Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
new file mode 100644
index 0000000..207a257
--- /dev/null
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -0,0 +1,939 @@
+/* Sniff out modules from ELF headers visible in memory segments.
+ Copyright (C) 2008-2012, 2014, 2015 Red Hat, Inc.
+ This file is part of elfutils.
+
+ This file is free software; you can redistribute it and/or modify
+ it under the terms of either
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at
+ your option) any later version
+
+ or
+
+ * 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
+
+ or both in parallel, as here.
+
+ 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 copies of the GNU General Public License and
+ the GNU Lesser General Public License along with this program. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include "../libelf/libelfP.h" /* For NOTE_ALIGN. */
+#undef _
+#include "libdwflP.h"
+#include "common.h"
+
+#include <elf.h>
+#include <gelf.h>
+#include <inttypes.h>
+#include <endian.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <system.h>
+
+
+/* A good size for the initial read from memory, if it's not too costly.
+ This more than covers the phdrs and note segment in the average 64-bit
+ binary. */
+
+#define INITIAL_READ 1024
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+# define MY_ELFDATA ELFDATA2LSB
+#else
+# define MY_ELFDATA ELFDATA2MSB
+#endif
+
+
+/* Return user segment index closest to ADDR but not above it.
+ If NEXT, return the closest to ADDR but not below it. */
+static int
+addr_segndx (Dwfl *dwfl, size_t segment, GElf_Addr addr, bool next)
+{
+ int ndx = -1;
+ do
+ {
+ if (dwfl->lookup_segndx[segment] >= 0)
+ ndx = dwfl->lookup_segndx[segment];
+ if (++segment >= dwfl->lookup_elts - 1)
+ return next ? ndx + 1 : ndx;
+ }
+ while (dwfl->lookup_addr[segment] < addr);
+
+ if (next)
+ {
+ while (dwfl->lookup_segndx[segment] < 0)
+ if (++segment >= dwfl->lookup_elts - 1)
+ return ndx + 1;
+ ndx = dwfl->lookup_segndx[segment];
+ }
+
+ return ndx;
+}
+
+/* Return whether there is SZ bytes available at PTR till END. */
+
+static bool
+buf_has_data (const void *ptr, const void *end, size_t sz)
+{
+ return ptr < end && (size_t) (end - ptr) >= sz;
+}
+
+/* Read SZ bytes into *RETP from *PTRP (limited by END) in format EI_DATA.
+ Function comes from src/readelf.c . */
+
+static bool
+buf_read_ulong (unsigned char ei_data, size_t sz,
+ const void **ptrp, const void *end, uint64_t *retp)
+{
+ if (! buf_has_data (*ptrp, end, sz))
+ return false;
+
+ union
+ {
+ uint64_t u64;
+ uint32_t u32;
+ } u;
+
+ memcpy (&u, *ptrp, sz);
+ (*ptrp) += sz;
+
+ if (retp == NULL)
+ return true;
+
+ if (MY_ELFDATA != ei_data)
+ {
+ if (sz == 4)
+ CONVERT (u.u32);
+ else
+ CONVERT (u.u64);
+ }
+ if (sz == 4)
+ *retp = u.u32;
+ else
+ *retp = u.u64;
+ return true;
+}
+
+/* Try to find matching entry for module from address MODULE_START to
+ MODULE_END in NT_FILE note located at NOTE_FILE of NOTE_FILE_SIZE
+ bytes in format EI_CLASS and EI_DATA. */
+
+static const char *
+handle_file_note (GElf_Addr module_start, GElf_Addr module_end,
+ unsigned char ei_class, unsigned char ei_data,
+ const void *note_file, size_t note_file_size)
+{
+ if (note_file == NULL)
+ return NULL;
+
