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gdb
gdb-6.6-buildid-locate.patch
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File gdb-6.6-buildid-locate.patch of Package gdb
From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Fedora GDB patches <invalid@email.com> Date: Fri, 27 Oct 2017 21:07:50 +0200 Subject: gdb-6.6-buildid-locate.patch ;; New locating of the matching binaries from the pure core file (build-id). ;;=push+jan diff --git a/gdb/build-id.c b/gdb/build-id.c --- a/gdb/build-id.c +++ b/gdb/build-id.c @@ -26,11 +26,67 @@ #include "objfiles.h" #include "filenames.h" #include "gdbcore.h" +#include "libbfd.h" +#include "gdbcore.h" +#include "gdbcmd.h" +#include "observable.h" +#include "elf/external.h" +#include "elf/internal.h" +#include "elf/common.h" +#include "elf-bfd.h" +#include <sys/stat.h> + +#define BUILD_ID_VERBOSE_NONE 0 +#define BUILD_ID_VERBOSE_FILENAMES 1 +#define BUILD_ID_VERBOSE_BINARY_PARSE 2 +static int build_id_verbose = BUILD_ID_VERBOSE_FILENAMES; +static void +show_build_id_verbose (struct ui_file *file, int from_tty, + struct cmd_list_element *c, const char *value) +{ + fprintf_filtered (file, _("Verbosity level of the build-id locator is %s.\n"), + value); +} +/* Locate NT_GNU_BUILD_ID and return its matching debug filename. + FIXME: NOTE decoding should be unified with the BFD core notes decoding. */ + +static struct bfd_build_id * +build_id_buf_get (bfd *templ, gdb_byte *buf, bfd_size_type size) +{ + bfd_byte *p; + + p = buf; + while (p < buf + size) + { + /* FIXME: bad alignment assumption. */ + Elf_External_Note *xnp = (Elf_External_Note *) p; + size_t namesz = H_GET_32 (templ, xnp->namesz); + size_t descsz = H_GET_32 (templ, xnp->descsz); + bfd_byte *descdata = (gdb_byte *) xnp->name + BFD_ALIGN (namesz, 4); + + if (H_GET_32 (templ, xnp->type) == NT_GNU_BUILD_ID + && namesz == sizeof "GNU" + && memcmp (xnp->name, "GNU", sizeof "GNU") == 0) + { + size_t sz = descsz; + gdb_byte *data = (gdb_byte *) descdata; + struct bfd_build_id *retval; + + retval = (struct bfd_build_id *) xmalloc (sizeof *retval - 1 + sz); + retval->size = sz; + memcpy (retval->data, data, sz); + + return retval; + } + p = descdata + BFD_ALIGN (descsz, 4); + } + return NULL; +} /* See build-id.h. */ const struct bfd_build_id * -build_id_bfd_get (bfd *abfd) +build_id_bfd_shdr_get (bfd *abfd) { if (!bfd_check_format (abfd, bfd_object)) return NULL; @@ -42,6 +98,348 @@ build_id_bfd_get (bfd *abfd) return NULL; } +/* Core files may have missing (corrupt) SHDR but PDHR is correct there. + bfd_elf_bfd_from_remote_memory () has too much overhead by + allocating/reading all the available ELF PT_LOADs. */ + +static struct bfd_build_id * +build_id_phdr_get (bfd *templ, bfd_vma loadbase, unsigned e_phnum, + Elf_Internal_Phdr *i_phdr) +{ + int i; + struct bfd_build_id *retval = NULL; + + for (i = 0; i < e_phnum; i++) + if (i_phdr[i].p_type == PT_NOTE && i_phdr[i].p_filesz > 0) + { + Elf_Internal_Phdr *hdr = &i_phdr[i]; + gdb_byte *buf; + int err; + + buf = (gdb_byte *) xmalloc (hdr->p_filesz); + err = target_read_memory (loadbase + i_phdr[i].p_vaddr, buf, + hdr->p_filesz); + if (err == 0) + retval = build_id_buf_get (templ, buf, hdr->p_filesz); + else + retval = NULL; + xfree (buf); + if (retval != NULL) + break; + } + return retval; +} + +/* First we validate the file by reading in the ELF header and checking + the magic number. */ + +static inline bfd_boolean +elf_file_p (Elf64_External_Ehdr *x_ehdrp64) +{ + gdb_assert (sizeof (Elf64_External_Ehdr) >= sizeof (Elf32_External_Ehdr)); + gdb_assert (offsetof (Elf64_External_Ehdr, e_ident) + == offsetof (Elf32_External_Ehdr, e_ident)); + gdb_assert (sizeof (((Elf64_External_Ehdr *) 0)->e_ident) + == sizeof (((Elf32_External_Ehdr *) 0)->e_ident)); + + return ((x_ehdrp64->e_ident[EI_MAG0] == ELFMAG0) + && (x_ehdrp64->e_ident[EI_MAG1] == ELFMAG1) + && (x_ehdrp64->e_ident[EI_MAG2] == ELFMAG2) + && (x_ehdrp64->e_ident[EI_MAG3] == ELFMAG3)); +} + +/* Translate an ELF file header in external format into an ELF file header in + internal format. */ + +#define H_GET_WORD(bfd, ptr) (is64 ? H_GET_64 (bfd, (ptr)) \ + : H_GET_32 (bfd, (ptr))) +#define H_GET_SIGNED_WORD(bfd, ptr) (is64 ? H_GET_S64 (bfd, (ptr)) \ + : H_GET_S32 (bfd, (ptr))) + +static void +elf_swap_ehdr_in (bfd *abfd, + const Elf64_External_Ehdr *src64, + Elf_Internal_Ehdr *dst) +{ + int is64 = bfd_get_arch_size (abfd) == 64; +#define SRC(field) (is64 ? src64->field \ + : ((const Elf32_External_Ehdr *) src64)->field) + + int signed_vma = get_elf_backend_data (abfd)->sign_extend_vma; + memcpy (dst->e_ident, SRC (e_ident), EI_NIDENT); + dst->e_type = H_GET_16 (abfd, SRC (e_type)); + dst->e_machine = H_GET_16 (abfd, SRC (e_machine)); + dst->e_version = H_GET_32 (abfd, SRC (e_version)); + if (signed_vma) + dst->e_entry = H_GET_SIGNED_WORD (abfd, SRC (e_entry)); + else + dst->e_entry = H_GET_WORD (abfd, SRC (e_entry)); + dst->e_phoff = H_GET_WORD (abfd, SRC (e_phoff)); + dst->e_shoff = H_GET_WORD (abfd, SRC (e_shoff)); + dst->e_flags = H_GET_32 (abfd, SRC (e_flags)); + dst->e_ehsize = H_GET_16 (abfd, SRC (e_ehsize)); + dst->e_phentsize = H_GET_16 (abfd, SRC (e_phentsize)); + dst->e_phnum = H_GET_16 (abfd, SRC (e_phnum)); + dst->e_shentsize = H_GET_16 (abfd, SRC (e_shentsize)); + dst->e_shnum = H_GET_16 (abfd, SRC (e_shnum)); + dst->e_shstrndx = H_GET_16 (abfd, SRC (e_shstrndx)); + +#undef SRC +} + +/* Translate an ELF program header table entry in external format into an + ELF program header table entry in internal format. */ + +static void +elf_swap_phdr_in (bfd *abfd, + const Elf64_External_Phdr *src64, + Elf_Internal_Phdr *dst) +{ + int is64 = bfd_get_arch_size (abfd) == 64; +#define SRC(field) (is64 ? src64->field \ + : ((const Elf32_External_Phdr *) src64)->field) + + int signed_vma = get_elf_backend_data (abfd)->sign_extend_vma; + + dst->p_type = H_GET_32 (abfd, SRC (p_type)); + dst->p_flags = H_GET_32 (abfd, SRC (p_flags)); + dst->p_offset = H_GET_WORD (abfd, SRC (p_offset)); + if (signed_vma) + { + dst->p_vaddr = H_GET_SIGNED_WORD (abfd, SRC (p_vaddr)); + dst->p_paddr = H_GET_SIGNED_WORD (abfd, SRC (p_paddr)); + } + else + { + dst->p_vaddr = H_GET_WORD (abfd, SRC (p_vaddr)); + dst->p_paddr = H_GET_WORD (abfd, SRC (p_paddr)); + } + dst->p_filesz = H_GET_WORD (abfd, SRC (p_filesz)); + dst->p_memsz = H_GET_WORD (abfd, SRC (p_memsz)); + dst->p_align = H_GET_WORD (abfd, SRC (p_align)); + +#undef SRC +} + +#undef H_GET_SIGNED_WORD +#undef H_GET_WORD + +static Elf_Internal_Phdr * +elf_get_phdr (bfd *templ, bfd_vma ehdr_vma, unsigned *e_phnum_pointer, + bfd_vma *loadbase_pointer) +{ + /* sizeof (Elf64_External_Ehdr) >= sizeof (Elf32_External_Ehdr) */ + Elf64_External_Ehdr x_ehdr64; /* Elf file header, external form */ + Elf_Internal_Ehdr i_ehdr; /* Elf file header, internal form */ + bfd_size_type x_phdrs_size; + gdb_byte *x_phdrs_ptr; + Elf_Internal_Phdr *i_phdrs; + int err; + unsigned int i; + bfd_vma loadbase; + int loadbase_set; + + gdb_assert (templ != NULL); + gdb_assert (sizeof (Elf64_External_Ehdr) >= sizeof (Elf32_External_Ehdr)); + + /* Read in the ELF header in external format. */ + err = target_read_memory (ehdr_vma, (bfd_byte *) &x_ehdr64, sizeof x_ehdr64); + if (err) + { + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Error reading ELF header at address 0x%lx"), + (unsigned long) ehdr_vma); + 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. */ + + if (! elf_file_p (&x_ehdr64) + || x_ehdr64.e_ident[EI_VERSION] != EV_CURRENT + || !((bfd_get_arch_size (templ) == 64 + && x_ehdr64.e_ident[EI_CLASS] == ELFCLASS64) + || (bfd_get_arch_size (templ) == 32 + && x_ehdr64.e_ident[EI_CLASS] == ELFCLASS32))) + { + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Unrecognized ELF header at address 0x%lx"), + (unsigned long) ehdr_vma); + return NULL; + } + + /* Check that file's byte order matches xvec's */ + switch (x_ehdr64.e_ident[EI_DATA]) + { + case ELFDATA2MSB: /* Big-endian */ + if (! bfd_header_big_endian (templ)) + { + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Unrecognized " + "big-endian ELF header at address 0x%lx"), + (unsigned long) ehdr_vma); + return NULL; + } + break; + case ELFDATA2LSB: /* Little-endian */ + if (! bfd_header_little_endian (templ)) + { + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Unrecognized " + "little-endian ELF header at address 0x%lx"), + (unsigned long) ehdr_vma); + return NULL; + } + break; + case ELFDATANONE: /* No data encoding specified */ + default: /* Unknown data encoding specified */ + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Unrecognized " + "ELF header endianity at address 0x%lx"), + (unsigned long) ehdr_vma); + return NULL; + } + + elf_swap_ehdr_in (templ, &x_ehdr64, &i_ehdr); + + /* The file header tells where to find the program headers. + These are what we use to actually choose what to read. */ + + if (i_ehdr.e_phentsize != (bfd_get_arch_size (templ) == 64 + ? sizeof (Elf64_External_Phdr) + : sizeof (Elf32_External_Phdr)) + || i_ehdr.e_phnum == 0) + { + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Invalid ELF program headers from the ELF header " + "at address 0x%lx"), (unsigned long) ehdr_vma); + return NULL; + } + + x_phdrs_size = (bfd_get_arch_size (templ) == 64 ? sizeof (Elf64_External_Phdr) + : sizeof (Elf32_External_Phdr)); + + i_phdrs = (Elf_Internal_Phdr *) xmalloc (i_ehdr.e_phnum * (sizeof *i_phdrs + x_phdrs_size)); + x_phdrs_ptr = (gdb_byte *) &i_phdrs[i_ehdr.e_phnum]; + err = target_read_memory (ehdr_vma + i_ehdr.e_phoff, (bfd_byte *) x_phdrs_ptr, + i_ehdr.e_phnum * x_phdrs_size); + if (err) + { + free (i_phdrs); + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Error reading " + "ELF program headers at address 0x%lx"), + (unsigned long) (ehdr_vma + i_ehdr.e_phoff)); + return NULL; + } + + loadbase = ehdr_vma; + loadbase_set = 0; + for (i = 0; i < i_ehdr.e_phnum; ++i) + { + elf_swap_phdr_in (templ, (Elf64_External_Phdr *) + (x_phdrs_ptr + i * x_phdrs_size), &i_phdrs[i]); + /* IA-64 vDSO may have two mappings for one segment, where one mapping + is executable only, and one is read only. We must not use the + executable one (PF_R is the first one, PF_X the second one). */ + if (i_phdrs[i].p_type == PT_LOAD && (i_phdrs[i].p_flags & PF_R)) + { + /* Only the first PT_LOAD segment indicates the file bias. + Next segments may have P_VADDR arbitrarily higher. + If the first segment has P_VADDR zero any next segment must not + confuse us, the first one sets LOADBASE certainly enough. */ + if (!loadbase_set && i_phdrs[i].p_offset == 0) + { + loadbase = ehdr_vma - i_phdrs[i].p_vaddr; + loadbase_set = 1; + } + } + } + + if (build_id_verbose >= BUILD_ID_VERBOSE_BINARY_PARSE) + warning (_("build-id: Found ELF header at address 0x%lx, loadbase 0x%lx"), + (unsigned long) ehdr_vma, (unsigned long) loadbase); + + *e_phnum_pointer = i_ehdr.e_phnum; + *loadbase_pointer = loadbase; + return i_phdrs; +} + +/* BUILD_ID_ADDR_GET gets ADDR located somewhere in the object. + Find the first section before ADDR containing an ELF header. + We rely on the fact the sections from multiple files do not mix. + FIXME: We should check ADDR is contained _inside_ the section with possibly + missing content (P_FILESZ < P_MEMSZ). These omitted sections are currently + hidden by _BFD_ELF_MAKE_SECTION_FROM_PHDR. */ + +static CORE_ADDR build_id_addr; +struct build_id_addr_sect + { + struct build_id_addr_sect *next; + asection *sect; + }; +static struct build_id_addr_sect *build_id_addr_sect; + +static void build_id_addr_candidate (bfd *abfd, asection *sect, void *obj) +{ + if (build_id_addr >= bfd_section_vma (abfd, sect)) + { + struct build_id_addr_sect *candidate; + + candidate = (struct build_id_addr_sect *) xmalloc (sizeof *candidate); + candidate->next = build_id_addr_sect; + build_id_addr_sect = candidate; + candidate->sect = sect; + } +} + +struct bfd_build_id * +build_id_addr_get (CORE_ADDR addr) +{ + struct build_id_addr_sect *candidate; + struct bfd_build_id *retval = NULL; + Elf_Internal_Phdr *i_phdr = NULL; + bfd_vma loadbase = 0; + unsigned e_phnum = 0; + + if (core_bfd == NULL) + return NULL; + + build_id_addr = addr; + gdb_assert (build_id_addr_sect == NULL); + bfd_map_over_sections (core_bfd, build_id_addr_candidate, NULL); + + /* Sections are sorted in the high-to-low VMAs order. + Stop the search on the first ELF header we find. + Do not continue the search even if it does not contain NT_GNU_BUILD_ID. */ + + for (candidate = build_id_addr_sect; candidate != NULL; + candidate = candidate->next) + { + i_phdr = elf_get_phdr (core_bfd, + bfd_section_vma (core_bfd, candidate->sect), + &e_phnum, &loadbase); + if (i_phdr != NULL) + break; + } + + if (i_phdr != NULL) + { + retval = build_id_phdr_get (core_bfd, loadbase, e_phnum, i_phdr); + xfree (i_phdr); + } + + while (build_id_addr_sect != NULL) + { + candidate = build_id_addr_sect; + build_id_addr_sect = candidate->next; + xfree (candidate); + } + + return retval; +} + /* See build-id.h. */ int @@ -50,7 +448,7 @@ build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check) const struct bfd_build_id *found; int retval = 0; - found = build_id_bfd_get (abfd); + found = build_id_bfd_shdr_get (abfd); if (found == NULL) warning (_("File \"%s\" has no build-id, file skipped"), @@ -65,62 +463,173 @@ build_id_verify (bfd *abfd, size_t check_len, const bfd_byte *check) return retval; } +static char * +link_resolve (const char *symlink, int level) +{ + char buf[PATH_MAX + 1], *target, *retval; + ssize_t got; + + if (level > 10) + return xstrdup (symlink); + + got = readlink (symlink, buf, sizeof (buf)); + if (got < 0 || got >= sizeof (buf)) + return xstrdup (symlink); + buf[got] = '\0'; + + if (IS_ABSOLUTE_PATH (buf)) + target = xstrdup (buf); + else + { + const std::string dir (ldirname (symlink)); + + target = xstrprintf ("%s" +#ifndef HAVE_DOS_BASED_FILE_SYSTEM + "/" +#else /* HAVE_DOS_BASED_FILE_SYSTEM */ + "\\" +#endif /* HAVE_DOS_BASED_FILE_SYSTEM */ + "%s", dir.c_str(), buf); + } + + retval = link_resolve (target, level + 1); + xfree (target); + return retval; +} + /* Helper for build_id_to_debug_bfd. LINK is a path to a potential build-id-based separate debug file, potentially a symlink to the real file. If the file exists and matches BUILD_ID, return a BFD reference to it. */ static gdb_bfd_ref_ptr -build_id_to_debug_bfd_1 (const std::string &link, size_t build_id_len, - const bfd_byte *build_id) +build_id_to_debug_bfd_1 (const std::string &orig_link, size_t build_id_len, + const bfd_byte *build_id, char **link_return, + int add_debug_suffix) { + gdb_bfd_ref_ptr ret_bfd = {}; + std::string ret_link; + if (separate_debug_file_debug) { - printf_unfiltered (_(" Trying %s..."), link.c_str ()); + printf_unfiltered (_(" Trying %s..."), orig_link.c_str ()); gdb_flush (gdb_stdout); } - /* lrealpath() is expensive even for the usually non-existent files. */ - gdb::unique_xmalloc_ptr<char> filename; - if (access (link.c_str (), F_OK) == 0) - filename.reset (lrealpath (link.c_str ())); - - if (filename == NULL) + for (unsigned seqno = 0;; seqno++) { - if (separate_debug_file_debug) - printf_unfiltered (_(" no, unable to compute real path\n")); + std::string link = orig_link; - return {}; - } + if (seqno > 0) + { + /* There can be multiple build-id symlinks pointing to real files + with the same build-id (such as hard links). Some of the real + files may not be installed. */ - /* We expect to be silent on the non-existing files. */ - gdb_bfd_ref_ptr debug_bfd = gdb_bfd_open (filename.get (), gnutarget, -1); + string_appendf (link, ".