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Mini Shell
Mini Shell
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
#include <subcmd/parse-options.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/sendfile.h>
#include <objtool/builtin.h>
#include <objtool/objtool.h>
#define ERROR(format, ...) \
fprintf(stderr, \
"error: objtool: " format "\n", \
##__VA_ARGS__)
const char *objname;
struct opts opts;
static const char * const check_usage[] = {
"objtool <actions> [<options>] file.o",
NULL,
};
static const char * const env_usage[] = {
"OBJTOOL_ARGS=\"<options>\"",
NULL,
};
static int parse_dump(const struct option *opt, const char *str, int unset)
{
if (!str || !strcmp(str, "orc")) {
opts.dump_orc = true;
return 0;
}
return -1;
}
static int parse_hacks(const struct option *opt, const char *str, int unset)
{
bool found = false;
/*
* Use strstr() as a lazy method of checking for comma-separated
* options.
*
* No string provided == enable all options.
*/
if (!str || strstr(str, "jump_label")) {
opts.hack_jump_label = true;
found = true;
}
if (!str || strstr(str, "noinstr")) {
opts.hack_noinstr = true;
found = true;
}
if (!str || strstr(str, "skylake")) {
opts.hack_skylake = true;
found = true;
}
return found ? 0 : -1;
}
const struct option check_options[] = {
OPT_GROUP("Actions:"),
OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
OPT_BOOLEAN(0, "orc", &opts.orc, "generate ORC metadata"),
OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"),
OPT_INTEGER(0, "prefix", &opts.prefix, "generate prefix symbols"),
OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
OPT_GROUP("Options:"),
OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
OPT_STRING('o', "output", &opts.output, "file", "output file name"),
OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
OPT_BOOLEAN(0, "Werror", &opts.werror, "return error on warnings"),
OPT_END(),
};
int cmd_parse_options(int argc, const char **argv, const char * const usage[])
{
const char *envv[16] = { };
char *env;
int envc;
env = getenv("OBJTOOL_ARGS");
if (env) {
envv[0] = "OBJTOOL_ARGS";
for (envc = 1; envc < ARRAY_SIZE(envv); ) {
envv[envc++] = env;
env = strchr(env, ' ');
if (!env)
break;
*env = '\0';
env++;
}
parse_options(envc, envv, check_options, env_usage, 0);
}
argc = parse_options(argc, argv, check_options, usage, 0);
if (argc != 1)
usage_with_options(usage, check_options);
return argc;
}
static bool opts_valid(void)
{
if (opts.hack_jump_label ||
opts.hack_noinstr ||
opts.ibt ||
opts.mcount ||
opts.noinstr ||
opts.orc ||
opts.retpoline ||
opts.sls ||
opts.stackval ||
opts.static_call ||
opts.uaccess) {
if (opts.dump_orc) {
ERROR("--dump can't be combined with other options");
return false;
}
return true;
}
if (opts.dump_orc)
return true;
ERROR("At least one command required");
return false;
}
static bool mnop_opts_valid(void)
{
if (opts.mnop && !opts.mcount) {
ERROR("--mnop requires --mcount");
return false;
}
return true;
}
static bool link_opts_valid(struct objtool_file *file)
{
if (opts.link)
return true;
if (has_multiple_files(file->elf)) {
ERROR("Linked object detected, forcing --link");
opts.link = true;
return true;
}
if (opts.noinstr) {
ERROR("--noinstr requires --link");
return false;
}
if (opts.ibt) {
ERROR("--ibt requires --link");
return false;
}
if (opts.unret) {
ERROR("--unret requires --link");
return false;
}
return true;
}
static int copy_file(const char *src, const char *dst)
{
size_t to_copy, copied;
int dst_fd, src_fd;
struct stat stat;
off_t offset = 0;
src_fd = open(src, O_RDONLY);
if (src_fd == -1) {
ERROR("can't open '%s' for reading", src);
return 1;
}
dst_fd = open(dst, O_WRONLY | O_CREAT | O_TRUNC, 0400);
if (dst_fd == -1) {
ERROR("can't open '%s' for writing", dst);
return 1;
}
if (fstat(src_fd, &stat) == -1) {
perror("fstat");
return 1;
}
if (fchmod(dst_fd, stat.st_mode) == -1) {
perror("fchmod");
return 1;
}
for (to_copy = stat.st_size; to_copy > 0; to_copy -= copied) {
copied = sendfile(dst_fd, src_fd, &offset, to_copy);
if (copied == -1) {
perror("sendfile");
return 1;
}
}
close(dst_fd);
close(src_fd);
return 0;
}
static char **save_argv(int argc, const char **argv)
{
char **orig_argv;
orig_argv = calloc(argc, sizeof(char *));
if (!orig_argv) {
perror("calloc");
return NULL;
}
for (int i = 0; i < argc; i++) {
orig_argv[i] = strdup(argv[i]);
if (!orig_argv[i]) {
perror("strdup");
return NULL;
}
};
return orig_argv;
}
#define ORIG_SUFFIX ".orig"
int objtool_run(int argc, const char **argv)
{
struct objtool_file *file;
char *backup = NULL;
char **orig_argv;
int ret = 0;
orig_argv = save_argv(argc, argv);
if (!orig_argv)
return 1;
cmd_parse_options(argc, argv, check_usage);
if (!opts_valid())
return 1;
objname = argv[0];
if (opts.dump_orc)
return orc_dump(objname);
if (!opts.dryrun && opts.output) {
/* copy original .o file to output file */
if (copy_file(objname, opts.output))
return 1;
/* from here on, work directly on the output file */
objname = opts.output;
}
file = objtool_open_read(objname);
if (!file)
goto err;
if (!mnop_opts_valid())
goto err;
if (!link_opts_valid(file))
goto err;
ret = check(file);
if (ret)
goto err;
if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
goto err;
return 0;
err:
if (opts.dryrun)
goto err_msg;
if (opts.output) {
unlink(opts.output);
goto err_msg;
}
/*
* Make a backup before kbuild deletes the file so the error
* can be recreated without recompiling or relinking.
*/
backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
if (!backup) {
perror("malloc");
return 1;
}
strcpy(backup, objname);
strcat(backup, ORIG_SUFFIX);
if (copy_file(objname, backup))
return 1;
err_msg:
fprintf(stderr, "%s", orig_argv[0]);
for (int i = 1; i < argc; i++) {
char *arg = orig_argv[i];
if (backup && !strcmp(arg, objname))
fprintf(stderr, " %s -o %s", backup, objname);
else
fprintf(stderr, " %s", arg);
}
fprintf(stderr, "\n");
return 1;
}
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