+ size_t sz;
+ switch (ei_class)
+ {
+ case ELFCLASS32:
+ sz = 4;
+ break;
+ case ELFCLASS64:
+ sz = 8;
+ break;
+ default:
+ return NULL;
+ }
+
+ const void *ptr = note_file;
+ const void *end = note_file + note_file_size;
+ uint64_t count;
+ if (! buf_read_ulong (ei_data, sz, &ptr, end, &count))
+ return NULL;
+ if (! buf_read_ulong (ei_data, sz, &ptr, end, NULL)) // page_size
+ return NULL;
+
+ uint64_t maxcount = (size_t) (end - ptr) / (3 * sz);
+ if (count > maxcount)
+ return NULL;
+
+ /* Where file names are stored. */
+ const char *fptr = ptr + 3 * count * sz;
+
+ ssize_t firstix = -1;
+ ssize_t lastix = -1;
+ for (size_t mix = 0; mix < count; mix++)
+ {
+ uint64_t mstart, mend, moffset;
+ if (! buf_read_ulong (ei_data, sz, &ptr, fptr, &mstart)
+ || ! buf_read_ulong (ei_data, sz, &ptr, fptr, &mend)
+ || ! buf_read_ulong (ei_data, sz, &ptr, fptr, &moffset))
+ return NULL;
+ if (mstart == module_start && moffset == 0)
+ firstix = lastix = mix;
+ if (firstix != -1 && mstart < module_end)
+ lastix = mix;
+ if (mend >= module_end)
+ break;
+ }
+ if (firstix == -1)
+ return NULL;
+
+ const char *retval = NULL;
+ for (ssize_t mix = 0; mix <= lastix; mix++)
+ {
+ const char *fnext = memchr (fptr, 0, (const char *) end - fptr);
+ if (fnext == NULL)
+ return NULL;
+ if (mix == firstix)
+ retval = fptr;
+ if (firstix < mix && mix <= lastix && strcmp (fptr, retval) != 0)
+ return NULL;
+ fptr = fnext + 1;
+ }
+ return retval;
+}
+
+/* Return true iff we are certain ELF cannot match BUILD_ID of
+ BUILD_ID_LEN bytes. Pass DISK_FILE_HAS_BUILD_ID as false if it is
+ certain ELF does not contain build-id (it is only a performance hit
+ to pass it always as true). */
+
+static bool
+invalid_elf (Elf *elf, bool disk_file_has_build_id,
+ const void *build_id, size_t build_id_len)
+{
+ if (! disk_file_has_build_id && build_id_len > 0)
+ {
+ /* Module found in segments with build-id is more reliable
+ than a module found via DT_DEBUG on disk without any
+ build-id. */
+ return true;
+ }
+ if (disk_file_has_build_id && build_id_len > 0)
+ {
+ const void *elf_build_id;
+ ssize_t elf_build_id_len;
+
+ /* If there is a build id in the elf file, check it. */
+ elf_build_id_len = INTUSE(dwelf_elf_gnu_build_id) (elf, &elf_build_id);
+ if (elf_build_id_len > 0)
+ {
+ if (build_id_len != (size_t) elf_build_id_len
+ || memcmp (build_id, elf_build_id, build_id_len) != 0)
+ return true;
+ }
+ }
+ return false;
+}
+
+int
+dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
+ Dwfl_Memory_Callback *memory_callback,
+ void *memory_callback_arg,
+ Dwfl_Module_Callback *read_eagerly,
+ void *read_eagerly_arg,
+ const void *note_file, size_t note_file_size,
+ const struct r_debug_info *r_debug_info)
+{
+ size_t segment = ndx;
+
+ if (segment >= dwfl->lookup_elts)
+ segment = dwfl->lookup_elts - 1;
+
+ while (segment > 0
+ && (dwfl->lookup_segndx[segment] > ndx
+ || dwfl->lookup_segndx[segment] == -1))
+ --segment;
+
+ while (dwfl->lookup_segndx[segment] < ndx)
+ if (++segment == dwfl->lookup_elts)
+ return 0;
+
+ GElf_Addr start = dwfl->lookup_addr[segment];
+
+ inline bool segment_read (int segndx,
+ void **buffer, size_t *buffer_available,
+ GElf_Addr addr, size_t minread)
+ {
+ return ! (*memory_callback) (dwfl, segndx, buffer, buffer_available,
