gdbserver build-id attribute generator

Producer part of the new "build-id" XML attribute.

gdb/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* features/library-list-svr4.dtd (library-list-svr4): New
	'build-id' attribute.

gdb/doc/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* gdb.texinfo (Library List Format for SVR4 Targets): Add
	'build-id' in description, example, new attribute in dtd.

gdb/gdbserver/ChangeLog
2015-07-15  Aleksandar Ristovski  <aristovski@qnx.com
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	gdbserver build-id attribute generator.
	* linux-low.c (nat/linux-maps.h, search.h, rsp-low.h): Include.
	(ElfXX_Ehdr, ElfXX_Phdr, ElfXX_Nhdr): New.
	(ELFXX_FLD, ELFXX_SIZEOF, ELFXX_ROUNDUP, BUILD_ID_INVALID): New.
	(find_phdr): New.
	(get_dynamic): Use find_pdhr to traverse program headers.
	(struct mapping_entry, mapping_entry_s, free_mapping_entry_vec)
	(compare_mapping_entry_range, struct find_memory_region_callback_data)
	(read_build_id, find_memory_region_callback, lrfind_mapping_entry)
	(get_hex_build_id): New.
	(linux_qxfer_libraries_svr4): Add optional build-id attribute
	to reply XML document.
This commit is contained in:
Jan Kratochvil 2015-07-15 17:37:28 +02:00
parent 9904185cfd
commit 700ca40f6f
6 changed files with 409 additions and 49 deletions

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@ -1,3 +1,10 @@
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* features/library-list-svr4.dtd (library-list-svr4): New
'build-id' attribute.
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>

View File

@ -1,3 +1,10 @@
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* gdb.texinfo (Library List Format for SVR4 Targets): Add
'build-id' in description, example, new attribute in dtd.
2015-07-08 Andrew Burgess <andrew.burgess@embecosm.com>
* gdb.texinfo (Selection): Update documentation for 'frame'

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@ -39513,6 +39513,8 @@ memory address. It is a displacement of absolute memory address against
address the file was prelinked to during the library load.
@item
@code{l_ld}, which is memory address of the @code{PT_DYNAMIC} segment
@item
@code{build-id}, hex encoded @code{NT_GNU_BUILD_ID} note, if it exists.
@end itemize
Additionally the single @code{main-lm} attribute specifies address of
@ -39530,7 +39532,7 @@ looks like this:
<library name="/lib/ld-linux.so.2" lm="0xe4f51c" l_addr="0xe2d000"
l_ld="0xe4eefc"/>
<library name="/lib/libc.so.6" lm="0xe4fbe8" l_addr="0x154000"
l_ld="0x152350"/>
l_ld="0x152350" build-id="9afccf7cc41e6293476223fe72480854"/>
</library-list-svr>
@end smallexample
@ -39539,13 +39541,14 @@ The format of an SVR4 library list is described by this DTD:
@smallexample
<!-- library-list-svr4: Root element with versioning -->
<!ELEMENT library-list-svr4 (library)*>
<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
<!ELEMENT library EMPTY>
<!ATTLIST library name CDATA #REQUIRED>
<!ATTLIST library lm CDATA #REQUIRED>
<!ATTLIST library l_addr CDATA #REQUIRED>
<!ATTLIST library l_ld CDATA #REQUIRED>
<!ATTLIST library name CDATA #REQUIRED>
<!ATTLIST library lm CDATA #REQUIRED>
<!ATTLIST library l_addr CDATA #REQUIRED>
<!ATTLIST library l_ld CDATA #REQUIRED>
<!ATTLIST library build-id CDATA #IMPLIED>
@end smallexample
@node Memory Map Format

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@ -6,11 +6,12 @@
<!-- library-list-svr4: Root element with versioning -->
<!ELEMENT library-list-svr4 (library)*>
<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
<!ATTLIST library-list-svr4 version CDATA #FIXED "1.0">
<!ATTLIST library-list-svr4 main-lm CDATA #IMPLIED>
<!ELEMENT library EMPTY>
<!ATTLIST library name CDATA #REQUIRED>
<!ATTLIST library lm CDATA #REQUIRED>
<!ATTLIST library l_addr CDATA #REQUIRED>
<!ATTLIST library l_ld CDATA #REQUIRED>
<!ATTLIST library name CDATA #REQUIRED>
<!ATTLIST library lm CDATA #REQUIRED>
<!ATTLIST library l_addr CDATA #REQUIRED>
<!ATTLIST library l_ld CDATA #REQUIRED>
<!ATTLIST library build-id CDATA #IMPLIED>

