From: Di Chen <dichen@redhat.com>
To: Mark Wielaard <mark@klomp.org>
Cc: elfutils-devel@sourceware.org
Subject: Re: [PATCH] PR28873 - Implement eu-readelf -D
Date: Sun, 2 Apr 2023 09:06:11 +0800 [thread overview]
Message-ID: <CAN-Pu7SRDRTCk5PdHW7nOHNc0mm+DO_9sRGnTMamF6c8QDveGw@mail.gmail.com> (raw)
In-Reply-To: <634598e6cf48b8d5a864f43ede8ec8731fc5cf51.camel@klomp.org>
[-- Attachment #1.1: Type: text/plain, Size: 27286 bytes --]
Thank you Mark.
I made the following changes:
* ChangeLog&NEWS update.
* syments initialization to 0.
* new function format update to GNU style.
* extract the shared part to a new function, reduce code redundancy.
The patch is ready for review again.
From 70ac6993744985b29935df6010e36bf9dbbd96d9 Mon Sep 17 00:00:00 2001
From: Di Chen <dichen@redhat.com>
Date: Mon, 27 Mar 2023 10:01:05 +0800
Subject: [PATCH] readelf: display dynamic symtab without section headers
This commit adds a new option "-D/--use-dynamic" to support printing the
dynamic symbol table from the PT_DYNAMIC segment. By using the
PT_DYNAMIC segment, eu-readelf can go through the contents of dynamic
section entries and the values of each tag. From that, we can get the
address and size of the dynamic symbol table, the address of the string
table, etc.
By using the new option "-D/--use-dynamic", eu-readelf can list the
symbols without section headers.
Example:
$ ./src/readelf -Ds a.out
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UNDEF
1: 0000000000000000 0 FUNC GLOBAL DEFAULT UNDEF
__libc_start_main@GLIBC_2.34 (2)
2: 0000000000000000 0 NOTYPE WEAK DEFAULT UNDEF
__gmon_start__
https://sourceware.org/bugzilla/show_bug.cgi?id=28873
Signed-off-by: Di Chen <dichen@redhat.com>
---
ChangeLog | 5 +
NEWS | 2 +
src/ChangeLog | 6 +
src/readelf.c | 531 ++++++++++++++++++++++++++++++++++++--------------
4 files changed, 393 insertions(+), 151 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 10c23002..ece07e97 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2023-03-27 Di Chen <dichen@redhat.com>
+
+ * NEWS: Support readelf -Ds for using dynamic segment to
+ print symbol table.
+
2023-03-03 Mark Wielaard <mark@klomp.org>
* NEWS: Add ELFCOMPRESS_ZSTD support for libelf and elfcompress.
diff --git a/NEWS b/NEWS
index 16e37eca..679d8bd5 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,8 @@ elfcompress: -t, --type= now support zstd if libelf has
been build with
backends: Add support for LoongArch and Synopsys ARCv2 processors.
+readelf: Support readelf -Ds, --use-dynamic --symbol.
+
Version 0.188 "no section left behind"
readelf: Add -D, --use-dynamic option.
diff --git a/src/ChangeLog b/src/ChangeLog
index c26dafdd..8aa269cd 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2023-03-27 Di Chen <dichen@redhat.com>
+
+ * readelf.c (options): Support dynamic symtab print with '-Ds'.
+ (process_symtab): New function.
+ (handle_dynamic_symtab): Likewise.
+
2023-03-03 Mark Wielaard <mark@klomp.org>
* readelf (process_elf_file): ebl_closebackend only after
diff --git a/src/readelf.c b/src/readelf.c
index 6950204e..70848c21 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -307,7 +307,21 @@ static void handle_relocs_rel (Ebl *ebl, GElf_Ehdr
*ehdr, Elf_Scn *scn,
static void handle_relocs_rela (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
GElf_Shdr *shdr);
static bool print_symtab (Ebl *ebl, int type);
-static void handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
+static bool handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
+static bool handle_dynamic_symtab (Ebl *ebl);
+static void
+process_symtab(
+ Ebl * ebl,
+ unsigned int nsyms,
+ Elf64_Word idx,
+ Elf32_Word verneed_stridx,
+ Elf32_Word verdef_stridx,
+ Elf_Data * symdata,
+ Elf_Data * versym_data,
+ Elf_Data * symstr_data,
+ Elf_Data * verneed_data,
+ Elf_Data * verdef_data,
+ Elf_Data * xndx_data);
static void print_verinfo (Ebl *ebl);
static void handle_verneed (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
static void handle_verdef (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
@@ -325,9 +339,12 @@ static void dump_archive_index (Elf *, const char *);
enum dyn_idx
{
+ i_symtab_shndx,
i_strsz,
i_verneed,
+ i_verneednum,
i_verdef,
+ i_verdefnum,
i_versym,
i_symtab,
i_strtab,
@@ -1042,7 +1059,7 @@ process_elf_file (Dwfl_Module *dwflmod, int fd)
symtab_printed |= print_symtab (ebl, SHT_DYNSYM);
if (print_version_info)
print_verinfo (ebl);
- if (print_symbol_table)
+ if (print_symbol_table && !use_dynamic_segment)
symtab_printed |= print_symtab (ebl, SHT_SYMTAB);
if ((print_symbol_table || print_dynsym_table)
@@ -2443,6 +2460,12 @@ handle_relocs_rela (Ebl *ebl, GElf_Ehdr *ehdr,
Elf_Scn *scn, GElf_Shdr *shdr)
static bool
print_symtab (Ebl *ebl, int type)
{
+ /* Use the dynamic section info to display symbol tables. */
+ if (use_dynamic_segment && type == SHT_DYNSYM)
+ {
+ return handle_dynamic_symtab(ebl);
+ }
+
/* Find the symbol table(s). For this we have to search through the
section table. */
Elf_Scn *scn = NULL;
@@ -2481,8 +2504,7 @@ print_symtab (Ebl *ebl, int type)
