projects/linux·blob v5.14 · refs

220 lines · 4.2 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015 Josh Poimboeuf <[email protected]>
4 */
5
6/*
7 * objtool:
8 *
9 * The 'check' subcmd analyzes every .o file and ensures the validity of its
10 * stack trace metadata. It enforces a set of rules on asm code and C inline
11 * assembly code so that stack traces can be reliable.
12 *
13 * For more information, see tools/objtool/Documentation/stack-validation.txt.
14 */
15
16#include <stdio.h>
17#include <stdbool.h>
18#include <string.h>
19#include <stdlib.h>
20#include <unistd.h>
21#include <subcmd/exec-cmd.h>
22#include <subcmd/pager.h>
23#include <linux/kernel.h>
24
25#include <objtool/builtin.h>
26#include <objtool/objtool.h>
27#include <objtool/warn.h>
28
29struct cmd_struct {
30 const char *name;
31 int (*fn)(int, const char **);
32 const char *help;
33};
34
35static const char objtool_usage_string[] =
36 "objtool COMMAND [ARGS]";
37
38static struct cmd_struct objtool_cmds[] = {
39 {"check", cmd_check, "Perform stack metadata validation on an object file" },
40 {"orc", cmd_orc, "Generate in-place ORC unwind tables for an object file" },
41};
42
43bool help;
44
45const char *objname;
46static struct objtool_file file;
47
48static bool objtool_create_backup(const char *_objname)
49{
50 int len = strlen(_objname);
51 char *buf, *base, *name = malloc(len+6);
52 int s, d, l, t;
53
54 if (!name) {
55 perror("failed backup name malloc");
56 return false;
57 }
58
59 strcpy(name, _objname);
60 strcpy(name + len, ".orig");
61
62 d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
63 if (d < 0) {
64 perror("failed to create backup file");
65 return false;
66 }
67
68 s = open(_objname, O_RDONLY);
69 if (s < 0) {
70 perror("failed to open orig file");
71 return false;
72 }
73
74 buf = malloc(4096);
75 if (!buf) {
76 perror("failed backup data malloc");
77 return false;
78 }
79
80 while ((l = read(s, buf, 4096)) > 0) {
81 base = buf;
82 do {
83 t = write(d, base, l);
84 if (t < 0) {
85 perror("failed backup write");
86 return false;
87 }
88 base += t;
89 l -= t;
90 } while (l);
91 }
92
93 if (l < 0) {
94 perror("failed backup read");
95 return false;
96 }
97
98 free(name);
99 free(buf);
100 close(d);
101 close(s);
102
103 return true;
104}
105
106struct objtool_file *objtool_open_read(const char *_objname)
107{
108 if (objname) {
109 if (strcmp(objname, _objname)) {
110 WARN("won't handle more than one file at a time");
111 return NULL;
112 }
113 return &file;
114 }
115 objname = _objname;
116
117 file.elf = elf_open_read(objname, O_RDWR);
118 if (!file.elf)
119 return NULL;
120
121 if (backup && !objtool_create_backup(objname)) {
122 WARN("can't create backup file");
123 return NULL;
124 }
125
126 INIT_LIST_HEAD(&file.insn_list);
127 hash_init(file.insn_hash);
128 INIT_LIST_HEAD(&file.retpoline_call_list);
129 INIT_LIST_HEAD(&file.static_call_list);
130 INIT_LIST_HEAD(&file.mcount_loc_list);
131 file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
132 file.ignore_unreachables = no_unreachable;
133 file.hints = false;
134
135 return &file;
136}
137
138static void cmd_usage(void)
139{
140 unsigned int i, longest = 0;
141
142 printf("\n usage: %s\n\n", objtool_usage_string);
143
144 for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
145 if (longest < strlen(objtool_cmds[i].name))
146 longest = strlen(objtool_cmds[i].name);
147 }
148
149 puts(" Commands:");
150 for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
151 printf(" %-*s ", longest, objtool_cmds[i].name);
152 puts(objtool_cmds[i].help);
153 }
154
155 printf("\n");
156
157 if (!help)
158 exit(129);
159 exit(0);
160}
161
162static void handle_options(int *argc, const char ***argv)
163{
164 while (*argc > 0) {
165 const char *cmd = (*argv)[0];
166
167 if (cmd[0] != '-')
168 break;
169
170 if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
171 help = true;
172 break;
173 } else {
174 fprintf(stderr, "Unknown option: %s\n", cmd);
175 cmd_usage();
176 }
177
178 (*argv)++;
179 (*argc)--;
180 }
181}
182
183static void handle_internal_command(int argc, const char **argv)
184{
185 const char *cmd = argv[0];
186 unsigned int i, ret;
187
188 for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
189 struct cmd_struct *p = objtool_cmds+i;
190
191 if (strcmp(p->name, cmd))
192 continue;
193
194 ret = p->fn(argc, argv);
195
196 exit(ret);
197 }
198
199 cmd_usage();
200}
201
202int main(int argc, const char **argv)
203{
204 static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
205
206 /* libsubcmd init */
207 exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
208 pager_init(UNUSED);
209
210 argv++;
211 argc--;
212 handle_options(&argc, &argv);
213
214 if (!argc || help)
215 cmd_usage();
216
217 handle_internal_command(argc, argv);
218
219 return 0;
220}