+ addr, minread, memory_callback_arg);
+ }
+
+ inline void release_buffer (void **buffer, size_t *buffer_available)
+ {
+ if (*buffer != NULL)
+ (void) segment_read (-1, buffer, buffer_available, 0, 0);
+ }
+
+ /* First read in the file header and check its sanity. */
+
+ void *buffer = NULL;
+ size_t buffer_available = INITIAL_READ;
+ Elf *elf = NULL;
+ int fd = -1;
+
+ /* We might have to reserve some memory for the phdrs. Set to NULL
+ here so we can always safely free it. */
+ void *phdrsp = NULL;
+
+ inline int finish (void)
+ {
+ free (phdrsp);
+ release_buffer (&buffer, &buffer_available);
+ if (elf != NULL)
+ elf_end (elf);
+ if (fd != -1)
+ close (fd);
+ return ndx;
+ }
+
+ if (segment_read (ndx, &buffer, &buffer_available,
+ start, sizeof (Elf64_Ehdr))
+ || memcmp (buffer, ELFMAG, SELFMAG) != 0)
+ return finish ();
+
+ inline bool read_portion (void **data, size_t *data_size,
+ GElf_Addr vaddr, size_t filesz)
+ {
+ if (vaddr - start + filesz > buffer_available
+ /* If we're in string mode, then don't consider the buffer we have
+ sufficient unless it contains the terminator of the string. */
+ || (filesz == 0 && memchr (vaddr - start + buffer, '\0',
+ buffer_available - (vaddr - start)) == NULL))
+ {
+ *data = NULL;
+ *data_size = filesz;
+ return segment_read (addr_segndx (dwfl, segment, vaddr, false),
+ data, data_size, vaddr, filesz);
+ }
+
+ /* We already have this whole note segment from our initial read. */
+ *data = vaddr - start + buffer;
+ *data_size = 0;
+ return false;
+ }
+
+ inline void finish_portion (void **data, size_t *data_size)
+ {
+ if (*data_size != 0)
+ release_buffer (data, data_size);
+ }
+
+ /* Extract the information we need from the file header. */
+ const unsigned char *e_ident;
+ unsigned char ei_class;
+ unsigned char ei_data;
+ uint16_t e_type;
+ union
+ {
+ Elf32_Ehdr e32;
+ Elf64_Ehdr e64;
+ } ehdr;
+ GElf_Off phoff;
+ uint_fast16_t phnum;
+ uint_fast16_t phentsize;
+ GElf_Off shdrs_end;
+ Elf_Data xlatefrom =
+ {
+ .d_type = ELF_T_EHDR,
+ .d_buf = (void *) buffer,
+ .d_version = EV_CURRENT,
+ };
+ Elf_Data xlateto =
+ {
+ .d_type = ELF_T_EHDR,
+ .d_buf = &ehdr,
+ .d_size = sizeof ehdr,
+ .d_version = EV_CURRENT,
+ };
+ e_ident = ((const unsigned char *) buffer);
+ ei_class = e_ident[EI_CLASS];
+ ei_data = e_ident[EI_DATA];
+ switch (ei_class)
+ {
+ case ELFCLASS32:
+ xlatefrom.d_size = sizeof (Elf32_Ehdr);
+ if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
+ return finish ();
+ e_type = ehdr.e32.e_type;
+ phoff = ehdr.e32.e_phoff;
+ phnum = ehdr.e32.e_phnum;
+ phentsize = ehdr.e32.e_phentsize;
+ if (phentsize != sizeof (Elf32_Phdr))
+ return finish ();
+ shdrs_end = ehdr.e32.e_shoff + ehdr.e32.e_shnum * ehdr.e32.e_shentsize;
+ break;
+
+ case ELFCLASS64:
+ xlatefrom.d_size = sizeof (Elf64_Ehdr);
+ if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
+ return finish ();
+ e_type = ehdr.e64.e_type;
+ phoff = ehdr.e64.e_phoff;
+ phnum = ehdr.e64.e_phnum;
+ phentsize = ehdr.e64.e_phentsize;
+ if (phentsize != sizeof (Elf64_Phdr))
+ return finish ();
+ shdrs_end = ehdr.e64.e_shoff + ehdr.e64.e_shnum * ehdr.e64.e_shentsize;
+ break;
+
+ default:
+ return finish ();
+ }
+
+ /* The file header tells where to find the program headers.
