diff options
Diffstat (limited to 'malloc/mtrace-impl.c')
| -rw-r--r-- | malloc/mtrace-impl.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/malloc/mtrace-impl.c b/malloc/mtrace-impl.c new file mode 100644 index 0000000..0e10ab7 --- /dev/null +++ b/malloc/mtrace-impl.c @@ -0,0 +1,226 @@ +/* mtrace implementation for `malloc'. + Copyright (C) 1991-2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Written April 2, 1991 by John Gilmore of Cygnus Support. + Based on mcheck.c by Mike Haertel. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + + +#include <malloc.h> +#include <mcheck.h> + +#include <dlfcn.h> +#include <fcntl.h> +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <inttypes.h> + +#include <libc-internal.h> +#include <dso_handle.h> + +#include <kernel-features.h> + +#define TRACE_BUFFER_SIZE 512 + +static FILE *mallstream; +static const char mallenv[] = "MALLOC_TRACE"; +static char *malloc_trace_buffer; + +static void +tr_where (const void *caller, Dl_info *info) +{ + if (caller != NULL) + { + if (info != NULL) + { + char *buf = (char *) ""; + if (info->dli_sname != NULL) + { + size_t len = strlen (info->dli_sname); + buf = alloca (len + 6 + 2 * sizeof (void *)); + char sign; + ptrdiff_t offset = + (ptrdiff_t) info->dli_saddr - (ptrdiff_t) caller; + + if (caller >= (const void *) info->dli_saddr) + { + sign = '+'; + offset = -offset; + } + else + sign = '-'; + + sprintf (buf, "(%s%c%" PRIxPTR ")", info->dli_sname, sign, + offset); + } + + fprintf (mallstream, "@ %s%s%s[%p] ", info->dli_fname ? : "", + info->dli_fname ? ":" : "", + buf, caller); + } + else + fprintf (mallstream, "@ [%p] ", caller); + } +} + +static Dl_info * +lock_and_info (const void *caller, Dl_info *mem) +{ + if (caller == NULL) + return NULL; + + Dl_info *res = dladdr (caller, mem) ? mem : NULL; + + flockfile (mallstream); + + return res; +} + +static void +free_mtrace (void *ptr, const void *caller) +{ + if (ptr == NULL) + return; + + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + tr_where (caller, info); + /* Be sure to print it first. */ + fprintf (mallstream, "- %p\n", ptr); + funlockfile (mallstream); +} + +static void +malloc_mtrace_after (void *block, size_t size, const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + /* We could be printing a NULL here; that's OK. */ + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + + funlockfile (mallstream); +} + +static void +realloc_mtrace_after (void *block, const void *oldptr, size_t size, + const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + if (block == NULL) + { + if (size != 0) + /* Failed realloc. */ + fprintf (mallstream, "! %p %#lx\n", oldptr, (unsigned long int) size); + else + fprintf (mallstream, "- %p\n", oldptr); + } + else if (oldptr == NULL) + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + else + { + fprintf (mallstream, "< %p\n", oldptr); + tr_where (caller, info); + fprintf (mallstream, "> %p %#lx\n", block, (unsigned long int) size); + } + + funlockfile (mallstream); +} + +static void +memalign_mtrace_after (void *block, size_t size, const void *caller) +{ + Dl_info mem; + Dl_info *info = lock_and_info (caller, &mem); + + tr_where (caller, info); + /* We could be printing a NULL here; that's OK. */ + fprintf (mallstream, "+ %p %#lx\n", block, (unsigned long int) size); + + funlockfile (mallstream); +} + +/* This function gets called to make sure all memory the library + allocates get freed and so does not irritate the user when studying + the mtrace output. */ +static void +release_libc_mem (void) +{ + /* Only call the free function if we still are running in mtrace mode. */ + if (mallstream != NULL) + __libc_freeres (); +} + +/* We enable tracing if the environment variable MALLOC_TRACE is set. */ + +static void +do_mtrace (void) +{ + static int added_atexit_handler; + char *mallfile; + + /* Don't panic if we're called more than once. */ + if (mallstream != NULL) + return; + + mallfile = secure_getenv (mallenv); + if (mallfile != NULL) + { + char *mtb = malloc (TRACE_BUFFER_SIZE); + if (mtb == NULL) + return; + + mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "wce"); + if (mallstream != NULL) + { + /* Be sure it doesn't malloc its buffer! */ + malloc_trace_buffer = mtb; + setvbuf (mallstream, malloc_trace_buffer, _IOFBF, TRACE_BUFFER_SIZE); + fprintf (mallstream, "= Start\n"); + if (!added_atexit_handler) + { + added_atexit_handler = 1; + __cxa_atexit ((void (*)(void *))release_libc_mem, NULL, + __dso_handle); + } + __malloc_debug_enable (MALLOC_MTRACE_HOOK); + } + else + free (mtb); + } +} + +static void +do_muntrace (void) +{ + __malloc_debug_disable (MALLOC_MTRACE_HOOK); + if (mallstream == NULL) + return; + + /* Do the reverse of what done in mtrace: first reset the hooks and + MALLSTREAM, and only after that write the trailer and close the + file. */ + FILE *f = mallstream; + mallstream = NULL; + + fprintf (f, "= End\n"); + fclose (f); +} |