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@ -1,3 +1,19 @@
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* linux-low.c (nat/linux-maps.h, search.h, rsp-low.h): Include.
(ElfXX_Ehdr, ElfXX_Phdr, ElfXX_Nhdr): New.
(ELFXX_FLD, ELFXX_SIZEOF, ELFXX_ROUNDUP, BUILD_ID_INVALID): New.
(find_phdr): New.
(get_dynamic): Use find_pdhr to traverse program headers.
(struct mapping_entry, mapping_entry_s, free_mapping_entry_vec)
(compare_mapping_entry_range, struct find_memory_region_callback_data)
(read_build_id, find_memory_region_callback, lrfind_mapping_entry)
(get_hex_build_id): New.
(linux_qxfer_libraries_svr4): Add optional build-id attribute
to reply XML document.
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>

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@ -22,6 +22,7 @@
#include "agent.h"
#include "tdesc.h"
#include "rsp-low.h"
#include "nat/linux-maps.h"
#include "nat/linux-nat.h"
#include "nat/linux-waitpid.h"
@ -43,9 +44,11 @@
#include <sys/stat.h>
#include <sys/vfs.h>
#include <sys/uio.h>
#include <search.h>
#include "filestuff.h"
#include "tracepoint.h"
#include "hostio.h"
#include "rsp-low.h"
#ifndef ELFMAG0
/* Don't include <linux/elf.h> here. If it got included by gdb_proc_service.h
then ELFMAG0 will have been defined. If it didn't get included by
@ -182,6 +185,31 @@ lwp_stop_reason (struct lwp_info *lwp)
return lwp->stop_reason;
}
typedef union ElfXX_Ehdr
{
Elf32_Ehdr _32;
Elf64_Ehdr _64;
} ElfXX_Ehdr;
typedef union ElfXX_Phdr
{
Elf32_Phdr _32;
Elf64_Phdr _64;
} ElfXX_Phdr;
typedef union ElfXX_Nhdr
{
Elf32_Nhdr _32;
Elf64_Nhdr _64;
} ElfXX_Nhdr;
#define ELFXX_FLD(elf64, hdr, fld) ((elf64) ? (hdr)._64.fld : (hdr)._32.fld)
#define ELFXX_SIZEOF(elf64, hdr) ((elf64) ? sizeof ((hdr)._64) \
: sizeof ((hdr)._32))
/* Round up to next 4 byte boundary. */
#define ELFXX_ROUNDUP_4(elf64, what) (((what) + 3) & ~(ULONGEST) 3)
#define BUILD_ID_INVALID "?"
/* A list of all unknown processes which receive stop signals. Some
other process will presumably claim each of these as forked
children momentarily. */
@ -6010,15 +6038,38 @@ get_phdr_phnum_from_proc_auxv (const int pid, const int is_elf64,
return 0;
}
/* Linearly traverse pheaders and look for P_TYPE pheader. */
static const void *
find_phdr (const int is_elf64, const void *const phdr_begin,
const void *const phdr_end, const ULONGEST p_type)
{
#define PHDR_NEXT(hdrp) ((const void *) ((const gdb_byte *) (hdrp) + \
ELFXX_SIZEOF (is_elf64, *hdrp)))
const ElfXX_Phdr *phdr = phdr_begin;
while (PHDR_NEXT (phdr) <= phdr_end)
{
if (ELFXX_FLD (is_elf64, *phdr, p_type) == p_type)
return phdr;
phdr = PHDR_NEXT (phdr);
}
return NULL;
#undef PHDR_NEXT
}
/* Return &_DYNAMIC (via PT_DYNAMIC) in the inferior, or 0 if not present. */
static CORE_ADDR
get_dynamic (const int pid, const int is_elf64)
{
CORE_ADDR phdr_memaddr, relocation;
int num_phdr, i;
int num_phdr;
unsigned char *phdr_buf;
const int phdr_size = is_elf64 ? sizeof (Elf64_Phdr) : sizeof (Elf32_Phdr);
const ElfXX_Phdr *phdr;
const int phdr_size = ELFXX_SIZEOF (is_elf64, *phdr);
if (get_phdr_phnum_from_proc_auxv (pid, is_elf64, &phdr_memaddr, &num_phdr))
return 0;
@ -6032,22 +6083,10 @@ get_dynamic (const int pid, const int is_elf64)
/* Compute relocation: it is expected to be 0 for "regular" executables,
non-zero for PIE ones. */
relocation = -1;
for (i = 0; relocation == -1 && i < num_phdr; i++)
