projects/linux·blob master · refs

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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2015-2017 Josh Poimboeuf <[email protected]>
4 */
5
6#include <subcmd/parse-options.h>
7#include <string.h>
8#include <stdlib.h>
9#include <fcntl.h>
10#include <unistd.h>
11#include <errno.h>
12#include <sys/stat.h>
13#include <sys/sendfile.h>
14#include <objtool/builtin.h>
15#include <objtool/objtool.h>
16#include <objtool/warn.h>
17
18#define ORIG_SUFFIX ".orig"
19
20int orig_argc;
21static char **orig_argv;
22const char *objname;
23struct opts opts;
24
25static const char * const check_usage[] = {
26 "objtool <actions> [<options>] file.o",
27 NULL,
28};
29
30static const char * const env_usage[] = {
31 "OBJTOOL_ARGS=\"<options>\"",
32 NULL,
33};
34
35static int parse_dump(const struct option *opt, const char *str, int unset)
36{
37 if (!str || !strcmp(str, "orc")) {
38 opts.dump_orc = true;
39 return 0;
40 }
41
42 return -1;
43}
44
45static int parse_hacks(const struct option *opt, const char *str, int unset)
46{
47 bool found = false;
48
49 /*
50 * Use strstr() as a lazy method of checking for comma-separated
51 * options.
52 *
53 * No string provided == enable all options.
54 */
55
56 if (!str || strstr(str, "jump_label")) {
57 opts.hack_jump_label = true;
58 found = true;
59 }
60
61 if (!str || strstr(str, "noinstr")) {
62 opts.hack_noinstr = true;
63 found = true;
64 }
65
66 if (!str || strstr(str, "skylake")) {
67 opts.hack_skylake = true;
68 found = true;
69 }
70
71 return found ? 0 : -1;
72}
73
74static const struct option check_options[] = {
75 OPT_GROUP("Actions:"),
76 OPT_STRING_OPTARG('d', "disas", &opts.disas, "function-pattern", "disassemble functions", "*"),
77 OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
78 OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
79 OPT_BOOLEAN(0, "klp-symids", &opts.klp_symids, "generate .klp.symids for duplicate symbol disambiguation"),
80 OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
81 OPT_BOOLEAN(0, "noabs", &opts.noabs, "reject absolute references in allocatable sections"),
82 OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
83 OPT_BOOLEAN(0, "orc", &opts.orc, "generate ORC metadata"),
84 OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
85 OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
86 OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"),
87 OPT_INTEGER(0, "prefix", &opts.prefix, "generate or grow prefix symbols for N-byte function padding"),
88 OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
89 OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
90 OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
91 OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
92 OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
93
94 OPT_GROUP("Options:"),
95 OPT_BOOLEAN(0, "cfi", &opts.cfi, "grow kCFI preamble symbols (use with --prefix)"),
96 OPT_BOOLEAN(0, "fineibt", &opts.fineibt, "create .cfi_sites section for FineIBT"),
97 OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
98 OPT_BOOLEAN(0, "backup", &opts.backup, "create backup (.orig) file on warning/error"),
99 OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
100 OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
101 OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
102 OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
103 OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
104 OPT_STRING('o', "output", &opts.output, "file", "output file name"),
105 OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
106 OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
107 OPT_STRING(0, "trace", &opts.trace, "func", "trace function validation"),
108 OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
109 OPT_BOOLEAN(0, "werror", &opts.werror, "return error on warnings"),
110 OPT_BOOLEAN(0, "wide", &opts.wide, "wide output"),
111
112 OPT_END(),
113};
114
115int cmd_parse_options(int argc, const char **argv, const char * const usage[])
116{
117 const char *envv[16] = { };
118 char *env;
119 int envc;
120
121 env = getenv("OBJTOOL_ARGS");
122 if (env) {
123 envv[0] = "OBJTOOL_ARGS";
124 for (envc = 1; envc < ARRAY_SIZE(envv); ) {
125 envv[envc++] = env;
126 env = strchr(env, ' ');
127 if (!env)
128 break;
129 *env = '\0';
130 env++;
131 }
132
133 parse_options(envc, envv, check_options, env_usage, 0);
134 }
135
136 env = getenv("OBJTOOL_VERBOSE");
137 if (env && !strcmp(env, "1"))
138 opts.verbose = true;
139
140 argc = parse_options(argc, argv, check_options, usage, 0);
