tools/objtool/objtool.c

   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 "builtin.h"
  25 #include "objtool.h"
  26 #include "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         file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment");
  66         file.ignore_unreachables = no_unreachable;
  67         file.hints = false;
  68
  69         return &file;
  70 }
  71
  72 static void cmd_usage(void)
  73 {
  74         unsigned int i, longest = 0;
  75
  76         printf("\n usage: %s\n\n", objtool_usage_string);
  77
  78         for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
  79                 if (longest < strlen(objtool_cmds[i].name))
  80                         longest = strlen(objtool_cmds[i].name);
  81         }
  82
  83         puts(" Commands:");
  84         for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
  85                 printf("   %-*s   ", longest, objtool_cmds[i].name);
  86                 puts(objtool_cmds[i].help);
  87         }
  88
  89         printf("\n");
  90
  91         if (!help)
  92                 exit(129);
  93         exit(0);
  94 }
  95
  96 static void handle_options(int *argc, const char ***argv)
  97 {
  98         while (*argc > 0) {
  99                 const char *cmd = (*argv)[0];
 100
 101                 if (cmd[0] != '-')
 102                         break;
 103
 104                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h")) {
 105                         help = true;
 106                         break;
 107                 } else {
 108                         fprintf(stderr, "Unknown option: %s\n", cmd);
 109                         cmd_usage();
 110                 }
 111
 112                 (*argv)++;
 113                 (*argc)--;
 114         }
 115 }
 116
 117 static void handle_internal_command(int argc, const char **argv)
 118 {
 119         const char *cmd = argv[0];
 120         unsigned int i, ret;
 121
 122         for (i = 0; i < ARRAY_SIZE(objtool_cmds); i++) {
 123                 struct cmd_struct *p = objtool_cmds+i;
 124
 125                 if (strcmp(p->name, cmd))
 126                         continue;
 127
 128                 ret = p->fn(argc, argv);
 129
 130                 exit(ret);
 131         }
 132
 133         cmd_usage();
 134 }
 135
 136 int main(int argc, const char **argv)
 137 {
 138         static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
 139
 140         /* libsubcmd init */
 141         exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
 142         pager_init(UNUSED);
 143
 144         argv++;
 145         argc--;
 146         handle_options(&argc, &argv);
 147
 148         if (!argc || help)
 149                 cmd_usage();
 150
 151         handle_internal_command(argc, argv);
 152
 153         return 0;
 154 }