if (is_elf64)
{
Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size);
if (p->p_type == PT_PHDR)
relocation = phdr_memaddr - p->p_vaddr;
}
else
{
Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size);
if (p->p_type == PT_PHDR)
relocation = phdr_memaddr - p->p_vaddr;
}
phdr = find_phdr (is_elf64, phdr_buf, phdr_buf + num_phdr * phdr_size,
PT_PHDR);
if (phdr != NULL)
relocation = phdr_memaddr - ELFXX_FLD (is_elf64, *phdr, p_vaddr);
if (relocation == -1)
{
/* PT_PHDR is optional, but necessary for PIE in general. Fortunately
@ -6063,23 +6102,11 @@ get_dynamic (const int pid, const int is_elf64)
return 0;
}
for (i = 0; i < num_phdr; i++)
{
if (is_elf64)
{
Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size);
phdr = find_phdr (is_elf64, phdr_buf, phdr_buf + num_phdr * phdr_size,
PT_DYNAMIC);
if (p->p_type == PT_DYNAMIC)
return p->p_vaddr + relocation;
}
else
{
Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size);
if (p->p_type == PT_DYNAMIC)
return p->p_vaddr + relocation;
}
}
if (phdr != NULL)
return ELFXX_FLD (is_elf64, *phdr, p_vaddr) + relocation;
return 0;
}
@ -6219,6 +6246,278 @@ struct link_map_offsets
int l_prev_offset;
};
/* Structure for holding a mapping. Only mapping
containing l_ld can have hex_build_id set. */
struct mapping_entry
{
/* Fields are populated from linux_find_memory_region parameters. */
ULONGEST vaddr;
ULONGEST size;
ULONGEST offset;
ULONGEST inode;
/* Hex encoded string allocated using xmalloc, and
needs to be freed. It can be NULL. */
char *hex_build_id;
};
typedef struct mapping_entry mapping_entry_s;
DEF_VEC_O(mapping_entry_s);
/* Free vector of mapping_entry_s objects. */
static void
free_mapping_entry_vec (VEC (mapping_entry_s) *lst)
{
int ix;
mapping_entry_s *p;
for (ix = 0; VEC_iterate (mapping_entry_s, lst, ix, p); ++ix)
xfree (p->hex_build_id);
VEC_free (mapping_entry_s, lst);
}
/* Used for finding a mapping containing the given
l_ld passed in K. */
static int
compare_mapping_entry_range (const void *const k, const void *const b)
{
const ULONGEST key = *(const CORE_ADDR *) k;
const mapping_entry_s *const p = b;
if (key < p->vaddr)
return -1;
if (key < p->vaddr + p->size)
return 0;
return 1;
}
struct find_memory_region_callback_data
{
unsigned is_elf64;
/* Return. Must be freed with free_mapping_entry_vec. */
VEC (mapping_entry_s) *list;
};
/* Read build-id from PT_NOTE.
Argument LOAD_ADDR represents run time virtual address corresponding to
the beginning of the first loadable segment. L_ADDR is displacement
as supplied by the dynamic linker. */
static void
read_build_id (struct find_memory_region_callback_data *const p,
mapping_entry_s *const bil, const CORE_ADDR load_addr,
const CORE_ADDR l_addr)
{
const int is_elf64 = p->is_elf64;
ElfXX_Ehdr ehdr;
if (linux_read_memory (load_addr, (unsigned char *) &ehdr,
ELFXX_SIZEOF (is_elf64, ehdr)) == 0
&& ELFXX_FLD (is_elf64, ehdr, e_ident[EI_MAG0]) == ELFMAG0
&& ELFXX_FLD (is_elf64, ehdr, e_ident[EI_MAG1]) == ELFMAG1
&& ELFXX_FLD (is_elf64, ehdr, e_ident[EI_MAG2]) == ELFMAG2
&& ELFXX_FLD (is_elf64, ehdr, e_ident[EI_MAG3]) == ELFMAG3)
{
const ElfXX_Phdr *phdr;
void *phdr_buf;
const unsigned e_phentsize = ELFXX_FLD (is_elf64, ehdr, e_phentsize);
if (ELFXX_FLD (is_elf64, ehdr, e_phnum) >= 100
|| e_phentsize != ELFXX_SIZEOF (is_elf64, *phdr))
{
/* Basic sanity check failed. */
warning (_("Could not identify program header at %s."),
