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ddb: Add CTF-based pretty printing

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Add basic CTF support and a CTF-powered pretty-printer to ddb.

The db_ctf.* files expose a basic interface for fetching type
data for ELF symbols, interacting with the CTF string table,
and translating type identifiers to type data.

The db_pprint.c file uses those interfaces to implement
a pretty-printer for all kernel ELF symbols.
The pretty-printer works with symbol names and arbitrary addresses:
pprint struct thread 0xffffffff8194ad90

Pretty-printing currently only works after the root filesystem
gets mounted because the CTF info is not available during
early boot.

Differential Revision:	https://reviews.freebsd.org/D37899
Approved by: markj (mentor)
This commit is contained in:
Bojan Novković 2024-03-22 04:01:34 +01:00
parent 312a05c39e
commit c21bc6f3c2
13 changed files with 1054 additions and 1 deletions
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26
share/man/man4/ddb.4
View file

@ -289,6 +289,32 @@ eax = xxxxxx
ecx = yyyyyy
.Ed
.Pp
.It Ic pprint Ns Oo Li / Ns Cm d depth Oc Oo Ar name Oc
Pretty-print symbol specified by
.Ar name
using CTF debugging data. Works for all symbols exported by the kernel and loaded kernel modules.
.Pp
If the
.Cm d
modifier has been specified, contents of structs nested up to
.Ar depth
levels deep will also be included in the output.
.Ed
.Pp
.It Ic pprint struct Ns Oo Li / Ns Cm d depth Ic Oc Oo Ar name Oc Ns Op Ns Ar addr
Print memory at
.Ar addr
as struct
.Ar name Ns .
Works for all structs defined by the kernel and loaded kernel modules.
.Pp
If the
.Cm d
modifier has been specified, contents of structs nested up to
.Ar depth
levels deep will also be included in the output.
.Ed
.Pp
.It Xo
.Ic write Ns Op Li / Ns Cm bhl
.Ar addr expr1 Op Ar expr2 ...

2
sys/conf/files
View file

@ -718,12 +718,14 @@ ddb/db_access.c optional ddb
ddb/db_break.c optional ddb
ddb/db_capture.c optional ddb
ddb/db_command.c optional ddb
ddb/db_ctf.c optional ddb
ddb/db_examine.c optional ddb
ddb/db_expr.c optional ddb
ddb/db_input.c optional ddb
ddb/db_lex.c optional ddb
ddb/db_main.c optional ddb
ddb/db_output.c optional ddb
ddb/db_pprint.c optional ddb
ddb/db_print.c optional ddb
ddb/db_ps.c optional ddb
ddb/db_run.c optional ddb

1
sys/ddb/db_command.c
View file

@ -163,6 +163,7 @@ static struct db_command db_cmds[] = {
DB_CMD("capture", db_capture_cmd, CS_OWN|DB_CMD_MEMSAFE),
DB_CMD("textdump", db_textdump_cmd, CS_OWN|DB_CMD_MEMSAFE),
DB_CMD("findstack", db_findstack_cmd, 0),
DB_CMD("pprint", db_pprint_cmd, CS_OWN),
};
struct db_command_table db_cmd_table = LIST_HEAD_INITIALIZER(db_cmd_table);

