From 57d4660468ef2674bb6afc2c5814d4b397a5eda9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= Date: Wed, 16 Oct 2019 12:10:22 +0000 Subject: grep: make PCRE1 aware of custom allocator MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 63e7e9d8b6 ("git-grep: Learn PCRE", 2011-05-09) didn't include a way to override the system alocator, and so it is incompatible with USE_NED_ALLOCATOR as reported by Dscho[1] (in similar code from PCRE2) Note that nedmalloc, as well as other custom allocators like jemalloc and mi-malloc, can be configured at runtime (via `LD_PRELOAD`), therefore we cannot know at compile time whether a custom allocator is used or not. Make the minimum change possible to ensure this combination is supported by extending `grep_init()` to set the PCRE1 specific functions to Git's idea of `malloc()` and `free()` and therefore making sure all allocations are done inside PCRE1 with the same allocator than the rest of Git. This change has negligible performance impact: PCRE needs to allocate memory once per program run for the character table and for each pattern compilation. These are both rare events compared to matching patterns against lines. Actual measurements[2] show that the impact is lost in the noise. [1] https://public-inbox.org/git/pull.306.git.gitgitgadget@gmail.com [2] https://public-inbox.org/git/7f42007f-911b-c570-17f6-1c6af0429586@web.de Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano diff --git a/grep.c b/grep.c index cd952ef..db6e0d8 100644 --- a/grep.c +++ b/grep.c @@ -150,12 +150,20 @@ int grep_config(const char *var, const char *value, void *cb) * Initialize one instance of grep_opt and copy the * default values from the template we read the configuration * information in an earlier call to git_config(grep_config). + * + * If using PCRE, make sure that the library is configured + * to use the same allocator as Git (e.g. nedmalloc on Windows). */ void grep_init(struct grep_opt *opt, struct repository *repo, const char *prefix) { struct grep_opt *def = &grep_defaults; int i; +#ifdef USE_LIBPCRE1 + pcre_malloc = malloc; + pcre_free = free; +#endif + memset(opt, 0, sizeof(*opt)); opt->repo = repo; opt->prefix = prefix; -- cgit v0.10.2-6-g49f6 From 513f2b0bbd47015640723a10210c527839e8946a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= Date: Wed, 16 Oct 2019 12:10:23 +0000 Subject: grep: make PCRE2 aware of custom allocator MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 94da9193a6 (grep: add support for PCRE v2, 2017-06-01) didn't include a way to override the system allocator, and so it is incompatible with custom allocators (e.g. nedmalloc). This problem became obvious when we tried to plug a memory leak by `free()`ing a data structure allocated by PCRE2, triggering a segfault in Windows (where we use nedmalloc by default). PCRE2 requires the use of a general context to override the allocator and therefore, there is a lot more code needed than in PCRE1, including a couple of wrapper functions. Extend the grep API with a "destructor" that could be called to cleanup any objects that were created and used globally. Update `builtin/grep.c` to use that new API, but any other future users should make sure to have matching `grep_init()`/`grep_destroy()` calls if they are using the pattern matching functionality. Move some of the logic that was before done per thread (in the workers) into an earlier phase to avoid degrading performance, but as the use of PCRE2 with custom allocators is better understood it is expected more of its functions will be instructed to use the custom allocator as well as was done in the original code[1] this work was based on. [1] https://public-inbox.org/git/3397e6797f872aedd18c6d795f4976e1c579514b.1565005867.git.gitgitgadget@gmail.com/ Reported-by: Johannes Schindelin Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano diff --git a/builtin/grep.c b/builtin/grep.c index 5600517..e49c20d 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -1145,5 +1145,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix) run_pager(&opt, prefix); clear_pathspec(&pathspec); free_grep_patterns(&opt); + grep_destroy(); return !hit; } diff --git a/grep.c b/grep.c index db6e0d8..296edbb 100644 --- a/grep.c +++ b/grep.c @@ -16,6 +16,20 @@ static int grep_source_is_binary(struct grep_source *gs, static struct grep_opt grep_defaults; +#ifdef USE_LIBPCRE2 +static pcre2_general_context *pcre2_global_context; + +static void *pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void *memory_data) +{ + return malloc(size); +} + +static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data) +{ + return free(pointer); +} +#endif + static const char *color_grep_slots[] = { [GREP_COLOR_CONTEXT] = "context", [GREP_COLOR_FILENAME] = "filename", @@ -153,12 +167,20 @@ int grep_config(const char *var, const char *value, void *cb) * * If using PCRE, make sure that the library is configured * to use the same allocator as Git (e.g. nedmalloc on Windows). + * + * Any allocated memory needs to be released in grep_destroy(). */ void grep_init(struct grep_opt *opt, struct repository *repo, const char *prefix) { struct grep_opt *def = &grep_defaults; int i; +#if defined(USE_LIBPCRE2) + if (!pcre2_global_context) + pcre2_global_context = pcre2_general_context_create( + pcre2_malloc, pcre2_free, NULL); +#endif + #ifdef USE_LIBPCRE1 pcre_malloc = malloc; pcre_free = free; @@ -186,6 +208,13 @@ void grep_init(struct grep_opt *opt, struct repository *repo, const char *prefix color_set(opt->colors[i], def->colors[i]); } +void grep_destroy(void) +{ +#ifdef USE_LIBPCRE2 + pcre2_general_context_free(pcre2_global_context); +#endif +} + static void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt) { /* @@ -505,9 +534,12 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt p->pcre2_compile_context = NULL; + /* pcre2_global_context is initialized in append_grep_pattern */ if (opt->ignore_case) { if (has_non_ascii(p->pattern)) { - character_tables = pcre2_maketables(NULL); + if (!pcre2_global_context) + BUG("pcre2_global_context uninitialized"); + character_tables = pcre2_maketables(pcre2_global_context); p->pcre2_compile_context = pcre2_compile_context_create(NULL); pcre2_set_character_tables(p->pcre2_compile_context, character_tables); } diff --git a/grep.h b/grep.h index 1875880..526c2db 100644 --- a/grep.h +++ b/grep.h @@ -189,6 +189,7 @@ struct grep_opt { void init_grep_defaults(struct repository *); int grep_config(const char *var, const char *value, void *); void grep_init(struct grep_opt *, struct repository *repo, const char *prefix); +void grep_destroy(void); void grep_commit_pattern_type(enum grep_pattern_type, struct grep_opt *opt); void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen, const char *origin, int no, enum grep_pat_token t); -- cgit v0.10.2-6-g49f6 From 10da030ab757c38a01507bf18e2484698000b791 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= Date: Wed, 16 Oct 2019 12:10:24 +0000 Subject: grep: avoid leak of chartables in PCRE2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 94da9193a6 ("grep: add support for PCRE v2", 2017-06-01) introduced a small memory leak visible with valgrind in t7813. Complete the creation of a PCRE2 specific variable that was missing from the original change and free the generated table just like it is done for PCRE1. Signed-off-by: Carlo Marcelo Arenas Belón Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano diff --git a/grep.c b/grep.c index 296edbb..9556d13 100644 --- a/grep.c +++ b/grep.c @@ -525,7 +525,6 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt PCRE2_UCHAR errbuf[256]; PCRE2_SIZE erroffset; int options = PCRE2_MULTILINE; - const uint8_t *character_tables = NULL; int jitret; int patinforet; size_t jitsizearg; @@ -539,9 +538,10 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt if (has_non_ascii(p->pattern)) { if (!pcre2_global_context) BUG("pcre2_global_context uninitialized"); - character_tables = pcre2_maketables(pcre2_global_context); + p->pcre2_tables = pcre2_maketables(pcre2_global_context); p->pcre2_compile_context = pcre2_compile_context_create(NULL); - pcre2_set_character_tables(p->pcre2_compile_context, character_tables); + pcre2_set_character_tables(p->pcre2_compile_context, + p->pcre2_tables); } options |= PCRE2_CASELESS; } @@ -645,6 +645,7 @@ static void free_pcre2_pattern(struct grep_pat *p) pcre2_match_data_free(p->pcre2_match_data); pcre2_jit_stack_free(p->pcre2_jit_stack); pcre2_match_context_free(p->pcre2_match_context); + free((void *)p->pcre2_tables); } #else /* !USE_LIBPCRE2 */ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt) diff --git a/grep.h b/grep.h index 526c2db..533165c 100644 --- a/grep.h +++ b/grep.h @@ -96,6 +96,7 @@ struct grep_pat { pcre2_compile_context *pcre2_compile_context; pcre2_match_context *pcre2_match_context; pcre2_jit_stack *pcre2_jit_stack; + const uint8_t *pcre2_tables; uint32_t pcre2_jit_on; kwset_t kws; unsigned fixed:1; -- cgit v0.10.2-6-g49f6