paddress (load_addr));
return;
}
phdr_buf = alloca (ELFXX_FLD (is_elf64, ehdr, e_phnum) * e_phentsize);
if (linux_read_memory (load_addr + ELFXX_FLD (is_elf64, ehdr, e_phoff),
phdr_buf,
ELFXX_FLD (is_elf64, ehdr, e_phnum) * e_phentsize)
!= 0)
{
warning (_("Could not read program header at %s."),
paddress (load_addr));
return;
}
phdr = phdr_buf;
for (;;)
{
gdb_byte *pt_note;
const gdb_byte *pt_end;
const ElfXX_Nhdr *nhdr;
CORE_ADDR note_addr;
phdr = find_phdr (p->is_elf64, phdr, (gdb_byte *) phdr_buf
+ ELFXX_FLD (is_elf64, ehdr, e_phnum) * e_phentsize,
PT_NOTE);
if (phdr == NULL)
break;
pt_note = xmalloc (ELFXX_FLD (is_elf64, *phdr, p_memsz));
note_addr = ELFXX_FLD (is_elf64, *phdr, p_vaddr) + l_addr;
if (linux_read_memory (note_addr, pt_note,
ELFXX_FLD (is_elf64, *phdr, p_memsz)) != 0)
{
xfree (pt_note);
warning (_("Could not read note at address 0x%s"),
paddress (note_addr));
break;
}
pt_end = pt_note + ELFXX_FLD (is_elf64, *phdr, p_memsz);
nhdr = (void *) pt_note;
while ((const gdb_byte *) nhdr < pt_end)
{
const size_t namesz
= ELFXX_ROUNDUP_4 (is_elf64, ELFXX_FLD (is_elf64, *nhdr,
n_namesz));
const size_t descsz
= ELFXX_ROUNDUP_4 (is_elf64, ELFXX_FLD (is_elf64, *nhdr,
n_descsz));
const size_t note_sz = (ELFXX_SIZEOF (is_elf64, *nhdr) + namesz
+ descsz);
if (((const gdb_byte *) nhdr + note_sz) > pt_end || note_sz == 0
|| descsz == 0)
{
warning (_("Malformed PT_NOTE at address 0x%s\n"),
paddress (note_addr + (gdb_byte *) nhdr - pt_note));
break;
}
if (ELFXX_FLD (is_elf64, *nhdr, n_type) == NT_GNU_BUILD_ID
&& ELFXX_FLD (is_elf64, *nhdr, n_namesz) == 4)
{
const char gnu[4] = "GNU\0";
const char *const pname
= (char *) nhdr + ELFXX_SIZEOF (is_elf64, *nhdr);
if (memcmp (pname, gnu, 4) == 0)
{
const size_t n_descsz = ELFXX_FLD (is_elf64, *nhdr,
n_descsz);
bil->hex_build_id = xmalloc (n_descsz * 2 + 1);
bin2hex ((const gdb_byte *) pname + namesz,
bil->hex_build_id, n_descsz);
xfree (pt_note);
return;
}
}
nhdr = (void *) ((gdb_byte *) nhdr + note_sz);
}
xfree (pt_note);
}
}
}
static linux_find_memory_region_ftype find_memory_region_callback;
/* Add mapping_entry. See linux_find_memory_ftype for the parameters
description. */
static int
find_memory_region_callback (ULONGEST vaddr, ULONGEST size, ULONGEST offset,
ULONGEST inode, int read, int write, int exec,
int modified, const char *filename, void *data)
{
if (inode != 0)
{
struct find_memory_region_callback_data *const p = data;
mapping_entry_s bil;
bil.vaddr = vaddr;
bil.size = size;
bil.offset = offset;
bil.inode = inode;
bil.hex_build_id = NULL;
VEC_safe_push (mapping_entry_s, p->list, &bil);
}
/* Continue the traversal. */
return 0;
}
/* Linear reverse find starting from RBEGIN towards REND looking for
the lowest vaddr mapping of the same inode and zero offset. */
static mapping_entry_s *
lrfind_mapping_entry (mapping_entry_s *const rbegin,
const mapping_entry_s *const rend)
{
mapping_entry_s *p;
for (p = rbegin - 1; p >= rend; --p)
if (p->offset == 0 && p->inode == rbegin->inode)
return p;
return NULL;
}
/* Get build-id for the given L_LD, where L_LD corresponds to
link_map.l_ld as specified by the dynamic linker.
DATA must point to already filled list of mapping_entry elements.
If build-id had not been read, read it and cache in corresponding
list element.
Return build_id as stored in the list element corresponding
to L_LD.