326
sys/ddb/db_ctf.c Normal file
View file

@ -0,0 +1,326 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2023 Bojan Novković <bnovkov@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ctype.h>
#include <sys/linker.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <ddb/ddb.h>
#include <ddb/db_ctf.h>
static const ctf_header_t *
db_ctf_fetch_cth(linker_ctf_t *lc)
{
return (const ctf_header_t *)lc->ctftab;
}
/*
* Tries to look up the ELF symbol -> CTF type identifier mapping by scanning
* the CTF object section.
*/
static uint32_t
sym_to_objtoff(linker_ctf_t *lc, const Elf_Sym *sym, const Elf_Sym *symtab,
const Elf_Sym *symtab_end)
{
const ctf_header_t *hp = db_ctf_fetch_cth(lc);
uint32_t objtoff = hp->cth_objtoff;
const size_t idwidth = 4;
/* Ignore non-object symbols */
if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT) {
return (DB_CTF_INVALID_OFF);
}
/* Sanity check */
if (!(sym >= symtab && sym <= symtab_end)) {
return (DB_CTF_INVALID_OFF);
}
for (const Elf_Sym *symp = symtab; symp < symtab_end; symp++) {
/* Make sure we do not go beyond the objtoff section */
if (objtoff >= hp->cth_funcoff) {
objtoff = DB_CTF_INVALID_OFF;
break;
}
if (symp->st_name == 0 || symp->st_shndx == SHN_UNDEF) {
continue;
}
if (symp->st_shndx == SHN_ABS && symp->st_value == 0) {
continue;
}
/* Skip non-object symbols */
if (ELF_ST_TYPE(symp->st_info) != STT_OBJECT) {
continue;
}
if (symp == sym) {
break;
}
objtoff += idwidth;
}
return (objtoff);
}
/*
* Returns the size of CTF type 't'.
*/
static u_int
db_ctf_type_size(struct ctf_type_v3 *t)
{
u_int vlen, kind, ssize;
u_int type_struct_size, kind_size;
vlen = CTF_V3_INFO_VLEN(t->ctt_info);
kind = CTF_V3_INFO_KIND(t->ctt_info);
ssize = ((t->ctt_size == CTF_V3_LSIZE_SENT) ? CTF_TYPE_LSIZE(t) :
t->ctt_size);
type_struct_size = ((t->ctt_size == CTF_V3_LSIZE_SENT) ?
sizeof(struct ctf_type_v3) :
sizeof(struct ctf_stype_v3));
switch (kind) {
case CTF_K_INTEGER:
case CTF_K_FLOAT:
kind_size = sizeof(uint32_t);
break;
case CTF_K_ARRAY:
kind_size = sizeof(struct ctf_array_v3);
break;
case CTF_K_UNION:
case CTF_K_STRUCT:
kind_size = vlen *
((ssize < CTF_V3_LSTRUCT_THRESH) ?
sizeof(struct ctf_member_v3) :
sizeof(struct ctf_lmember_v3));
break;
case CTF_K_ENUM:
kind_size = vlen * sizeof(struct ctf_enum);
break;
case CTF_K_FUNCTION:
kind_size = vlen * sizeof(uint32_t);
break;
case CTF_K_UNKNOWN:
case CTF_K_FORWARD:
case CTF_K_POINTER:
case CTF_K_TYPEDEF:
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
kind_size = 0;
break;
default:
db_printf("Error: invalid CTF type kind encountered\n");
return (-1);
}
return (type_struct_size + kind_size);
}
/*
* Looks up type name 'name' in the CTF string table and returns the
* corresponding CTF type struct, if any.
*/
struct ctf_type_v3 *
db_ctf_typename_to_type(linker_ctf_t *lc, const char *name)
{
const ctf_header_t *hp = db_ctf_fetch_cth(lc);
char *start, *cur, *end;
uint32_t stroff = hp->cth_stroff;
uint32_t typeoff = hp->cth_typeoff;
uint32_t name_stroff;
const uint8_t *ctfstart = (const uint8_t *)hp + sizeof(ctf_header_t);
u_int skiplen;
/* Scan ctf strtab for typename. */
start = cur = __DECONST(char *, hp) + sizeof(ctf_header_t) +
hp->cth_stroff;
end = cur + hp->cth_strlen;
while (cur < end) {
if (strcmp(cur, name) == 0)
break;
cur += strlen(cur) + 1;
}
if (cur >= end)
return (NULL);
name_stroff = (uint32_t)(cur - start);
