[RFC PATCH v3 4/7] scripts/sortextable: refactor do_func() function

Shile Zhang
2019-11-15T06:48:53Z

Refine the loop, naming and code structure, make the code more readable
and extendable, no functional changes.

Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com>
---
scripts/sortextable.c | 4 +-
scripts/sortextable.h | 115 ++++++++++++++++++++++--------------------
2 files changed, 61 insertions(+), 58 deletions(-)

diff --git a/scripts/sortextable.c b/scripts/sortextable.c
index e5384e86b58c..efa2839865cd 100644
--- a/scripts/sortextable.c
+++ b/scripts/sortextable.c
@@ -320,7 +320,7 @@ static int do_file(char const *const fname, void *addr)
"unrecognized ET_EXEC/ET_DYN file: %s\n", fname);
break;
}
- rc = do32(ehdr, fname, custom_sort);
+ rc = do_sort_32(ehdr, fname, custom_sort);
break;
case ELFCLASS64:
{
@@ -332,7 +332,7 @@ static int do_file(char const *const fname, void *addr)
fname);
break;
}
- rc = do64(ghdr, fname, custom_sort);
+ rc = do_sort_64(ghdr, fname, custom_sort);
}
break;
default:
diff --git a/scripts/sortextable.h b/scripts/sortextable.h
index a2e3af7bf211..6485513f7cae 100644
--- a/scripts/sortextable.h
+++ b/scripts/sortextable.h
@@ -12,7 +12,7 @@

#undef extable_ent_size
#undef compare_extable
-#undef do_func
+#undef do_sort
#undef Elf_Addr
#undef Elf_Ehdr
#undef Elf_Shdr
@@ -34,7 +34,7 @@
#ifdef SORTEXTABLE_64
# define extable_ent_size 16
# define compare_extable compare_extable_64
-# define do_func do64
+# define do_sort do_sort_64
# define Elf_Addr Elf64_Addr
# define Elf_Ehdr Elf64_Ehdr
# define Elf_Shdr Elf64_Shdr
@@ -55,7 +55,7 @@
#else
# define extable_ent_size 8
# define compare_extable compare_extable_32
-# define do_func do32
+# define do_sort do_sort_32
# define Elf_Addr Elf32_Addr
# define Elf_Ehdr Elf32_Ehdr
# define Elf_Shdr Elf32_Shdr
@@ -87,81 +87,81 @@ static int compare_extable(const void *a, const void *b)
return 0;
}

-static int do_func(Elf_Ehdr *ehdr,
+static int do_sort(Elf_Ehdr *ehdr,
char const *const fname,
table_sort_t custom_sort)
{
- Elf_Shdr *shdr;
- Elf_Shdr *shstrtab_sec;
+ Elf_Shdr *s, *shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
Elf_Shdr *strtab_sec = NULL;
Elf_Shdr *symtab_sec = NULL;
Elf_Shdr *extab_sec = NULL;
Elf_Sym *sym;
const Elf_Sym *symtab;
- Elf32_Word *symtab_shndx_start = NULL;
- Elf_Sym *sort_needed_sym;
+ Elf32_Word *symtab_shndx = NULL;
+ Elf_Sym *sort_needed_sym = NULL;
Elf_Shdr *sort_needed_sec;
Elf_Rel *relocs = NULL;
int relocs_size = 0;
- uint32_t *sort_done_location;
- const char *secstrtab;
+ uint32_t *sort_needed_loc;
+ const char *secstrings;
const char *strtab;
char *extab_image;
int extab_index = 0;
int i;
int idx;
- unsigned int num_sections;
- unsigned int secindex_strings;
+ unsigned int shnum;
+ unsigned int shstrndx;

- shdr = (Elf_Shdr *)((char *)ehdr + _r(&ehdr->e_shoff));
+ shstrndx = r2(&ehdr->e_shstrndx);
+ if (shstrndx == SHN_XINDEX)
+ shstrndx = r(&shdr[0].sh_link);
+ secstrings = (const char *)ehdr + _r(&shdr[shstrndx].sh_offset);

- num_sections = r2(&ehdr->e_shnum);
- if (num_sections == SHN_UNDEF)
- num_sections = _r(&shdr[0].sh_size);
+ shnum = r2(&ehdr->e_shnum);
+ if (shnum == SHN_UNDEF)
+ shnum = _r(&shdr[0].sh_size);