_("cannot get section [%zd] header: %s"),
elf_ndxscn (scn), elf_errmsg (-1));
}
- handle_symtab (ebl, scn, shdr);
- symtab_printed = true;
+ symtab_printed = handle_symtab (ebl, scn, shdr);
}
}
@@ -2491,6 +2513,179 @@ print_symtab (Ebl *ebl, int type)
static void
+process_symtab (Ebl *ebl, unsigned int nsyms, Elf64_Word idx,
+ Elf32_Word verneed_stridx, Elf32_Word verdef_stridx,
+ Elf_Data *symdata, Elf_Data *versym_data,
+ Elf_Data *symstr_data, Elf_Data *verneed_data,
+ Elf_Data *verdef_data, Elf_Data *xndx_data)
+{
+ for (unsigned int cnt = 0; cnt < nsyms; ++cnt)
+ {
+ char typebuf[64];
+ char bindbuf[64];
+ char scnbuf[64];
+ Elf32_Word xndx;
+ GElf_Sym sym_mem;
+ GElf_Sym *sym
+ = gelf_getsymshndx (symdata, xndx_data, cnt, &sym_mem, &xndx);
+
+ if (unlikely (sym == NULL))
+ continue;
+
+ /* Determine the real section index. */
+ if (likely (sym->st_shndx != SHN_XINDEX))
+ xndx = sym->st_shndx;
+
+ printf (_ ("\
+%5u: %0*" PRIx64 " %6" PRId64 " %-7s %-6s %-9s %6s %s"),
+ cnt, gelf_getclass (ebl->elf) == ELFCLASS32 ? 8 : 16,
+ sym->st_value, sym->st_size,
+ ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info),
typebuf,
+ sizeof (typebuf)),
+ ebl_symbol_binding_name (ebl, GELF_ST_BIND (sym->st_info),
+ bindbuf, sizeof (bindbuf)),
+ get_visibility_type (GELF_ST_VISIBILITY (sym->st_other)),
+ ebl_section_name (ebl, sym->st_shndx, xndx, scnbuf,
+ sizeof (scnbuf), NULL, shnum),
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf + sym->st_name
+ : elf_strptr (ebl->elf, idx, sym->st_name));
+
+ if (versym_data != NULL)
+ {
+ /* Get the version information. */
+ GElf_Versym versym_mem;
+ GElf_Versym *versym = gelf_getversym (versym_data, cnt,
&versym_mem);
+
+ if (versym != NULL && ((*versym & 0x8000) != 0 || *versym > 1))
+ {
+ bool is_nobits = false;
+ bool check_def = xndx != SHN_UNDEF;
+
+ if (xndx < SHN_LORESERVE || sym->st_shndx == SHN_XINDEX)
+ {
+ GElf_Shdr symshdr_mem;
+ GElf_Shdr *symshdr = gelf_getshdr (
+ elf_getscn (ebl->elf, xndx), &symshdr_mem);
+
+ is_nobits
+ = (symshdr != NULL && symshdr->sh_type ==
SHT_NOBITS);
+ }
+
+ if (is_nobits || !check_def)
+ {
+ /* We must test both. */
+ GElf_Vernaux vernaux_mem;
+ GElf_Vernaux *vernaux = NULL;
+ size_t vn_offset = 0;
+
+ GElf_Verneed verneed_mem;
+ GElf_Verneed *verneed
+ = gelf_getverneed (verneed_data, 0, &verneed_mem);
+ while (verneed != NULL)
+ {
+ size_t vna_offset = vn_offset;
+
+ vernaux = gelf_getvernaux (verneed_data,
+ vna_offset +=
verneed->vn_aux,
+ &vernaux_mem);
+ while (vernaux != NULL && vernaux->vna_other !=
*versym
+ && vernaux->vna_next != 0
+ && (verneed_data->d_size - vna_offset
+ >= vernaux->vna_next))
+ {
+ /* Update the offset. */
+ vna_offset += vernaux->vna_next;
+
+ vernaux = (vernaux->vna_next == 0
+ ? NULL
+ : gelf_getvernaux (verneed_data,
+ vna_offset,
+ &vernaux_mem));
+ }
+
+ /* Check whether we found the version. */
+ if (vernaux != NULL && vernaux->vna_other == *versym)
+ /* Found it. */
+ break;
+
+ if (verneed_data->d_size - vn_offset <
verneed->vn_next)
+ break;
+
+ vn_offset += verneed->vn_next;
+ verneed
+ = (verneed->vn_next == 0
+ ? NULL
+ : gelf_getverneed (verneed_data,
vn_offset,
+ &verneed_mem));
+ }
+
+ if (vernaux != NULL && vernaux->vna_other == *versym)
+ {
+ printf ("@%s (%u)",
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf
+ + vernaux->vna_name
+ : elf_strptr (ebl->elf, verneed_stridx,
+ vernaux->vna_name),
+ (unsigned int)vernaux->vna_other);
+ check_def = 0;
+ }
+ else if (unlikely (!is_nobits))
+ error (0, 0, _ ("bad dynamic symbol"));
+ else
+ check_def = 1;
+ }
+
+ if (check_def && *versym != 0x8001)
+ {
+ /* We must test both. */
+ size_t vd_offset = 0;
+
+ GElf_Verdef verdef_mem;
+ GElf_Verdef *verdef
+ = gelf_getverdef (verdef_data, 0, &verdef_mem);
+ while (verdef != NULL)
+ {
+ if (verdef->vd_ndx == (*versym & 0x7fff))
+ /* Found the definition. */
+ break;
+
+ if (verdef_data->d_size - vd_offset <
verdef->vd_next)
+ break;
+
+ vd_offset += verdef->vd_next;
+ verdef = (verdef->vd_next == 0
+ ? NULL
+ : gelf_getverdef (verdef_data,
vd_offset,
+ &verdef_mem));
+ }
+
+ if (verdef != NULL)
+ {
+ GElf_Verdaux verdaux_mem;
+ GElf_Verdaux *verdaux = gelf_getverdaux (
+ verdef_data, vd_offset + verdef->vd_aux,
+ &verdaux_mem);
+
+ if (verdaux != NULL)
+ printf ((*versym & 0x8000) ? "@%s" : "@@%s",
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf
+ + verdaux->vda_name
+ : elf_strptr (ebl->elf, verdef_stridx,
+ verdaux->vda_name));
+ }
+ }
+ }
+ }
+
+ putchar_unlocked ('\n');
+ }
+}
+
+
+static bool
handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
{
Elf_Data *versym_data = NULL;
@@ -2504,7 +2699,7 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr
*shdr)
/* Get the data of the section. */
Elf_Data *data = elf_getdata (scn, NULL);
if (data == NULL)
- return;
+ return false;
/* Find out whether we have other sections we might need. */
Elf_Scn *runscn = NULL;
@@ -2574,163 +2769,186 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr
*shdr)
Num: Value Size Type Bind Vis Ndx Name\n"),
stdout);
- for (unsigned int cnt = 0; cnt < nsyms; ++cnt)