%u", seqno); + } - if (debug_bfd == NULL) - { - if (separate_debug_file_debug) - printf_unfiltered (_(" no, unable to open.\n")); + if (add_debug_suffix) + link += ".debug"; + + ret_link = link; + + struct stat statbuf_trash; + + /* `access' automatically dereferences LINK. */ + if (lstat (link.c_str (), &statbuf_trash) != 0) + { + /* Stop increasing SEQNO. */ + break; + } + + /* lrealpath() is expensive even for the usually non-existent files. */ + gdb::unique_xmalloc_ptr<char> filename; + + if (access (link.c_str (), F_OK) == 0) + filename.reset (lrealpath (link.c_str ())); + + if (filename == NULL) + { + if (separate_debug_file_debug) + printf_unfiltered (_(" no, unable to compute real path\n")); + + continue; + } + + /* We expect to be silent on the non-existing files. */ + gdb_bfd_ref_ptr debug_bfd = gdb_bfd_open (filename.get (), gnutarget, -1); + + if (debug_bfd == NULL) + { + if (separate_debug_file_debug) + printf_unfiltered (_(" no, unable to open.\n")); + + continue; + } + + if (!build_id_verify (debug_bfd.get(), build_id_len, build_id)) + { + if (separate_debug_file_debug) + printf_unfiltered (_(" no, build-id does not match.\n")); + + continue; + } - return {}; + ret_bfd = debug_bfd; + break; } - if (!build_id_verify (debug_bfd.get(), build_id_len, build_id)) + std::string link_all; + + if (ret_bfd != NULL) { if (separate_debug_file_debug) - printf_unfiltered (_(" no, build-id does not match.\n")); + printf_unfiltered (_(" yes!\n")); + } + else + { + /* If none of the real files is found report as missing file + always the non-.%u-suffixed file. */ + std::string link0 = orig_link; + + if (add_debug_suffix) + link0 += ".debug"; + + /* If the symlink has target request to install the target. + BASE-debuginfo.rpm contains the symlink but BASE.rpm may be missing. + https://bugzilla.redhat.com/show_bug.cgi?id=981154 */ + std::string link0_resolved (link_resolve (link0.c_str (), 0)); - return {}; + if (link_all.empty ()) + link_all = link0_resolved; + else + { + /* Use whitespace instead of DIRNAME_SEPARATOR to be compatible with + its possible use as an argument for installation command. */ + link_all += " " + link0_resolved; + } } - if (separate_debug_file_debug) - printf_unfiltered (_(" yes!\n")); + if (link_return != NULL) + { + if (ret_bfd != NULL) + { + *link_return = xstrdup (ret_link.c_str ()); + } + else + { + *link_return = xstrdup (link_all.c_str ()); + } + } - return debug_bfd; + return ret_bfd; } /* See build-id.h. */ gdb_bfd_ref_ptr -build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) +build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id, + char **link_return, int add_debug_suffix) { /* Keep backward compatibility so that DEBUG_FILE_DIRECTORY being "" will cause "/.build-id/..." lookups. */ @@ -143,16 +652,16 @@ build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) if (size > 0) { size--; - string_appendf (link, "%02x/", (unsigned) *data++); + string_appendf (link, "%02x", (unsigned) *data++); } - + if (size > 0) + link += "/"; while (size-- > 0) string_appendf (link, "%02x", (unsigned) *data++); - link += ".debug"; - gdb_bfd_ref_ptr debug_bfd - = build_id_to_debug_bfd_1 (link, build_id_len, build_id); + = build_id_to_debug_bfd_1 (link, build_id_len, build_id, + link_return, add_debug_suffix); if (debug_bfd != NULL) return debug_bfd; @@ -166,7 +675,8 @@ build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) if (strcmp (gdb_sysroot, TARGET_SYSROOT_PREFIX) != 0) { link = gdb_sysroot + link; - debug_bfd = build_id_to_debug_bfd_1 (link, build_id_len, build_id); + debug_bfd = build_id_to_debug_bfd_1 (link, build_id_len, build_id, + link_return, add_debug_suffix); if (debug_bfd != NULL) return debug_bfd; } @@ -175,22 +685,190 @@ build_id_to_debug_bfd (size_t build_id_len, const bfd_byte *build_id) return {}; } +char * +build_id_to_filename (const struct bfd_build_id *build_id, char **link_return) +{ + gdb_bfd_ref_ptr abfd; + char *result; + + abfd = build_id_to_debug_bfd (build_id->size, build_id->data, link_return, 0); + if (abfd == NULL) + return NULL; + + result = xstrdup (bfd_get_filename (abfd)); + abfd.release (); + return result; +} + +/* This MISSING_FILEPAIR_HASH tracker is used only for the duplicite messages + Try to install the hash file ... + avoidance. */ + +struct missing_filepair + { + char *binary; + char *debug; + char data[1]; + }; + +static struct htab *missing_filepair_hash; +static struct obstack missing_filepair_obstack; + +static void * +missing_filepair_xcalloc (size_t nmemb, size_t nmemb_size) +{ + void *retval; + size_t size = nmemb * nmemb_size; + + retval = obstack_alloc (&missing_filepair_obstack, size); + memset (retval, 0, size); + return retval; +} + +static hashval_t +missing_filepair_hash_func (const struct missing_filepair *elem) +{ + hashval_t retval = 0; + + retval ^= htab_hash_string (elem->binary); + if (elem->debug != NULL) + retval ^= htab_hash_string (elem->debug); + + return retval; +} + +static int +missing_filepair_eq (const struct missing_filepair *elem1, + const struct missing_filepair *elem2) +{ + return strcmp (elem1->binary, elem2->binary) == 0 + && ((elem1->debug == NULL) == (elem2->debug == NULL)) + && (elem1->debug == NULL || strcmp (elem1->debug, elem2->debug) == 0); +} + +static void +missing_filepair_change (void) +{ + if (missing_filepair_hash != NULL) + { + obstack_free (&missing_filepair_obstack, NULL); + /* All their memory came just from missing_filepair_OBSTACK. */ + missing_filepair_hash = NULL; + } +} + +static void +debug_print_executable_changed (void) +{ + missing_filepair_change (); +} + +/* Notify user the file BINARY with (possibly NULL) associated separate debug + information file DEBUG is missing. DEBUG may or may not be the build-id + file such as would be: + /usr/lib/debug/.build-id/dd/b1d2ce632721c47bb9e8679f369e2295ce71be.debug + */ + +void +debug_print_missing (const char *binary, const char *debug) +{ + size_t binary_len0 = strlen (binary) + 1; + size_t debug_len0 = debug ? strlen (debug) + 1 : 0; + struct missing_filepair missing_filepair_find; + struct missing_filepair *missing_filepair; + struct missing_filepair **slot; + + if (build_id_verbose < BUILD_ID_VERBOSE_FILENAMES) + return; + + if (missing_filepair_hash == NULL) + { + obstack_init (&missing_filepair_obstack); + missing_filepair_hash = htab_create_alloc (64, + (hashval_t (*) (const void *)) missing_filepair_hash_func, + (int (*) (const void *, const void *)) missing_filepair_eq, NULL, + missing_filepair_xcalloc, NULL); + } + + /* Use MISSING_FILEPAIR_FIND first instead of calling obstack_alloc with + obstack_free in the case of a (rare) match. The problem is ALLOC_F for + MISSING_FILEPAIR_HASH allocates from MISSING_FILEPAIR_OBSTACK maintenance + structures for MISSING_FILEPAIR_HASH. Calling obstack_free would possibly + not to free only MISSING_FILEPAIR but also some such structures (allocated + during the htab_find_slot call). */ + + missing_filepair_find.binary = (char *) binary; + missing_filepair_find.debug = (char *) debug; + slot = (struct missing_filepair **) htab_find_slot (missing_filepair_hash, + &missing_filepair_find, + INSERT); + + /* While it may be still printed duplicitely with the missing debuginfo file + * it is due to once printing about the binary file build-id link and once + * about the .debug file build-id link as both the build-id symlinks are + * located in the debuginfo package. */ + + if (*slot != NULL) + return; + + missing_filepair = (struct missing_filepair *) obstack_alloc (&missing_filepair_obstack, + sizeof (*missing_filepair) - 1 + + binary_len0 + debug_len0); + missing_filepair->binary = missing_filepair->data; + memcpy (missing_filepair->binary, binary, binary_len0); + if (debug != NULL) + { + missing_filepair->debug = missing_filepair->binary + binary_len0; + memcpy (missing_filepair->debug, debug, debug_len0); + } + else + missing_filepair->debug = NULL; + + *slot = missing_filepair; + + /* We do not collect and flush these messages as each such message + already requires its own separate lines. */ + + fprintf_unfiltered (gdb_stdlog, + _("Missing separate debuginfo for %s\n"), binary); + if (debug != NULL) + fprintf_unfiltered (gdb_stdlog, _("Try to install the hash file %s\n"), + debug); +} + /* See build-id.h. */ std::string -find_separate_debug_file_by_buildid (struct objfile *objfile) +find_separate_debug_file_by_buildid (struct objfile *objfile, + gdb::unique_xmalloc_ptr<char> *build_id_filename_return) { const struct bfd_build_id *build_id; - build_id = build_id_bfd_get (objfile->obfd); + if (build_id_filename_return) + *build_id_filename_return = NULL; + + build_id = build_id_bfd_shdr_get (objfile->obfd); if (build_id != NULL) { if (separate_debug_file_debug) printf_unfiltered (_("\nLooking for separate debug info (build-id) for " "%s\n"), objfile_name (objfile)); + char *build_id_filename_cstr = NULL; gdb_bfd_ref_ptr abfd (build_id_to_debug_bfd (build_id->size, - build_id->data)); + build_id->data, + (!build_id_filename_return ? NULL : &build_id_filename_cstr), 1)); + if (build_id_filename_return) + { + if (!build_id_filename_cstr) + gdb_assert (!*build_id_filename_return); + else + { + *build_id_filename_return = gdb::unique_xmalloc_ptr<char> (build_id_filename_cstr); + build_id_filename_cstr = NULL; + } + } + /* Prevent looping on a stripped .debug file. */ if (abfd != NULL && filename_cmp (bfd_get_filename (abfd.get ()), @@ -203,3 +881,21 @@ find_separate_debug_file_by_buildid (struct objfile *objfile) return std::string (); } + +extern void _initialize_build_id (void); + +void +_initialize_build_id (void) +{ + add_setshow_zinteger_cmd ("build-id-verbose", no_class, &build_id_verbose, + _("\ +Set debugging level of the build-id locator."), _("\ +Show debugging level of the build-id locator."), _("\ +Level 1 (default) enables printing the missing debug filenames,\n\ +level 2 also prints the parsing of binaries to find the