+ These are what we need to find the boundaries of the module.
+ Without them, we don't have a module to report. */
+
+ if (phnum == 0)
+ return finish ();
+
+ xlatefrom.d_type = xlateto.d_type = ELF_T_PHDR;
+ xlatefrom.d_size = phnum * phentsize;
+
+ void *ph_buffer = NULL;
+ size_t ph_buffer_size = 0;
+ if (read_portion (&ph_buffer, &ph_buffer_size,
+ start + phoff, xlatefrom.d_size))
+ return finish ();
+
+ xlatefrom.d_buf = ph_buffer;
+
+ bool class32 = ei_class == ELFCLASS32;
+ size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
+ if (unlikely (phnum > SIZE_MAX / phdr_size))
+ return finish ();
+ const size_t phdrsp_bytes = phnum * phdr_size;
+ phdrsp = malloc (phdrsp_bytes);
+ if (unlikely (phdrsp == NULL))
+ return finish ();
+
+ xlateto.d_buf = phdrsp;
+ xlateto.d_size = phdrsp_bytes;
+
+ /* Track the bounds of the file visible in memory. */
+ GElf_Off file_trimmed_end = 0; /* Proper p_vaddr + p_filesz end. */
+ GElf_Off file_end = 0; /* Rounded up to effective page size. */
+ GElf_Off contiguous = 0; /* Visible as contiguous file from START. */
+ GElf_Off total_filesz = 0; /* Total size of data to read. */
+
+ /* Collect the bias between START and the containing PT_LOAD's p_vaddr. */
+ GElf_Addr bias = 0;
+ bool found_bias = false;
+
+ /* Collect the unbiased bounds of the module here. */
+ GElf_Addr module_start = -1l;
+ GElf_Addr module_end = 0;
+ GElf_Addr module_address_sync = 0;
+
+ /* If we see PT_DYNAMIC, record it here. */
+ GElf_Addr dyn_vaddr = 0;
+ GElf_Xword dyn_filesz = 0;
+
+ /* Collect the build ID bits here. */
+ void *build_id = NULL;
+ size_t build_id_len = 0;
+ GElf_Addr build_id_vaddr = 0;
+
+ /* Consider a PT_NOTE we've found in the image. */
+ inline void consider_notes (GElf_Addr vaddr, GElf_Xword filesz)
+ {
+ /* If we have already seen a build ID, we don't care any more. */
+ if (build_id != NULL || filesz == 0)
+ return;
+
+ void *data;
+ size_t data_size;
+ if (read_portion (&data, &data_size, vaddr, filesz))
+ return;
+
+ assert (sizeof (Elf32_Nhdr) == sizeof (Elf64_Nhdr));
+
+ void *notes;
+ if (ei_data == MY_ELFDATA)
+ notes = data;
+ else
+ {
+ notes = malloc (filesz);
+ if (unlikely (notes == NULL))
+ return;
+ xlatefrom.d_type = xlateto.d_type = ELF_T_NHDR;
+ xlatefrom.d_buf = (void *) data;
+ xlatefrom.d_size = filesz;
+ xlateto.d_buf = notes;
+ xlateto.d_size = filesz;
+ if (elf32_xlatetom (&xlateto, &xlatefrom,
+ ehdr.e32.e_ident[EI_DATA]) == NULL)
+ goto done;
+ }
+
+ const GElf_Nhdr *nh = notes;
+ while ((const void *) nh < (const void *) notes + filesz)
+ {
+ const void *note_name = nh + 1;
+ const void *note_desc = note_name + NOTE_ALIGN (nh->n_namesz);
+ if (unlikely ((size_t) ((const void *) notes + filesz
+ - note_desc) < nh->n_descsz))
+ break;
+
+ if (nh->n_type == NT_GNU_BUILD_ID
+ && nh->n_descsz > 0
+ && nh->n_namesz == sizeof "GNU"
+ && !memcmp (note_name, "GNU", sizeof "GNU"))
+ {
+ build_id_vaddr = note_desc - (const void *) notes + vaddr;
+ build_id_len = nh->n_descsz;
+ build_id = malloc (nh->n_descsz);
+ if (likely (build_id != NULL))
+ memcpy (build_id, note_desc, build_id_len);
+ break;
+ }
+
+ nh = note_desc + NOTE_ALIGN (nh->n_descsz);