- {
- char typebuf[64];
- char bindbuf[64];
- char scnbuf[64];
- Elf32_Word xndx;
- GElf_Sym sym_mem;
- GElf_Sym *sym = gelf_getsymshndx (data, xndx_data, cnt, &sym_mem,
&xndx);
-
- if (unlikely (sym == NULL))
- continue;
-
- /* Determine the real section index. */
- if (likely (sym->st_shndx != SHN_XINDEX))
- xndx = sym->st_shndx;
-
- printf (_("\
-%5u: %0*" PRIx64 " %6" PRId64 " %-7s %-6s %-9s %6s %s"),
- cnt,
- class == ELFCLASS32 ? 8 : 16,
- sym->st_value,
- sym->st_size,
- ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info),
- typebuf, sizeof (typebuf)),
- ebl_symbol_binding_name (ebl, GELF_ST_BIND (sym->st_info),
- bindbuf, sizeof (bindbuf)),
- get_visibility_type (GELF_ST_VISIBILITY (sym->st_other)),
- ebl_section_name (ebl, sym->st_shndx, xndx, scnbuf,
- sizeof (scnbuf), NULL, shnum),
- elf_strptr (ebl->elf, shdr->sh_link, sym->st_name));
-
- if (versym_data != NULL)
- {
- /* Get the version information. */
- GElf_Versym versym_mem;
- GElf_Versym *versym = gelf_getversym (versym_data, cnt, &versym_mem);
-
- if (versym != NULL && ((*versym & 0x8000) != 0 || *versym > 1))
- {
- bool is_nobits = false;
- bool check_def = xndx != SHN_UNDEF;
-
- if (xndx < SHN_LORESERVE || sym->st_shndx == SHN_XINDEX)
- {
- GElf_Shdr symshdr_mem;
- GElf_Shdr *symshdr =
- gelf_getshdr (elf_getscn (ebl->elf, xndx), &symshdr_mem);
-
- is_nobits = (symshdr != NULL
- && symshdr->sh_type == SHT_NOBITS);
- }
+ process_symtab(ebl, nsyms, shdr->sh_link, verneed_stridx, verdef_stridx,
+ data, versym_data, NULL, verneed_data, verdef_data, xndx_data);
+ return true;
+}
- if (is_nobits || ! check_def)
- {
- /* We must test both. */
- GElf_Vernaux vernaux_mem;
- GElf_Vernaux *vernaux = NULL;
- size_t vn_offset = 0;
-
- GElf_Verneed verneed_mem;
- GElf_Verneed *verneed = gelf_getverneed (verneed_data, 0,
- &verneed_mem);
- while (verneed != NULL)
- {
- size_t vna_offset = vn_offset;
-
- vernaux = gelf_getvernaux (verneed_data,
- vna_offset += verneed->vn_aux,
- &vernaux_mem);
- while (vernaux != NULL
- && vernaux->vna_other != *versym
- && vernaux->vna_next != 0
- && (verneed_data->d_size - vna_offset
- >= vernaux->vna_next))
- {
- /* Update the offset. */
- vna_offset += vernaux->vna_next;
-
- vernaux = (vernaux->vna_next == 0
- ? NULL
- : gelf_getvernaux (verneed_data,
- vna_offset,
- &vernaux_mem));
- }
- /* Check whether we found the version. */
- if (vernaux != NULL && vernaux->vna_other == *versym)
- /* Found it. */
- break;
+static bool
+handle_dynamic_symtab (Ebl *ebl)
+{
+ GElf_Phdr *phdr = NULL;
+ /* phnum is a static variable which already fetched in function
+ * process_elf_file. */
+ for (size_t i = 0; i < phnum; ++i)
+ {
+ GElf_Phdr phdr_mem;
+ phdr = gelf_getphdr (ebl->elf, i, &phdr_mem);
+ if (phdr->p_type == PT_DYNAMIC)
+ {
+ break;
+ }
+ }
+ if (phdr == NULL)
+ return false;
- if (verneed_data->d_size - vn_offset < verneed->vn_next)
- break;
+ GElf_Addr addrs[i_max] = {
+ 0,
+ };
+ GElf_Off offs[i_max] = {
+ 0,
+ };
+ get_dynscn_addrs (ebl->elf, phdr, addrs);
+ find_offsets (ebl->elf, 0, i_max, addrs, offs);
- vn_offset += verneed->vn_next;
- verneed = (verneed->vn_next == 0
- ? NULL
- : gelf_getverneed (verneed_data, vn_offset,
- &verneed_mem));
- }
+ size_t syments = 0;
- if (vernaux != NULL && vernaux->vna_other == *versym)
- {
- printf ("@%s (%u)",
- elf_strptr (ebl->elf, verneed_stridx,
- vernaux->vna_name),
- (unsigned int) vernaux->vna_other);
- check_def = 0;
- }
- else if (unlikely (! is_nobits))
- error (0, 0, _("bad dynamic symbol"));
- else
- check_def = 1;
- }
+ GElf_Ehdr ehdr_mem;
+ GElf_Ehdr *ehdr = gelf_getehdr (ebl->elf, &ehdr_mem);
- if (check_def && *versym != 0x8001)
- {
- /* We must test both. */
- size_t vd_offset = 0;
+ if (offs[i_hash] != 0)
+ {
+ /* In the original format, .hash says the size of .dynsym. */
- GElf_Verdef verdef_mem;
- GElf_Verdef *verdef = gelf_getverdef (verdef_data, 0,
- &verdef_mem);
- while (verdef != NULL)
- {
- if (verdef->vd_ndx == (*versym & 0x7fff))
- /* Found the definition. */
- break;
+ size_t entsz = SH_ENTSIZE_HASH (ehdr);
+ Elf_Data *data
+ = elf_getdata_rawchunk (ebl->elf, offs[i_hash] + entsz, entsz,
+ (entsz == 4 ? ELF_T_WORD : ELF_T_XWORD));
+ if (data != NULL)
+ syments = (entsz == 4 ? *(const GElf_Word *)data->d_buf
+ : *(const GElf_Xword *)data->d_buf);
+ }
+ if (offs[i_gnu_hash] != 0 && syments == 0)
+ {
+ /* In the new format, we can derive it with some work. */
- if (verdef_data->d_size - vd_offset < verdef->vd_next)
- break;
+ const struct
+ {
+ Elf32_Word nbuckets;
+ Elf32_Word symndx;
+ Elf32_Word maskwords;
+ Elf32_Word shift2;
+ } * header;
+
+ Elf_Data *data = elf_getdata_rawchunk (ebl->elf, offs[i_gnu_hash],
+ sizeof *header, ELF_T_WORD);
+ if (data != NULL)
+ {
+ header = data->d_buf;
+ Elf32_Word nbuckets = header->nbuckets;
+ Elf32_Word symndx = header->symndx;
+ GElf_Off buckets_at
+ = (offs[i_gnu_hash] + sizeof *header
+ + (gelf_getclass (ebl->elf) * sizeof (Elf32_Word)
+ * header->maskwords));
+
+ // elf_getdata_rawchunk takes a size_t, make sure it
+ // doesn't overflow.