identificators."), + NULL, + show_build_id_verbose, + &setlist, &showlist); + + gdb::observers::executable_changed.attach (debug_print_executable_changed); +} diff --git a/gdb/build-id.h b/gdb/build-id.h --- a/gdb/build-id.h +++ b/gdb/build-id.h @@ -23,9 +23,10 @@ #include "gdb_bfd.h" #include "common/rsp-low.h" -/* Locate NT_GNU_BUILD_ID from ABFD and return its content. */ +/* Separate debuginfo files have corrupted PHDR but SHDR is correct there. + Locate NT_GNU_BUILD_ID from ABFD and return its content. */ -extern const struct bfd_build_id *build_id_bfd_get (bfd *abfd); +extern const struct bfd_build_id *build_id_bfd_shdr_get (bfd *abfd); /* Return true if ABFD has NT_GNU_BUILD_ID matching the CHECK value. Otherwise, issue a warning and return false. */ @@ -39,14 +40,19 @@ extern int build_id_verify (bfd *abfd, the caller. */ extern gdb_bfd_ref_ptr build_id_to_debug_bfd (size_t build_id_len, - const bfd_byte *build_id); + const bfd_byte *build_id, + char **link_return, + int add_debug_suffix); + +extern char *build_id_to_filename (const struct bfd_build_id *build_id, + char **link_return); /* Find the separate debug file for OBJFILE, by using the build-id associated with OBJFILE's BFD. If successful, returns the file name for the separate debug file, otherwise, return an empty string. */ -extern std::string find_separate_debug_file_by_buildid - (struct objfile *objfile); +extern std::string find_separate_debug_file_by_buildid (struct objfile *objfile, + gdb::unique_xmalloc_ptr<char> *build_id_filename_return); /* Return an hex-string representation of BUILD_ID. */ diff --git a/gdb/coffread.c b/gdb/coffread.c --- a/gdb/coffread.c +++ b/gdb/coffread.c @@ -732,7 +732,8 @@ coff_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags) /* Try to add separate debug file if no symbols table found. */ if (!objfile_has_partial_symbols (objfile)) { - std::string debugfile = find_separate_debug_file_by_buildid (objfile); + std::string debugfile = find_separate_debug_file_by_buildid (objfile, + NULL); if (debugfile.empty ()) debugfile = find_separate_debug_file_by_debuglink (objfile); diff --git a/gdb/corelow.c b/gdb/corelow.c --- a/gdb/corelow.c +++ b/gdb/corelow.c @@ -43,6 +43,10 @@ #include "gdb_bfd.h" #include "completer.h" #include "common/filestuff.h" +#include "auxv.h" +#include "elf/common.h" +#include "gdbcmd.h" +#include "build-id.h" #ifndef O_LARGEFILE #define O_LARGEFILE 0 @@ -320,6 +324,54 @@ add_to_thread_list (bfd *abfd, asection *asect, void *reg_sect_arg) inferior_ptid = ptid; /* Yes, make it current. */ } +static int build_id_core_loads = 1; + +static void +build_id_locate_exec (int from_tty) +{ + CORE_ADDR at_entry; + struct bfd_build_id *build_id; + char *execfilename; + char *build_id_filename; + struct cleanup *back_to; + + if (exec_bfd != NULL || symfile_objfile != NULL) + return; + + if (target_auxv_search (current_top_target (), AT_ENTRY, &at_entry) <= 0) + return; + + build_id = build_id_addr_get (at_entry); + if (build_id == NULL) + return; + back_to = make_cleanup (xfree, build_id); + + /* SYMFILE_OBJFILE should refer to the main executable (not only to its + separate debug info file). gcc44+ keeps .eh_frame only in the main + executable without its duplicate .debug_frame in the separate debug info + file - such .eh_frame would not be found if SYMFILE_OBJFILE would refer + directly to the separate debug info file. */ + + execfilename = build_id_to_filename (build_id, &build_id_filename); + make_cleanup (xfree, build_id_filename); + + if (execfilename != NULL) + { + make_cleanup (xfree, execfilename); + exec_file_attach (execfilename, from_tty); + symbol_file_add_main (execfilename, + symfile_add_flag (!from_tty ? 0 : SYMFILE_VERBOSE)); + if (symfile_objfile != NULL) + symfile_objfile->flags |= OBJF_BUILD_ID_CORE_LOADED; + } + else + debug_print_missing (_("the main executable file"), build_id_filename); + + do_cleanups (back_to); + + /* No automatic SOLIB_ADD as the libraries would get read twice. */ +} + /* Issue a message saying we have no core to debug, if FROM_TTY. */ static void @@ -455,6 +507,14 @@ core_target_open (const char *arg, int from_tty) switch_to_thread (thread); } + /* Find the build_id identifiers. If it gets executed after + POST_CREATE_INFERIOR we would clash with asking to discard the already + loaded VDSO symbols. If it gets executed before bfd_map_over_sections + INFERIOR_PTID is still not set and libthread_db initialization crashes on + PID == 0 in ps_pglobal_lookup. */ + if (build_id_core_loads != 0) + build_id_locate_exec (from_tty); + post_create_inferior (target, from_tty); /* Now go through the target stack looking for threads since there @@ -1063,4 +1123,11 @@ void _initialize_corelow (void) { add_target (core_target_info, core_target_open, filename_completer); + + add_setshow_boolean_cmd ("build-id-core-loads", class_files, + &build_id_core_loads, _("\ +Set whether CORE-FILE loads the build-id associated files automatically."), _("\ +Show whether CORE-FILE loads the build-id associated files automatically."), + NULL, NULL, NULL, + &setlist, &showlist); } diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -19949,6 +19949,27 @@ information files. @end table +You can also adjust the current verbosity of the @dfn{build id} locating. + +@table @code + +@kindex set build-id-verbose +@item set build-id-verbose 0 +No additional messages are printed. + +@item set build-id-verbose 1 +Missing separate debug filenames are printed. + +@item set build-id-verbose 2 +Missing separate debug filenames are printed and also all the parsing of the +binaries to find their @dfn{build id} content is printed. + +@kindex show build-id-verbose +@item show build-id-verbose +Show the current verbosity value for the @dfn{build id} content locating. + +@end table + @cindex @code{.gnu_debuglink} sections @cindex debug link sections A debug link is a special section of the executable file named diff --git a/gdb/dwarf-index-cache.c b/gdb/dwarf-index-cache.c --- a/gdb/dwarf-index-cache.c +++ b/gdb/dwarf-index-cache.c @@ -93,7 +93,7 @@ index_cache::store (struct dwarf2_per_objfile *dwarf2_per_objfile) if (!enabled ()) return; - const bfd_build_id *build_id = build_id_bfd_get (obj->obfd); + const bfd_build_id *build_id = build_id_bfd_shdr_get (obj->obfd); if (build_id == nullptr) { if (debug_index_cache) diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c --- a/gdb/dwarf2read.c +++ b/gdb/dwarf2read.c @@ -2727,7 +2727,7 @@ dwarf2_get_dwz_file (struct dwarf2_per_objfile *dwarf2_per_objfile) } if (dwz_bfd == NULL) - dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid); + dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid, NULL, 1); if (dwz_bfd == NULL) error (_("could not find '.gnu_debugaltlink' file for %s"), @@ -6237,7 +6237,7 @@ get_gdb_index_contents_from_section (objfile *obj, T *section_owner) static gdb::array_view<const gdb_byte> get_gdb_index_contents_from_cache (objfile *obj, dwarf2_per_objfile *dwarf2_obj) { - const bfd_build_id *build_id = build_id_bfd_get (obj->obfd); + const bfd_build_id *build_id = build_id_bfd_shdr_get (obj->obfd); if (build_id == nullptr) return {}; @@ -6250,7 +6250,7 @@ get_gdb_index_contents_from_cache (objfile *obj, dwarf2_per_objfile *dwarf2_obj) static gdb::array_view<const gdb_byte> get_gdb_index_contents_from_cache_dwz (objfile *obj, dwz_file *dwz) { - const bfd_build_id *build_id = build_id_bfd_get (dwz->dwz_bfd.get ()); + const bfd_build_id *build_id = build_id_bfd_shdr_get (dwz->dwz_bfd.get ()); if (build_id == nullptr) return {}; diff --git a/gdb/elfread.c b/gdb/elfread.c --- a/gdb/elfread.c +++ b/gdb/elfread.c @@ -1287,7 +1287,9 @@ elf_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags) && objfile->separate_debug_objfile == NULL && objfile->separate_debug_objfile_backlink == NULL) { - std::string debugfile = find_separate_debug_file_by_buildid (objfile); + gdb::unique_xmalloc_ptr<char> build_id_filename; + std::string debugfile + = find_separate_debug_file_by_buildid (objfile, &build_id_filename); if (debugfile.empty ()) debugfile = find_separate_debug_file_by_debuglink (objfile); @@ -1299,6 +1301,10 @@ elf_symfile_read (struct objfile *objfile, symfile_add_flags symfile_flags) symbol_file_add_separate (debug_bfd.get (), debugfile.c_str (), symfile_flags, objfile); } + /* Check if any separate debug info has been extracted out. */ + else if (bfd_get_section_by_name (objfile->obfd, ".gnu_debuglink") + != NULL) + debug_print_missing (objfile_name (objfile), build_id_filename.get ()); } } diff --git a/gdb/objfiles.h b/gdb/objfiles.h --- a/gdb/objfiles.h +++ b/gdb/objfiles.h @@ -554,6 +554,10 @@ struct objfile htab_t static_links {}; }; +/* This file was loaded according to the BUILD_ID_CORE_LOADS rules. */ + +#define OBJF_BUILD_ID_CORE_LOADED static_cast<enum objfile_flag>(1 << 12) + /* Declarations for functions defined in objfiles.c */ extern struct gdbarch *get_objfile_arch (const struct objfile *); diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c --- a/gdb/python/py-objfile.c +++ b/gdb/python/py-objfile.c @@ -132,7 +132,7 @@ objfpy_get_build_id (PyObject *self, void *closure) TRY { - build_id = build_id_bfd_get (objfile->obfd); + build_id = build_id_bfd_shdr_get (objfile->obfd); } CATCH (except, RETURN_MASK_ALL) { @@ -535,7 +535,7 @@ objfpy_lookup_objfile_by_build_id (const char *build_id) /* Don't return separate debug files. */ if (objfile->separate_debug_objfile_backlink != NULL) continue; - obfd_build_id = build_id_bfd_get (objfile->obfd); + obfd_build_id = build_id_bfd_shdr_get (objfile->obfd); if (obfd_build_id == NULL) continue; if (objfpy_build_id_matches (obfd_build_id, build_id)) diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -45,6 +45,7 @@ #include "auxv.h" #include "gdb_bfd.h" #include "probe.h" +#include "build-id.h" static struct link_map_offsets *svr4_fetch_link_map_offsets (void); static int svr4_have_link_map_offsets (void); @@ -1345,9 +1346,51 @@ svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm, continue; } - strncpy (newobj->so_name, buffer.get (), SO_NAME_MAX_PATH_SIZE - 1); - newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; - strcpy (newobj->so_original_name, newobj->so_name); + { + struct