/* Scan for type containing the found stroff. */
while (typeoff < stroff) {
struct ctf_type_v3 *t =
(struct ctf_type_v3 *)(__DECONST(uint8_t *, ctfstart) +
typeoff);
/* We found the type struct */
if (t->ctt_name == name_stroff) {
break;
}
if ((skiplen = db_ctf_type_size(t)) == -1) {
return (NULL);
}
typeoff += skiplen;
}
if (typeoff < stroff) {
return (struct ctf_type_v3 *)(__DECONST(uint8_t *, ctfstart) +
typeoff);
} else { /* A type struct was not found */
return (NULL);
}
}
/*
* Wrapper used by the kernel linker CTF routines.
* Currently used to implement lookup of CTF types accross all loaded kernel
* modules.
*/
bool
db_ctf_lookup_typename(linker_ctf_t *lc, const char *typename)
{
return (db_ctf_typename_to_type(lc, typename) != NULL);
}
/*
* Returns the type corresponding to the 'typeid' parameter from the CTF type
* section.
*/
struct ctf_type_v3 *
db_ctf_typeid_to_type(db_ctf_sym_data_t sd, uint32_t typeid)
{
const ctf_header_t *hp = db_ctf_fetch_cth(&sd->lc);
const uint8_t *ctfstart = (const uint8_t *)hp + sizeof(ctf_header_t);
uint32_t typeoff = hp->cth_typeoff;
uint32_t stroff = hp->cth_stroff;
/* CTF typeids start at 0x1 */
size_t cur_typeid = 1;
u_int skiplen;
/* Find corresponding type */
while (typeoff < stroff) {
struct ctf_type_v3 *t =
(struct ctf_type_v3 *)(__DECONST(uint8_t *, ctfstart) +
typeoff);
/* We found the type struct */
if (cur_typeid == typeid) {
break;
}
cur_typeid++;
if ((skiplen = db_ctf_type_size(t)) == -1) {
return (NULL);
}
typeoff += skiplen;
}
if (typeoff < stroff) {
return (struct ctf_type_v3 *)(__DECONST(uint8_t *, ctfstart) +
typeoff);
} else { /* A type struct was not found */
return (NULL);
}
}
const char *
db_ctf_stroff_to_str(db_ctf_sym_data_t sd, uint32_t off)
{
const ctf_header_t *hp = db_ctf_fetch_cth(&sd->lc);
uint32_t stroff = hp->cth_stroff + off;
const char *ret;
if (stroff >= (hp->cth_stroff + hp->cth_strlen)) {
return ("invalid");
}
ret = ((const char *)hp + sizeof(ctf_header_t)) + stroff;
if (*ret == '\0') {
return (NULL);
}
return (ret);
}
/*
* Tries to find the type of the symbol specified in 'sd->sym'.
*/
struct ctf_type_v3 *
db_ctf_sym_to_type(db_ctf_sym_data_t sd)
{
uint32_t objtoff, typeid;
const Elf_Sym *symtab, *symtab_end;
if (sd->sym == NULL) {
return (NULL);
}
symtab = sd->lc.symtab;
symtab_end = symtab + sd->lc.nsym;
objtoff = sym_to_objtoff(&sd->lc, sd->sym, symtab, symtab_end);
/* Sanity check - should not happen */
if (objtoff == DB_CTF_INVALID_OFF) {
db_printf("Could not find CTF object offset.\n");
return (NULL);
}
typeid = *(
const uint32_t *)(sd->lc.ctftab + sizeof(ctf_header_t) + objtoff);
return (db_ctf_typeid_to_type(sd, typeid));
}
/*
* Scans the kernel file and all loaded module for symbol 'name'.
*/
int
db_ctf_find_symbol(const char *name, db_ctf_sym_data_t sd)
{
int error;
c_linker_sym_t lsym = NULL;
error = linker_ctf_lookup_sym_ddb(name, &lsym, &sd->lc);
if (error != 0) {
db_printf(
"failed to look up symbol and CTF info for %s: error %d\n",
name, error);
return (error);
}
sd->sym = __DECONST(Elf_Sym *, lsym);
return (0);
}
/*
* Scans the kernel file and all loaded module for type specified by 'typename'.
*/
struct ctf_type_v3 *
db_ctf_find_typename(db_ctf_sym_data_t sd, const char *typename)
{
if (linker_ctf_lookup_typename_ddb(&sd->lc, typename) != 0) {
return (NULL);
}
return (db_ctf_typename_to_type(&sd->lc, typename));
}

