objtool: Extract elf_strtab_concat()

Create a common helper to append strings to a strtab.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/20210326151259.941474004@infradead.org

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 7b65ae3beea4a56b39a1c03d6d4f28ce5a8df776..c278a04874adc0a4e41804841c5962c1a83fb13f 100644 (file)
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -673,13 +673,48 @@ err:
        return NULL;
 }
 
+static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
+{
+       Elf_Data *data;
+       Elf_Scn *s;
+       int len;
+
+       if (!strtab)
+               strtab = find_section_by_name(elf, ".strtab");
+       if (!strtab) {
+               WARN("can't find .strtab section");
+               return -1;
+       }
+
+       s = elf_getscn(elf->elf, strtab->idx);
+       if (!s) {
+               WARN_ELF("elf_getscn");
+               return -1;
+       }
+
+       data = elf_newdata(s);
+       if (!data) {
+               WARN_ELF("elf_newdata");
+               return -1;
+       }
+
+       data->d_buf = str;
+       data->d_size = strlen(str) + 1;
+       data->d_align = 1;
+
+       len = strtab->len;
+       strtab->len += data->d_size;
+       strtab->changed = true;
+
+       return len;
+}
+
 struct section *elf_create_section(struct elf *elf, const char *name,
                                   unsigned int sh_flags, size_t entsize, int nr)
 {
        struct section *sec, *shstrtab;
        size_t size = entsize * nr;
        Elf_Scn *s;
-       Elf_Data *data;
 
        sec = malloc(sizeof(*sec));
        if (!sec) {
@@ -736,7 +771,6 @@ struct section *elf_create_section(struct elf *elf, const char *name,
        sec->sh.sh_addralign = 1;
        sec->sh.sh_flags = SHF_ALLOC | sh_flags;
 
-
        /* Add section name to .shstrtab (or .strtab for Clang) */
        shstrtab = find_section_by_name(elf, ".shstrtab");
        if (!shstrtab)
@@ -745,27 +779,9 @@ struct section *elf_create_section(struct elf *elf, const char *name,
                WARN("can't find .shstrtab or .strtab section");
                return NULL;
        }
-
-       s = elf_getscn(elf->elf, shstrtab->idx);
-       if (!s) {
-               WARN_ELF("elf_getscn");
+       sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
+       if (sec->sh.sh_name == -1)
                return NULL;
-       }
-
-       data = elf_newdata(s);
-       if (!data) {
-               WARN_ELF("elf_newdata");
-               return NULL;
-       }
-
-       data->d_buf = sec->name;
-       data->d_size = strlen(name) + 1;
-       data->d_align = 1;
-
-       sec->sh.sh_name = shstrtab->len;
-
-       shstrtab->len += strlen(name) + 1;
-       shstrtab->changed = true;
 
        list_add_tail(&sec->list, &elf->sections);
        elf_hash_add(elf->section_hash, &sec->hash, sec->idx);