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elfcopy: Use libelftc's string table routines to build .shstrtab.

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This replaces some hand-rolled routines and is substantially faster
since libelftc uses a hash table for lookups and insertions, whereas
elfcopy would perform a linear scan of the table.

PR:		234949
Reviewed by:	emaste
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D20473
This commit is contained in:
markj 2019-06-04 18:34:05 +00:00
parent 57cb8d51d0
commit bec7330290
5 changed files with 30 additions and 98 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
contrib/elftoolchain/elfcopy/ascii.c
View File

@ -378,9 +378,6 @@ done:
errx(EXIT_FAILURE, "gelf_update_ehdr() failed: %s",
elf_errmsg(-1));
/* Generate section name string table (.shstrtab). */
set_shstrtab(ecp);
/* Update sh_name pointer for each section header entry. */
update_shdr(ecp, 0);
@ -605,9 +602,6 @@ done:
errx(EXIT_FAILURE, "gelf_update_ehdr() failed: %s",
elf_errmsg(-1));
/* Generate section name string table (.shstrtab). */
set_shstrtab(ecp);
/* Update sh_name pointer for each section header entry. */
update_shdr(ecp, 0);

5
contrib/elftoolchain/elfcopy/binary.c
View File

@ -250,11 +250,8 @@ create_elf_from_binary(struct elfcopy *ecp, int ifd, const char *ifn)
errx(EXIT_FAILURE, "gelf_update_ehdr() failed: %s",
elf_errmsg(-1));
/* Generate section name string table (.shstrtab). */
ecp->flags |= SYMTAB_EXIST;
set_shstrtab(ecp);
/* Update sh_name pointer for each section header entry. */
ecp->flags |= SYMTAB_EXIST;
update_shdr(ecp, 0);
/* Properly set sh_link field of .symtab section. */

3
contrib/elftoolchain/elfcopy/elfcopy.h
View File

@ -135,6 +135,8 @@ struct section {
int pseudo;
int nocopy;
Elftc_String_Table *strtab;
TAILQ_ENTRY(section) sec_list; /* next section */
};
@ -313,7 +315,6 @@ struct sec_action *lookup_sec_act(struct elfcopy *_ecp,
struct symop *lookup_symop_list(struct elfcopy *_ecp, const char *_name,
unsigned int _op);
void resync_sections(struct elfcopy *_ecp);
void set_shstrtab(struct elfcopy *_ecp);
void setup_phdr(struct elfcopy *_ecp);
void update_shdr(struct elfcopy *_ecp, int _update_link);

6
contrib/elftoolchain/elfcopy/main.c
View File

@ -388,9 +388,6 @@ create_elf(struct elfcopy *ecp)
*/
copy_content(ecp);
/* Generate section name string table (.shstrtab). */
set_shstrtab(ecp);
/*
* Second processing of output sections: Update section headers.
* At this stage we set name string index, update st_link and st_info
@ -486,6 +483,9 @@ free_elf(struct elfcopy *ecp)
/* Free symbol table buffers. */
free_symtab(ecp);
/* Free section name string table. */
elftc_string_table_destroy(ecp->shstrtab->strtab);
/* Free internal section list. */
if (!TAILQ_EMPTY(&ecp->v_sec)) {
TAILQ_FOREACH_SAFE(sec, &ecp->v_sec, sec_list, sec_temp) {