64
sys/ddb/db_ctf.h Normal file
View file

@ -0,0 +1,64 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2023 Bojan Novković <bnovkov@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _DDB_DB_CTF_H_
#define _DDB_DB_CTF_H_
#include <sys/types.h>
#include <sys/ctf.h>
#include <sys/linker.h>
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
#define DB_CTF_INVALID_OFF 0xffffffff
struct db_ctf_sym_data {
linker_ctf_t lc;
Elf_Sym *sym;
};
typedef struct db_ctf_sym_data *db_ctf_sym_data_t;
/*
* Routines for finding symbols and CTF info accross all loaded linker files.
*/
int db_ctf_find_symbol(const char *name, db_ctf_sym_data_t sd);
struct ctf_type_v3 *db_ctf_find_typename(db_ctf_sym_data_t sd,
const char *typename);
bool db_ctf_lookup_typename(linker_ctf_t *lc, const char *typename);
/*
* Routines for working with CTF data.
*/
struct ctf_type_v3 *db_ctf_sym_to_type(db_ctf_sym_data_t sd);
const char *db_ctf_stroff_to_str(db_ctf_sym_data_t sd, uint32_t off);
struct ctf_type_v3 *db_ctf_typename_to_type(linker_ctf_t *lc, const char *name);
struct ctf_type_v3 *db_ctf_typeid_to_type(db_ctf_sym_data_t sd,
uint32_t typeid);
#endif /* !_DDB_DB_CTF_H_ */