+#if SIZE_MAX <= UINT32_MAX
+ if (nbuckets > SIZE_MAX / sizeof (Elf32_Word))
+ data = NULL;
+ else
+#endif
+ data = elf_getdata_rawchunk (ebl->elf, buckets_at,
+ nbuckets * sizeof (Elf32_Word),
+ ELF_T_WORD);
+ if (data != NULL && symndx < nbuckets)
+ {
+ const Elf32_Word *const buckets = data->d_buf;
+ Elf32_Word maxndx = symndx;
+ for (Elf32_Word bucket = 0; bucket < nbuckets; ++bucket)
+ if (buckets[bucket] > maxndx)
+ maxndx = buckets[bucket];
+
+ GElf_Off hasharr_at
+ = (buckets_at + nbuckets * sizeof (Elf32_Word));
+ hasharr_at += (maxndx - symndx) * sizeof (Elf32_Word);
+ do
+ {
+ data = elf_getdata_rawchunk (
+ ebl->elf, hasharr_at, sizeof (Elf32_Word),
ELF_T_WORD);
+ if (data != NULL && (*(const Elf32_Word *)data->d_buf &
1u))
+ {
+ syments = maxndx + 1;
+ break;
+ }
+ ++maxndx;
+ hasharr_at += sizeof (Elf32_Word);
+ }
+ while (data != NULL);
+ }
+ }
+ }
+ if (offs[i_strtab] > offs[i_symtab] && syments == 0)
+ syments = ((offs[i_strtab] - offs[i_symtab])
+ / gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT));
- vd_offset += verdef->vd_next;
- verdef = (verdef->vd_next == 0
- ? NULL
- : gelf_getverdef (verdef_data, vd_offset,
- &verdef_mem));
- }
+ if (syments <= 0 || offs[i_strtab] == 0 || offs[i_symtab] == 0)
+ {
+ error_exit (0, _ ("Dynamic symbol information is not available for "
+ "displaying symbols."));
+ }
- if (verdef != NULL)
- {
- GElf_Verdaux verdaux_mem;
- GElf_Verdaux *verdaux
- = gelf_getverdaux (verdef_data,
- vd_offset + verdef->vd_aux,
- &verdaux_mem);
-
- if (verdaux != NULL)
- printf ((*versym & 0x8000) ? "@%s" : "@@%s",
- elf_strptr (ebl->elf, verdef_stridx,
- verdaux->vda_name));
- }
- }
- }
- }
+ /* All the data chunk initializaion. */
+ Elf_Data *symdata = NULL;
+ Elf_Data *symstrdata = NULL;
+ Elf_Data *versym_data = NULL;
+ Elf_Data *verdef_data = NULL;
+ Elf_Data *verneed_data = NULL;
- putchar_unlocked ('\n');
- }
+ symdata = elf_getdata_rawchunk (
+ ebl->elf, offs[i_symtab],
+ gelf_fsize (ebl->elf, ELF_T_SYM, syments, EV_CURRENT), ELF_T_SYM);
+ symstrdata = elf_getdata_rawchunk (ebl->elf, offs[i_strtab],
addrs[i_strsz],
+ ELF_T_BYTE);
+ versym_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_versym], syments * sizeof (Elf64_Half), ELF_T_HALF);
+
+ /* Get the verneed_data without vernaux. */
+ verneed_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verneed], addrs[i_verneednum] * sizeof
(Elf64_Verneed),
+ ELF_T_VNEED);
+ size_t vernauxnum = 0;
+ size_t vn_next_offset = 0;
+
+ for (size_t i = 0; i < addrs[i_verneednum]; i++)
+ {
+ GElf_Verneed *verneed
+ = (GElf_Verneed *)(verneed_data->d_buf + vn_next_offset);
+ vernauxnum += verneed->vn_cnt;
+ vn_next_offset += verneed->vn_next;
+ }
+
+ /* Update the verneed_data to include the vernaux. */
+ verneed_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verneed],
+ (addrs[i_verneednum] + vernauxnum) * sizeof (GElf_Verneed),
ELF_T_VNEED);
+
+ /* Get the verdef_data without verdaux. */
+ verdef_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verdef], addrs[i_verdefnum] * sizeof (Elf64_Verdef),
+ ELF_T_VDEF);
+ size_t verdauxnum = 0;
+ size_t vd_next_offset = 0;
+
+ for (size_t i = 0; i < addrs[i_verdefnum]; i++)
+ {
+ GElf_Verdef *verdef
+ = (GElf_Verdef *)(verdef_data->d_buf + vd_next_offset);
+ verdauxnum += verdef->vd_cnt;
+ vd_next_offset += verdef->vd_next;
+ }
+
+ /* Update the verdef_data to include the verdaux. */
+ verdef_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verdef],
+ (addrs[i_verdefnum] + verdauxnum) * sizeof (GElf_Verdef),
ELF_T_VDEF);
+
+ unsigned int nsyms = (unsigned int)syments;
+ process_symtab (ebl, nsyms, 0, 0, 0, symdata, versym_data, symstrdata,
+ verneed_data, verdef_data, NULL);
+ return true;
}
@@ -4990,13 +5208,24 @@ get_dynscn_addrs(Elf *elf, GElf_Phdr *phdr,
GElf_Addr addrs[i_max])
addrs[i_verdef] = dyn->d_un.d_ptr;
break;
+ case DT_VERDEFNUM:
+ addrs[i_verdefnum] = dyn->d_un.d_val;
+ break;
+
case DT_VERNEED:
addrs[i_verneed] = dyn->d_un.d_ptr;
break;
+ case DT_VERNEEDNUM:
+ addrs[i_verneednum] = dyn->d_un.d_val;
+ break;
+
case DT_STRSZ:
addrs[i_strsz] = dyn->d_un.d_val;
break;
+ case DT_SYMTAB_SHNDX:
+ addrs[i_symtab_shndx] = dyn->d_un.d_ptr;
+ break;
}
}
}
--
2.39.2
On Fri, Feb 17, 2023 at 12:12 AM Mark Wielaard <mark@klomp.org> wrote:
> Hi,
>
> On Sat, 2023-02-11 at 00:17 +0800, Di Chen via Elfutils-devel wrote:
> > From bdc19de94bff8f8812611b9ba8c0116a650d0fb5 Mon Sep 17 00:00:00 2001
> > From: Di Chen <dichen@redhat.com>
> > Date: Fri, 13 Jan 2023 20:12:43 +0800
> > Subject: [PATCH] readelf: display dynamic symtab without section headers
> >
> > This commit adds a new option "-D/--use-dynamic" to support printing the
> > dynamic symbol table from the PT_DYNAMIC segment. By using the
> > PT_DYNAMIC segment, eu-readelf can go through the contents of dynamic
> > section entries and the values of each tag. From that, we can get the
> > address and size of the dynamic symbol table, the address of the string
> > table, etc.
> >
> > By using the new option "-D/--use-dynamic", eu-readelf can list the
> > symbols without section headers.
> >
> > Example:
> > $ ./src/readelf -Ds a.out
> > 0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UNDEF
> > 1: 0000000000000000 0 FUNC GLOBAL DEFAULT UNDEF
> > __libc_start_main@GLIBC_2.34 (2)
> > 2: 0000000000000000 0 NOTYPE WEAK DEFAULT UNDEF
> > __gmon_start__
> >
> > https://sourceware.org/bugzilla/show_bug.cgi?id=28873
> >
> > Signed-off-by: Di Chen <dichen@redhat.com>
>
> Very nice.
