diff options
Diffstat (limited to 'libctf/ctf-open-bfd.c')
| -rw-r--r-- | libctf/ctf-open-bfd.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/libctf/ctf-open-bfd.c b/libctf/ctf-open-bfd.c new file mode 100644 index 0000000..d6d442e --- /dev/null +++ b/libctf/ctf-open-bfd.c @@ -0,0 +1,351 @@ +/* Opening CTF files with BFD. + Copyright (C) 2019 Free Software Foundation, Inc. + + This file is part of libctf. + + libctf 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 3, 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; see the file COPYING. If not see + <http://www.gnu.org/licenses/>. */ + +#include <ctf-impl.h> +#include <stddef.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <errno.h> +#include <string.h> +#include <fcntl.h> +#include <elf.h> +#include <bfd.h> + +#include "elf-bfd.h" + +/* Make a new struct ctf_archive_internal wrapper for a ctf_archive or a + ctf_file. Closes ARC and/or FP on error. Arrange to free the SYMSECT and + STRSECT interior on close. */ + +static struct ctf_archive_internal * +ctf_new_archive_internal (int is_archive, struct ctf_archive *arc, + ctf_file_t *fp, const ctf_sect_t *symsect, + const ctf_sect_t *strsect, + int *errp) +{ + struct ctf_archive_internal *arci; + + if ((arci = calloc (1, sizeof (struct ctf_archive_internal))) == NULL) + { + if (is_archive) + ctf_arc_close_internal (arc); + else + ctf_file_close (fp); + return (ctf_set_open_errno (errp, errno)); + } + arci->ctfi_is_archive = is_archive; + if (is_archive) + arci->ctfi_archive = arc; + else + arci->ctfi_file = fp; + if (symsect) + memcpy (&arci->ctfi_symsect, symsect, sizeof (struct ctf_sect)); + if (strsect) + memcpy (&arci->ctfi_strsect, strsect, sizeof (struct ctf_sect)); + + return arci; +} + +/* Free the BFD bits of a CTF file on ctf_file_close(). */ + +static void +ctf_bfdclose (struct ctf_archive_internal *arci) +{ + if (arci->ctfi_abfd != NULL) + if (!bfd_close_all_done (arci->ctfi_abfd)) + ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); +} + +/* Open a CTF file given the specified BFD. */ + +ctf_archive_t * +ctf_bfdopen (struct bfd *abfd, int *errp) +{ + ctf_archive_t *arc; + asection *ctf_asect; + bfd_byte *contents; + ctf_sect_t ctfsect; + + libctf_init_debug(); + + if ((ctf_asect = bfd_get_section_by_name (abfd, _CTF_SECTION)) == NULL) + { + return (ctf_set_open_errno (errp, ECTF_NOCTFDATA)); + } + + if (!bfd_malloc_and_get_section (abfd, ctf_asect, &contents)) + { + ctf_dprintf ("ctf_bfdopen(): cannot malloc CTF section: %s\n", + bfd_errmsg (bfd_get_error())); + return (ctf_set_open_errno (errp, ECTF_FMT)); + } + + ctfsect.cts_name = _CTF_SECTION; + ctfsect.cts_type = SHT_PROGBITS; + ctfsect.cts_flags = 0; + ctfsect.cts_entsize = 1; + ctfsect.cts_offset = 0; + ctfsect.cts_size = bfd_section_size (abfd, ctf_asect); + ctfsect.cts_data = contents; + + if ((arc = ctf_bfdopen_ctfsect (abfd, &ctfsect, errp)) != NULL) + { + arc->ctfi_data = (void *) ctfsect.cts_data; + return arc; + } + + free (contents); + return NULL; /* errno is set for us. */ +} + +/* Open a CTF file given the specified BFD and CTF section (which may contain a + CTF archive or a file). Takes ownership of the ctfsect, and frees it + later. */ + +ctf_archive_t * +ctf_bfdopen_ctfsect (struct bfd *abfd, const