diff options
Diffstat (limited to 'libdw/fde.c')
| -rw-r--r-- | libdw/fde.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/libdw/fde.c b/libdw/fde.c new file mode 100644 index 00000000..f38eed7e --- /dev/null +++ b/libdw/fde.c @@ -0,0 +1,306 @@ +/* FDE reading. + Copyright (C) 2009 Red Hat, Inc. + This file is part of Red Hat elfutils. + + Red Hat elfutils is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by the + Free Software Foundation; version 2 of the License. + + Red Hat elfutils 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License along + with Red Hat elfutils; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. + + In addition, as a special exception, Red Hat, Inc. gives You the + additional right to link the code of Red Hat elfutils with code licensed + under any Open Source Initiative certified open source license + (http://www.opensource.org/licenses/index.php) which requires the + distribution of source code with any binary distribution and to + distribute linked combinations of the two. Non-GPL Code permitted under + this exception must only link to the code of Red Hat elfutils through + those well defined interfaces identified in the file named EXCEPTION + found in the source code files (the "Approved Interfaces"). The files + of Non-GPL Code may instantiate templates or use macros or inline + functions from the Approved Interfaces without causing the resulting + work to be covered by the GNU General Public License. Only Red Hat, + Inc. may make changes or additions to the list of Approved Interfaces. + Red Hat's grant of this exception is conditioned upon your not adding + any new exceptions. If you wish to add a new Approved Interface or + exception, please contact Red Hat. You must obey the GNU General Public + License in all respects for all of the Red Hat elfutils code and other + code used in conjunction with Red Hat elfutils except the Non-GPL Code + covered by this exception. If you modify this file, you may extend this + exception to your version of the file, but you are not obligated to do + so. If you do not wish to provide this exception without modification, + you must delete this exception statement from your version and license + this file solely under the GPL without exception. + + Red Hat elfutils is an included package of the Open Invention Network. + An included package of the Open Invention Network is a package for which + Open Invention Network licensees cross-license their patents. No patent + license is granted, either expressly or impliedly, by designation as an + included package. Should you wish to participate in the Open Invention + Network licensing program, please visit www.openinventionnetwork.com + <http://www.openinventionnetwork.com>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include "cfi.h" +#include <search.h> +#include <stdlib.h> + +#include "encoded-value.h" + +static int +compare_fde (const void *a, const void *b) +{ + const struct dwarf_fde *fde1 = a; + const struct dwarf_fde *fde2 = b; + + /* Find out which of the two arguments is the search value. + It has end offset 0. */ + if (fde1->end == 0) + { + if (fde1->start < fde2->start) + return -1; + if (fde1->start >= fde2->end) + return 1; + } + else + { + if (fde2->start < fde1->start) + return 1; + if (fde2->start >= fde1->end) + return -1; + } + + return 0; +} + +static struct dwarf_fde * +intern_fde (Dwarf_CFI *cache, const Dwarf_FDE *entry) +{ + /* Look up the new entry's CIE. */ + struct dwarf_cie *cie = __libdw_find_cie (cache, entry->CIE_pointer); + if (cie == NULL) + return (void *) -1l; + + struct dwarf_fde *fde = malloc (sizeof (struct dwarf_fde)); + if (fde == NULL) + { + __libdw_seterrno (DWARF_E_NOMEM); + return NULL; + } + + fde->instructions = entry->start; + fde->instructions_end = entry->end; + if (unlikely (read_encoded_value (cache, cie->fde_encoding, + &fde->instructions, &fde->start)) + || unlikely (read_encoded_value (cache, cie->fde_encoding & 0x0f, + &fde->instructions, &fde->end))) + return NULL; + fde->end += fde->start; + + fde->cie = cie; + + if (cie->sized_augmentation_data) + { + /* The CIE augmentation says the FDE has a DW_FORM_block + before its actual instruction stream. */ + Dwarf_Word len; + get_uleb128 (len, fde->instructions); + if ((Dwarf_Word) (fde->instructions_end < fde->instructions) < len) + { + free (fde); + __libdw_seterrno (DWARF_E_INVALID_DWARF); + return NULL; + } + fde->instructions += len; + } + else + /* We had to understand