>
> Note that my local build (gcc 12.2.1) says:
>
> In function ‘handle_dynamic_symtab’,
> inlined from ‘print_symtab’ at
> /home/mark/src/elfutils/src/readelf.c:2451:9:
> /home/mark/src/elfutils/src/readelf.c:2535:29: error: ‘syments’ may be
> used uninitialized [-Werror=maybe-uninitialized]
> 2535 | if (offs[i_gnu_hash] != 0 && syments == 0) {
> | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
> /home/mark/src/elfutils/src/readelf.c: In function ‘print_symtab’:
> /home/mark/src/elfutils/src/readelf.c:2519:10: note: ‘syments’ was
> declared here
> 2519 | size_t syments;
> | ^~~~~~~
>
> And I think it is correct. We have 3 different ways of trying to set
> syments. We should initialize syments to zero so each check knows
> whether a previous one succeeded or not.
>
> I have not been very picky about missing ChangeLog entries, but in this
> case it would really help understanding what was changed.
>
> Specifically it would be nice to note that the code in
> handle_dynamic_symtab to calculate the syments was lifted from
> libdwfl/dwfl_module_getdwarf.c.
>
> Lets keep the indentation GNU style, like in dwfl_module_getdwarf.c, I
> don't think the new indentation is helpful.
>
> Finally the actual printing of the symbols and processing the version
> information in handle_dynamic_symtab look like they were mostly copied
> from handle_symtab. Can that code be shared?
>
> Thanks,
>
> Mark
>
>
[-- Attachment #2: 0001-readelf-display-dynamic-symtab-without-section-heade.patch --]
[-- Type: text/x-patch, Size: 23763 bytes --]
From 70ac6993744985b29935df6010e36bf9dbbd96d9 Mon Sep 17 00:00:00 2001
From: Di Chen <dichen@redhat.com>
Date: Mon, 27 Mar 2023 10:01:05 +0800
Subject: [PATCH] readelf: display dynamic symtab without section headers
This commit adds a new option "-D/--use-dynamic" to support printing the
dynamic symbol table from the PT_DYNAMIC segment. By using the
PT_DYNAMIC segment, eu-readelf can go through the contents of dynamic
section entries and the values of each tag. From that, we can get the
address and size of the dynamic symbol table, the address of the string
table, etc.
By using the new option "-D/--use-dynamic", eu-readelf can list the
symbols without section headers.
Example:
$ ./src/readelf -Ds a.out
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UNDEF
1: 0000000000000000 0 FUNC GLOBAL DEFAULT UNDEF __libc_start_main@GLIBC_2.34 (2)
2: 0000000000000000 0 NOTYPE WEAK DEFAULT UNDEF __gmon_start__
https://sourceware.org/bugzilla/show_bug.cgi?id=28873
Signed-off-by: Di Chen <dichen@redhat.com>
---
ChangeLog | 5 +
NEWS | 2 +
src/ChangeLog | 6 +
src/readelf.c | 531 ++++++++++++++++++++++++++++++++++++--------------
4 files changed, 393 insertions(+), 151 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 10c23002..ece07e97 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2023-03-27 Di Chen <dichen@redhat.com>
+
+ * NEWS: Support readelf -Ds for using dynamic segment to
+ print symbol table.
+
2023-03-03 Mark Wielaard <mark@klomp.org>
* NEWS: Add ELFCOMPRESS_ZSTD support for libelf and elfcompress.
diff --git a/NEWS b/NEWS
index 16e37eca..679d8bd5 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,8 @@ elfcompress: -t, --type= now support zstd if libelf has been build with
backends: Add support for LoongArch and Synopsys ARCv2 processors.
+readelf: Support readelf -Ds, --use-dynamic --symbol.
+
Version 0.188 "no section left behind"
readelf: Add -D, --use-dynamic option.
diff --git a/src/ChangeLog b/src/ChangeLog
index c26dafdd..8aa269cd 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2023-03-27 Di Chen <dichen@redhat.com>
+
+ * readelf.c (options): Support dynamic symtab print with '-Ds'.
+ (process_symtab): New function.
+ (handle_dynamic_symtab): Likewise.
+
2023-03-03 Mark Wielaard <mark@klomp.org>
* readelf (process_elf_file): ebl_closebackend only after
diff --git a/src/readelf.c b/src/readelf.c
index 6950204e..70848c21 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -307,7 +307,21 @@ static void handle_relocs_rel (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
static void handle_relocs_rela (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn,
GElf_Shdr *shdr);
static bool print_symtab (Ebl *ebl, int type);
-static void handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
+static bool handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
+static bool handle_dynamic_symtab (Ebl *ebl);
+static void
+process_symtab(
+ Ebl * ebl,
+ unsigned int nsyms,
+ Elf64_Word idx,
+ Elf32_Word verneed_stridx,
+ Elf32_Word verdef_stridx,
+ Elf_Data * symdata,
+ Elf_Data * versym_data,
+ Elf_Data * symstr_data,
+ Elf_Data * verneed_data,
+ Elf_Data * verdef_data,
+ Elf_Data * xndx_data);
static void print_verinfo (Ebl *ebl);
static void handle_verneed (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
static void handle_verdef (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr);
@@ -325,9 +339,12 @@ static void dump_archive_index (Elf *, const char *);
enum dyn_idx
{
+ i_symtab_shndx,
i_strsz,
i_verneed,
+ i_verneednum,
i_verdef,
+ i_verdefnum,
i_versym,
i_symtab,
i_strtab,
@@ -1042,7 +1059,7 @@ process_elf_file (Dwfl_Module *dwflmod, int fd)
symtab_printed |= print_symtab (ebl, SHT_DYNSYM);
if (print_version_info)
print_verinfo (ebl);
- if (print_symbol_table)
+ if (print_symbol_table && !use_dynamic_segment)