ctf_sect_t *ctfsect, int *errp) +{ + struct ctf_archive *arc = NULL; + ctf_archive_t *arci; + ctf_file_t *fp = NULL; + ctf_sect_t *symsectp = NULL; + ctf_sect_t *strsectp = NULL; + const char *bfderrstr = NULL; + int is_archive; + + asection *sym_asect; + ctf_sect_t symsect, strsect; + /* TODO: handle SYMTAB_SHNDX. */ + + if ((sym_asect = bfd_section_from_elf_index (abfd, + elf_onesymtab (abfd))) != NULL) + { + Elf_Internal_Shdr *symhdr = &elf_symtab_hdr (abfd); + asection *str_asect = NULL; + bfd_byte *contents; + + if (symhdr->sh_link != SHN_UNDEF && + symhdr->sh_link <= elf_numsections (abfd)) + str_asect = bfd_section_from_elf_index (abfd, symhdr->sh_link); + + Elf_Internal_Shdr *strhdr = elf_elfsections (abfd)[symhdr->sh_link]; + + if (sym_asect && str_asect) + { + if (!bfd_malloc_and_get_section (abfd, str_asect, &contents)) + { + bfderrstr = "Cannot malloc string table"; + free (contents); + goto err; + } + strsect.cts_data = contents; + strsect.cts_name = (char *) strsect.cts_data + strhdr->sh_name; + strsect.cts_type = strhdr->sh_type; + strsect.cts_flags = strhdr->sh_flags; + strsect.cts_entsize = strhdr->sh_size; + strsect.cts_offset = strhdr->sh_offset; + strsectp = &strsect; + + if (!bfd_malloc_and_get_section (abfd, sym_asect, &contents)) + { + bfderrstr = "Cannot malloc symbol table"; + free (contents); + goto err_free_str; + } + + symsect.cts_name = (char *) strsect.cts_data + symhdr->sh_name; + symsect.cts_type = symhdr->sh_type; + symsect.cts_flags = symhdr->sh_flags; + symsect.cts_entsize = symhdr->sh_size; + symsect.cts_data = contents; + symsect.cts_offset = symhdr->sh_offset; + symsectp = &symsect; + } + } + + if (ctfsect->cts_size > sizeof (uint64_t) && + ((*(uint64_t *) ctfsect->cts_data) == CTFA_MAGIC)) + { + is_archive = 1; + if ((arc = ctf_arc_bufopen ((void *) ctfsect->cts_data, + ctfsect->cts_size, errp)) == NULL) + goto err_free_sym; + } + else + { + is_archive = 0; + if ((fp = ctf_bufopen (ctfsect, symsectp, strsectp, errp)) == NULL) + { + ctf_dprintf ("ctf_internal_open(): cannot open CTF: %s\n", + ctf_errmsg (*errp)); + goto err_free_sym; + } + } + arci = ctf_new_archive_internal (is_archive, arc, fp, symsectp, strsectp, + errp); + + if (arci) + return arci; + err_free_sym: + free ((void *) symsect.cts_data); +err_free_str: + free ((void *) strsect.cts_data); +err: _libctf_unused_; + if (bfderrstr) + { + ctf_dprintf ("ctf_bfdopen(): %s: %s\n", bfderrstr, + bfd_errmsg (bfd_get_error())); + ctf_set_open_errno (errp, ECTF_FMT); + } + return NULL; +} + +/* Open the specified file descriptor and return a pointer to a CTF archive that + contains one or more CTF containers. The file can be an ELF file, a raw CTF + file, or a CTF archive. The caller is responsible for closing the file + descriptor when it is no longer needed. If this is an ELF file, TARGET, if + non-NULL, should be the name of a suitable BFD target. */ + +ctf_archive_t * +ctf_fdopen (int fd, const char *filename, const char *target, int *errp) +{ + ctf_archive_t *arci; + bfd *abfd; + int nfd; + + struct stat st; + ssize_t nbytes; + + ctf_preamble_t ctfhdr; + uint64_t arc_magic; + + memset (&ctfhdr, 0, sizeof (ctfhdr)); + + libctf_init_debug(); + + if (fstat (fd, &st) == -1) + return (ctf_set_open_errno (errp, errno)); + + if ((nbytes = ctf_pread (fd, &ctfhdr, sizeof (ctfhdr), 0)) <= 0) + return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); + + /* If we have read enough bytes to form a CTF header and the magic + string matches, attempt to interpret the file as raw CTF. */ + + if ((size_t) nbytes >= sizeof (ctf_preamble_t) && + ctfhdr.ctp_magic == CTF_MAGIC) + { + ctf_file_t *fp = NULL; + void *data; + + if (ctfhdr.ctp_version > CTF_VERSION) + return (ctf_set_open_errno (errp, ECTF_CTFVERS)); + + if ((data = ctf_mmap (st.st_size, 0, fd)) == NULL) + return (ctf_set_open_errno (errp, errno)); + + if ((fp = ctf_simple_open (data, (size_t) st.st_size, NULL, 0, 0, + NULL, 0, errp)) == NULL) + ctf_munmap (data, (size_t) st.st_size); + fp->ctf_data_mmapped = data; + fp->ctf_data_mmapped_len = (size_t) st.st_size; + + return ctf_new_archive_internal (0, NULL, fp, NULL, NULL, errp); + } + + if ((nbytes = ctf_pread (fd, &arc_magic, sizeof (arc_magic), 0)) <= 0) + return (ctf_set_open_errno (errp, nbytes < 0 ? errno : ECTF_FMT)); + + if ((size_t) nbytes >= sizeof (uint64_t) && arc_magic == CTFA_MAGIC) + { + struct ctf_archive *arc; + + if ((arc = ctf_arc_open_internal (filename, errp)) == NULL) + return NULL; /* errno is set for us. */ + + return ctf_new_archive_internal (1, arc, NULL, NULL, NULL, errp); + } + + /* Attempt to open the file with BFD. We must dup the fd first, since bfd + takes ownership of the passed fd. */ + + if ((nfd = dup (fd)) < 0) + return (ctf_set_open_errno (errp, errno)); + + if ((abfd = bfd_fdopenr (filename, target, nfd)) == NULL) + { + ctf_dprintf ("Cannot open BFD from %s: %s\n", + filename ? filename : "(unknown file)", + bfd_errmsg (bfd_get_error())); + return (ctf_set_open_errno (errp, ECTF_FMT)); + } + + if (!bfd_check_format (abfd, bfd_object)) + { + ctf_dprintf ("BFD format problem in %s: %s\n", + filename ? filename : "(unknown file)", + bfd_errmsg (bfd_get_error())); + if (bfd_get_error() == bfd_error_file_ambiguously_recognized) + return (ctf_set_open_errno (errp, ECTF_BFD_AMBIGUOUS)); + else + return (ctf_set_open_errno (errp, ECTF_FMT)); + } + + if ((arci = ctf_bfdopen (abfd, errp)) == NULL) + { + if (!bfd_close_all_done (abfd)) + ctf_dprintf ("Cannot close BFD: %s\n", bfd_errmsg (bfd_get_error())); + return NULL; /* errno is set for us. */ + } + arci->ctfi_bfd_close = ctf_bfdclose; + arci->ctfi_abfd = abfd; + + return arci; +} + +/* Open the specified file and return a pointer to a CTF container. The file + can be either an ELF file or raw CTF file. This is just a convenient + wrapper around ctf_fdopen() for callers. */ + +ctf_archive_t * +ctf_open (const char *filename, const char *target, int *errp) +{ + ctf_archive_t *arc; + int fd; + + if ((fd = open (filename, O_RDONLY)) == -1) + { + if (errp != NULL) + *errp = errno; + return NULL; + } + + arc = ctf_fdopen (fd, filename, target, errp); + (void) close (fd); + return arc; +} + +/* Public entry point: open a CTF archive, or CTF file. Returns the archive, or + NULL and an error in *err. Despite the fact that this uses CTF archives, it + must be in this file to avoid dragging in BFD into non-BFD-using programs. */ +ctf_archive_t * +ctf_arc_open (const char *filename, int *errp) +{ + return ctf_open (filename, NULL, errp); +} |