the >4GB `hash-object --literally` test to the hash algorithm step for LLP64 systems. This patch lets the SHA1DC code use `size_t`, making it compatible with LLP64 data models (as used e.g. by Windows). The interested reader of this patch will note that we adjust the signature of the `git_SHA1DCUpdate()` function without updating _any_ call site. This certainly puzzled at least one reviewer already, so here is an explanation: This function is never called directly, but always via the macro `platform_SHA1_Update`, which is usually called via the macro `git_SHA1_Update`. However, we never call `git_SHA1_Update()` directly in `struct git_hash_algo`. Instead, we call `git_hash_sha1_update()`, which is defined thusly: static void git_hash_sha1_update(git_hash_ctx *ctx, const void *data, size_t len) { git_SHA1_Update(&ctx->sha1, data, len); } i.e. it contains an implicit downcast from `size_t` to `unsigned long` (before this here patch). With this patch, there is no downcast anymore. With this patch, finally, the t1007-hash-object.sh "files over 4GB hash literally" test case is fixed. Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- object-file.c | 4 ++-- sha1dc_git.c | 3 +-- sha1dc_git.h | 2 +- t/t1007-hash-object.sh | 2 +- 4 files changed, 5 insertions(+), 6 deletions(-) diff --git a/object-file.c b/object-file.c index 5615908967..90d2087b19 100644 --- a/object-file.c +++ b/object-file.c @@ -507,7 +507,7 @@ cleanup: } static void hash_object_body(const struct git_hash_algo *algo, struct git_hash_ctx *c, - const void *buf, unsigned long len, + const void *buf, size_t len, struct object_id *oid, char *hdr, size_t *hdrlen) { @@ -527,7 +527,7 @@ static void write_object_file_prepare(const struct git_hash_algo *algo, /* Generate the header */ *hdrlen = format_object_header(hdr, *hdrlen, type, len); - /* Sha1.. */ + /* Hash (function pointers) computation */ hash_object_body(algo, &c, buf, len, oid, hdr, hdrlen); } diff --git a/sha1dc_git.c b/sha1dc_git.c index 9b675a046e..fe58d7962a 100644 --- a/sha1dc_git.c +++ b/sha1dc_git.c @@ -27,10 +27,9 @@ void git_SHA1DCFinal(unsigned char hash[20], SHA1_CTX *ctx) /* * Same as SHA1DCUpdate, but adjust types to match git's usual interface. */ -void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *vdata, unsigned long len) +void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *vdata, size_t len) { const char *data = vdata; - /* We expect an unsigned long, but sha1dc only takes an int */ while (len > INT_MAX) { SHA1DCUpdate(ctx, data, INT_MAX); data += INT_MAX; diff --git a/sha1dc_git.h b/sha1dc_git.h index f6f880cabe..0bcf1aa84b 100644 --- a/sha1dc_git.h +++ b/sha1dc_git.h @@ -15,7 +15,7 @@ void git_SHA1DCInit(SHA1_CTX *); #endif void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *); -void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len); +void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, size_t len); #define platform_SHA_IS_SHA1DC /* used by "test-tool sha1-is-sha1dc" */ diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh index 7867fd1dbf..10382a815e 100755 --- a/t/t1007-hash-object.sh +++ b/t/t1007-hash-object.sh @@ -261,7 +261,7 @@ test_expect_success '--stdin outside of repository (uses default hash)' ' test_cmp expect actual ' -test_expect_failure EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ +test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ 'files over 4GB hash literally' ' test-tool genzeros $((5*1024*1024*1024)) >big && test_oid large5GB >expect && From c8273e76eb84882636bf13199a3cbe287744c47f Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Mon, 6 Dec 2021 22:26:50 +0000 Subject: [PATCH 4/6] hash-object --stdin: verify that it works with >4GB/LLP64 Just like the `hash-object --literally` code path, the `--stdin` code path also needs to use `size_t` instead of `unsigned long` to represent memory sizes, otherwise it would cause problems on platforms using the LLP64 data model (such as Windows). To limit the scope of the test case, the object is explicitly not written to the object store, nor are any filters applied. The `big` file from the previous test case is reused to save setup time; To avoid relying on that side effect, it is generated if it does not exist (e.g. when running via `sh t1007-*.sh --long --run=1,41`). Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- t/t1007-hash-object.sh | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh index 10382a815e..59efee3aff 100755 --- a/t/t1007-hash-object.sh +++ b/t/t1007-hash-object.sh @@ -269,4 +269,12 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ test_cmp expect actual ' +test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ + 'files over 4GB hash correctly via --stdin' ' + { test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } && + test_oid large5GB >expect && + git hash-object --stdin actual && + test_cmp expect actual +' + test_done From 8f2446647d0c8450c079e664c611acccb77e8f3a Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Mon, 6 Dec 2021 22:42:46 +0000 Subject: [PATCH 5/6] hash-object: add another >4GB/LLP64 test case To complement the `--stdin` and `--literally` test cases that verify that we can hash files larger than 4GB on 64-bit platforms using the LLP64 data model, here is a test case that exercises `hash-object` _without_ any options. Just as before, we use the `big` file from the previous test case if it exists to save on setup time, otherwise generate it. Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- t/t1007-hash-object.sh | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh index 59efee3aff..f2722380ee 100755 --- a/t/t1007-hash-object.sh +++ b/t/t1007-hash-object.sh @@ -277,4 +277,12 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ test_cmp expect actual ' +test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ + 'files over 4GB hash correctly' ' + { test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } && + test_oid large5GB >expect && + git hash-object -- big >actual && + test_cmp expect actual +' + test_done From b8c422adedb398570b27889ed8a93539ce912804 Mon Sep 17 00:00:00 2001 From: Philip Oakley Date: Tue, 7 Dec 2021 09:53:41 +0000 Subject: [PATCH 6/6] hash-object: add a >4GB/LLP64 test case using filtered input To verify that the `clean` side of the `clean`/`smudge` filter code is correct with regards to LLP64 (read: to ensure that `size_t` is used instead of `unsigned long`), here is a test case using a trivial filter, specifically _not_ writing anything to the object store to limit the scope of the test case. As in previous commits, the `big` file from previous test cases is reused if available, to save setup time, otherwise re-generated. Signed-off-by: Philip Oakley Signed-off-by: Johannes Schindelin --- t/t1007-hash-object.sh | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh index f2722380ee..841a6671d1 100755 --- a/t/t1007-hash-object.sh +++ b/t/t1007-hash-object.sh @@ -285,4 +285,16 @@ test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ test_cmp expect actual ' +# This clean filter does nothing, other than excercising the interface. +# We ensure that cleaning doesn't mangle large files on 64-bit Windows. +test_expect_success EXPENSIVE,SIZE_T_IS_64BIT,!LONG_IS_64BIT \ + 'hash filtered files over 4GB correctly' ' + { test -f big || test-tool genzeros $((5*1024*1024*1024)) >big; } && + test_oid large5GB >expect && + test_config filter.null-filter.clean "cat" && + echo "big filter=null-filter" >.gitattributes && + git hash-object -- big >actual && + test_cmp expect actual +' + test_done