symtab_printed |= print_symtab (ebl, SHT_SYMTAB);
if ((print_symbol_table || print_dynsym_table)
@@ -2443,6 +2460,12 @@ handle_relocs_rela (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn, GElf_Shdr *shdr)
static bool
print_symtab (Ebl *ebl, int type)
{
+ /* Use the dynamic section info to display symbol tables. */
+ if (use_dynamic_segment && type == SHT_DYNSYM)
+ {
+ return handle_dynamic_symtab(ebl);
+ }
+
/* Find the symbol table(s). For this we have to search through the
section table. */
Elf_Scn *scn = NULL;
@@ -2481,8 +2504,7 @@ print_symtab (Ebl *ebl, int type)
_("cannot get section [%zd] header: %s"),
elf_ndxscn (scn), elf_errmsg (-1));
}
- handle_symtab (ebl, scn, shdr);
- symtab_printed = true;
+ symtab_printed = handle_symtab (ebl, scn, shdr);
}
}
@@ -2491,6 +2513,179 @@ print_symtab (Ebl *ebl, int type)
static void
+process_symtab (Ebl *ebl, unsigned int nsyms, Elf64_Word idx,
+ Elf32_Word verneed_stridx, Elf32_Word verdef_stridx,
+ Elf_Data *symdata, Elf_Data *versym_data,
+ Elf_Data *symstr_data, Elf_Data *verneed_data,
+ Elf_Data *verdef_data, Elf_Data *xndx_data)
+{
+ for (unsigned int cnt = 0; cnt < nsyms; ++cnt)
+ {
+ char typebuf[64];
+ char bindbuf[64];
+ char scnbuf[64];
+ Elf32_Word xndx;
+ GElf_Sym sym_mem;
+ GElf_Sym *sym
+ = gelf_getsymshndx (symdata, xndx_data, cnt, &sym_mem, &xndx);
+
+ if (unlikely (sym == NULL))
+ continue;
+
+ /* Determine the real section index. */
+ if (likely (sym->st_shndx != SHN_XINDEX))
+ xndx = sym->st_shndx;
+
+ printf (_ ("\
+%5u: %0*" PRIx64 " %6" PRId64 " %-7s %-6s %-9s %6s %s"),
+ cnt, gelf_getclass (ebl->elf) == ELFCLASS32 ? 8 : 16,
+ sym->st_value, sym->st_size,
+ ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info), typebuf,
+ sizeof (typebuf)),
+ ebl_symbol_binding_name (ebl, GELF_ST_BIND (sym->st_info),
+ bindbuf, sizeof (bindbuf)),
+ get_visibility_type (GELF_ST_VISIBILITY (sym->st_other)),
+ ebl_section_name (ebl, sym->st_shndx, xndx, scnbuf,
+ sizeof (scnbuf), NULL, shnum),
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf + sym->st_name
+ : elf_strptr (ebl->elf, idx, sym->st_name));
+
+ if (versym_data != NULL)
+ {
+ /* Get the version information. */
+ GElf_Versym versym_mem;
+ GElf_Versym *versym = gelf_getversym (versym_data, cnt, &versym_mem);
+
+ if (versym != NULL && ((*versym & 0x8000) != 0 || *versym > 1))
+ {
+ bool is_nobits = false;
+ bool check_def = xndx != SHN_UNDEF;
+
+ if (xndx < SHN_LORESERVE || sym->st_shndx == SHN_XINDEX)
+ {
+ GElf_Shdr symshdr_mem;
+ GElf_Shdr *symshdr = gelf_getshdr (
+ elf_getscn (ebl->elf, xndx), &symshdr_mem);
+
+ is_nobits
+ = (symshdr != NULL && symshdr->sh_type == SHT_NOBITS);
+ }
+
+ if (is_nobits || !check_def)
+ {
+ /* We must test both. */
+ GElf_Vernaux vernaux_mem;
+ GElf_Vernaux *vernaux = NULL;
+ size_t vn_offset = 0;
+
+ GElf_Verneed verneed_mem;
+ GElf_Verneed *verneed
+ = gelf_getverneed (verneed_data, 0, &verneed_mem);
+ while (verneed != NULL)
+ {
+ size_t vna_offset = vn_offset;
+
+ vernaux = gelf_getvernaux (verneed_data,
+ vna_offset += verneed->vn_aux,
+ &vernaux_mem);
+ while (vernaux != NULL && vernaux->vna_other != *versym
+ && vernaux->vna_next != 0
+ && (verneed_data->d_size - vna_offset
+ >= vernaux->vna_next))
+ {
+ /* Update the offset. */
+ vna_offset += vernaux->vna_next;
+
+ vernaux = (vernaux->vna_next == 0
+ ? NULL
+ : gelf_getvernaux (verneed_data,
+ vna_offset,
+ &vernaux_mem));
+ }
+
+ /* Check whether we found the version. */
+ if (vernaux != NULL && vernaux->vna_other == *versym)
+ /* Found it. */
+ break;
+
+ if (verneed_data->d_size - vn_offset < verneed->vn_next)
+ break;
+
+ vn_offset += verneed->vn_next;
+ verneed
+ = (verneed->vn_next == 0
+ ? NULL
+ : gelf_getverneed (verneed_data, vn_offset,
+ &verneed_mem));
+ }
+
+ if (vernaux != NULL && vernaux->vna_other == *versym)
+ {
+ printf ("@%s (%u)",
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf
+ + vernaux->vna_name
+ : elf_strptr (ebl->elf, verneed_stridx,
+ vernaux->vna_name),
+ (unsigned int)vernaux->vna_other);
+ check_def = 0;
+ }
+ else if (unlikely (!is_nobits))
+ error (0, 0, _ ("bad dynamic symbol"));
+ else
+ check_def = 1;
+ }
+
+ if (check_def && *versym != 0x8001)
+ {
+ /* We must test both. */
+ size_t vd_offset = 0;
+
+ GElf_Verdef verdef_mem;
+ GElf_Verdef *verdef
+ = gelf_getverdef (verdef_data, 0, &verdef_mem);
+ while (verdef != NULL)
+ {
+ if (verdef->vd_ndx == (*versym & 0x7fff))
+ /* Found the definition. */
+ break;
+
+ if (verdef_data->d_size - vd_offset < verdef->vd_next)
+ break;
+
+ vd_offset += verdef->vd_next;
+ verdef = (verdef->vd_next == 0
+ ? NULL
+ : gelf_getverdef (verdef_data, vd_offset,
+ &verdef_mem));
+ }
+
+ if (verdef != NULL)
+ {
+ GElf_Verdaux verdaux_mem;
+ GElf_Verdaux *verdaux = gelf_getverdaux (
+ verdef_data, vd_offset + verdef->vd_aux,
+ &verdaux_mem);
+
+ if (verdaux != NULL)
+ printf ((*versym & 0x8000) ? "@%s" : "@@%s",
+ use_dynamic_segment == true
+ ? (char *)symstr_data->d_buf
+ + verdaux->vda_name
+ : elf_strptr (ebl->elf, verdef_stridx,
+ verdaux->vda_name));
+ }
+ }
+ }
+ }
+
+ putchar_unlocked ('\n');
+ }
+}
+
+
+static bool
handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
{
Elf_Data *versym_data = NULL;
@@ -2504,7 +2699,7 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
/* Get the data of the section. */
Elf_Data *data = elf_getdata (scn, NULL);