- secindex_strings = r2(&ehdr->e_shstrndx);
- if (secindex_strings == SHN_XINDEX)
- secindex_strings = r(&shdr[0].sh_link);
-
- shstrtab_sec = shdr + secindex_strings;
- secstrtab = (const char *)ehdr + _r(&shstrtab_sec->sh_offset);
- for (i = 0; i < num_sections; i++) {
- idx = r(&shdr[i].sh_name);
- if (!strcmp(secstrtab + idx, "__ex_table")) {
- extab_sec = shdr + i;
+ for (i = 0, s = shdr; s < shdr + shnum; i++, s++) {
+ idx = r(&s->sh_name);
+ if (!strcmp(secstrings + idx, "__ex_table")) {
+ extab_sec = s;
extab_index = i;
}
- if ((r(&shdr[i].sh_type) == SHT_REL ||
- r(&shdr[i].sh_type) == SHT_RELA) &&
- r(&shdr[i].sh_info) == extab_index) {
- relocs = (void *)ehdr + _r(&shdr[i].sh_offset);
- relocs_size = _r(&shdr[i].sh_size);
+ if (!strcmp(secstrings + idx, ".symtab"))
+ symtab_sec = s;
+ if (!strcmp(secstrings + idx, ".strtab"))
+ strtab_sec = s;
+
+ if ((r(&s->sh_type) == SHT_REL ||
+ r(&s->sh_type) == SHT_RELA) &&
+ r(&s->sh_info) == extab_index) {
+ relocs = (void *)ehdr + _r(&s->sh_offset);
+ relocs_size = _r(&s->sh_size);
}
- if (!strcmp(secstrtab + idx, ".symtab"))
- symtab_sec = shdr + i;
- if (!strcmp(secstrtab + idx, ".strtab"))
- strtab_sec = shdr + i;
- if (r(&shdr[i].sh_type) == SHT_SYMTAB_SHNDX)
- symtab_shndx_start = (Elf32_Word *)(
- (const char *)ehdr + _r(&shdr[i].sh_offset));
+ if (r(&s->sh_type) == SHT_SYMTAB_SHNDX)
+ symtab_shndx = (Elf32_Word *)((const char *)ehdr +
+ _r(&s->sh_offset));
}
- if (!strtab_sec) {
- fprintf(stderr, "no .strtab in file: %s\n", fname);
+
+ if (!extab_sec) {
+ fprintf(stderr, "no __ex_table in file: %s\n", fname);
return -1;
}
+
if (!symtab_sec) {
fprintf(stderr, "no .symtab in file: %s\n", fname);
return -1;
}
- symtab = (const Elf_Sym *)((const char *)ehdr +
- _r(&symtab_sec->sh_offset));
- if (!extab_sec) {
- fprintf(stderr, "no __ex_table in file: %s\n", fname);
+
+ if (!strtab_sec) {
+ fprintf(stderr, "no .strtab in file: %s\n", fname);
return -1;
}
- strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);

extab_image = (void *)ehdr + _r(&extab_sec->sh_offset);
+ strtab = (const char *)ehdr + _r(&strtab_sec->sh_offset);
+ symtab = (const Elf_Sym *)((const char *)ehdr +
+ _r(&symtab_sec->sh_offset));

if (custom_sort) {
custom_sort(extab_image, _r(&extab_sec->sh_size));
@@ -170,38 +170,41 @@ static int do_func(Elf_Ehdr *ehdr,
qsort(extab_image, num_entries,
extable_ent_size, compare_extable);
}
+
/* If there were relocations, we no longer need them. */
if (relocs)
memset(relocs, 0, relocs_size);

- /* find main_extable_sort_needed */
- sort_needed_sym = NULL;
- for (i = 0; i < _r(&symtab_sec->sh_size) / sizeof(Elf_Sym); i++) {
- sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
- sym += i;
+ /* find the flag main_extable_sort_needed */
+ for (sym = (void *)ehdr + _r(&symtab_sec->sh_offset);
+ sym < sym + _r(&symtab_sec->sh_size) / sizeof(Elf_Sym);
+ sym++) {
if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT)
continue;
- idx = r(&sym->st_name);
- if (!strcmp(strtab + idx, "main_extable_sort_needed")) {
+ if (!strcmp(strtab + r(&sym->st_name),
+ "main_extable_sort_needed")) {
sort_needed_sym = sym;
break;
}
}
+
if (!sort_needed_sym) {
fprintf(stderr,
"no main_extable_sort_needed symbol in file: %s\n",
fname);
return -1;
}
+
sort_needed_sec = &shdr[get_secindex(r2(&sym->st_shndx),
sort_needed_sym - symtab,
- symtab_shndx_start)];
- sort_done_location = (void *)ehdr +
+ symtab_shndx)];
+ sort_needed_loc = (void *)ehdr +
_r(&sort_needed_sec->sh_offset) +
_r(&sort_needed_sym->st_value) -
_r(&sort_needed_sec->sh_addr);

- /* We sorted it, clear the flag. */
- w(0, sort_done_location);
+ /* extable has been sorted, clear the flag */
+ w(0, sort_needed_loc);
+
return 0;
}
--
2.24.0.rc2