+ }
+
+ done:
+ if (notes != data)
+ free (notes);
+ finish_portion (&data, &data_size);
+ }
+
+ /* Consider each of the program headers we've read from the image. */
+ inline void consider_phdr (GElf_Word type,
+ GElf_Addr vaddr, GElf_Xword memsz,
+ GElf_Off offset, GElf_Xword filesz,
+ GElf_Xword align)
+ {
+ switch (type)
+ {
+ case PT_DYNAMIC:
+ dyn_vaddr = vaddr;
+ dyn_filesz = filesz;
+ break;
+
+ case PT_NOTE:
+ /* We calculate from the p_offset of the note segment,
+ because we don't yet know the bias for its p_vaddr. */
+ consider_notes (start + offset, filesz);
+ break;
+
+ case PT_LOAD:
+ align = dwfl->segment_align > 1 ? dwfl->segment_align : align ?: 1;
+
+ GElf_Addr vaddr_end = (vaddr + memsz + align - 1) & -align;
+ GElf_Addr filesz_vaddr = filesz < memsz ? vaddr + filesz : vaddr_end;
+ GElf_Off filesz_offset = filesz_vaddr - vaddr + offset;
+
+ if (file_trimmed_end < offset + filesz)
+ {
+ file_trimmed_end = offset + filesz;
+
+ /* Trim the last segment so we don't bother with zeros
+ in the last page that are off the end of the file.
+ However, if the extra bit in that page includes the
+ section headers, keep them. */
+ if (shdrs_end <= filesz_offset && shdrs_end > file_trimmed_end)
+ {
+ filesz += shdrs_end - file_trimmed_end;
+ file_trimmed_end = shdrs_end;
+ }
+ }
+
+ total_filesz += filesz;
+
+ if (file_end < filesz_offset)
+ {
+ file_end = filesz_offset;
+ if (filesz_vaddr - start == filesz_offset)
+ contiguous = file_end;
+ }
+
+ if (!found_bias && (offset & -align) == 0
+ && likely (filesz_offset >= phoff + phnum * phentsize))
+ {
+ bias = start - vaddr;
+ found_bias = true;
+ }
+
+ if ((vaddr & -align) < module_start)
+ {
+ module_start = vaddr & -align;
+ module_address_sync = vaddr + memsz;
+ }
+
+ if (module_end < vaddr_end)
+ module_end = vaddr_end;
+ break;
+ }
+ }
+
+ Elf32_Phdr (*p32)[phnum] = phdrsp;
+ Elf64_Phdr (*p64)[phnum] = phdrsp;
+ if (ei_class == ELFCLASS32)
+ {
+ if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
+ found_bias = false; /* Trigger error check. */
+ else
+ for (uint_fast16_t i = 0; i < phnum; ++i)
+ consider_phdr ((*p32)[i].p_type,
+ (*p32)[i].p_vaddr, (*p32)[i].p_memsz,
+ (*p32)[i].p_offset, (*p32)[i].p_filesz,
+ (*p32)[i].p_align);
+ }
+ else
+ {
+ if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
+ found_bias = false; /* Trigger error check. */
+ else
+ for (uint_fast16_t i = 0; i < phnum; ++i)
+ consider_phdr ((*p64)[i].p_type,
+ (*p64)[i].p_vaddr, (*p64)[i].p_memsz,
+ (*p64)[i].p_offset, (*p64)[i].p_filesz,
+ (*p64)[i].p_align);
+ }
+
+ finish_portion (&ph_buffer, &ph_buffer_size);
+
+ /* We must have seen the segment covering offset 0, or else the ELF
+ header we read at START was not produced by these program headers. */
+ if (unlikely (!found_bias))
+ {
+ free (build_id);
+ return finish ();
+ }
+
+ /* Now we know enough to report a module for sure: its bounds. */
+ module_start += bias;
+ module_end += bias;
+
+ dyn_vaddr += bias;
+
+ /* NAME found from link map has precedence over DT_SONAME possibly read
+ below. */
+ bool name_is_final = false;
+
+ /* Try to match up DYN_VADDR against L_LD as found in link map.