450
sys/ddb/db_pprint.c Normal file
View file

@ -0,0 +1,450 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2022 Bojan Novković <bnovkov@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ctype.h>
#include <sys/linker.h>
#include <machine/stdarg.h>
#include <ddb/ddb.h>
#include <ddb/db_ctf.h>
#include <ddb/db_lex.h>
#include <ddb/db_sym.h>
#include <ddb/db_access.h>
#define DB_PPRINT_DEFAULT_DEPTH 1
static void db_pprint_type(db_addr_t addr, struct ctf_type_v3 *type,
u_int depth);
static u_int max_depth = DB_PPRINT_DEFAULT_DEPTH;
static struct db_ctf_sym_data sym_data;
/*
* Pretty-prints a CTF_INT type.
*/
static inline void
db_pprint_int(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
uint32_t data;
size_t type_struct_size;
type_struct_size = (type->ctt_size == CTF_V3_LSIZE_SENT) ?
sizeof(struct ctf_type_v3) :
sizeof(struct ctf_stype_v3);
data = db_get_value((db_expr_t)type + type_struct_size,
sizeof(uint32_t), 0);
u_int bits = CTF_INT_BITS(data);
boolean_t sign = !!(CTF_INT_ENCODING(data) & CTF_INT_SIGNED);
if (db_pager_quit) {
return;
}
if (bits > 64) {
db_printf("Invalid size '%d' found for integer type\n", bits);
return;
}
db_printf("0x%lx",
db_get_value(addr, (bits / 8) ? (bits / 8) : 1, sign));
}
/*
* Pretty-prints a struct. Nested structs are pretty-printed up 'depth' nested
* levels.
*/
static inline void
db_pprint_struct(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
size_t type_struct_size;
size_t struct_size;
struct ctf_type_v3 *mtype;
const char *mname;
db_addr_t maddr;
u_int vlen;
type_struct_size = (type->ctt_size == CTF_V3_LSIZE_SENT) ?
sizeof(struct ctf_type_v3) :
sizeof(struct ctf_stype_v3);
struct_size = ((type->ctt_size == CTF_V3_LSIZE_SENT) ?
CTF_TYPE_LSIZE(type) :
type->ctt_size);
vlen = CTF_V3_INFO_VLEN(type->ctt_info);
if (db_pager_quit) {
return;
}
if (depth > max_depth) {
db_printf("{ ... }");
return;
}
db_printf("{\n");
if (struct_size < CTF_V3_LSTRUCT_THRESH) {
struct ctf_member_v3 *mp, *endp;
mp = (struct ctf_member_v3 *)((db_addr_t)type +
type_struct_size);
endp = mp + vlen;
for (; mp < endp; mp++) {
if (db_pager_quit) {
return;
}
mtype = db_ctf_typeid_to_type(&sym_data, mp->ctm_type);
maddr = addr + mp->ctm_offset;
mname = db_ctf_stroff_to_str(&sym_data, mp->ctm_name);
db_indent = depth;
if (mname != NULL) {
db_iprintf("%s = ", mname);
} else {
db_iprintf("");
}
db_pprint_type(maddr, mtype, depth + 1);
db_printf(",\n");
}
} else {
struct ctf_lmember_v3 *mp, *endp;
mp = (struct ctf_lmember_v3 *)((db_addr_t)type +
type_struct_size);
endp = mp + vlen;
for (; mp < endp; mp++) {
if (db_pager_quit) {
return;
}
mtype = db_ctf_typeid_to_type(&sym_data, mp->ctlm_type);
maddr = addr + CTF_LMEM_OFFSET(mp);
mname = db_ctf_stroff_to_str(&sym_data, mp->ctlm_name);
db_indent = depth;
if (mname != NULL) {
db_iprintf("%s = ", mname);
} else {
db_iprintf("");
}
db_pprint_type(maddr, mtype, depth + 1);
db_printf(",");
}
}
db_indent = depth - 1;
db_iprintf("}");
}
/*
* Pretty-prints an array. Each array member is printed out in a separate line
* indented with 'depth' spaces.
*/
static inline void
db_pprint_arr(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
struct ctf_type_v3 *elem_type;
struct ctf_array_v3 *arr;
db_addr_t elem_addr, end;
size_t type_struct_size;
size_t elem_size;
type_struct_size = (type->ctt_size == CTF_V3_LSIZE_SENT) ?
sizeof(struct ctf_type_v3) :
sizeof(struct ctf_stype_v3);
arr = (struct ctf_array_v3 *)((db_addr_t)type + type_struct_size);
elem_type = db_ctf_typeid_to_type(&sym_data, arr->cta_contents);
elem_size = ((elem_type->ctt_size == CTF_V3_LSIZE_SENT) ?
CTF_TYPE_LSIZE(elem_type) :
elem_type->ctt_size);
elem_addr = addr;
end = addr + (arr->cta_nelems * elem_size);
db_indent = depth;
db_printf("[\n");
/* Loop through and print individual elements. */
for (; elem_addr < end; elem_addr += elem_size) {
if (db_pager_quit) {
return;
}
db_iprintf("");
db_pprint_type(elem_addr, elem_type, depth);
if ((elem_addr + elem_size) < end) {
db_printf(",\n");
}
}
db_printf("\n");
db_indent = depth - 1;
db_iprintf("]");
}
/*
* Pretty-prints an enum value. Also prints out symbolic name of value, if any.
*/
static inline void
db_pprint_enum(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
struct ctf_enum *ep, *endp;
size_t type_struct_size;
const char *valname;
db_expr_t val;
u_int vlen;
type_struct_size = (type->ctt_size == CTF_V3_LSIZE_SENT) ?
sizeof(struct ctf_type_v3) :
sizeof(struct ctf_stype_v3);
vlen = CTF_V3_INFO_VLEN(type->ctt_info);
val = db_get_value(addr, sizeof(int), 0);
if (db_pager_quit) {
return;
}
ep = (struct ctf_enum *)((db_addr_t)type + type_struct_size);
endp = ep + vlen;
for (; ep < endp; ep++) {