if (data == NULL)
- return;
+ return false;
/* Find out whether we have other sections we might need. */
Elf_Scn *runscn = NULL;
@@ -2574,163 +2769,186 @@ handle_symtab (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
Num: Value Size Type Bind Vis Ndx Name\n"),
stdout);
- for (unsigned int cnt = 0; cnt < nsyms; ++cnt)
- {
- char typebuf[64];
- char bindbuf[64];
- char scnbuf[64];
- Elf32_Word xndx;
- GElf_Sym sym_mem;
- GElf_Sym *sym = gelf_getsymshndx (data, xndx_data, cnt, &sym_mem, &xndx);
-
- if (unlikely (sym == NULL))
- continue;
-
- /* Determine the real section index. */
- if (likely (sym->st_shndx != SHN_XINDEX))
- xndx = sym->st_shndx;
-
- printf (_("\
-%5u: %0*" PRIx64 " %6" PRId64 " %-7s %-6s %-9s %6s %s"),
- cnt,
- class == ELFCLASS32 ? 8 : 16,
- sym->st_value,
- sym->st_size,
- ebl_symbol_type_name (ebl, GELF_ST_TYPE (sym->st_info),
- typebuf, sizeof (typebuf)),
- ebl_symbol_binding_name (ebl, GELF_ST_BIND (sym->st_info),
- bindbuf, sizeof (bindbuf)),
- get_visibility_type (GELF_ST_VISIBILITY (sym->st_other)),
- ebl_section_name (ebl, sym->st_shndx, xndx, scnbuf,
- sizeof (scnbuf), NULL, shnum),
- elf_strptr (ebl->elf, shdr->sh_link, sym->st_name));
-
- if (versym_data != NULL)
- {
- /* Get the version information. */
- GElf_Versym versym_mem;
- GElf_Versym *versym = gelf_getversym (versym_data, cnt, &versym_mem);
-
- if (versym != NULL && ((*versym & 0x8000) != 0 || *versym > 1))
- {
- bool is_nobits = false;
- bool check_def = xndx != SHN_UNDEF;
-
- if (xndx < SHN_LORESERVE || sym->st_shndx == SHN_XINDEX)
- {
- GElf_Shdr symshdr_mem;
- GElf_Shdr *symshdr =
- gelf_getshdr (elf_getscn (ebl->elf, xndx), &symshdr_mem);
-
- is_nobits = (symshdr != NULL
- && symshdr->sh_type == SHT_NOBITS);
- }
+ process_symtab(ebl, nsyms, shdr->sh_link, verneed_stridx, verdef_stridx,
+ data, versym_data, NULL, verneed_data, verdef_data, xndx_data);
+ return true;
+}
- if (is_nobits || ! check_def)
- {
- /* We must test both. */
- GElf_Vernaux vernaux_mem;
- GElf_Vernaux *vernaux = NULL;
- size_t vn_offset = 0;
-
- GElf_Verneed verneed_mem;
- GElf_Verneed *verneed = gelf_getverneed (verneed_data, 0,
- &verneed_mem);
- while (verneed != NULL)
- {
- size_t vna_offset = vn_offset;
-
- vernaux = gelf_getvernaux (verneed_data,
- vna_offset += verneed->vn_aux,
- &vernaux_mem);
- while (vernaux != NULL
- && vernaux->vna_other != *versym
- && vernaux->vna_next != 0
- && (verneed_data->d_size - vna_offset
- >= vernaux->vna_next))
- {
- /* Update the offset. */
- vna_offset += vernaux->vna_next;
-
- vernaux = (vernaux->vna_next == 0
- ? NULL
- : gelf_getvernaux (verneed_data,
- vna_offset,
- &vernaux_mem));
- }
- /* Check whether we found the version. */
- if (vernaux != NULL && vernaux->vna_other == *versym)
- /* Found it. */
- break;
+static bool
+handle_dynamic_symtab (Ebl *ebl)
+{
+ GElf_Phdr *phdr = NULL;
+ /* phnum is a static variable which already fetched in function
+ * process_elf_file. */
+ for (size_t i = 0; i < phnum; ++i)
+ {
+ GElf_Phdr phdr_mem;
+ phdr = gelf_getphdr (ebl->elf, i, &phdr_mem);
+ if (phdr->p_type == PT_DYNAMIC)
+ {
+ break;
+ }
+ }
+ if (phdr == NULL)
+ return false;
- if (verneed_data->d_size - vn_offset < verneed->vn_next)
- break;
+ GElf_Addr addrs[i_max] = {
+ 0,
+ };
+ GElf_Off offs[i_max] = {
+ 0,
+ };
+ get_dynscn_addrs (ebl->elf, phdr, addrs);
+ find_offsets (ebl->elf, 0, i_max, addrs, offs);
- vn_offset += verneed->vn_next;
- verneed = (verneed->vn_next == 0
- ? NULL
- : gelf_getverneed (verneed_data, vn_offset,
- &verneed_mem));
- }
+ size_t syments = 0;
- if (vernaux != NULL && vernaux->vna_other == *versym)
- {
- printf ("@%s (%u)",
- elf_strptr (ebl->elf, verneed_stridx,
- vernaux->vna_name),
- (unsigned int) vernaux->vna_other);
- check_def = 0;
- }
- else if (unlikely (! is_nobits))
- error (0, 0, _("bad dynamic symbol"));
- else
- check_def = 1;
- }
+ GElf_Ehdr ehdr_mem;
+ GElf_Ehdr *ehdr = gelf_getehdr (ebl->elf, &ehdr_mem);
- if (check_def && *versym != 0x8001)
- {
- /* We must test both. */
- size_t vd_offset = 0;
+ if (offs[i_hash] != 0)
+ {
+ /* In the original format, .hash says the size of .dynsym. */
- GElf_Verdef verdef_mem;
- GElf_Verdef *verdef = gelf_getverdef (verdef_data, 0,
- &verdef_mem);
- while (verdef != NULL)
- {
- if (verdef->vd_ndx == (*versym & 0x7fff))
- /* Found the definition. */
- break;
+ size_t entsz = SH_ENTSIZE_HASH (ehdr);
+ Elf_Data *data
+ = elf_getdata_rawchunk (ebl->elf, offs[i_hash] + entsz, entsz,
+ (entsz == 4 ? ELF_T_WORD : ELF_T_XWORD));
+ if (data != NULL)
+ syments = (entsz == 4 ? *(const GElf_Word *)data->d_buf
+ : *(const GElf_Xword *)data->d_buf);
+ }
+ if (offs[i_gnu_hash] != 0 && syments == 0)
+ {
+ /* In the new format, we can derive it with some work. */
- if (verdef_data->d_size - vd_offset < verdef->vd_next)
- break;
+ const struct
+ {
+ Elf32_Word nbuckets;
+ Elf32_Word symndx;
+ Elf32_Word maskwords;
+ Elf32_Word shift2;
+ } * header;
+
+ Elf_Data *data = elf_getdata_rawchunk (ebl->elf, offs[i_gnu_hash],
+ sizeof *header, ELF_T_WORD);
+ if (data != NULL)
+ {
+ header = data->d_buf;
+ Elf32_Word nbuckets = header->nbuckets;
+ Elf32_Word symndx = header->symndx;
+ GElf_Off buckets_at
+ = (offs[i_gnu_hash] + sizeof *header
+ + (gelf_getclass (ebl->elf) * sizeof (Elf32_Word)
+ * header->maskwords));
+
+ // elf_getdata_rawchunk takes a size_t, make sure it
+ // doesn't overflow.
