xref: /openbmc/linux/tools/objtool/objtool.c (revision 31e67366)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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 <subcmd/exec-cmd.h>
21 #include <subcmd/pager.h>
22 #include <linux/kernel.h>
23 
24 #include <objtool/builtin.h>
25 #include <objtool/objtool.h>
26 #include <objtool/warn.h>
27 
28 struct cmd_struct {
29 	const char *name;
30 	int (*fn)(int, const char **);
31 	const char *help;
32 };
33 
34 static const char objtool_usage_string[] =
35 	"objtool COMMAND [ARGS]";
36 
37 static struct cmd_struct objtool_cmds[] = {
38 	{"check",	cmd_check,	"Perform stack metadata validation on an object file" },
39 	{"orc",		cmd_orc,	"Generate in-place ORC unwind tables for an object file" },
40 };
41 
42 bool help;
43 
44 const char *objname;
45 static struct objtool_file file;
46 
47 struct objtool_file *objtool_open_read(const char *_objname)
48 {
49 	if (objname) {
50 		if (strcmp(objname, _objname)) {
51 			WARN("won't handle more than one file at a time");
52 			return NULL;
53 		}
54 		return &file;
55 	}
56 	objname = _objname;
57 
58 	file.elf = elf_open_read(objname, O_RDWR);
59 	if (!file.elf)
60 		return NULL;
61 
62 	INIT_LIST_HEAD(&file.insn_list);
63 	hash_init(file.insn_hash);
64 	INIT_LIST_HEAD(&file.static_call_list);
65 	INIT_LIST_HEAD(&file.mcount_loc_list);
66 	file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
67 	file.ignore_unreachables = no_unreachable;
68 	file.hints = false;
69 
70 	return &file;
71 }
72 
73 static void cmd_usage(void)
74 {
75 	unsigned int i, longest = 0;
76 
77 	printf("\n usage: %s\n\n", objtool_usage_string);
78 
79 	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
80 		if (longest < strlen(objtool_cmds[i].name))
81 			longest = strlen(objtool_cmds[i].name);
82 	}
83 
84 	puts(" Commands:");
85 	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
86 		printf("   %-*s   ", longest, objtool_cmds[i].name);
87 		puts(objtool_cmds[i].help);
88 	}
89 
90 	printf("\n");
91 
92 	if (!help)
93 		exit(129);
94 	exit(0);
95 }
96 
97 static void handle_options(int *argc, const char ***argv)
98 {
99 	while (*argc > 0) {
100 		const char *cmd = (*argv)[0];
101 
102 		if (cmd[0] != '-')
103 			break;
104 
105 		if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
106 			help = true;
107 			break;
108 		} else {
109 			fprintf(stderr, "Unknown option: %s\n", cmd);
110 			cmd_usage();
111 		}
112 
113 		(*argv)++;
114 		(*argc)--;
115 	}
116 }
117 
118 static void handle_internal_command(int argc, const char **argv)
119 {
120 	const char *cmd = argv[0];
121 	unsigned int i, ret;
122 
123 	for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
124 		struct cmd_struct *p = objtool_cmds+i;
125 
126 		if (strcmp(p->name, cmd))
127 			continue;
128 
129 		ret = p->fn(argc, argv);
130 
131 		exit(ret);
132 	}
133 
134 	cmd_usage();
135 }
136 
137 int main(int argc, const char **argv)
138 {
139 	static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
140 
141 	/* libsubcmd init */
142 	exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
143 	pager_init(UNUSED);
144 
145 	argv++;
146 	argc--;
147 	handle_options(&argc, &argv);
148 
149 	if (!argc || help)
150 		cmd_usage();
151 
152 	handle_internal_command(argc, argv);
153 
154 	return 0;
155 }
156