if (val == ep->cte_value) {
valname = db_ctf_stroff_to_str(&sym_data, ep->cte_name);
if (valname != NULL)
db_printf("%s (0x%lx)", valname, val);
else
db_printf("(0x%lx)", val);
break;
}
}
}
/*
* Pretty-prints a pointer. If the 'depth' parameter is less than the
* 'max_depth' global var, the pointer is "dereference", i.e. the contents of
* the memory it points to are also printed. The value of the pointer is printed
* otherwise.
*/
static inline void
db_pprint_ptr(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
struct ctf_type_v3 *ref_type;
const char *qual = "";
const char *name;
db_addr_t val;
u_int kind;
ref_type = db_ctf_typeid_to_type(&sym_data, type->ctt_type);
kind = CTF_V3_INFO_KIND(ref_type->ctt_info);
switch (kind) {
case CTF_K_STRUCT:
qual = "struct ";
break;
case CTF_K_VOLATILE:
qual = "volatile ";
break;
case CTF_K_CONST:
qual = "const ";
break;
default:
break;
}
val = db_get_value(addr, sizeof(db_addr_t), false);
if (depth < max_depth) {
/* Print contents of memory pointed to by this pointer. */
db_pprint_type(addr, ref_type, depth + 1);
} else {
name = db_ctf_stroff_to_str(&sym_data, ref_type->ctt_name);
db_indent = depth;
if (name != NULL)
db_printf("(%s%s *) 0x%lx", qual, name, val);
else
db_printf("0x%lx", val);
}
}
/*
* Pretty-print dispatching function.
*/
static void
db_pprint_type(db_addr_t addr, struct ctf_type_v3 *type, u_int depth)
{
if (db_pager_quit) {
return;
}
if (type == NULL) {
db_printf("unknown type");
return;
}
switch (CTF_V3_INFO_KIND(type->ctt_info)) {
case CTF_K_INTEGER:
db_pprint_int(addr, type, depth);
break;
case CTF_K_UNION:
case CTF_K_STRUCT:
db_pprint_struct(addr, type, depth);
break;
case CTF_K_FUNCTION:
case CTF_K_FLOAT:
db_indent = depth;
db_iprintf("0x%lx", addr);
break;
case CTF_K_POINTER:
db_pprint_ptr(addr, type, depth);
break;
case CTF_K_TYPEDEF:
case CTF_K_VOLATILE:
case CTF_K_RESTRICT:
case CTF_K_CONST: {
struct ctf_type_v3 *ref_type = db_ctf_typeid_to_type(&sym_data,
type->ctt_type);
db_pprint_type(addr, ref_type, depth);
break;
}
case CTF_K_ENUM:
db_pprint_enum(addr, type, depth);
break;
case CTF_K_ARRAY:
db_pprint_arr(addr, type, depth);
break;
case CTF_K_UNKNOWN:
case CTF_K_FORWARD:
default:
break;
}
}
/*
* Symbol pretty-printing command.
* Syntax: pprint [/d depth] <sym_name>
*/
static void
db_pprint_symbol_cmd(const char *name)
{
db_addr_t addr;
int db_indent_old;
const char *type_name = NULL;
struct ctf_type_v3 *type = NULL;
if (db_pager_quit) {
return;
}
/* Clear symbol and CTF info */
memset(&sym_data, 0, sizeof(struct db_ctf_sym_data));
if (db_ctf_find_symbol(name, &sym_data) != 0) {
db_error("Symbol not found\n");
}
if (ELF_ST_TYPE(sym_data.sym->st_info) != STT_OBJECT) {
db_error("Symbol is not a variable\n");
}
addr = sym_data.sym->st_value;
type = db_ctf_sym_to_type(&sym_data);
if (type == NULL) {
db_error("Can't find CTF type info\n");
}
type_name = db_ctf_stroff_to_str(&sym_data, type->ctt_name);
if (type_name != NULL)
db_printf("%s ", type_name);
db_printf("%s = ", name);
db_indent_old = db_indent;
db_pprint_type(addr, type, 0);
db_indent = db_indent_old;
}
/*
* Command for pretty-printing arbitrary addresses.
* Syntax: pprint [/d depth] struct <struct_name> <addr>
*/
static void
db_pprint_struct_cmd(db_expr_t addr, const char *struct_name)
{
int db_indent_old;
struct ctf_type_v3 *type = NULL;
type = db_ctf_find_typename(&sym_data, struct_name);
if (type == NULL) {
db_error("Can't find CTF type info\n");
return;
}
db_printf("struct %s ", struct_name);
db_printf("%p = ", (void *)addr);
db_indent_old = db_indent;
db_pprint_type(addr, type, 0);
db_indent = db_indent_old;
}
/*
* Pretty print an address or a symbol.
*/
void
db_pprint_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
{
int t = 0;
const char *name;
/* Set default depth */
max_depth = DB_PPRINT_DEFAULT_DEPTH;
/* Parse print modifiers */
t = db_read_token();
if (t == tSLASH) {
t = db_read_token();
if (t != tIDENT) {
db_error("Invalid flag passed\n");
}
/* Parse desired depth level */
if (strcmp(db_tok_string, "d") == 0) {
t = db_read_token();
if (t != tNUMBER) {
db_error("Invalid depth provided\n");
}
max_depth = db_tok_number;
} else {
db_error("Invalid flag passed\n");
}
/* Fetch next token */
t = db_read_token();
}
/* Parse subcomannd */
if (t == tIDENT) {
if (strcmp(db_tok_string, "struct") == 0) {
t = db_read_token();
if (t != tIDENT) {
db_error("Invalid struct type name provided\n");
}
name = db_tok_string;
if (db_expression(&addr) == 0) {
db_error("Address not provided\n");
}
db_pprint_struct_cmd(addr, name);
} else {
name = db_tok_string;
db_pprint_symbol_cmd(name);
}
} else {
db_error("Invalid subcommand\n");
}
db_skip_to_eol();
}

