diff options
Diffstat (limited to 'libdwarf/dwarf_elf_init.c')
| -rw-r--r-- | libdwarf/dwarf_elf_init.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/libdwarf/dwarf_elf_init.c b/libdwarf/dwarf_elf_init.c new file mode 100644 index 00000000..d69d7474 --- /dev/null +++ b/libdwarf/dwarf_elf_init.c @@ -0,0 +1,197 @@ +/* Create descriptor from ELF handle for processing file. + Copyright (C) 2000, 2002 Red Hat, Inc. + Written by Ulrich Drepper <drepper@redhat.com>, 2000. + + This program is Open Source software; you can redistribute it and/or + modify it under the terms of the Open Software License version 1.0 as + published by the Open Source Initiative. + + You should have received a copy of the Open Software License along + with this program; if not, you may obtain a copy of the Open Software + License version 1.0 from http://www.opensource.org/licenses/osl.php or + by writing the Open Source Initiative c/o Lawrence Rosen, Esq., + 3001 King Ranch Road, Ukiah, CA 95482. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <assert.h> +#include <endian.h> +#include <gelf.h> +#include <stdlib.h> +#include <string.h> + +#include <libdwarfP.h> + + +/* Section names. */ +static const char dwarf_scnnames[IDX_last][17] = +{ + [IDX_debug_info] = ".debug_info", + [IDX_debug_abbrev] = ".debug_abbrev", + [IDX_debug_aranges] = ".debug_aranges", + [IDX_debug_line] = ".debug_line", + [IDX_debug_frame] = ".debug_frame", + [IDX_eh_frame] = ".eh_frame", + [IDX_debug_loc] = ".debug_loc", + [IDX_debug_pubnames] = ".debug_pubnames", + [IDX_debug_str] = ".debug_str", + [IDX_debug_funcnames] = ".debug_funcnames", + [IDX_debug_typenames] = ".debug_typenames", + [IDX_debug_varnames] = ".debug_varnames", + [IDX_debug_weaknames] = ".debug_weaknames", + [IDX_debug_macinfo] = ".debug_macinfo" +}; +#define ndwarf_scnnames (sizeof (dwarf_scnnames) / sizeof (dwarf_scnnames[0])) + + +int +dwarf_elf_init (elf, access, errhand, errarg, dbg, error) + Elf *elf; + Dwarf_Unsigned access; + Dwarf_Handler errhand; + Dwarf_Ptr errarg; + Dwarf_Debug *dbg; + Dwarf_Error *error; +{ + int result = DW_DLV_ERROR; + Dwarf_Debug newdbg; + GElf_Ehdr ehdr_mem; + GElf_Ehdr *ehdr; + Elf_Scn *scn; + + /* XXX For now nothing but read-only support is available. */ + if (access != DW_DLC_READ) + abort (); + + /* Get the ELF header of the file. We need various pieces of + information from it. */ + ehdr = gelf_getehdr (elf, &ehdr_mem); + if (ehdr == NULL) + { + struct Dwarf_Debug_s tmpdbg; + + tmpdbg.dbg_errhand = errhand; + tmpdbg.dbg_errarg = errarg; + + if (elf_kind (elf) != ELF_K_ELF) + __libdwarf_error (&tmpdbg, error, DW_E_NOELF); + else + __libdwarf_error (&tmpdbg, error, DW_E_GETEHDR_ERROR); + + return result; + } + + /* Allocate and fill the result data structure. */ + newdbg = (Dwarf_Debug) calloc (1, sizeof (struct Dwarf_Debug_s)); + if (newdbg == NULL) + { + struct Dwarf_Debug_s tmpdbg; + + tmpdbg.dbg_errhand = errhand; + tmpdbg.dbg_errarg = errarg; + + __libdwarf_error (&tmpdbg, error, DW_E_NOMEM); + } + else + { + /* We have been able to allocate the memory for the debug handle. */ + newdbg->dbg_errhand = errhand; + newdbg->dbg_errarg = errarg; + newdbg->elf = elf; + if ((BYTE_ORDER == LITTLE_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2MSB) + || (BYTE_ORDER == BIG_ENDIAN + && ehdr->e_ident[EI_DATA] == ELFDATA2LSB)) + newdbg->other_byte_order = 1; + newdbg->access = access; +#ifdef DWARF_DEBUG + newdbg->memtag = DW_DLA_DEBUG; +#endif + + /* All done. */ + *dbg = newdbg; + result = DW_DLV_OK; + + /* Find out whether the file actually has the necessary DWARF + sections. */ + scn = NULL; + while ((scn = elf_nextscn (elf, scn)) != NULL) + { + GElf_Shdr shdr_mem; + GElf_Shdr *shdr; + const char *scnname; + size_t cnt; + Elf_Data *data; + + /* Get the section header data. */ + shdr = gelf_getshdr (scn, &shdr_mem); + if (shdr == NULL) + /* This should never happen. If it does something is + wrong in the libelf library. */ + abort (); + + /* We recognize the DWARF section by their names. This is + not very safe and stable but the best we can do. */ + scnname = elf_strptr (elf, ehdr->e_shstrndx, shdr->sh_name); + if (scnname == NULL) + { + /* The section name must be valid. Otherwise is the ELF file + invalid. */ + __libdwarf_error (newdbg, error, DW_E_INVALID_ELF); + break; + } + + /* Recognize the various sections. Most names start with + .debug_. */ + for (cnt = 0; cnt < ndwarf_scnnames; ++cnt) + if (strcmp (scnname, dwarf_scnnames[cnt]) == 0) + break; + + if (cnt < ndwarf_scnnames) + { + /* Found it. Remember where the data is. */ + assert (cnt < IDX_last); + if (unlikely (newdbg->sections[cnt].addr != NULL)) + { + /* A section appears twice. That's bad. */ + __libdwarf_error (newdbg, error, DW_E_INVALID_DWARF); + break; + } + + /* Get the section data. */ + data = elf_getdata (scn, NULL); + if (data != NULL && data->d_size != 0) + { + /* Yep, there is actually data available. */ + newdbg->sections[cnt].addr = data->d_buf; + newdbg->sections[cnt].size = data->d_size; + } + } + } + + if (scn == NULL) + { + /* We looked at all the sections. Now determine whether all + the sections with debugging information we need are there. + + XXX Which sections are absolutely necessary? Add tests + if necessary. For now we require only .debug_info. Hopefully + this is correct. */ + if (newdbg->sections[IDX_debug_info].addr == NULL) + { + __libdwarf_error (newdbg, error, DW_E_NO_DWARF); + result = DW_DLV_NO_ENTRY; + } + else + result = DW_DLV_OK; + } + + if (result != DW_DLV_OK) + /* Something went wrong. */ + free (newdbg); + } + + return result; +} |