summaryrefslogtreecommitdiff
path: root/tools/objtool/objtool.c
blob: a7ecc32e35125d49fae642d9d57c104620a625bb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
 */

#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>

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 (opts.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.return_thunk_list);
	INIT_LIST_HEAD(&file.static_call_list);
	INIT_LIST_HEAD(&file.mcount_loc_list);
	INIT_LIST_HEAD(&file.endbr_list);
	file.ignore_unreachables = opts.no_unreachable;
	file.hints = false;

	return &file;
}

void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
{
	if (!opts.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;
}

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);

	objtool_run(argc, argv);

	return 0;
}