/* ELF support for BFD. Copyright (C) 1991 Free Software Foundation, Inc. Written by Fred Fish @ Cygnus Support, from information published in "UNIX System V Release 4, Programmers Guide: ANSI C and Programming Support Tools". This file is part of BFD, the Binary File Descriptor library. This program 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; either version 2 of the License, or (at your option) any later version. This program 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 this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /**************************************** WARNING This is only a partial ELF implementation, incorporating only those parts that are required to get gdb up and running. It is expected that it will be expanded to a full ELF implementation at some future date. Unimplemented stubs call abort() to ensure that they get proper attention if they are ever called. The stubs are here since this version was hacked from the COFF version, and thus they will probably go away or get expanded appropriately in a future version. fnf@cygnus.com *****************************************/ /* Problems and other issues to resolve. (1) BFD expects there to be some fixed number of "sections" in the object file. I.E. there is a "section_count" variable in the bfd structure which contains the number of sections. However, ELF supports multiple "views" of a file. In particular, with current implementations, executable files typically have two tables, a program header table and a section header table, both of which partition the executable. In ELF-speak, the "linking view" of the file uses the section header table to access "sections" within the file, and the "execution view" uses the program header table to access "segments" within the file. "Segments" typically may contain all the data from one or more "sections". Note that the section header table is optional in ELF executables, but it is this information that is most useful to gdb. If the section header table is missing, then gdb should probably try to make do with the program header table. (FIXME) */ #include "bfd.h" #include "sysdep.h" #include "libbfd.h" #include "obstack.h" #include "elf/common.h" #include "elf/internal.h" #include "elf/external.h" #ifdef HAVE_PROCFS /* Some core file support requires host /proc files */ #include #else #define bfd_prstatus(abfd, descdata, descsz, filepos) /* Define away */ #define bfd_fpregset(abfd, descdata, descsz, filepos) /* Define away */ #define bfd_prpsinfo(abfd, descdata, descsz, filepos) /* Define away */ #endif /* Forward data declarations */ extern bfd_target elf_little_vec, elf_big_vec; /* Currently the elf_symbol_type struct just contains the generic bfd symbol structure. */ typedef struct { asymbol symbol; } elf_symbol_type; /* Some private data is stashed away for future use using the tdata pointer in the bfd structure. This information is different for ELF core files and other ELF files. */ typedef struct elf_core_tdata_struct { void *prstatus; /* The raw /proc prstatus structure */ void *prpsinfo; /* The raw /proc prpsinfo structure */ } elf_core_tdata; #define core_prpsinfo(bfd) (((bfd)->tdata.elf_core_data) -> prpsinfo) #define core_prstatus(bfd) (((bfd)->tdata.elf_core_data) -> prstatus) typedef struct elf_obj_tdata_struct { file_ptr symtab_filepos; /* Offset to start of ELF symtab section */ long symtab_filesz; /* Size of ELF symtab section */ file_ptr strtab_filepos; /* Offset to start of ELF string tbl section */ long strtab_filesz; /* Size of ELF string tbl section */ } elf_obj_tdata; #define elf_tdata(bfd) ((bfd) -> tdata.elf_obj_data) #define elf_symtab_filepos(bfd) (elf_tdata(bfd) -> symtab_filepos) #define elf_symtab_filesz(bfd) (elf_tdata(bfd) -> symtab_filesz) #define elf_strtab_filepos(bfd) (elf_tdata(bfd) -> strtab_filepos) #define elf_strtab_filesz(bfd) (elf_tdata(bfd) -> strtab_filesz) /* Translate an ELF symbol in external format into an ELF symbol in internal format. */ static void DEFUN(elf_swap_symbol_in,(abfd, src, dst), bfd *abfd AND Elf_External_Sym *src AND Elf_Internal_Sym *dst) { dst -> st_name = bfd_h_get_32 (abfd, (bfd_byte *) src -> st_name); dst -> st_value = bfd_h_get_32 (abfd, (bfd_byte *) src -> st_value); dst -> st_size = bfd_h_get_32 (abfd, (bfd_byte *) src -> st_size); dst -> st_info = bfd_h_get_8 (abfd, (bfd_byte *) src -> st_info); dst -> st_other = bfd_h_get_8 (abfd, (bfd_byte *) src -> st_other); dst -> st_shndx = bfd_h_get_16 (abfd, (bfd_byte *) src -> st_shndx); } /* Translate an ELF file header in external format into an ELF file header in internal format. */ static void DEFUN(elf_swap_ehdr_in,(abfd, src, dst), bfd *abfd AND Elf_External_Ehdr *src AND Elf_Internal_Ehdr *dst) { memcpy (dst -> e_ident, src -> e_ident, EI_NIDENT); dst -> e_type = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_type); dst -> e_machine = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_machine); dst -> e_version = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_version); dst -> e_entry = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_entry); dst -> e_phoff = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_phoff); dst -> e_shoff = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_shoff); dst -> e_flags = bfd_h_get_32 (abfd, (bfd_byte *) src -> e_flags); dst -> e_ehsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_ehsize); dst -> e_phentsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_phentsize); dst -> e_phnum = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_phnum); dst -> e_shentsize = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shentsize); dst -> e_shnum = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shnum); dst -> e_shstrndx = bfd_h_get_16 (abfd, (bfd_byte *) src -> e_shstrndx); } /* Translate an ELF section header table entry in external format into an ELF section header table entry in internal format. */ static void DEFUN(elf_swap_shdr_in,(abfd, src, dst), bfd *abfd AND Elf_External_Shdr *src AND Elf_Internal_Shdr *dst) { dst -> sh_name = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_name); dst -> sh_type = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_type); dst -> sh_flags = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_flags); dst -> sh_addr = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_addr); dst -> sh_offset = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_offset); dst -> sh_size = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_size); dst -> sh_link = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_link); dst -> sh_info = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_info); dst -> sh_addralign = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_addralign); dst -> sh_entsize = bfd_h_get_32 (abfd, (bfd_byte *) src -> sh_entsize); } /* Translate an ELF program header table entry in external format into an ELF program header table entry in internal format. */ static void DEFUN(elf_swap_phdr_in,(abfd, src, dst), bfd *abfd AND Elf_External_Phdr *src AND Elf_Internal_Phdr *dst) { dst -> p_type = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_type); dst -> p_offset = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_offset); dst -> p_vaddr = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_vaddr); dst -> p_paddr = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_paddr); dst -> p_filesz = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_filesz); dst -> p_memsz = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_memsz); dst -> p_flags = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_flags); dst -> p_align = bfd_h_get_32 (abfd, (bfd_byte *) src -> p_align); } /* Create a new bfd section from an ELF section header. */ static boolean DEFUN(bfd_section_from_shdr, (abfd, hdr, shstrtab), bfd *abfd AND Elf_Internal_Shdr *hdr AND char *shstrtab) { asection *newsect; char *name; name = hdr -> sh_name ? shstrtab + hdr -> sh_name : "unnamed"; newsect = bfd_make_section (abfd, name); if (!newsect) return false; newsect -> vma = hdr -> sh_addr; newsect -> _raw_size = hdr -> sh_size; if (!(hdr -> sh_type == SHT_NOBITS)) { newsect -> filepos = hdr -> sh_offset; newsect -> flags |= SEC_HAS_CONTENTS; } if (hdr -> sh_flags & SHF_ALLOC) { newsect -> flags |= SEC_ALLOC; if (hdr -> sh_type != SHT_NOBITS) { newsect -> flags |= SEC_LOAD; } } if (!(hdr -> sh_flags & SHF_WRITE)) { newsect -> flags |= SEC_READONLY; } if (hdr -> sh_flags & SHF_EXECINSTR) { newsect -> flags |= SEC_CODE; /* FIXME: may only contain SOME code */ } else { newsect -> flags |= SEC_DATA; } if (hdr -> sh_type == SHT_SYMTAB) { abfd -> flags |= HAS_SYMS; } return (true); } /* Create a new bfd section from an ELF program header. Since program segments have no names, we generate a synthetic name of the form segment, where NUM is generally the index in the program header table. For segments that are split (see below) we generate the names segmenta and segmentb. Note that some program segments may have a file size that is different than (less than) the memory size. All this means is that at execution the system must allocate the amount of memory specified by the memory size, but only initialize it with the first "file size" bytes read from the file. This would occur for example, with program segments consisting of combined data+bss. To handle the above situation, this routine generates TWO bfd sections for the single program segment. The first has the length specified by the file size of the segment, and the second has the length specified by the difference between the two sizes. In effect, the segment is split into it's initialized and uninitialized parts. */ static boolean DEFUN(bfd_section_from_phdr, (abfd, hdr, index), bfd *abfd AND Elf_Internal_Phdr *hdr AND int index) { asection *newsect; char *name; char namebuf[64]; int split; split = ((hdr -> p_memsz > 0) && (hdr -> p_filesz > 0) && (hdr -> p_memsz > hdr -> p_filesz)); sprintf (namebuf, split ? "segment%da" : "segment%d", index); name = bfd_alloc (abfd, strlen (namebuf) + 1); (void) strcpy (name, namebuf); newsect = bfd_make_section (abfd, name); newsect -> vma = hdr -> p_vaddr; newsect -> _raw_size = hdr -> p_filesz; newsect -> filepos = hdr -> p_offset; newsect -> flags |= SEC_HAS_CONTENTS; if (hdr -> p_type == PT_LOAD) { newsect -> flags |= SEC_ALLOC; newsect -> flags |= SEC_LOAD; if (hdr -> p_flags & PF_X) { /* FIXME: all we known is that it has execute PERMISSION, may be data. */ newsect -> flags |= SEC_CODE; } } if (!(hdr -> p_flags & PF_W)) { newsect -> flags |= SEC_READONLY; } if (split) { sprintf (namebuf, "segment%db", index); name = bfd_alloc (abfd, strlen (namebuf) + 1); (void) strcpy (name, namebuf); newsect = bfd_make_section (abfd, name); newsect -> vma = hdr -> p_vaddr + hdr -> p_filesz; newsect -> _raw_size = hdr -> p_memsz - hdr -> p_filesz; if (hdr -> p_type == PT_LOAD) { newsect -> flags |= SEC_ALLOC; if (hdr -> p_flags & PF_X) { newsect -> flags |= SEC_CODE; } } if (!(hdr -> p_flags & PF_W)) { newsect -> flags |= SEC_READONLY; } } return (true); } #ifdef HAVE_PROCFS static void DEFUN(bfd_prstatus,(abfd, descdata, descsz, filepos), bfd *abfd AND char *descdata AND int descsz AND long filepos) { asection *newsect; if (descsz == sizeof (prstatus_t)) { newsect = bfd_make_section (abfd, ".reg"); newsect -> _raw_size = sizeof (gregset_t); newsect -> filepos = filepos + (long) (((prstatus_t *)0) -> pr_reg); newsect -> flags = SEC_ALLOC | SEC_HAS_CONTENTS; newsect -> alignment_power = 2; if ((core_prstatus (abfd) = bfd_alloc (abfd, descsz)) != NULL) { memcpy (core_prstatus (abfd), descdata, descsz); } } } /* Stash a copy of the prpsinfo structure away for future use. */ static void DEFUN(bfd_prpsinfo,(abfd, descdata, descsz, filepos), bfd *abfd AND char *descdata AND int descsz AND long filepos) { asection *newsect; if (descsz == sizeof (prpsinfo_t)) { if ((core_prpsinfo (abfd) = bfd_alloc (abfd, descsz)) != NULL) { bcopy (descdata, core_prpsinfo (abfd), descsz); } } } static void DEFUN(bfd_fpregset,(abfd, descdata, descsz, filepos), bfd *abfd AND char *descdata AND int descsz AND long filepos) { asection *newsect; if (descsz == sizeof (fpregset_t)) { newsect = bfd_make_section (abfd, ".reg2"); newsect -> _raw_size = sizeof (fpregset_t); newsect -> filepos = filepos; newsect -> flags = SEC_ALLOC | SEC_HAS_CONTENTS; newsect -> alignment_power = 2; } } #endif /* HAVE_PROCFS */ /* Return a pointer to the args (including the command name) that were seen by the program that generated the core dump. Note that for some reason, a spurious space is tacked onto the end of the args in some (at least one anyway) implementations, so strip it off if it exists. */ char * DEFUN(elf_core_file_failing_command, (abfd), bfd *abfd) { #ifdef HAVE_PROCFS if (core_prpsinfo (abfd)) { prpsinfo_t *p = core_prpsinfo (abfd); char *scan = p -> pr_psargs; while (*scan++) {;} scan -= 2; if ((scan > p -> pr_psargs) && (*scan == ' ')) { *scan = '\000'; } return (p -> pr_psargs); } #endif return (NULL); } /* Return the number of the signal that caused the core dump. Presumably, since we have a core file, we got a signal of some kind, so don't bother checking the other process status fields, just return the signal number. */ static int DEFUN(elf_core_file_failing_signal, (abfd), bfd *abfd) { #ifdef HAVE_PROCFS if (core_prstatus (abfd)) { return (((prstatus_t *)(core_prstatus (abfd))) -> pr_cursig); } #endif return (-1); } /* Check to see if the core file could reasonably be expected to have come for the current executable file. Note that by default we return true unless we find something that indicates that there might be a problem. */ static boolean DEFUN(elf_core_file_matches_executable_p, (core_bfd, exec_bfd), bfd *core_bfd AND bfd *exec_bfd) { #ifdef HAVE_PROCFS char *corename; char *execname; #endif /* First, xvecs must match since both are ELF files for the same target. */ if (core_bfd->xvec != exec_bfd->xvec) { bfd_error = system_call_error; return (false); } #ifdef HAVE_PROCFS /* If no prpsinfo, just return true. Otherwise, grab the last component of the exec'd pathname from the prpsinfo. */ if (core_prpsinfo (core_bfd)) { corename = (((struct prpsinfo *) core_prpsinfo (core_bfd)) -> pr_fname); } else { return (true); } /* Find the last component of the executable pathname. */ if ((execname = strrchr (exec_bfd -> filename, '/')) != NULL) { execname++; } else { execname = (char *) exec_bfd -> filename; } /* See if they match */ return (strcmp (execname, corename) ? false : true); #else return (true); #endif /* HAVE_PROCFS */ } /* ELF core