+ Segments sniffing may guess invalid address as the first read-only memory
+ mapping may not be dumped to the core file (if ELF headers are not dumped)
+ and the ELF header is dumped first with the read/write mapping of the same
+ file at higher addresses. */
+ if (r_debug_info != NULL)
+ for (const struct r_debug_info_module *module = r_debug_info->module;
+ module != NULL; module = module->next)
+ if (module_start <= module->l_ld && module->l_ld < module_end)
+ {
+ /* L_LD read from link map must be right while DYN_VADDR is unsafe.
+ Therefore subtract DYN_VADDR and add L_LD to get a possibly
+ corrective displacement for all addresses computed so far. */
+ GElf_Addr fixup = module->l_ld - dyn_vaddr;
+ if ((fixup & (dwfl->segment_align - 1)) == 0
+ && module_start + fixup <= module->l_ld
+ && module->l_ld < module_end + fixup)
+ {
+ module_start += fixup;
+ module_end += fixup;
+ dyn_vaddr += fixup;
+ bias += fixup;
+ if (module->name[0] != '\0')
+ {
+ name = basename (module->name);
+ name_is_final = true;
+ }
+ break;
+ }
+ }
+
+ if (r_debug_info != NULL)
+ {
+ bool skip_this_module = false;
+ for (struct r_debug_info_module *module = r_debug_info->module;
+ module != NULL; module = module->next)
+ if ((module_end > module->start && module_start < module->end)
+ || dyn_vaddr == module->l_ld)
+ {
+ if (module->elf != NULL
+ && invalid_elf (module->elf, module->disk_file_has_build_id,
+ build_id, build_id_len))
+ {
+ elf_end (module->elf);
+ close (module->fd);
+ module->elf = NULL;
+ module->fd = -1;
+ }
+ if (module->elf != NULL)
+ {
+ /* Ignore this found module if it would conflict in address
+ space with any already existing module of DWFL. */
+ skip_this_module = true;
+ }
+ }
+ if (skip_this_module)
+ {
+ free (build_id);
+ return finish ();
+ }
+ }
+
+ const char *file_note_name = handle_file_note (module_start, module_end,
+ ei_class, ei_data,
+ note_file, note_file_size);
+ if (file_note_name)
+ {
+ name = file_note_name;
+ name_is_final = true;
+ bool invalid = false;
+ fd = open (name, O_RDONLY);
+ if (fd >= 0)
+ {
+ Dwfl_Error error = __libdw_open_file (&fd, &elf, true, false);
+ if (error == DWFL_E_NOERROR)
+ invalid = invalid_elf (elf, true /* disk_file_has_build_id */,
+ build_id, build_id_len);
+ }
+ if (invalid)
+ {
+ /* The file was there, but the build_id didn't match. We
+ still want to report the module, but need to get the ELF
+ some other way if possible. */
+ close (fd);
+ fd = -1;
+ elf_end (elf);
+ elf = NULL;
+ }
+ }
+
+ /* Our return value now says to skip the segments contained
+ within the module. */
+ ndx = addr_segndx (dwfl, segment, module_end, true);
+
+ /* Examine its .dynamic section to get more interesting details.
+ If it has DT_SONAME, we'll use that as the module name.
+ If it has a DT_DEBUG, then it's actually a PIE rather than a DSO.
