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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
*/
/*
* objtool:
*
* The 'check' subcmd analyzes every .o file and ensures the validity of its
* stack trace metadata. It enforces a set of rules on asm code and C inline
* assembly code so that stack traces can be reliable.
*
* For more information, see tools/objtool/Documentation/stack-validation.txt.
*/
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <subcmd/exec-cmd.h>
#include <subcmd/pager.h>
#include <linux/kernel.h>
#include <objtool/builtin.h>
#include <objtool/objtool.h>
#include <objtool/warn.h>
struct cmd_struct {
const char *name;
int (*fn)(int, const char **);
const char *help;
};
static const char objtool_usage_string[] =
"objtool COMMAND [ARGS]";
static struct cmd_struct objtool_cmds[] = {
{"check", cmd_check, "Perform stack metadata validation on an object file" },
{"orc", cmd_orc, "Generate in-place ORC unwind tables for an object file" },
};
bool help;
const char *objname;
static struct objtool_file file;
static bool objtool_create_backup(const char *_objname)
{
int len = strlen(_objname);
char *buf, *base, *name = malloc(len+6);
int s, d, l, t;
if (!name) {
perror("failed backup name malloc");
return false;
}
strcpy(name, _objname);
strcpy(name + len, ".orig");
d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
if (d < 0) {
perror("failed to create backup file");
return false;
}
s = open(_objname, O_RDONLY);
if (s < 0) {
perror("failed to open orig file");
return false;
}
buf = malloc(4096);
if (!buf) {
perror("failed backup data malloc");
return false;
}
while ((l = read(s, buf, 4096)) > 0) {
base = buf;
do {
t = write(d, base, l);
if (t < 0) {
perror("failed backup write");
return false;
}
base += t;
l -= t;
} while (l);
}
if (l < 0) {
perror("failed backup read");
return false;
}
free(name);
free(buf);
close(d);
close(s);
return true;
}
struct objtool_file *objtool_open_read(const char *_objname)
{
if (objname) {
if (strcmp(objname, _objname)) {
WARN("won't handle more than one file at a time");
return NULL;
}
return &file;
}
objname = _objname;
file.elf = elf_open_read(objname, O_RDWR);
if (!file.elf)
return NULL;
if (backup && !objtool_create_backup(objname)) {
WARN("can't create backup file");
return NULL;
}
INIT_LIST_HEAD(&file.insn_list);
hash_init(file.insn_hash);
INIT_LIST_HEAD(&file.retpoline_call_list);
INIT_LIST_HEAD(&file.static_call_list);
INIT_LIST_HEAD(&file.mcount_loc_list);
file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
file.ignore_unreachables = no_unreachable;
file.hints = false;
return &file;
}
void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
{
if (!noinstr)
return;
if (!f->pv_ops) {
WARN("paravirt confusion");
return;
}
/*
* These functions will be patched into native code,
* see paravirt_patch().
*/
if (!strcmp(func->name, "_paravirt_nop") ||
!strcmp(func->name, "_paravirt_ident_64"))
return;
/* already added this function */
if (!list_empty(&func->pv_target))
return;
list_add(&func->pv_target, &f->pv_ops[idx].targets);
f->pv_ops[idx].clean = false;
}
static void cmd_usage(void)
{
unsigned int i, longest = 0;
printf("\n usage: %s\n\n", objtool_usage_string);
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
if (longest < strlen(objtool_cmds[i].name))
longest = strlen(objtool_cmds[i].name);
}
puts(" Commands:");
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
printf(" %-*s ", longest, objtool_cmds[i].name);
puts(objtool_cmds[i].help);
}
printf("\n");
if (!help)
exit(129);
exit(0);
}
static void handle_options(int *argc, const char ***argv)
{
while (*argc > 0) {
const char *cmd = (*argv)[0];
if (cmd[0] != '-')
break;
if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
help = true;
break;
} else {
fprintf(stderr, "Unknown option: %s\n", cmd);
cmd_usage();
}
(*argv)++;
(*argc)--;
}
}
static void handle_internal_command(int argc, const char **argv)
{
const char *cmd = argv[0];
unsigned int i, ret;
for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
struct cmd_struct *p = objtool_cmds+i;
if (strcmp(p->name, cmd))
continue;
ret = p->fn(argc, argv);
exit(ret);
}
cmd_usage();
}
int main(int argc, const char **argv)
{
static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
/* libsubcmd init */
exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
pager_init(UNUSED);
argv++;
argc--;
handle_options(&argc, &argv);
if (!argc || help)
cmd_usage();
handle_internal_command(argc, argv);
return 0;
}
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