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Diffstat (limited to 'deps/jemalloc/include/jemalloc/internal/hook.h')
-rw-r--r-- | deps/jemalloc/include/jemalloc/internal/hook.h | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/deps/jemalloc/include/jemalloc/internal/hook.h b/deps/jemalloc/include/jemalloc/internal/hook.h new file mode 100644 index 000000000..ee246b1e0 --- /dev/null +++ b/deps/jemalloc/include/jemalloc/internal/hook.h @@ -0,0 +1,163 @@ +#ifndef JEMALLOC_INTERNAL_HOOK_H +#define JEMALLOC_INTERNAL_HOOK_H + +#include "jemalloc/internal/tsd.h" + +/* + * This API is *extremely* experimental, and may get ripped out, changed in API- + * and ABI-incompatible ways, be insufficiently or incorrectly documented, etc. + * + * It allows hooking the stateful parts of the API to see changes as they + * happen. + * + * Allocation hooks are called after the allocation is done, free hooks are + * called before the free is done, and expand hooks are called after the + * allocation is expanded. + * + * For realloc and rallocx, if the expansion happens in place, the expansion + * hook is called. If it is moved, then the alloc hook is called on the new + * location, and then the free hook is called on the old location (i.e. both + * hooks are invoked in between the alloc and the dalloc). + * + * If we return NULL from OOM, then usize might not be trustworthy. Calling + * realloc(NULL, size) only calls the alloc hook, and calling realloc(ptr, 0) + * only calls the free hook. (Calling realloc(NULL, 0) is treated as malloc(0), + * and only calls the alloc hook). + * + * Reentrancy: + * Reentrancy is guarded against from within the hook implementation. If you + * call allocator functions from within a hook, the hooks will not be invoked + * again. + * Threading: + * The installation of a hook synchronizes with all its uses. If you can + * prove the installation of a hook happens-before a jemalloc entry point, + * then the hook will get invoked (unless there's a racing removal). + * + * Hook insertion appears to be atomic at a per-thread level (i.e. if a thread + * allocates and has the alloc hook invoked, then a subsequent free on the + * same thread will also have the free hook invoked). + * + * The *removal* of a hook does *not* block until all threads are done with + * the hook. Hook authors have to be resilient to this, and need some + * out-of-band mechanism for cleaning up any dynamically allocated memory + * associated with their hook. + * Ordering: + * Order of hook execution is unspecified, and may be different than insertion + * order. + */ + +#define HOOK_MAX 4 + +enum hook_alloc_e { + hook_alloc_malloc, + hook_alloc_posix_memalign, + hook_alloc_aligned_alloc, + hook_alloc_calloc, + hook_alloc_memalign, + hook_alloc_valloc, + hook_alloc_mallocx, + + /* The reallocating functions have both alloc and dalloc variants */ + hook_alloc_realloc, + hook_alloc_rallocx, +}; +/* + * We put the enum typedef after the enum, since this file may get included by + * jemalloc_cpp.cpp, and C++ disallows enum forward declarations. + */ +typedef enum hook_alloc_e hook_alloc_t; + +enum hook_dalloc_e { + hook_dalloc_free, + hook_dalloc_dallocx, + hook_dalloc_sdallocx, + + /* + * The dalloc halves of reallocation (not called if in-place expansion + * happens). + */ + hook_dalloc_realloc, + hook_dalloc_rallocx, +}; +typedef enum hook_dalloc_e hook_dalloc_t; + + +enum hook_expand_e { + hook_expand_realloc, + hook_expand_rallocx, + hook_expand_xallocx, +}; +typedef enum hook_expand_e hook_expand_t; + +typedef void (*hook_alloc)( + void *extra, hook_alloc_t type, void *result, uintptr_t result_raw, + uintptr_t args_raw[3]); + +typedef void (*hook_dalloc)( + void *extra, hook_dalloc_t type, void *address, uintptr_t args_raw[3]); + +typedef void (*hook_expand)( + void *extra, hook_expand_t type, void *address, size_t old_usize, + size_t new_usize, uintptr_t result_raw, uintptr_t args_raw[4]); + +typedef struct hooks_s hooks_t; +struct hooks_s { + hook_alloc alloc_hook; + hook_dalloc dalloc_hook; + hook_expand expand_hook; + void *extra; +}; + +/* + * Begin implementation details; everything above this point might one day live + * in a public API. Everything below this point never will. + */ + +/* + * The realloc pathways haven't gotten any refactoring love in a while, and it's + * fairly difficult to pass information from the entry point to the hooks. We + * put the informaiton the hooks will need into a struct to encapsulate + * everything. + * + * Much of these pathways are force-inlined, so that the compiler can avoid + * materializing this struct until we hit an extern arena function. For fairly + * goofy reasons, *many* of the realloc paths hit an extern arena function. + * These paths are cold enough that it doesn't matter; eventually, we should + * rewrite the realloc code to make the expand-in-place and the + * free-then-realloc paths more orthogonal, at which point we don't need to + * spread the hook logic all over the place. + */ +typedef struct hook_ralloc_args_s hook_ralloc_args_t; +struct hook_ralloc_args_s { + /* I.e. as opposed to rallocx. */ + bool is_realloc; + /* + * The expand hook takes 4 arguments, even if only 3 are actually used; + * we add an extra one in case the user decides to memcpy without + * looking too closely at the hooked function. + */ + uintptr_t args[4]; +}; + +/* + * Returns an opaque handle to be used when removing the hook. NULL means that + * we couldn't install the hook. + */ +bool hook_boot(); + +void *hook_install(tsdn_t *tsdn, hooks_t *hooks); +/* Uninstalls the hook with the handle previously returned from hook_install. */ +void hook_remove(tsdn_t *tsdn, void *opaque); + +/* Hooks */ + +void hook_invoke_alloc(hook_alloc_t type, void *result, uintptr_t result_raw, + uintptr_t args_raw[3]); + +void hook_invoke_dalloc(hook_dalloc_t type, void *address, + uintptr_t args_raw[3]); + +void hook_invoke_expand(hook_expand_t type, void *address, size_t old_usize, + size_t new_usize, uintptr_t result_raw, uintptr_t args_raw[4]); + +#endif /* JEMALLOC_INTERNAL_HOOK_H */ |