+ We need its DT_STRTAB and DT_STRSZ to decipher DT_SONAME,
+ and they also tell us the essential portion of the file
+ for fetching symbols. */
+ GElf_Addr soname_stroff = 0;
+ GElf_Addr dynstr_vaddr = 0;
+ GElf_Xword dynstrsz = 0;
+ bool execlike = false;
+ inline bool consider_dyn (GElf_Sxword tag, GElf_Xword val)
+ {
+ switch (tag)
+ {
+ default:
+ return false;
+
+ case DT_DEBUG:
+ execlike = true;
+ break;
+
+ case DT_SONAME:
+ soname_stroff = val;
+ break;
+
+ case DT_STRTAB:
+ dynstr_vaddr = val;
+ break;
+
+ case DT_STRSZ:
+ dynstrsz = val;
+ break;
+ }
+
+ return soname_stroff != 0 && dynstr_vaddr != 0 && dynstrsz != 0;
+ }
+
+ const size_t dyn_entsize = (ei_class == ELFCLASS32
+ ? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn));
+ void *dyn_data = NULL;
+ size_t dyn_data_size = 0;
+ if (dyn_filesz != 0 && dyn_filesz % dyn_entsize == 0
+ && ! read_portion (&dyn_data, &dyn_data_size, dyn_vaddr, dyn_filesz))
+ {
+ void *dyns = malloc (dyn_filesz);
+ Elf32_Dyn (*d32)[dyn_filesz / sizeof (Elf32_Dyn)] = dyns;
+ Elf64_Dyn (*d64)[dyn_filesz / sizeof (Elf64_Dyn)] = dyns;
+ if (unlikely (dyns == NULL))
+ return finish ();
+
+ xlatefrom.d_type = xlateto.d_type = ELF_T_DYN;
+ xlatefrom.d_buf = (void *) dyn_data;
+ xlatefrom.d_size = dyn_filesz;
+ xlateto.d_buf = dyns;
+ xlateto.d_size = dyn_filesz;
+
+ if (ei_class == ELFCLASS32)
+ {
+ if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
+ for (size_t i = 0; i < dyn_filesz / sizeof (Elf32_Dyn); ++i)
+ if (consider_dyn ((*d32)[i].d_tag, (*d32)[i].d_un.d_val))
+ break;
+ }
+ else
+ {
+ if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
+ for (size_t i = 0; i < dyn_filesz / sizeof (Elf64_Dyn); ++i)
+ if (consider_dyn ((*d64)[i].d_tag, (*d64)[i].d_un.d_val))
+ break;
+ }
+ free (dyns);
+ }
+ finish_portion (&dyn_data, &dyn_data_size);
+
+ /* We'll use the name passed in or a stupid default if not DT_SONAME. */
+ if (name == NULL)
+ name = e_type == ET_EXEC ? "[exe]" : execlike ? "[pie]" : "[dso]";
+
+ void *soname = NULL;
+ size_t soname_size = 0;
+ if (! name_is_final && dynstrsz != 0 && dynstr_vaddr != 0)
+ {
+ /* We know the bounds of the .dynstr section.
+
+ The DYNSTR_VADDR pointer comes from the .dynamic section
+ (DT_STRTAB, detected above). Ordinarily the dynamic linker
+ will have adjusted this pointer in place so it's now an
+ absolute address. But sometimes .dynamic is read-only (in
+ vDSOs and odd architectures), and sometimes the adjustment
+ just hasn't happened yet in the memory image we looked at.
+ So treat DYNSTR_VADDR as an absolute address if it falls
+ within the module bounds, or try applying the phdr bias
+ when that adjusts it to fall within the module bounds. */
+
+ if ((dynstr_vaddr < module_start || dynstr_vaddr >= module_end)
+ && dynstr_vaddr + bias >= module_start
+ && dynstr_vaddr + bias < module_end)
+ dynstr_vaddr += bias;
+
+ if (unlikely (dynstr_vaddr + dynstrsz > module_end))
+ dynstrsz = 0;
+
+ /* Try to get the DT_SONAME string. */
+ if (soname_stroff != 0 && soname_stroff + 1 < dynstrsz
+ && ! read_portion (&soname, &soname_size,
+ dynstr_vaddr + soname_stroff, 0))
+ name = soname;
+ }
+
+ /* Now that we have chosen the module's name and bounds, report it.
