From 41f677100e15f315f638774fbd055e497fc90069 Mon Sep 17 00:00:00 2001 From: Elliott Hughes Date: Sun, 15 Feb 2015 12:34:33 -0800 Subject: Export elfutils headers and lose the version number from the path. Having the version number in the path just means that diffs for updates are completely unusable. perf refers to libdw.h, libdwfl.h, and version.h as and so on, so we do still need to do some manual work there, but let's use symlinks rather than duplicating the header files. Change-Id: I9fd3c5f5024bde12747fdb1c06d21cdcb3418f03 --- src/libdwfl/core-file.c | 484 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 484 insertions(+) create mode 100644 src/libdwfl/core-file.c (limited to 'src/libdwfl/core-file.c') diff --git a/src/libdwfl/core-file.c b/src/libdwfl/core-file.c new file mode 100644 index 00000000..1b556dde --- /dev/null +++ b/src/libdwfl/core-file.c @@ -0,0 +1,484 @@ +/* Core file handling. + Copyright (C) 2008-2010 Red Hat, Inc. + This file is part of Red Hat elfutils. + + Red Hat elfutils is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by the + Free Software Foundation; version 2 of the License. + + Red Hat elfutils is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License along + with Red Hat elfutils; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. + + In addition, as a special exception, Red Hat, Inc. gives You the + additional right to link the code of Red Hat elfutils with code licensed + under any Open Source Initiative certified open source license + (http://www.opensource.org/licenses/index.php) which requires the + distribution of source code with any binary distribution and to + distribute linked combinations of the two. Non-GPL Code permitted under + this exception must only link to the code of Red Hat elfutils through + those well defined interfaces identified in the file named EXCEPTION + found in the source code files (the "Approved Interfaces"). The files + of Non-GPL Code may instantiate templates or use macros or inline + functions from the Approved Interfaces without causing the resulting + work to be covered by the GNU General Public License. Only Red Hat, + Inc. may make changes or additions to the list of Approved Interfaces. + Red Hat's grant of this exception is conditioned upon your not adding + any new exceptions. If you wish to add a new Approved Interface or + exception, please contact Red Hat. You must obey the GNU General Public + License in all respects for all of the Red Hat elfutils code and other + code used in conjunction with Red Hat elfutils except the Non-GPL Code + covered by this exception. If you modify this file, you may extend this + exception to your version of the file, but you are not obligated to do + so. If you do not wish to provide this exception without modification, + you must delete this exception statement from your version and license + this file solely under the GPL without exception. + + Red Hat elfutils is an included package of the Open Invention Network. + An included package of the Open Invention Network is a package for which + Open Invention Network licensees cross-license their patents. No patent + license is granted, either expressly or impliedly, by designation as an + included package. Should you wish to participate in the Open Invention + Network licensing program, please visit www.openinventionnetwork.com + . */ + +#include +#include "../libelf/libelfP.h" /* For NOTE_ALIGN. */ +#undef _ +#include "libdwflP.h" +#include + +#include +#include +#include +#include +#include "system.h" + + +/* This is a prototype of what a new libelf interface might be. + This implementation is pessimal for non-mmap cases and should + be replaced by more diddling inside libelf internals. */ +static Elf * +elf_begin_rand (Elf *parent, loff_t offset, loff_t size, loff_t *next) +{ + if (parent == NULL) + return NULL; + + /* On failure return, we update *NEXT to point back at OFFSET. */ + inline Elf *fail (int error) + { + if (next != NULL) + *next = offset; + //__libelf_seterrno (error); + __libdwfl_seterrno (DWFL_E (LIBELF, error)); + return NULL; + } + + loff_t min = (parent->kind == ELF_K_ELF ? + (parent->class == ELFCLASS32 + ? sizeof (Elf32_Ehdr) : sizeof (Elf64_Ehdr)) + : parent->kind == ELF_K_AR ? SARMAG + : 0); + + if (unlikely (offset < min) + || unlikely (offset >= (loff_t) parent->maximum_size)) + return fail (ELF_E_RANGE); + + /* For an archive, fetch just the size field + from the archive header to override SIZE. */ + if (parent->kind == ELF_K_AR) + { + struct ar_hdr h = { .ar_size = "" }; + + if (unlikely (parent->maximum_size - offset < sizeof h)) + return fail (ELF_E_RANGE); + + if (parent->map_address != NULL) + memcpy (h.ar_size, parent->map_address + parent->start_offset + offset, + sizeof h.ar_size); + else if (unlikely (pread_retry (parent->fildes, + h.ar_size, sizeof (h.ar_size), + parent->start_offset + offset + + offsetof (struct ar_hdr, ar_size)) + != sizeof (h.ar_size))) + return fail (ELF_E_READ_ERROR); + + offset += sizeof h; + + char *endp; + size = strtoll (h.ar_size, &endp, 10); + if (unlikely (endp == h.ar_size) + || unlikely ((loff_t) parent->maximum_size - offset < size)) + return fail (ELF_E_INVALID_ARCHIVE); + } + + if (unlikely ((loff_t) parent->maximum_size - offset < size)) + return fail (ELF_E_RANGE); + + /* Even if we fail at this point, update *NEXT to point past the file. */ + if (next != NULL) + *next = offset + size; + + if (unlikely (offset == 0) + && unlikely (size == (loff_t) parent->maximum_size)) + return elf_clone (parent, parent->cmd); + + /* Note the image is guaranteed live only as long as PARENT + lives. Using elf_memory is quite suboptimal if the whole + file is not mmap'd. We really should have something like + a generalization of the archive support. */ + Elf_Data *data = elf_getdata_rawchunk (parent, offset, size, ELF_T_BYTE); + if (data == NULL) + return NULL; + assert ((loff_t) data->d_size == size); + return elf_memory (data->d_buf, size); +} + + +int +dwfl_report_core_segments (Dwfl *dwfl, Elf *elf, size_t phnum, GElf_Phdr *notes) +{ + if (unlikely (dwfl == NULL)) + return -1; + + int result = 0; + + if (notes != NULL) + notes->p_type = PT_NULL; + + for (size_t ndx = 0; result >= 0 && ndx < phnum; ++ndx) + { + GElf_Phdr phdr_mem; + GElf_Phdr *phdr = gelf_getphdr (elf, ndx, &phdr_mem); + if (unlikely (phdr == NULL)) + { + __libdwfl_seterrno (DWFL_E_LIBELF); + return -1; + } + switch (phdr->p_type) + { + case PT_LOAD: + result = dwfl_report_segment (dwfl, ndx, phdr, 0, NULL); + break; + + case PT_NOTE: + if (notes != NULL) + { + *notes = *phdr; + notes = NULL; + } + break; + } + } + + return result; +} + +/* Never read more than this much without mmap. */ +#define MAX_EAGER_COST 8192 + +static bool +core_file_read_eagerly (Dwfl_Module *mod, + void **userdata __attribute__ ((unused)), + const char *name __attribute__ ((unused)), + Dwarf_Addr start __attribute__ ((unused)), + void **buffer, size_t *buffer_available, + GElf_Off cost, GElf_Off worthwhile, + GElf_Off whole, + GElf_Off contiguous __attribute__ ((unused)), + void *arg, Elf **elfp) +{ + Elf *core = arg; + + if (whole <= *buffer_available) + { + /* All there ever was, we already have on hand. */ + + if (core->map_address == NULL) + { + /* We already malloc'd the buffer. */ + *elfp = elf_memory (*buffer, whole); + if (unlikely (*elfp == NULL)) + return false; + + (*elfp)->flags |= ELF_F_MALLOCED; + *buffer = NULL; + *buffer_available = 0; + return true; + } + + /* We can use the image inside the core file directly. */ + *elfp = elf_begin_rand (core, *buffer - core->map_address, whole, NULL); + *buffer = NULL; + *buffer_available = 0; + return *elfp != NULL; + } + + /* We don't have the whole file. + Figure out if this is better than nothing. */ + + if (worthwhile == 0) + /* Caller doesn't think so. */ + return false; + + /* + XXX would like to fall back to partial file via memory + when build id find_elf fails + also, link_map name may give file name from disk better than partial here + requires find_elf hook re-doing the magic to fall back if no file found + */ + + if (mod->build_id_len > 0) + /* There is a build ID that could help us find the whole file, + which might be more useful than what we have. + We'll just rely on that. */ + return false; + + if (core->map_address != NULL) + /* It's cheap to get, so get it. */ + return true; + + /* Only use it if there isn't too much to be read. */ + return cost <= MAX_EAGER_COST; +} + +bool +dwfl_elf_phdr_memory_callback (Dwfl *dwfl, int ndx, + void **buffer, size_t *buffer_available, + GElf_Addr vaddr, + size_t minread, + void *arg) +{ + Elf *elf = arg; + + if (ndx == -1) + { + /* Called for cleanup. */ + if (elf->map_address == NULL) + free (*buffer); + *buffer = NULL; + *buffer_available = 0; + return false; + } + + const GElf_Off align = dwfl->segment_align ?: 1; + GElf_Phdr phdr; + + do + if (unlikely (gelf_getphdr (elf, ndx++, &phdr) == NULL)) + return false; + while (phdr.p_type != PT_LOAD + || ((phdr.p_vaddr + phdr.p_memsz + align - 1) & -align) <= vaddr); + + GElf_Off start = vaddr - phdr.p_vaddr + phdr.p_offset; + GElf_Off end; + GElf_Addr end_vaddr; + + inline void update_end () + { + end = (phdr.p_offset + phdr.p_filesz + align - 1) & -align; + end_vaddr = (phdr.p_vaddr + phdr.p_memsz + align - 1) & -align; + } + + update_end (); + + /* Use following contiguous segments to get towards SIZE. */ + inline bool more (size_t size) + { + while (end <= start || end - start < size) + { + if (phdr.p_filesz < phdr.p_memsz) + /* This segment is truncated, so no following one helps us. */ + return false; + + if (unlikely (gelf_getphdr (elf, ndx++, &phdr) == NULL)) + return false; + + if (phdr.p_type == PT_LOAD) + { + if (phdr.p_offset > end + || phdr.p_vaddr > end_vaddr) + /* It's discontiguous! */ + return false; + + update_end (); + } + } + return true; + } + + /* We need at least this much. */ + if (! more (minread)) + return false; + + /* See how much more we can get of what the caller wants. */ + (void) more (*buffer_available); + + /* If it's already on hand anyway, use as much as there is. */ + if (elf->map_address != NULL) + (void) more (elf->maximum_size - start); + + /* Make sure we don't look past the end of the actual file, + even if the headers tell us to. */ + if (unlikely (end > elf->maximum_size)) + end = elf->maximum_size; + + /* If the file is too small, there is nothing at all to get. */ + if (unlikely (start >= end)) + return false; + + if (elf->map_address != NULL) + { + void *contents = elf->map_address + elf->start_offset + start; + size_t size = end - start; + + if (minread == 0) /* String mode. */ + { + const void *eos = memchr (contents, '\0', size); + if (unlikely (eos == NULL) || unlikely (eos == contents)) + return false; + size = eos + 1 - contents; + } + + if (*buffer == NULL) + { + *buffer = contents; + *buffer_available = size; + } + else + { + *buffer_available = MIN (size, *buffer_available); + memcpy (*buffer, contents, *buffer_available); + } + } + else + { + void *into = *buffer; + if (*buffer == NULL) + { + *buffer_available = MIN (minread ?: 512, + MAX (4096, MIN (end - start, + *buffer_available))); + into = malloc (*buffer_available); + if (unlikely (into == NULL)) + { + __libdwfl_seterrno (DWFL_E_NOMEM); + return false; + } + } + + ssize_t nread = pread_retry (elf->fildes, into, *buffer_available, start); + if (nread < (ssize_t) minread) + { + if (into != *buffer) + free (into); + if (nread < 0) + __libdwfl_seterrno (DWFL_E_ERRNO); + return false; + } + + if (minread == 0) /* String mode. */ + { + const void *eos = memchr (into, '\0', nread); + if (unlikely (eos == NULL) || unlikely (eos == into)) + { + if (*buffer == NULL) + free (into); + return false; + } + nread = eos + 1 - into; + } + + if (*buffer == NULL) + *buffer = into; + *buffer_available = nread; + } + + return true; +} + +int +dwfl_core_file_report (Dwfl *dwfl, Elf *elf) +{ + size_t phnum; + if (unlikely (elf_getphdrnum (elf, &phnum) != 0)) + { + __libdwfl_seterrno (DWFL_E_LIBELF); + return -1; + } + + /* First report each PT_LOAD segment. */ + GElf_Phdr notes_phdr; + int ndx = dwfl_report_core_segments (dwfl, elf, phnum, ¬es_phdr); + if (unlikely (ndx <= 0)) + return ndx; + + /* Now sniff segment contents for modules. */ + int sniffed = 0; + ndx = 0; + do + { + int seg = dwfl_segment_report_module (dwfl, ndx, NULL, + &dwfl_elf_phdr_memory_callback, elf, + core_file_read_eagerly, elf); + if (unlikely (seg < 0)) + return seg; + if (seg > ndx) + { + ndx = seg; + ++sniffed; + } + else + ++ndx; + } + while (ndx < (int) phnum); + + /* Next, we should follow the chain from DT_DEBUG. */ + + const void *auxv = NULL; + size_t auxv_size = 0; + if (likely (notes_phdr.p_type == PT_NOTE)) + { + /* PT_NOTE -> NT_AUXV -> AT_PHDR -> PT_DYNAMIC -> DT_DEBUG */ + + Elf_Data *notes = elf_getdata_rawchunk (elf, + notes_phdr.p_offset, + notes_phdr.p_filesz, + ELF_T_NHDR); + if (likely (notes != NULL)) + { + size_t pos = 0; + GElf_Nhdr nhdr; + size_t name_pos; + size_t desc_pos; + while ((pos = gelf_getnote (notes, pos, &nhdr, + &name_pos, &desc_pos)) > 0) + if (nhdr.n_type == NT_AUXV + && nhdr.n_namesz == sizeof "CORE" + && !memcmp (notes->d_buf + name_pos, "CORE", sizeof "CORE")) + { + auxv = notes->d_buf + desc_pos; + auxv_size = nhdr.n_descsz; + break; + } + } + } + + /* Now we have NT_AUXV contents. From here on this processing could be + used for a live process with auxv read from /proc. */ + + int listed = dwfl_link_map_report (dwfl, auxv, auxv_size, + dwfl_elf_phdr_memory_callback, elf); + + /* We return the number of modules we found if we found any. + If we found none, we return -1 instead of 0 if there was an + error rather than just nothing found. If link_map handling + failed, we still have the sniffed modules. */ + return sniffed == 0 || listed > sniffed ? listed : sniffed; +} +INTDEF (dwfl_core_file_report) -- cgit v1.2.3