1
sys/ddb/ddb.h
View file

@ -297,6 +297,7 @@ db_cmdfcn_t db_trace_until_matching_cmd;
db_cmdfcn_t db_unscript_cmd;
db_cmdfcn_t db_watchpoint_cmd;
db_cmdfcn_t db_write_cmd;
db_cmdfcn_t db_pprint_cmd;
/*
* Interface between DDB and the DDB output capture facility.

40
sys/kern/kern_ctf.c
View file

@ -27,6 +27,10 @@
*/
#include <sys/ctf.h>
#include <sys/kdb.h>
#include <sys/linker.h>
#include <ddb/db_ctf.h>
/*
* Note this file is included by both link_elf.c and link_elf_obj.c.
@ -86,6 +90,9 @@ link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
return (0);
}
if (panicstr != NULL || kdb_active)
return (ENXIO);
/*
* We need to try reading the CTF data. Flag no CTF data present
* by default and if we actually succeed in reading it, we'll
@ -288,3 +295,36 @@ link_elf_ctf_get(linker_file_t lf, linker_ctf_t *lc)
return (error);
}
static int
link_elf_ctf_get_ddb(linker_file_t lf, linker_ctf_t *lc)
{
elf_file_t ef = (elf_file_t)lf;
/*
* Check whether CTF data was loaded or if a
* previous loading attempt failed (ctfcnt == -1).
*/
if (ef->ctfcnt <= 0) {
return (ENOENT);
}
lc->ctftab = ef->ctftab;
lc->ctfcnt = ef->ctfcnt;
lc->symtab = ef->ddbsymtab;
lc->strtab = ef->ddbstrtab;
lc->strcnt = ef->ddbstrcnt;
lc->nsym = ef->ddbsymcnt;
return (0);
}
static int
link_elf_ctf_lookup_typename(linker_file_t lf, linker_ctf_t *lc,
const char *typename)
{
if (link_elf_ctf_get_ddb(lf, lc))
return (ENOENT);
return (db_ctf_lookup_typename(lc, typename) ? 0 : ENOENT);
}

68
sys/kern/kern_linker.c
View file

@ -328,6 +328,26 @@ linker_file_register_sysctls(linker_file_t lf, bool enable)
sx_xlock(&kld_sx);
}
/*
* Invoke the LINKER_CTF_GET implementation for this file. Existing
* implementations will load CTF info from the filesystem upon the first call
* and cache it in the kernel thereafter.
*/
static void
linker_ctf_load_file(linker_file_t file)
{
linker_ctf_t lc;
int error;
error = linker_ctf_get(file, &lc);
if (error == 0)
return;
if (bootverbose) {
printf("failed to load CTF for %s: %d\n", file->filename,
error);
}
}
static void
linker_file_enable_sysctls(linker_file_t lf)
{
@ -490,6 +510,11 @@ linker_load_file(const char *filename, linker_file_t *result)
return (ENOEXEC);
}
linker_file_enable_sysctls(lf);
/*
* Ask the linker to load CTF data for this file.
*/
linker_ctf_load_file(lf);
EVENTHANDLER_INVOKE(kld_load, lf);
*result = lf;
return (0);
@ -782,6 +807,35 @@ linker_ctf_get(linker_file_t file, linker_ctf_t *lc)
return (LINKER_CTF_GET(file, lc));
}
int
linker_ctf_lookup_typename_ddb(linker_ctf_t *lc, const char *typename)
{
#ifdef DDB
linker_file_t lf;
TAILQ_FOREACH (lf, &linker_files, link){
if (LINKER_CTF_LOOKUP_TYPENAME(lf, lc, typename) == 0)
return (0);
}
#endif
return (ENOENT);
}
int
linker_ctf_lookup_sym_ddb(const char *symname, c_linker_sym_t *sym,
linker_ctf_t *lc)
{
#ifdef DDB
linker_file_t lf;
TAILQ_FOREACH (lf, &linker_files, link){
if (LINKER_LOOKUP_DEBUG_SYMBOL_CTF(lf, symname, sym, lc) == 0)
return (0);
}
#endif
return (ENOENT);
}
static int
linker_file_add_dependency(linker_file_t file, linker_file_t dep)
{
@ -1781,9 +1835,21 @@ linker_preload(void *arg)
sx_xunlock(&kld_sx);
/* woohoo! we made it! */
}
SYSINIT(preload, SI_SUB_KLD, SI_ORDER_MIDDLE, linker_preload, NULL);
static void
linker_mountroot(void *arg __unused)
{
linker_file_t lf;
sx_xlock(&kld_sx);
TAILQ_FOREACH (lf, &linker_files, link) {
linker_ctf_load_file(lf);
}
sx_xunlock(&kld_sx);
}
EVENTHANDLER_DEFINE(mountroot, linker_mountroot, NULL, 0);
/*
* Handle preload files that failed to load any modules.
*/