141 if (argc != 1)
142 usage_with_options(usage, check_options);
143 return argc;
144}
145
146static bool opts_valid(void)
147{
148 if (opts.mnop && !opts.mcount) {
149 ERROR("--mnop requires --mcount");
150 return false;
151 }
152
153 if (opts.noinstr && !opts.link) {
154 ERROR("--noinstr requires --link");
155 return false;
156 }
157
158 if (opts.ibt && !opts.link) {
159 ERROR("--ibt requires --link");
160 return false;
161 }
162
163 if (opts.unret && !opts.link) {
164 ERROR("--unret requires --link");
165 return false;
166 }
167
168 if (opts.cfi && !opts.prefix) {
169 ERROR("--cfi requires --prefix");
170 return false;
171 }
172
173 if (opts.fineibt && !opts.cfi) {
174 ERROR("--fineibt requires --cfi");
175 return false;
176 }
177
178 if (opts.klp_symids && !opts.link) {
179 ERROR("--klp-symids requires --link");
180 return false;
181 }
182
183 if (opts.disas ||
184 opts.hack_jump_label ||
185 opts.hack_noinstr ||
186 opts.ibt ||
187 opts.klp_symids ||
188 opts.mcount ||
189 opts.noabs ||
190 opts.noinstr ||
191 opts.orc ||
192 opts.retpoline ||
193 opts.rethunk ||
194 opts.sls ||
195 opts.stackval ||
196 opts.static_call ||
197 opts.uaccess) {
198 if (opts.dump_orc) {
199 ERROR("--dump can't be combined with other actions");
200 return false;
201 }
202
203 return true;
204 }
205
206 if (opts.dump_orc)
207 return true;
208
209 ERROR("At least one action required");
210 return false;
211}
212
213static int copy_file(const char *src, const char *dst)
214{
215 size_t to_copy, copied;
216 int dst_fd, src_fd;
217 struct stat stat;
218 off_t offset = 0;
219
220 src_fd = open(src, O_RDONLY);
221 if (src_fd == -1) {
222 ERROR("can't open %s for reading: %s", src, strerror(errno));
223 return 1;
224 }
225
226 dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400);
227 if (dst_fd == -1) {
228 ERROR("can't open %s for writing: %s", dst, strerror(errno));
229 return 1;
230 }
231
232 if (fstat(src_fd, &stat) == -1) {
233 ERROR_GLIBC("fstat");
234 return 1;
235 }
236
237 if (fchmod(dst_fd, stat.st_mode) == -1) {
238 ERROR_GLIBC("fchmod");
239 return 1;
240 }
241
242 for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) {
243 copied = sendfile(dst_fd, src_fd, &offset, to_copy);
244 if (copied == -1) {
245 ERROR_GLIBC("sendfile");
246 return 1;
247 }
248 }
249
250 close(dst_fd);
251 close(src_fd);
252 return 0;
253}
254
255static void save_argv(int argc, const char **argv)
256{
257 orig_argv = calloc(argc, sizeof(char *));
258 if (!orig_argv) {
259 ERROR_GLIBC("calloc");
260 exit(1);
261 }
262
263 for (int i = 0; i < argc; i++) {
264 orig_argv[i] = strdup(argv[i]);
265 if (!orig_argv[i]) {
266 ERROR_GLIBC("strdup(%s)", argv[i]);
267 exit(1);
268 }
269 }
270}
271
272int make_backup(void)
273{
274 char *backup;
275
276 /*
277 * Make a backup before kbuild deletes the file so the error
278 * can be recreated without recompiling or relinking.
279 */
280 backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
281 if (!backup) {
282 ERROR_GLIBC("malloc");
283 return 1;
284 }
285
286 strcpy(backup, objname);
287 strcat(backup, ORIG_SUFFIX);
288 if (copy_file(objname, backup))
289 return 1;
290
291 /*
292 * Print the cmdline args to make it easier to recreate.
293 */
294
295 fprintf(stderr, "%s", orig_argv[0]);
296
297 for (int i = 1; i < orig_argc; i++) {
298 char *arg = orig_argv[i];
299
300 /* Modify the printed args to use the backup */
301 if (!opts.output && !strcmp(arg, objname))
302 fprintf(stderr, " %s -o %s", backup, objname);
303 else
304 fprintf(stderr, " %s", arg);
305 }
306
307 fprintf(stderr, "\n");
308 return 0;
309}
310
311int objtool_run(int argc, const char **argv)
312{
313 struct objtool_file *file;
314 int ret = 0;
315
316 orig_argc = argc;
317 save_argv(argc, argv);
318
319 cmd_parse_options(argc, argv, check_usage);
320
321 if (!opts_valid())
322 return 1;
323
324 objname = argv[0];
325
326 if (opts.dump_orc)
327 return orc_dump(objname);
328
329 if (!opts.dryrun && opts.output) {
330 /* copy original .o file to output file */
331 if (copy_file(objname, opts.output))
332 return 1;
333
334 /* from here on, work directly on the output file */
335 objname = opts.output;
336 }
337
338 file = objtool_open_read(objname);
339 if (!file)
340 return 1;
341
342 if (!opts.link && has_multiple_files(file->elf)) {
343 ERROR("Linked object requires --link");
344 return 1;
345 }
346
347 ret = check(file);
348 if (ret)
349 return ret;
350
351 if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
352 return 1;
353
354 return elf_close(file->elf);
355}