NULL may be returned if build-id could not be fetched.
Returned string must not be freed explicitly. */
static const char *
get_hex_build_id (const CORE_ADDR l_addr, const CORE_ADDR l_ld,
struct find_memory_region_callback_data *const data)
{
mapping_entry_s *bil;
bil = bsearch (&l_ld, VEC_address (mapping_entry_s, data->list),
VEC_length (mapping_entry_s, data->list),
sizeof (mapping_entry_s), compare_mapping_entry_range);
if (bil == NULL)
return NULL;
if (bil->hex_build_id == NULL)
{
mapping_entry_s *bil_min;
bil_min = lrfind_mapping_entry (bil, VEC_address (mapping_entry_s,
data->list));
if (bil_min != NULL)
read_build_id (data, bil, bil_min->vaddr, l_addr);
else
{
/* Do not try to find hex_build_id again. */
bil->hex_build_id = xstrdup (BUILD_ID_INVALID);
warning (_("Could not determine load address; mapping entry with "
"offset 0 corresponding to l_ld = 0x%s could not be "
"found; build-id can not be used."),
paddress (l_ld));
}
}
return bil->hex_build_id;
}
/* Construct qXfer:libraries-svr4:read reply. */
static int
@ -6231,6 +6530,15 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
struct process_info_private *const priv = current_process ()->priv;
char filename[PATH_MAX];
int pid, is_elf64;
struct find_memory_region_callback_data data;
/* COREFILTER_ANON_PRIVATE and COREFILTER_ANON_SHARED do not have an
associated file so it is not expected it could have an ELF header. */
const enum filterflags filterflags = (COREFILTER_MAPPED_PRIVATE
| COREFILTER_MAPPED_SHARED
| COREFILTER_ELF_HEADERS
| COREFILTER_HUGETLB_PRIVATE
| COREFILTER_HUGETLB_SHARED);
static const struct link_map_offsets lmo_32bit_offsets =
{
@ -6273,6 +6581,14 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
lmo = is_elf64 ? &lmo_64bit_offsets : &lmo_32bit_offsets;
ptr_size = is_elf64 ? 8 : 4;
data.is_elf64 = is_elf64;
data.list = NULL;
VEC_reserve (mapping_entry_s, data.list, 16);
if (linux_find_memory_regions_full (pid, filterflags,
find_memory_region_callback, &data)
< 0)
warning (_("Finding memory regions failed"));
while (annex[0] != '\0')
{
const char *sep;
@ -6379,6 +6695,7 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
/* 6x the size for xml_escape_text below. */
size_t len = 6 * strlen ((char *) libname);
char *name;
const char *hex_enc_build_id = NULL;
if (!header_done)
{
@ -6387,7 +6704,11 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
header_done = 1;
}
while (allocated < p - document + len + 200)
hex_enc_build_id = get_hex_build_id (l_addr, l_ld, &data);
while (allocated < (p - document + len + 200
+ (hex_enc_build_id != NULL
? strlen (hex_enc_build_id) : 0)))
{
/* Expand to guarantee sufficient storage. */
uintptr_t document_len = p - document;
@ -6399,9 +6720,13 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
name = xml_escape_text ((char *) libname);
p += sprintf (p, "<library name=\"%s\" lm=\"0x%lx\" "
"l_addr=\"0x%lx\" l_ld=\"0x%lx\"/>",
"l_addr=\"0x%lx\" l_ld=\"0x%lx\"",
name, (unsigned long) lm_addr,
(unsigned long) l_addr, (unsigned long) l_ld);
if (hex_enc_build_id != NULL
&& strcmp (hex_enc_build_id, BUILD_ID_INVALID) != 0)
p += sprintf (p, " build-id=\"%s\"", hex_enc_build_id);
p += sprintf (p, "/>");
free (name);
}
}
@ -6428,6 +6753,7 @@ linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf,
memcpy (readbuf, document + offset, len);
xfree (document);
free_mapping_entry_vec (data.list);
return len;
}