37
sys/kern/link_elf.c
View file

@ -68,6 +68,10 @@
#include "linker_if.h"
#ifdef DDB_CTF
#include <ddb/db_ctf.h>
#endif
#define MAXSEGS 4
typedef struct elf_file {
@ -141,6 +145,9 @@ static int link_elf_lookup_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_lookup_debug_symbol_ctf(linker_file_t lf,
const char *name, c_linker_sym_t *sym, linker_ctf_t *lc);
static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
linker_symval_t *);
static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
@ -167,6 +174,7 @@ static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *);
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
KOBJMETHOD(linker_lookup_debug_symbol_ctf, link_elf_lookup_debug_symbol_ctf),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
@ -178,6 +186,7 @@ static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
KOBJMETHOD(linker_ctf_lookup_typename, link_elf_ctf_lookup_typename),
KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
#ifdef VIMAGE
@ -1587,6 +1596,34 @@ link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
return (ENOENT);
}
static int
link_elf_lookup_debug_symbol_ctf(linker_file_t lf, const char *name,
c_linker_sym_t *sym, linker_ctf_t *lc)
{
elf_file_t ef = (elf_file_t)lf;
const Elf_Sym *symp;
const char *strp;
int i;
for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) {
strp = ef->ddbstrtab + symp->st_name;
if (strcmp(name, strp) == 0) {
if (symp->st_shndx != SHN_UNDEF ||
(symp->st_value != 0 &&
(ELF_ST_TYPE(symp->st_info) == STT_FUNC ||
ELF_ST_TYPE(symp->st_info) ==
STT_GNU_IFUNC))) {
*sym = (c_linker_sym_t)symp;
break;
}
return (ENOENT);
}
}
/* Populate CTF info structure if symbol was found. */
return (i < ef->ddbsymcnt ? link_elf_ctf_get_ddb(lf, lc) : ENOENT);
}
static int
link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval, bool see_local)

14
sys/kern/link_elf_obj.c
View file

@ -131,6 +131,8 @@ static int link_elf_lookup_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_lookup_debug_symbol(linker_file_t, const char *,
c_linker_sym_t *);
static int link_elf_lookup_debug_symbol_ctf(linker_file_t lf,
const char *name, c_linker_sym_t *sym, linker_ctf_t *lc);
static int link_elf_symbol_values(linker_file_t, c_linker_sym_t,
linker_symval_t *);
static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t,
@ -159,6 +161,7 @@ static int elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps,
static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol),
KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol),
KOBJMETHOD(linker_lookup_debug_symbol_ctf, link_elf_lookup_debug_symbol_ctf),
KOBJMETHOD(linker_symbol_values, link_elf_symbol_values),
KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values),
KOBJMETHOD(linker_search_symbol, link_elf_search_symbol),
@ -170,6 +173,7 @@ static kobj_method_t link_elf_methods[] = {
KOBJMETHOD(linker_each_function_name, link_elf_each_function_name),
KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval),
KOBJMETHOD(linker_ctf_get, link_elf_ctf_get),
KOBJMETHOD(linker_ctf_lookup_typename, link_elf_ctf_lookup_typename),
KOBJMETHOD(linker_symtab_get, link_elf_symtab_get),
KOBJMETHOD(linker_strtab_get, link_elf_strtab_get),
#ifdef VIMAGE
@ -1475,6 +1479,16 @@ link_elf_lookup_debug_symbol(linker_file_t lf, const char *name,
return (link_elf_lookup_symbol1(lf, name, sym, true));
}
static int
link_elf_lookup_debug_symbol_ctf(linker_file_t lf, const char *name,
c_linker_sym_t *sym, linker_ctf_t *lc)
{
if (link_elf_lookup_debug_symbol(lf, name, sym))
return (ENOENT);
return (link_elf_ctf_get_ddb(lf, lc));
}
static int
link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym,
linker_symval_t *symval, bool see_local)

23
sys/kern/linker_if.m
View file

@ -115,6 +115,29 @@ METHOD int ctf_get {
linker_ctf_t *lc;
};
#
# Look up a CTF type in the file's CTF section
# and return CTF info in the linker CTF structure.
# Return ENOENT if typename is not found, otherwise zero.
#
METHOD int ctf_lookup_typename {
linker_file_t file;
linker_ctf_t *lc;
const char *typename;
};
#
# Lookup a symbol in the file's symbol table and the file's CTF info.
# Return ENOENT if either the symbol or its CTF
# data is not loaded, otherwise return zero.
#
METHOD int lookup_debug_symbol_ctf {
linker_file_t file;
const char *name;
c_linker_sym_t *sym;
linker_ctf_t *lc;
};
#
# Get the symbol table, returning it in **symtab. Return the
# number of symbols, otherwise zero.

3
sys/sys/linker.h
View file

@ -319,6 +319,9 @@ typedef struct linker_ctf {
} linker_ctf_t;
int linker_ctf_get(linker_file_t, linker_ctf_t *);
int linker_ctf_lookup_sym_ddb(const char *symname, c_linker_sym_t *sym,
linker_ctf_t *lc);
int linker_ctf_lookup_typename_ddb(linker_ctf_t *lc, const char *typename);
int elf_cpu_load_file(linker_file_t);
int elf_cpu_unload_file(linker_file_t);