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 #include <stdio.h>
   7 #include <stdbool.h>
   8 #include <string.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <subcmd/exec-cmd.h>
  12 #include <subcmd/pager.h>
  13 #include <linux/kernel.h>
  14
  15 #include <objtool/builtin.h>
  16 #include <objtool/objtool.h>
  17 #include <objtool/warn.h>
  18
  19 bool help;
  20
  21 const char *objname;
  22 static struct objtool_file file;
  23
  24 static bool objtool_create_backup(const char *_objname)
  25 {
  26         int len = strlen(_objname);
  27         char *buf, *base, *name = malloc(len+6);
  28         int s, d, l, t;
  29
  30         if (!name) {
  31                 perror("failed backup name malloc");
  32                 return false;
  33         }
  34
  35         strcpy(name, _objname);
  36         strcpy(name + len, ".orig");
  37
  38         d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
  39         if (d < 0) {
  40                 perror("failed to create backup file");
  41                 return false;
  42         }
  43
  44         s = open(_objname, O_RDONLY);
  45         if (s < 0) {
  46                 perror("failed to open orig file");
  47                 return false;
  48         }
  49
  50         buf = malloc(4096);
  51         if (!buf) {
  52                 perror("failed backup data malloc");
  53                 return false;
  54         }
  55
  56         while ((l = read(s, buf, 4096)) > 0) {
  57                 base = buf;
  58                 do {
  59                         t = write(d, base, l);
  60                         if (t < 0) {
  61                                 perror("failed backup write");
  62                                 return false;
  63                         }
  64                         base += t;
  65                         l -= t;
  66                 } while (l);
  67         }
  68
  69         if (l < 0) {
  70                 perror("failed backup read");
  71                 return false;
  72         }
  73
  74         free(name);
  75         free(buf);
  76         close(d);
  77         close(s);
  78
  79         return true;
  80 }
  81
  82 struct objtool_file *objtool_open_read(const char *_objname)
  83 {
  84         if (objname) {
  85                 if (strcmp(objname, _objname)) {
  86                         WARN("won't handle more than one file at a time");
  87                         return NULL;
  88                 }
  89                 return &file;
  90         }
  91         objname = _objname;
  92
  93         file.elf = elf_open_read(objname, O_RDWR);
  94         if (!file.elf)
  95                 return NULL;
  96
  97         if (opts.backup && !objtool_create_backup(objname)) {
  98                 WARN("can't create backup file");
  99                 return NULL;
 100         }
 101
 102         hash_init(file.insn_hash);
 103         INIT_LIST_HEAD(&file.retpoline_call_list);
 104         INIT_LIST_HEAD(&file.return_thunk_list);
 105         INIT_LIST_HEAD(&file.static_call_list);
 106         INIT_LIST_HEAD(&file.mcount_loc_list);
 107         INIT_LIST_HEAD(&file.endbr_list);
 108         INIT_LIST_HEAD(&file.call_list);
 109         file.ignore_unreachables = opts.no_unreachable;
 110         file.hints = false;
 111
 112         return &file;
 113 }
 114
 115 void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
 116 {
 117         if (!opts.noinstr)
 118                 return;
 119
 120         if (!f->pv_ops) {
 121                 WARN("paravirt confusion");
 122                 return;
 123         }
 124
 125         /*
 126          * These functions will be patched into native code,
 127          * see paravirt_patch().
 128          */
 129         if (!strcmp(func->name, "_paravirt_nop") ||
 130             !strcmp(func->name, "_paravirt_ident_64"))
 131                 return;
 132
 133         /* already added this function */
 134         if (!list_empty(&func->pv_target))
 135                 return;
 136
 137         list_add(&func->pv_target, &f->pv_ops[idx].targets);
 138         f->pv_ops[idx].clean = false;
 139 }
 140
 141 int main(int argc, const char **argv)
 142 {
 143         static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
 144
 145         /* libsubcmd init */
 146         exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
 147         pager_init(UNUSED);
 148
 149         return objtool_run(argc, argv);
 150 }