108
contrib/elftoolchain/elfcopy/sections.c
View File

@ -42,19 +42,18 @@ static void check_section_rename(struct elfcopy *ecp, struct section *s);
static void filter_reloc(struct elfcopy *ecp, struct section *s);
static int get_section_flags(struct elfcopy *ecp, const char *name);
static void insert_sections(struct elfcopy *ecp);
static void insert_to_strtab(struct section *t, const char *s);
static int is_append_section(struct elfcopy *ecp, const char *name);
static int is_compress_section(struct elfcopy *ecp, const char *name);
static int is_debug_section(const char *name);
static int is_dwo_section(const char *name);
static int is_modify_section(struct elfcopy *ecp, const char *name);
static int is_print_section(struct elfcopy *ecp, const char *name);
static int lookup_string(struct section *t, const char *s);
static void modify_section(struct elfcopy *ecp, struct section *s);
static void pad_section(struct elfcopy *ecp, struct section *s);
static void print_data(const char *d, size_t sz);
static void print_section(struct section *s);
static void *read_section(struct section *s, size_t *size);
static void set_shstrtab(struct elfcopy *ecp);
static void update_reloc(struct elfcopy *ecp, struct section *s);
static void update_section_group(struct elfcopy *ecp, struct section *s);
@ -1336,10 +1335,9 @@ insert_sections(struct elfcopy *ecp)
void
add_to_shstrtab(struct elfcopy *ecp, const char *name)
{
struct section *s;
s = ecp->shstrtab;
insert_to_strtab(s, name);
if (elftc_string_table_insert(ecp->shstrtab->strtab, name) == 0)
errx(EXIT_FAILURE, "elftc_string_table_insert failed");
}
void
@ -1349,6 +1347,9 @@ update_shdr(struct elfcopy *ecp, int update_link)
GElf_Shdr osh;
int elferr;
/* Finalize the section name string table (.shstrtab). */
set_shstrtab(ecp);
TAILQ_FOREACH(s, &ecp->v_sec, sec_list) {
if (s->pseudo)
continue;
@ -1358,7 +1359,8 @@ update_shdr(struct elfcopy *ecp, int update_link)
elf_errmsg(-1));
/* Find section name in string table and set sh_name. */
osh.sh_name = lookup_string(ecp->shstrtab, s->name);
osh.sh_name = elftc_string_table_lookup(ecp->shstrtab->strtab,
s->name);
/*
* sh_link needs to be updated, since the index of the
@ -1408,19 +1410,22 @@ init_shstrtab(struct elfcopy *ecp)
s->loadable = 0;
s->type = SHT_STRTAB;
s->vma = 0;
s->strtab = elftc_string_table_create(0);
insert_to_strtab(s, "");
insert_to_strtab(s, ".symtab");
insert_to_strtab(s, ".strtab");
insert_to_strtab(s, ".shstrtab");
add_to_shstrtab(ecp, "");
add_to_shstrtab(ecp, ".symtab");
add_to_shstrtab(ecp, ".strtab");
add_to_shstrtab(ecp, ".shstrtab");
}
void
static void
set_shstrtab(struct elfcopy *ecp)
{
struct section *s;
Elf_Data *data;
GElf_Shdr sh;
const char *image;
size_t sz;
s = ecp->shstrtab;
@ -1453,19 +1458,21 @@ set_shstrtab(struct elfcopy *ecp)
* which are reserved for this in the beginning of shstrtab.
*/
if (!(ecp->flags & SYMTAB_EXIST)) {
s->sz -= sizeof(".symtab\0.strtab");
memmove(s->buf, (char *)s->buf + sizeof(".symtab\0.strtab"),
s->sz);
elftc_string_table_remove(s->strtab, ".symtab");
elftc_string_table_remove(s->strtab, ".strtab");
}
sh.sh_size = s->sz;
image = elftc_string_table_image(s->strtab, &sz);
s->sz = sz;
sh.sh_size = sz;
if (!gelf_update_shdr(s->os, &sh))
errx(EXIT_FAILURE, "gelf_update_shdr() failed: %s",
elf_errmsg(-1));
data->d_align = 1;
data->d_buf = s->buf;
data->d_size = s->sz;
data->d_buf = (void *)(uintptr_t)image;
data->d_size = sz;
data->d_off = 0;
data->d_type = ELF_T_BYTE;
data->d_version = EV_CURRENT;
@ -1591,73 +1598,6 @@ add_gnu_debuglink(struct elfcopy *ecp)
ecp->flags |= SEC_ADD;
}
static void
insert_to_strtab(struct section *t, const char *s)
{
const char *r;
char *b, *c;
size_t len, slen;
int append;
if (t->sz == 0) {
t->cap = 512;
if ((t->buf = malloc(t->cap)) == NULL)
err(EXIT_FAILURE, "malloc failed");
}
slen = strlen(s);
append = 0;
b = t->buf;
for (c = b; c < b + t->sz;) {
len = strlen(c);
if (!append && len >= slen) {
r = c + (len - slen);
if (strcmp(r, s) == 0)
return;
} else if (len < slen && len != 0) {
r = s + (slen - len);
if (strcmp(c, r) == 0) {
t->sz -= len + 1;
memmove(c, c + len + 1, t->sz - (c - b));
append = 1;
continue;
}
}
c += len + 1;
}
while (t->sz + slen + 1 >= t->cap) {
t->cap *= 2;
if ((t->buf = realloc(t->buf, t->cap)) == NULL)
err(EXIT_FAILURE, "realloc failed");
}
b = t->buf;
strncpy(&b[t->sz], s, slen);
b[t->sz + slen] = '\0';
t->sz += slen + 1;
}
static int
lookup_string(struct section *t, const char *s)
{
const char *b, *c, *r;
size_t len, slen;
slen = strlen(s);
b = t->buf;
for (c = b; c < b + t->sz;) {
len = strlen(c);
if (len >= slen) {
r = c + (len - slen);
if (strcmp(r, s) == 0)
return (r - b);
}
c += len + 1;
}
return (-1);
}
static uint32_t crctable[256] =
{
0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL,