diff options
author | Edward Thomson <ethomson@edwardthomson.com> | 2018-10-21 13:10:06 +0100 |
---|---|---|
committer | Edward Thomson <ethomson@edwardthomson.com> | 2018-10-21 13:15:24 +0100 |
commit | 2e34efaab1ec85a5a4ba522147edec9114d065d3 (patch) | |
tree | d36a2ec606c4e1bc83c71f9b656301fc331bf661 | |
parent | 305e801acb2b13dca4e08ad00c638c22337c25bf (diff) | |
download | libgit2-2e34efaab1ec85a5a4ba522147edec9114d065d3.tar.gz |
buf::oom tests: use custom allocator for oom failuresethomson/buf_oom_test
Create a custom allocator for the `buf::oom` tests that will fail with
out-of-memory errors in predictable ways. We were previously trying to
guess the way that various allocators on various platforms would fail
in a way such that `malloc`/`realloc` would return `NULL` (instead of
aborting the application, or appearing suspicious to various
instrumentation or static code analysis tools like valgrind.)
Introduce a fake `malloc` and `realloc` that will return `NULL` on
allocations requesting more than 100 bytes. Otherwise, we proxy to the
default allocator. (It's important to use the _default_ allocator, not
just call `malloc`, since the default allocator on Windows CI builds may
be the debugging C runtime allocators which would not be compatible with
a standard `malloc`.)
-rw-r--r-- | tests/buf/oom.c | 76 |
1 files changed, 39 insertions, 37 deletions
diff --git a/tests/buf/oom.c b/tests/buf/oom.c index ec3bad997..726234ef8 100644 --- a/tests/buf/oom.c +++ b/tests/buf/oom.c @@ -1,57 +1,59 @@ #include "clar_libgit2.h" #include "buffer.h" -/* - * We want to use some ridiculous size that `malloc` will fail with - * but that does not otherwise interfere with testing. On Linux, choose - * a number that is large enough to fail immediately but small enough - * that valgrind doesn't believe it to erroneously be a negative number. - * On macOS, choose a number that is large enough to fail immediately - * without having libc print warnings to stderr. - */ -#if defined(GIT_ARCH_64) && defined(__linux__) -# define TOOBIG 0x0fffffffffffffff -#elif defined(GIT_ARCH_64) -# define TOOBIG 0xffffffffffffff00 -#endif - -/** - * If we make a ridiculously large request the first time we - * actually allocate some space in the git_buf, the realloc() - * will fail. And because the git_buf_grow() wrapper always - * sets mark_oom, the code in git_buf_try_grow() will free - * the internal buffer and set it to git_buf__oom. - * - * We initialized the internal buffer to (the static variable) - * git_buf__initbuf. The purpose of this test is to make sure - * that we don't try to free the static buffer. - * - * Skip this test entirely on 32-bit platforms; a buffer large enough - * to guarantee malloc failures is so large that valgrind considers - * it likely to be an error. - */ +/* Override default allocators with ones that will fail predictably. */ + +static git_allocator std_alloc; +static git_allocator oom_alloc; + +static void *oom_malloc(size_t n, const char *file, int line) +{ + /* Reject any allocation of more than 100 bytes */ + return (n > 100) ? NULL : std_alloc.gmalloc(n, file, line); +} + +static void *oom_realloc(void *p, size_t n, const char *file, int line) +{ + /* Reject any allocation of more than 100 bytes */ + return (n > 100) ? NULL : std_alloc.grealloc(p, n, file, line); +} + +void test_buf_oom__initialize(void) +{ + git_stdalloc_init_allocator(&std_alloc); + git_stdalloc_init_allocator(&oom_alloc); + + oom_alloc.gmalloc = oom_malloc; + oom_alloc.grealloc = oom_realloc; + + cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ALLOCATOR, &oom_alloc)); +} + +void test_buf_oom__cleanup(void) +{ + cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ALLOCATOR, NULL)); +} + void test_buf_oom__grow(void) { -#ifdef GIT_ARCH_64 git_buf buf = GIT_BUF_INIT; - git_buf_clear(&buf); + cl_git_pass(git_buf_grow(&buf, 42)); + cl_assert(!git_buf_oom(&buf)); - cl_assert(git_buf_grow(&buf, TOOBIG) == -1); + cl_assert(git_buf_grow(&buf, 101) == -1); cl_assert(git_buf_oom(&buf)); git_buf_dispose(&buf); -#else - cl_skip(); -#endif } void test_buf_oom__grow_by(void) { git_buf buf = GIT_BUF_INIT; - buf.size = SIZE_MAX-10; + cl_git_pass(git_buf_grow_by(&buf, 42)); + cl_assert(!git_buf_oom(&buf)); - cl_assert(git_buf_grow_by(&buf, 50) == -1); + cl_assert(git_buf_grow_by(&buf, 101) == -1); cl_assert(git_buf_oom(&buf)); } |