The following commit has been merged into the objtool/core branch of tip: Commit-ID: 327695eb9e3461b09d5cd5baef5df6526dd240c6 Gitweb: https://git.kernel.org/tip/327695eb9e3461b09d5cd5baef5df6526dd240c6 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Fri, 26 Feb 2021 10:59:59 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Wed, 03 Mar 2021 09:38:31 +01:00 objtool: Add --backup Teach objtool to write backups files, such that it becomes easier to see what objtool did to the object file. Backup files will be ${name}.orig. Suggested-by: Borislav Petkov <bp@xxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Acked-by: Borislav Petkov <bp@xxxxxxx> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lkml.kernel.org/r/YD4obT3aoXPWl7Ax@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx --- tools/objtool/builtin-check.c | 4 +- tools/objtool/include/objtool/builtin.h | 3 +- tools/objtool/objtool.c | 64 ++++++++++++++++++++++++- 3 files changed, 69 insertions(+), 2 deletions(-) diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index c3a85d8..97f063d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -18,7 +18,8 @@ #include <objtool/builtin.h> #include <objtool/objtool.h> -bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr; +bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, + validate_dup, vmlinux, mcount, noinstr, backup; static const char * const check_usage[] = { "objtool check [<options>] file.o", @@ -37,6 +38,7 @@ const struct option check_options[] = { OPT_BOOLEAN('n', "noinstr", &noinstr, "noinstr validation for vmlinux.o"), OPT_BOOLEAN('l', "vmlinux", &vmlinux, "vmlinux.o validation"), OPT_BOOLEAN('M', "mcount", &mcount, "generate __mcount_loc"), + OPT_BOOLEAN('B', "backup", &backup, "create .orig files before modification"), OPT_END(), }; diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index 2502bb2..d019210 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -8,7 +8,8 @@ #include <subcmd/parse-options.h> extern const struct option check_options[]; -extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, validate_dup, vmlinux, mcount, noinstr; +extern bool no_fp, no_unreachable, retpoline, module, backtrace, uaccess, stats, + validate_dup, vmlinux, mcount, noinstr, backup; extern int cmd_check(int argc, const char **argv); extern int cmd_orc(int argc, const char **argv); diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c index 7b97ce4..43c1836 100644 --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -17,6 +17,7 @@ #include <stdbool.h> #include <string.h> #include <stdlib.h> +#include <unistd.h> #include <subcmd/exec-cmd.h> #include <subcmd/pager.h> #include <linux/kernel.h> @@ -44,6 +45,64 @@ bool help; const char *objname; static struct objtool_file file; +static bool objtool_create_backup(const char *_objname) +{ + int len = strlen(_objname); + char *buf, *base, *name = malloc(len+6); + int s, d, l, t; + + if (!name) { + perror("failed backup name malloc"); + return false; + } + + strcpy(name, _objname); + strcpy(name + len, ".orig"); + + d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644); + if (d < 0) { + perror("failed to create backup file"); + return false; + } + + s = open(_objname, O_RDONLY); + if (s < 0) { + perror("failed to open orig file"); + return false; + } + + buf = malloc(4096); + if (!buf) { + perror("failed backup data malloc"); + return false; + } + + while ((l = read(s, buf, 4096)) > 0) { + base = buf; + do { + t = write(d, base, l); + if (t < 0) { + perror("failed backup write"); + return false; + } + base += t; + l -= t; + } while (l); + } + + if (l < 0) { + perror("failed backup read"); + return false; + } + + free(name); + free(buf); + close(d); + close(s); + + return true; +} + struct objtool_file *objtool_open_read(const char *_objname) { if (objname) { @@ -59,6 +118,11 @@ struct objtool_file *objtool_open_read(const char *_objname) if (!file.elf) return NULL; + if (backup && !objtool_create_backup(objname)) { + WARN("can't create backup file"); + return NULL; + } + INIT_LIST_HEAD(&file.insn_list); hash_init(file.insn_hash); INIT_LIST_HEAD(&file.static_call_list);
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