files contain a segment of type PT_NOTE, that holds much of the information that would normally be available from the /proc interface for the process, at the time the process dumped core. Currently this includes copies of the prstatus, prpsinfo, and fpregset structures. Since these structures are potentially machine dependent in size and ordering, bfd provides two levels of support for them. The first level, available on all machines since it does not require that the host have /proc support or the relevant include files, is to create a bfd section for each of the prstatus, prpsinfo, and fpregset structures, without any interpretation of their contents. With just this support, the bfd client will have to interpret the structures itself. Even with /proc support, it might want these full structures for it's own reasons. In the second level of support, where HAVE_PROCFS is defined, bfd will pick apart the structures to gather some additional information that clients may want, such as the general register set, the name of the exec'ed file and its arguments, the signal (if any) that caused the core dump, etc. */ static boolean DEFUN(elf_corefile_note, (abfd, hdr), bfd *abfd AND Elf_Internal_Phdr *hdr) { Elf_External_Note *x_note_p; /* Elf note, external form */ Elf_Internal_Note i_note; /* Elf note, internal form */ char *buf = NULL; /* Entire note segment contents */ char *namedata; /* Name portion of the note */ char *descdata; /* Descriptor portion of the note */ char *sectname; /* Name to use for new section */ long filepos; /* File offset to descriptor data */ asection *newsect; if (hdr -> p_filesz > 0 && (buf = (char *) bfd_xmalloc (hdr -> p_filesz)) != NULL && bfd_seek (abfd, hdr -> p_offset, SEEK_SET) != -1L && bfd_read ((PTR) buf, hdr -> p_filesz, 1, abfd) == hdr -> p_filesz) { x_note_p = (Elf_External_Note *) buf; while ((char *) x_note_p < (buf + hdr -> p_filesz)) { i_note.namesz = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p -> namesz); i_note.descsz = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p -> descsz); i_note.type = bfd_h_get_32 (abfd, (bfd_byte *) x_note_p -> type); namedata = x_note_p -> name; descdata = namedata + BFD_ALIGN (i_note.namesz, 4); filepos = hdr -> p_offset + (descdata - buf); switch (i_note.type) { case NT_PRSTATUS: /* process descdata as prstatus info */ bfd_prstatus (abfd, descdata, i_note.descsz, filepos); sectname = ".prstatus"; break; case NT_FPREGSET: /* process descdata as fpregset info */ bfd_fpregset (abfd, descdata, i_note.descsz, filepos); sectname = ".fpregset"; break; case NT_PRPSINFO: /* process descdata as prpsinfo */ bfd_prpsinfo (abfd, descdata, i_note.descsz, filepos); sectname = ".prpsinfo"; break; default: /* Unknown descriptor, just ignore it. */ sectname = NULL; break; } if (sectname != NULL) { newsect = bfd_make_section (abfd, sectname); newsect -> _raw_size = i_note.descsz; newsect -> filepos = filepos; newsect -> flags = SEC_ALLOC | SEC_HAS_CONTENTS; newsect -> alignment_power = 2; } x_note_p = (Elf_External_Note *) (descdata + BFD_ALIGN (i_note.descsz, 4)); } } if (buf != NULL) { free (buf); } return true; } /* Read a specified number of bytes at a specified offset in an ELF file, into a newly allocated buffer, and return a pointer to the buffer. */ static char * DEFUN(elf_read, (abfd, offset, size), bfd *abfd AND long offset AND int size) { char *buf; if ((buf = bfd_alloc (abfd, size)) == NULL) { bfd_error = no_memory; return (NULL); } if (bfd_seek (abfd, offset, SEEK_SET) == -1) { bfd_error = system_call_error; return (NULL); } if (bfd_read ((PTR) buf, size, 1, abfd) != size) { bfd_error = system_call_error; return (NULL); } return (buf); } /* Begin processing a given object. First we validate the file by reading in the ELF header and checking the magic number. */ static bfd_target * DEFUN (elf_object_p, (abfd), bfd *abfd) { Elf_External_Ehdr x_ehdr; /* Elf file header, external form */ Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form */ Elf_External_Shdr x_shdr; /* Section header table entry, external form */ Elf_Internal_Shdr *i_shdrp; /* Section header table, internal form */ int shindex; char *shstrtab; /* Internal copy of section header stringtab */ int shstrtabsize; /* Size of section header string table */ Elf_Off offset; /* Temp place to stash file offsets */ /* Read in the ELF header in external format. */ if (bfd_read ((PTR) &x_ehdr, sizeof (x_ehdr), 1, abfd) != sizeof (x_ehdr)) { bfd_error = system_call_error; return (NULL); } /* Now check to see if we have a valid ELF file, and one that BFD can make use of. The magic number must match, the address size ('class') and byte-swapping must match our XVEC entry, and it must have a section header table (FIXME: See comments re sections at top of this file). */ if (x_ehdr.e_ident[EI_MAG0] != ELFMAG0 || x_ehdr.e_ident[EI_MAG1] != ELFMAG1 || x_ehdr.e_ident[EI_MAG2] != ELFMAG2 || x_ehdr.e_ident[EI_MAG3] != ELFMAG3) { wrong: bfd_error = wrong_format; return (NULL); } /* FIXME, Check EI_VERSION here ! */ switch (x_ehdr.e_ident[EI_CLASS]) { case ELFCLASSNONE: /* address size not specified */ goto wrong; /* No support if can't tell address size */ case ELFCLASS32: /* 32-bit addresses */ break; case ELFCLASS64: /* 64-bit addresses */ goto wrong; /* FIXME: 64 bits not yet supported */ default: goto wrong; /* No support if unknown address class */ } /* Switch xvec to match the specified byte order. */ switch (x_ehdr.e_ident[EI_DATA]) { case ELFDATA2MSB: /* Big-endian */ if (!abfd->xvec->header_byteorder_big_p) goto wrong; break; case ELFDATA2LSB: /* Little-endian */ if (abfd->xvec->header_byteorder_big_p) goto wrong; break; case ELFDATANONE: /* No data encoding specified */ default: /* Unknown data encoding specified */ goto wrong; } /* Allocate an instance of the elf_obj_tdata structure and hook it up to the tdata pointer in the bfd. */ if ((abfd -> tdata.elf_obj_data = (elf_obj_tdata*) bfd_zalloc (abfd, sizeof (elf_obj_tdata))) == NULL) { bfd_error = no_memory; return (NULL); } /* Now that we know the byte order, swap in the rest of the header */ elf_swap_ehdr_in (abfd, &x_ehdr, &i_ehdr); /* If there is no section header table, we're hosed. */ if (i_ehdr.e_shoff == 0) goto wrong; if (i_ehdr.e_type == ET_EXEC || i_ehdr.e_type == ET_DYN) { abfd -> flags |= EXEC_P; } /* Allocate space for copies of the section header table in external and internal form, seek to the section header table in the file, read it in, and convert it to internal form. As a simple sanity check, verify that the what BFD thinks is the size of each section header table entry actually matches the size recorded in the file. */ if (i_ehdr.e_shentsize != sizeof (x_shdr)) goto wrong; if ((i_shdrp = (Elf_Internal_Shdr *) bfd_alloc (abfd, sizeof (*i_shdrp) * i_ehdr.e_shnum)) == NULL) { bfd_error = no_memory; return (NULL); } if (bfd_seek (abfd, i_ehdr.e_shoff, SEEK_SET) == -1) { bfd_error = system_call_error; return (NULL); } for (shindex = 0; shindex < i_ehdr.e_shnum; shindex++) { if (bfd_read ((PTR) &x_shdr, sizeof (x_shdr), 1, abfd) != sizeof (x_shdr)) { bfd_error = system_call_error; return (NULL); } elf_swap_shdr_in (abfd, &x_shdr, i_shdrp + shindex); } /* Read in the string table containing the names of the sections. We will need the base pointer to this table later. */ shstrtabsize = i_shdrp[i_ehdr.e_shstrndx].sh_size; offset = i_shdrp[i_ehdr.e_shstrndx].sh_offset; if ((shstrtab = elf_read (abfd, offset, shstrtabsize)) == NULL) { return (NULL); } /* Once all of the section headers have been read and converted, we can start processing them. Note that the first section header is a dummy placeholder entry, so we ignore it. We also watch for the symbol table section and remember the file offset and section size for both the symbol table section and the associated string table section. */ for (shindex = 1; shindex < i_ehdr.e_shnum; shindex++) { Elf_Internal_Shdr *hdr = i_shdrp + shindex; bfd_section_from_shdr (abfd, hdr, shstrtab); if (hdr -> sh_type == SHT_SYMTAB) { elf_symtab_filepos (abfd) = hdr -> sh_offset; elf_symtab_filesz (abfd) = hdr -> sh_size; elf_strtab_filepos (abfd) = (i_shdrp + hdr -> sh_link) -> sh_offset; elf_strtab_filesz (abfd) = (i_shdrp + hdr -> sh_link) -> sh_size; } } /* Remember the entry point specified in the ELF file header. */ bfd_get_start_address (abfd) = i_ehdr.e_entry; return (abfd->xvec); } /* Core files are simply standard ELF formatted files that partition the file using the execution view of the file (program header table) rather than the linking view. In fact, there is no section header table in a core file. The process status information (including the contents of the general register set) and the floating point register set are stored in a segment of type PT_NOTE. We handcraft a couple of extra bfd sections that allow standard bfd access to the general registers (.reg) and the floating point registers (.reg2). */ static bfd_target * DEFUN (elf_core_file_p, (abfd), bfd *abfd) { Elf_External_Ehdr x_ehdr; /* Elf file header, external form */ Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form */ Elf_External_Phdr x_phdr; /* Program header table entry, external form */ Elf_Internal_Phdr *i_phdrp; /* Program header table, internal form */ int phindex; /* Read in the ELF header in external format. */ if (bfd_read ((PTR) &x_ehdr, sizeof (x_ehdr), 1, abfd) != sizeof (x_ehdr)) { bfd_error = system_call_error; return (NULL); } /* Now check to see if we have a valid ELF file, and one that BFD can make use of. The magic number must match, the address size ('class') and byte-swapping must match our XVEC entry, and it must have a program header table (FIXME: See comments re segments at top of this file). */ if (x_ehdr.e_ident[EI_MAG0] != ELFMAG0 || x_ehdr.e_ident[EI_MAG1] != ELFMAG1 || x_ehdr.e_ident[EI_MAG2] != ELFMAG2 || x_ehdr.e_ident[EI_MAG3] != ELFMAG3) { wrong: bfd_error = wrong_format; return (NULL); } /* FIXME, Check EI_VERSION here ! */ switch (x_ehdr.e_ident[EI_CLASS]) { case ELFCLASSNONE: /* address size not specified */ goto wrong; /* No support if can't tell address size */ case ELFCLASS32: /* 32-bit addresses */ break; case ELFCLASS64: /* 64-bit addresses */ goto wrong; /* FIXME: 64 bits not yet supported */ default: goto wrong; /* No support if unknown address class */ } /* Switch xvec to match the specified byte order. */ switch (x_ehdr.e_ident[EI_DATA]) { case ELFDATA2MSB: /* Big-endian */ abfd->xvec = &elf_big_vec; break; case ELFDATA2LSB: /* Little-endian */ abfd->xvec = &elf_little_vec; break; case ELFDATANONE: /* No data encoding specified */ default: /* Unknown data encoding specified */ goto wrong; } /* Now that we know the byte order, swap in the rest of the header */ elf_swap_ehdr_in (abfd, &x_ehdr, &i_ehdr); /* If there is no program header, or the type is not a core file, then we are hosed. */ if (i_ehdr.e_phoff == 0 || i_ehdr.e_type != ET_CORE) goto wrong; /* Allocate an instance of the elf_core_tdata structure and hook it up to the tdata pointer in the bfd. */ if ((abfd -> tdata.elf_core_data = (elf_core_tdata *) bfd_zalloc (abfd, sizeof (elf_core_tdata))) == NULL) { bfd_error = no_memory; return (NULL); } /* Allocate space for copies of the program header table in external and internal form, seek to the program header table in the file, read it in, and convert it to internal form. As a simple sanity check, verify that the what BFD thinks is the size of each program header table entry actually matches the size recorded in the file. */ if (i_ehdr.e_phentsize != sizeof (x_phdr)) goto wrong; if ((i_phdrp = (Elf_Internal_Phdr *) bfd_alloc (abfd, sizeof (*i_phdrp) * i_ehdr.e_phnum)) == NULL) { bfd_error = no_memory; return (NULL); } if (bfd_seek (abfd, i_ehdr.e_phoff, SEEK_SET) == -1) { bfd_error = system_call_error; return (NULL); } for (phindex = 0; phindex < i_ehdr.e_phnum; phindex++) { if (bfd_read ((PTR) &x_phdr, sizeof (x_phdr), 1, abfd) != sizeof (x_phdr)) { bfd_error = system_call_error; return (NULL); } elf_swap_phdr_in (abfd, &x_phdr, i_phdrp + phindex); } /* Once all of the program headers have been read and converted, we can start processing them. */ for (phindex = 0; phindex < i_ehdr.e_phnum; phindex++) { bfd_section_from_phdr (abfd, i_phdrp + phindex, phindex); if ((i_phdrp + phindex) -> p_type == PT_NOTE) { elf_corefile_note (abfd, i_phdrp + phindex); } } /* Remember the entry point specified in the ELF file header. */ bfd_get_start_address (abfd) = i_ehdr.e_entry; return (abfd->xvec); } static boolean DEFUN (elf_mkobject, (abfd), bfd *abfd) { fprintf (stderr, "elf_mkobject unimplemented\n"); fflush (stderr); abort (); return (false); } static boolean DEFUN (elf_write_object_contents, (abfd), bfd *abfd) { fprintf (stderr, "elf_write_object_contents unimplemented\n"); fflush (stderr); abort (); return (false); } /* Given an index of a section, retrieve a pointer to it. Note that for our purposes, sections are indexed by {1, 2, ...} with 0 being an illegal index. */ static struct sec * DEFUN (section_from_bfd_index, (abfd, index), bfd *abfd AND int index) { if (index > 0) { struct sec *answer = abfd -> sections; while (--index > 0) { answer = answer -> next; } return (answer); } return (NULL); } static boolean DEFUN (elf_slurp_symbol_table, (abfd), bfd *abfd) { int symcount; /* Number of external ELF symbols */ char *strtab; /* Buffer for raw ELF string table section */ asymbol *sym; /* Pointer to current bfd symbol */ asymbol *symbase; /* Buffer for generated bfd symbols */ asymbol **vec; /* Pointer to current bfd symbol pointer */ Elf_Internal_Sym i_sym; Elf_External_Sym x_sym; if (bfd_get_outsymbols (abfd) != NULL) { return (true); } /* Slurp in the string table. We will keep it around permanently, as long as the bfd is in use, since we will end up setting up pointers into it for the names of all the symbols. */ strtab = elf_read (abfd, elf_strtab_filepos(abfd), elf_strtab_filesz(abfd)); if (strtab == NULL) { return (false); } /* Read each raw ELF symbol, converting from external ELF form to internal ELF form, and then using the information to create a canonical bfd symbol table entry. Note that be allocate the initial bfd canonical symbol buffer based on a one-to-one mapping of the ELF symbols to canonical symbols. However, it is likely that not all the ELF symbols will be used, so there will be some space leftover at the end. Once we know how many symbols we actual generate, we realloc the buffer to the correct size and then build the pointer vector. */ if (bfd_seek (abfd, elf_symtab_filepos (abfd), SEEK_SET) == -1) { bfd_error = system_call_error; return (false); } symcount = elf_symtab_filesz(abfd) / sizeof (Elf_External_Sym); sym = symbase = (asymbol *) bfd_zalloc (abfd, symcount * sizeof (asymbol)); while (symcount-- > 0) { if (bfd_read ((PTR) &x_sym, sizeof (x_sym), 1, abfd) != sizeof (x_sym)) { bfd_error = system_call_error; return (false); } elf_swap_symbol_in (abfd, &x_sym, &i_sym); if (i_sym.st_name > 0) { sym -> the_bfd = abfd; sym -> name = strtab + i_sym.st_name; sym -> value = i_sym.st_value; if (i_sym.st_shndx > 0 && i_sym.st_shndx < SHN_LORESERV) { /* Note: This code depends upon there being an ordered one-for-one mapping of ELF sections to bfd sections. */ sym -> section = section_from_bfd_index (abfd, i_sym.st_shndx); } else if (i_sym.st_shndx == SHN_ABS) { sym -> section = &bfd_abs_section; } else if (i_sym.st_shndx == SHN_COMMON) { sym -> section = &bfd_com_section; } switch (ELF_ST_BIND (i_sym.st_info)) { case STB_LOCAL: sym -> flags |= BSF_LOCAL; break; case STB_GLOBAL: sym -> flags |= (BSF_GLOBAL | BSF_EXPORT); break; case STB_WEAK: sym -> flags |= BSF_WEAK; break; } sym++; } } bfd_get_symcount(abfd) = symcount = sym - symbase; sym = symbase = (asymbol *) bfd_realloc (abfd, symbase, symcount * sizeof (asymbol)); bfd_get_outsymbols(abfd) = vec = (asymbol **) bfd_alloc (abfd, symcount * sizeof (asymbol *)); while (symcount-- > 0) { *vec++ = sym++; } return (true); } /* Return the number of bytes required to hold the symtab vector. Note that we base it on the count plus 1, since we will null terminate the vector allocated based on this size. */ static unsigned int DEFUN (elf_get_symtab_upper_bound, (abfd), bfd *abfd) { unsigned int symtab_size = 0; if (elf_slurp_symbol_table (abfd)) { symtab_size = (bfd_get_symcount (abfd) + 1) * (sizeof (asymbol)); } return (symtab_size); } static unsigned int elf_get_reloc_upper_bound (abfd, asect) bfd *abfd; sec_ptr asect; { fprintf (stderr, "elf_get_reloc_upper_bound unimplemented\n"); fflush (stderr); abort (); return (0); } static unsigned int elf_canonicalize_reloc (abfd, section, relptr, symbols) bfd *abfd; sec_ptr section; arelent **relptr; asymbol **symbols; { fprintf (stderr, "elf_canonicalize_reloc unimplemented\n"); fflush (stderr); abort (); return (0); } static unsigned int DEFUN (elf_get_symtab, (abfd, alocation), bfd *abfd AND asymbol **alocation) { unsigned int symcount; asymbol **vec; if (!elf_slurp_symbol_table (abfd)) { return (0); } else { symcount = bfd_get_symcount (abfd); vec = bfd_get_outsymbols (abfd); while (symcount-- > 0) { *alocation++ = *vec++; } *alocation++ = NULL; return (bfd_get_symcount (abfd)); } } static asymbol * DEFUN (elf_make_empty_symbol, (abfd), bfd *abfd) { elf_symbol_type *new; new = (elf_symbol_type *) bfd_zalloc (abfd, sizeof (elf_symbol_type)); if (new == NULL) { bfd_error = no_memory; return (NULL); } else { new -> symbol.the_bfd = abfd; return (&new -> symbol); } } static void DEFUN (elf_print_symbol,(ignore_abfd, filep, symbol, how), bfd *ignore_abfd AND PTR filep AND asymbol *symbol AND bfd_print_symbol_type how) { fprintf (stderr, "elf_print_symbol unimplemented\n"); fflush (stderr); abort (); } static alent * DEFUN (elf_get_lineno,(ignore_abfd, symbol), bfd *ignore_abfd AND asymbol *symbol) { fprintf (stderr, "elf_get_lineno unimplemented\n"); fflush (stderr); abort (); return (NULL); } static boolean DEFUN (elf_set_arch_mach,(abfd, arch, machine), bfd *abfd AND enum bfd_architecture arch AND unsigned long machine) { fprintf (stderr, "elf_set_arch_mach unimplemented\n"); fflush (stderr); /* Allow any architecture to be supported by the elf backend */ return bfd_default_set_arch_mach(abfd, arch, machine); } static boolean DEFUN (elf_find_nearest_line,(abfd, section, symbols, offset, filename_ptr, functionname_ptr, line_ptr), bfd *abfd AND asection *section AND asymbol **symbols AND bfd_vma offset AND CONST char **filename_ptr AND CONST char **functionname_ptr AND unsigned int *line_ptr) { fprintf (stderr, "elf_find_nearest_line unimplemented\n"); fflush (stderr); abort (); return (false); } static int DEFUN (elf_sizeof_headers, (abfd, reloc), bfd *abfd AND boolean reloc) { fprintf (stderr, "elf_sizeof_headers unimplemented\n"); fflush (stderr); abort (); return (0); } /* This structure contains everything that BFD knows about a target. It includes things like its byte order, name, what routines to call to do various operations, etc. Every BFD points to a target structure with its "xvec" member. There are two such structures here: one for big-endian machines and one for little-endian machines. */ /* Archives are generic or unimplemented. */ #define elf_slurp_armap bfd_false #define elf_slurp_extended_name_table _bfd_slurp_extended_name_table #define elf_truncate_arname bfd_dont_truncate_arname #define elf_openr_next_archived_file bfd_generic_openr_next_archived_file #define elf_generic_stat_arch_elt