+ If we found a build ID, report that too. */
+
+ Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, name,
+ module_start, module_end);
+
+ // !execlike && ET_EXEC is PIE.
+ // execlike && !ET_EXEC is a static executable.
+ if (mod != NULL && (execlike || ehdr.e32.e_type == ET_EXEC))
+ mod->is_executable = true;
+
+ if (likely (mod != NULL) && build_id != NULL
+ && unlikely (INTUSE(dwfl_module_report_build_id) (mod,
+ build_id,
+ build_id_len,
+ build_id_vaddr)))
+ {
+ mod->gc = true;
+ mod = NULL;
+ }
+
+ /* At this point we do not need BUILD_ID or NAME any more.
+ They have been copied. */
+ free (build_id);
+ finish_portion (&soname, &soname_size);
+
+ if (unlikely (mod == NULL))
+ {
+ ndx = -1;
+ return finish ();
+ }
+
+ /* We have reported the module. Now let the caller decide whether we
+ should read the whole thing in right now. */
+
+ const GElf_Off cost = (contiguous < file_trimmed_end ? total_filesz
+ : buffer_available >= contiguous ? 0
+ : contiguous - buffer_available);
+ const GElf_Off worthwhile = ((dynstr_vaddr == 0 || dynstrsz == 0) ? 0
+ : dynstr_vaddr + dynstrsz - start);
+ const GElf_Off whole = MAX (file_trimmed_end, shdrs_end);
+
+ if (elf == NULL
+ && (*read_eagerly) (MODCB_ARGS (mod), &buffer, &buffer_available,
+ cost, worthwhile, whole, contiguous,
+ read_eagerly_arg, &elf)
+ && elf == NULL)
+ {
+ /* The caller wants to read the whole file in right now, but hasn't
+ done it for us. Fill in a local image of the virtual file. */
+
+ void *contents = calloc (1, file_trimmed_end);
+ if (unlikely (contents == NULL))
+ return finish ();
+
+ inline void final_read (size_t offset, GElf_Addr vaddr, size_t size)
+ {
+ void *into = contents + offset;
+ size_t read_size = size;
+ (void) segment_read (addr_segndx (dwfl, segment, vaddr, false),
+ &into, &read_size, vaddr, size);
+ }
+
+ if (contiguous < file_trimmed_end)
+ {
+ /* We can't use the memory image verbatim as the file image.
+ So we'll be reading into a local image of the virtual file. */
+
+ inline void read_phdr (GElf_Word type, GElf_Addr vaddr,
+ GElf_Off offset, GElf_Xword filesz)
+ {
+ if (type == PT_LOAD)
+ final_read (offset, vaddr + bias, filesz);
+ }
+
+ if (ei_class == ELFCLASS32)
+ for (uint_fast16_t i = 0; i < phnum; ++i)
+ read_phdr ((*p32)[i].p_type, (*p32)[i].p_vaddr,
+ (*p32)[i].p_offset, (*p32)[i].p_filesz);
+ else
+ for (uint_fast16_t i = 0; i < phnum; ++i)
+ read_phdr ((*p64)[i].p_type, (*p64)[i].p_vaddr,
+ (*p64)[i].p_offset, (*p64)[i].p_filesz);
+ }
+ else
+ {
+ /* The whole file sits contiguous in memory,
+ but the caller didn't want to just do it. */
+
+ const size_t have = MIN (buffer_available, file_trimmed_end);
+ memcpy (contents, buffer, have);
+
+ if (have < file_trimmed_end)
+ final_read (have, start + have, file_trimmed_end - have);
+ }
+
+ elf = elf_memory (contents, file_trimmed_end);
+ if (unlikely (elf == NULL))
+ free (contents);
+ else
+ elf->flags |= ELF_F_MALLOCED;
+ }
+
+ if (elf != NULL)
+ {
+ /* Install the file in the module. */
+ mod->main.elf = elf;
+ elf = NULL;
+ fd = -1;
+ mod->main.vaddr = module_start - bias;
+ mod->main.address_sync = module_address_sync;
+ mod->main_bias = bias;
+ }
+
+ return finish ();
+}