all of the CIE augmentation string. + We've recorded the number of data bytes in FDEs. */ + fde->instructions += cie->fde_augmentation_data_size; + + /* Add the new entry to the search tree. */ + if (tsearch (fde, &cache->fde_tree, &compare_fde) == NULL) + { + free (fde); + __libdw_seterrno (DWARF_E_NOMEM); + return NULL; + } + + return fde; +} + +static struct dwarf_fde * +fde_by_offset (Dwarf_CFI *cache, Dwarf_Addr address, Dwarf_Off offset) +{ + Dwarf_CFI_Entry entry; + Dwarf_Off next_offset; + int result = INTUSE(dwarf_next_cfi) (cache->e_ident, + &cache->data->d, CFI_IS_EH (cache), + offset, &next_offset, &entry); + if (result != 0) + { + if (result > 0) + invalid: + __libdw_seterrno (DWARF_E_INVALID_DWARF); + return NULL; + } + + if (unlikely (dwarf_cfi_cie_p (&entry))) + goto invalid; + + /* We have a new FDE to consider. */ + struct dwarf_fde *fde = intern_fde (cache, &entry.fde); + if (fde == (void *) -1l || fde == NULL) + return NULL; + + /* If this happened to be what we would have read next, notice it. */ + if (cache->next_offset == offset) + cache->next_offset = next_offset; + + /* Sanity check the address range. */ + if (address < fde->start || address >= fde->end) + goto invalid; + + return fde; +} + +/* Use a binary search table in .eh_frame_hdr format, yield an FDE offset. */ +static Dwarf_Off +binary_search_fde (Dwarf_CFI *cache, Dwarf_Addr address) +{ + const size_t size = 2 * encoded_value_size (&cache->data->d, cache->e_ident, + cache->search_table_encoding, + NULL); + + /* Dummy used by read_encoded_value. */ + Dwarf_CFI dummy_cfi = + { + .e_ident = cache->e_ident, + .datarel = cache->search_table_vaddr, + .frame_vaddr = cache->search_table_vaddr, + }; + + size_t l = 0, u = cache->search_table_entries; + while (l < u) + { + size_t idx = (l + u) / 2; + + const uint8_t *p = &cache->search_table[idx * size]; + Dwarf_Addr start; + if (unlikely (read_encoded_value (&dummy_cfi, + cache->search_table_encoding, &p, + &start))) + break; + if (address < start) + u = idx; + else + { + Dwarf_Addr fde; + if (unlikely (read_encoded_value (&dummy_cfi, + cache->search_table_encoding, &p, + &fde))) + break; + if (address >= start) + { + l = idx + 1; + + /* If this is the last entry, its upper bound is assumed to be + the end of the module. + XXX really should be end of containing PT_LOAD segment */ + if (l < cache->search_table_entries) + { + /* Look at the start address in the following entry. */ + Dwarf_Addr end; + if (unlikely (read_encoded_value + (&dummy_cfi, cache->search_table_encoding, &p, + &end))) + break; + if (address >= end) + continue; + } + + return fde - cache->frame_vaddr; + } + } + } + + return (Dwarf_Off) -1l; +} + +struct dwarf_fde * +internal_function +__libdw_find_fde (Dwarf_CFI *cache, Dwarf_Addr address) +{ + /* Look for a cached FDE covering this address. */ + + const struct dwarf_fde fde_key = { .start = address, .end = 0 }; + struct dwarf_fde **found = tfind (&fde_key, &cache->fde_tree, &compare_fde); + if (found != NULL) + return *found; + + /* Use .eh_frame_hdr binary search table if possible. */ + if (cache->search_table != NULL) + { + Dwarf_Off offset = binary_search_fde (cache, address); + if (offset == (Dwarf_Off) -1l) + goto no_match; + return fde_by_offset (cache, address, offset); + } + + /* It's not there. Read more CFI entries until we find it. */ + while (1) + { + Dwarf_Off last_offset = cache->next_offset; + Dwarf_CFI_Entry entry; + int result = INTUSE(dwarf_next_cfi) (cache->e_ident, + &cache->data->d, CFI_IS_EH (cache), + last_offset, &cache->next_offset, + &entry); + if (result > 0) + break; + if (result < 0) + { + if (cache->next_offset == last_offset) + /* We couldn't progress past the bogus FDE. */ + break; + /* Skip the loser and look at the next entry. */ + continue; + } + + if (dwarf_cfi_cie_p (&entry)) + { + /* This is a CIE, not an FDE. We eagerly intern these + because the next FDE will usually refer to this CIE. */ + __libdw_intern_cie (cache, last_offset, &entry.cie); + continue; + } + + /* We have a new FDE to consider. */ + struct dwarf_fde *fde = intern_fde (cache, &entry.fde); + + if (fde == (void *) -1l) /* Bad FDE, but we can keep looking. */ + continue; + + if (fde == NULL) /* Bad data. */ + return NULL; + + /* Is this the one we're looking for? */ + if (fde->start <= address && fde->end > address) + return fde; + } + + no_match: + /* We found no FDE covering this address. */ + __libdw_seterrno (DWARF_E_NO_MATCH); + return NULL; +} |