+#if SIZE_MAX <= UINT32_MAX
+ if (nbuckets > SIZE_MAX / sizeof (Elf32_Word))
+ data = NULL;
+ else
+#endif
+ data = elf_getdata_rawchunk (ebl->elf, buckets_at,
+ nbuckets * sizeof (Elf32_Word),
+ ELF_T_WORD);
+ if (data != NULL && symndx < nbuckets)
+ {
+ const Elf32_Word *const buckets = data->d_buf;
+ Elf32_Word maxndx = symndx;
+ for (Elf32_Word bucket = 0; bucket < nbuckets; ++bucket)
+ if (buckets[bucket] > maxndx)
+ maxndx = buckets[bucket];
+
+ GElf_Off hasharr_at
+ = (buckets_at + nbuckets * sizeof (Elf32_Word));
+ hasharr_at += (maxndx - symndx) * sizeof (Elf32_Word);
+ do
+ {
+ data = elf_getdata_rawchunk (
+ ebl->elf, hasharr_at, sizeof (Elf32_Word), ELF_T_WORD);
+ if (data != NULL && (*(const Elf32_Word *)data->d_buf & 1u))
+ {
+ syments = maxndx + 1;
+ break;
+ }
+ ++maxndx;
+ hasharr_at += sizeof (Elf32_Word);
+ }
+ while (data != NULL);
+ }
+ }
+ }
+ if (offs[i_strtab] > offs[i_symtab] && syments == 0)
+ syments = ((offs[i_strtab] - offs[i_symtab])
+ / gelf_fsize (ebl->elf, ELF_T_SYM, 1, EV_CURRENT));
- vd_offset += verdef->vd_next;
- verdef = (verdef->vd_next == 0
- ? NULL
- : gelf_getverdef (verdef_data, vd_offset,
- &verdef_mem));
- }
+ if (syments <= 0 || offs[i_strtab] == 0 || offs[i_symtab] == 0)
+ {
+ error_exit (0, _ ("Dynamic symbol information is not available for "
+ "displaying symbols."));
+ }
- if (verdef != NULL)
- {
- GElf_Verdaux verdaux_mem;
- GElf_Verdaux *verdaux
- = gelf_getverdaux (verdef_data,
- vd_offset + verdef->vd_aux,
- &verdaux_mem);
-
- if (verdaux != NULL)
- printf ((*versym & 0x8000) ? "@%s" : "@@%s",
- elf_strptr (ebl->elf, verdef_stridx,
- verdaux->vda_name));
- }
- }
- }
- }
+ /* All the data chunk initializaion. */
+ Elf_Data *symdata = NULL;
+ Elf_Data *symstrdata = NULL;
+ Elf_Data *versym_data = NULL;
+ Elf_Data *verdef_data = NULL;
+ Elf_Data *verneed_data = NULL;
- putchar_unlocked ('\n');
- }
+ symdata = elf_getdata_rawchunk (
+ ebl->elf, offs[i_symtab],
+ gelf_fsize (ebl->elf, ELF_T_SYM, syments, EV_CURRENT), ELF_T_SYM);
+ symstrdata = elf_getdata_rawchunk (ebl->elf, offs[i_strtab], addrs[i_strsz],
+ ELF_T_BYTE);
+ versym_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_versym], syments * sizeof (Elf64_Half), ELF_T_HALF);
+
+ /* Get the verneed_data without vernaux. */
+ verneed_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verneed], addrs[i_verneednum] * sizeof (Elf64_Verneed),
+ ELF_T_VNEED);
+ size_t vernauxnum = 0;
+ size_t vn_next_offset = 0;
+
+ for (size_t i = 0; i < addrs[i_verneednum]; i++)
+ {
+ GElf_Verneed *verneed
+ = (GElf_Verneed *)(verneed_data->d_buf + vn_next_offset);
+ vernauxnum += verneed->vn_cnt;
+ vn_next_offset += verneed->vn_next;
+ }
+
+ /* Update the verneed_data to include the vernaux. */
+ verneed_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verneed],
+ (addrs[i_verneednum] + vernauxnum) * sizeof (GElf_Verneed), ELF_T_VNEED);
+
+ /* Get the verdef_data without verdaux. */
+ verdef_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verdef], addrs[i_verdefnum] * sizeof (Elf64_Verdef),
+ ELF_T_VDEF);
+ size_t verdauxnum = 0;
+ size_t vd_next_offset = 0;
+
+ for (size_t i = 0; i < addrs[i_verdefnum]; i++)
+ {
+ GElf_Verdef *verdef
+ = (GElf_Verdef *)(verdef_data->d_buf + vd_next_offset);
+ verdauxnum += verdef->vd_cnt;
+ vd_next_offset += verdef->vd_next;
+ }
+
+ /* Update the verdef_data to include the verdaux. */
+ verdef_data = elf_getdata_rawchunk (
+ ebl->elf, offs[i_verdef],
+ (addrs[i_verdefnum] + verdauxnum) * sizeof (GElf_Verdef), ELF_T_VDEF);
+
+ unsigned int nsyms = (unsigned int)syments;
+ process_symtab (ebl, nsyms, 0, 0, 0, symdata, versym_data, symstrdata,
+ verneed_data, verdef_data, NULL);
+ return true;
}
@@ -4990,13 +5208,24 @@ get_dynscn_addrs(Elf *elf, GElf_Phdr *phdr, GElf_Addr addrs[i_max])
addrs[i_verdef] = dyn->d_un.d_ptr;
break;
+ case DT_VERDEFNUM:
+ addrs[i_verdefnum] = dyn->d_un.d_val;
+ break;
+
case DT_VERNEED:
addrs[i_verneed] = dyn->d_un.d_ptr;
break;
+ case DT_VERNEEDNUM:
+ addrs[i_verneednum] = dyn->d_un.d_val;
+ break;
+
case DT_STRSZ:
addrs[i_strsz] = dyn->d_un.d_val;
break;
+ case DT_SYMTAB_SHNDX:
+ addrs[i_symtab_shndx] = dyn->d_un.d_ptr;
+ break;
}
}
}
--
2.39.2
next prev parent reply other threads:[~2023-04-02 1:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-10 16:17 Di Chen
2023-02-16 16:02 ` Mark Wielaard
2023-04-02 1:06 ` Di Chen [this message]
2023-04-18 19:49 ` Mark Wielaard
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