bfd_build_id *build_id; + + strncpy (newobj->so_original_name, buffer.get (), SO_NAME_MAX_PATH_SIZE - 1); + newobj->so_original_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; + /* May get overwritten below. */ + strcpy (newobj->so_name, newobj->so_original_name); + + build_id = build_id_addr_get (((lm_info_svr4 *) newobj->lm_info)->l_ld); + if (build_id != NULL) + { + char *name, *build_id_filename; + + /* Missing the build-id matching separate debug info file + would be handled while SO_NAME gets loaded. */ + name = build_id_to_filename (build_id, &build_id_filename); + if (name != NULL) + { + strncpy (newobj->so_name, name, SO_NAME_MAX_PATH_SIZE - 1); + newobj->so_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0'; + xfree (name); + } + else + { + debug_print_missing (newobj->so_name, build_id_filename); + + /* In the case the main executable was found according to + its build-id (from a core file) prevent loading + a different build of a library with accidentally the + same SO_NAME. + + It suppresses bogus backtraces (and prints "??" there + instead) if the on-disk files no longer match the + running program version. */ + + if (symfile_objfile != NULL + && (symfile_objfile->flags + & OBJF_BUILD_ID_CORE_LOADED) != 0) + newobj->so_name[0] = 0; + } + + xfree (build_id_filename); + xfree (build_id); + } + } /* If this entry has no name, or its name matches the name for the main executable, don't include it in the list. */ diff --git a/gdb/symfile.h b/gdb/symfile.h --- a/gdb/symfile.h +++ b/gdb/symfile.h @@ -531,6 +531,10 @@ void expand_symtabs_matching void map_symbol_filenames (symbol_filename_ftype *fun, void *data, int need_fullname); +/* build-id support. */ +extern struct bfd_build_id *build_id_addr_get (CORE_ADDR addr); +extern void debug_print_missing (const char *binary, const char *debug); + /* From dwarf2read.c */ /* Names for a dwarf2 debugging section. The field NORMAL is the normal diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp --- a/gdb/testsuite/gdb.base/corefile.exp +++ b/gdb/testsuite/gdb.base/corefile.exp @@ -311,3 +311,33 @@ gdb_test_multiple "core-file $corefile" $test { pass $test } } + + +# Test auto-loading of binary files through build-id from the core file. +set buildid [build_id_debug_filename_get $binfile] +set wholetest "binfile found by build-id" +if {$buildid == ""} { + untested "$wholetest (binary has no build-id)" +} else { + gdb_exit + gdb_start + + regsub {\.debug$} $buildid {} buildid + set debugdir [standard_output_file ${testfile}-debugdir] + file delete -force -- $debugdir + file mkdir $debugdir/[file dirname $buildid] + file copy $binfile $debugdir/$buildid + + set test "show debug-file-directory" + gdb_test_multiple $test $test { + -re "The directory where separate debug symbols are searched for is \"(.*)\"\\.\r\n$gdb_prompt $" { + set debugdir_orig $expect_out(1,string) + pass $test + } + } + gdb_test_no_output "set debug-file-directory $debugdir:$debugdir_orig" "set debug-file-directory" + gdb_test "show build-id-core-loads" {Whether CORE-FILE loads the build-id associated files automatically is on\.} + gdb_test "core-file $corefile" "\r\nProgram terminated with .*" "core-file without executable" + gdb_test "info files" "Local exec file:\r\n\[ \t\]*`[string_to_regexp $debugdir/$buildid]', file type .*" + pass $wholetest +} diff --git a/gdb/testsuite/gdb.base/new-ui-pending-input.exp b/gdb/testsuite/gdb.base/new-ui-pending-input.exp --- a/gdb/testsuite/gdb.base/new-ui-pending-input.exp +++ b/gdb/testsuite/gdb.base/new-ui-pending-input.exp @@ -62,6 +62,7 @@ proc test_command_line_new_ui_pending_input {} { set options "" append options " -iex \"set height 0\"" append options " -iex \"set width 0\"" + append options " -iex \"set build-id-verbose 0\"" append options " -iex \"new-ui console $extra_tty_name\"" append options " -ex \"b $bpline\"" append options " -ex \"run\"" diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -1716,6 +1716,16 @@ proc default_gdb_start { } { warning "Couldn't set the width to 0." } } + # Turn off the missing warnings as the testsuite does not expect it. + send_gdb "set build-id-verbose 0\n" + gdb_expect 10 { + -re "$gdb_prompt $" { + verbose "Disabled the missing debug infos warnings." 2 + } + timeout { + warning "Could not disable the missing debug infos warnings.." + } + } return 0 } diff --git a/gdb/testsuite/lib/mi-support.exp b/gdb/testsuite/lib/mi-support.exp --- a/gdb/testsuite/lib/mi-support.exp +++ b/gdb/testsuite/lib/mi-support.exp @@ -309,6 +309,16 @@ proc default_mi_gdb_start { args } { warning "Couldn't set the width to 0." } } + # Turn off the missing warnings as the testsuite does not expect it. + send_gdb "190-gdb-set build-id-verbose 0\n" + gdb_expect 10 { + -re ".*190-gdb-set build-id-verbose 0\r\n190\\\^done\r\n$mi_gdb_prompt$" { + verbose "Disabled the missing debug infos warnings." 2 + } + timeout { + warning "Could not disable the missing debug infos warnings.." + } + } if { $separate_inferior_pty } { mi_create_inferior_pty
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