bfd_generic_stat_arch_elt #define elf_write_armap (PROTO (boolean, (*), \ (bfd *arch, unsigned int elength, struct orl *map, unsigned int orl_count, \ int stridx))) bfd_false /* Ordinary section reading and writing */ #define elf_new_section_hook _bfd_dummy_new_section_hook #define elf_get_section_contents bfd_generic_get_section_contents #define elf_set_section_contents bfd_generic_set_section_contents #define elf_close_and_cleanup bfd_generic_close_and_cleanup #define elf_bfd_debug_info_start bfd_void #define elf_bfd_debug_info_end bfd_void #define elf_bfd_debug_info_accumulate (PROTO(void,(*),(bfd*, struct sec *))) bfd_void #define elf_bfd_get_relocated_section_contents \ bfd_generic_get_relocated_section_contents #define elf_bfd_relax_section bfd_generic_relax_section bfd_target elf_big_vec = { /* name: identify kind of target */ "elf-big", /* flavour: general indication about file */ bfd_target_elf_flavour, /* byteorder_big_p: data is big endian */ true, /* header_byteorder_big_p: header is also big endian */ true, /* object_flags: mask of all file flags */ (HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT), /* section_flags: mask of all section flags */ (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY | SEC_DATA), /* ar_pad_char: pad character for filenames within an archive header FIXME: this really has nothing to do with ELF, this is a characteristic of the archiver and/or os and should be independently tunable */ '/', /* ar_max_namelen: maximum number of characters in an archive header FIXME: this really has nothing to do with ELF, this is a characteristic of the archiver and should be independently tunable. This value is a WAG (wild a** guess) */ 15, /* align_power_min: minimum alignment restriction for any section FIXME: this value may be target machine dependent */ 3, /* Routines to byte-swap various sized integers from the data sections */ _do_getb64, _do_putb64, _do_getb32, _do_putb32, _do_getb16, _do_putb16, /* Routines to byte-swap various sized integers from the file headers */ _do_getb64, _do_putb64, _do_getb32, _do_putb32, _do_getb16, _do_putb16, /* bfd_check_format: check the format of a file being read */ { _bfd_dummy_target, /* unknown format */ elf_object_p, /* assembler/linker output (object file) */ bfd_generic_archive_p, /* an archive */ elf_core_file_p /* a core file */ }, /* bfd_set_format: set the format of a file being written */ { bfd_false, elf_mkobject, _bfd_generic_mkarchive, bfd_false }, /* bfd_write_contents: write cached information into a file being written */ { bfd_false, elf_write_object_contents, _bfd_write_archive_contents, bfd_false }, /* Initialize a jump table with the standard macro. All names start with "elf" */ JUMP_TABLE(elf), /* SWAP_TABLE */ NULL, NULL, NULL }; bfd_target elf_little_vec = { /* name: identify kind of target */ "elf-little", /* flavour: general indication about file */ bfd_target_elf_flavour, /* byteorder_big_p: data is big endian */ false, /* Nope -- this one's little endian */ /* header_byteorder_big_p: header is also big endian */ false, /* Nope -- this one's little endian */ /* object_flags: mask of all file flags */ (HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS | DYNAMIC | WP_TEXT), /* section_flags: mask of all section flags */ (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY | SEC_DATA), /* ar_pad_char: pad character for filenames within an archive header FIXME: this really has nothing to do with ELF, this is a characteristic of the archiver and/or os and should be independently tunable */ '/', /* ar_max_namelen: maximum number of characters in an archive header FIXME: this really has nothing to do with ELF, this is a characteristic of the archiver and should be independently tunable. This value is a WAG (wild a** guess) */ 15, /* align_power_min: minimum alignment restriction for any section FIXME: this value may be target machine dependent */ 3, /* Routines to byte-swap various sized integers from the data sections */ _do_getl64, _do_putl64, _do_getl32, _do_putl32, _do_getl16, _do_putl16, /* Routines to byte-swap various sized integers from the file headers */ _do_getl64, _do_putl64, _do_getl32, _do_putl32, _do_getl16, _do_putl16, /* bfd_check_format: check the format of a file being read */ { _bfd_dummy_target, /* unknown format */ elf_object_p, /* assembler/linker output (object file) */ bfd_generic_archive_p, /* an archive */ elf_core_file_p /* a core file */ }, /* bfd_set_format: set the format of a file being written */ { bfd_false, elf_mkobject, _bfd_generic_mkarchive, bfd_false }, /* bfd_write_contents: write cached information into a file being written */ { bfd_false, elf_write_object_contents, _bfd_write_archive_contents, bfd_false }, /* Initialize a jump table with the standard macro. All names start with "elf" */ JUMP_TABLE(elf), /* SWAP_TABLE */ NULL, NULL, NULL };