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Merge pull request #55 from spartacus06/fixes

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Fixes for symbol collisions in add-patches-section and cleanup
This commit is contained in:
Josh Poimboeuf 2014-03-18 13:14:58 -05:00
commit b9f55460ed
2 changed files with 47 additions and 56 deletions
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92
kpatch-build/add-patches-section.c
View File

@ -70,7 +70,7 @@ struct sym {
};
struct symlist {
struct sym *head;
struct sym *head, *tail;
size_t len;
};
@ -131,8 +131,11 @@ static void insert_sym(struct symlist *list, GElf_Sym *sym, char *name,
newsym->name = name;
newsym->index = index;
newsym->next = list->head;
list->head = newsym;
if (list->tail)
list->tail->next = newsym;
if (!list->head)
list->head = newsym;
list->tail = newsym;
}
static void find_section_by_name(struct elf *elf, char *name, struct section *sec)
@ -174,11 +177,6 @@ static void create_symlist(struct elf *elf, struct symlist *symlist)
if (!data)
ERROR("elf_getdata");
/* find (local) function symbols
* NOTE: If the function symbol is in the kpatch-gen file, it needs
* to be patched. If the function didn't need to be patched,
* it wouldn't have been incldued in the kpatch-gen file.
*/
symlist->len = sh->sh_size / sh->sh_entsize;
for (i = 0; i < symlist->len; i++) {
if (!gelf_getsym(data, i, &sym))
@ -192,16 +190,44 @@ static void create_symlist(struct elf *elf, struct symlist *symlist)
}
}
static struct sym *find_symbol_by_name(struct symlist *list, char *name)
static struct sym *find_symbol_by_name(struct symlist *list, struct sym *sym,
char *hint)
{
struct sym *cur;
struct sym *cur, *ret = NULL;
char *name = sym->name, *curfile = NULL;
/* try to find a local symbol in the hint file first */
if (hint && GELF_ST_BIND(sym->sym.st_info) == STB_LOCAL) {
for_each_sym(list, cur) {
if (GELF_ST_TYPE(cur->sym.st_info) == STT_FILE)
curfile = cur->name;
if (!curfile || strcmp(curfile, hint))
continue;
if (!strcmp(cur->name, name)) {
if (ret)
ERROR("unresolvable symbol ambiguity for symbol '%s' in file '%s'", name, hint);
ret = cur;
}
}
}
if (ret)
return ret;
/* search globally for the symbol */
for_each_sym(list, cur)
if (!strcmp(cur->name, name))
if (GELF_ST_BIND(sym->sym.st_info) == STB_GLOBAL &&
!strcmp(cur->name, name))
return cur;
return NULL;
}
/*
* TODO: de-dup common code above these point with code
* in link-vmlinux-syms.c
*/
int main(int argc, char **argv)
{
struct symlist symlist, symlistv;
@ -218,6 +244,7 @@ int main(int argc, char **argv)
GElf_Shdr sh, *shp;
GElf_Ehdr eh;
GElf_Sym sym;
char *hint = NULL;
/* set elf version (required by libelf) */
if (elf_version(EV_CURRENT) == EV_NONE)
@ -240,12 +267,15 @@ int main(int argc, char **argv)
/* lookup patched functions in vmlinux */
for_each_sym(&symlist, cur) {
if (GELF_ST_TYPE(cur->sym.st_info) == STT_FILE)
hint = cur->name;
if (GELF_ST_TYPE(cur->sym.st_info) != STT_FUNC)
continue;
printf("found patched function %s\n", cur->name);
vsym = find_symbol_by_name(&symlistv, cur->name);
vsym = find_symbol_by_name(&symlistv, cur, hint);
if (!vsym)
ERROR("couldn't find patched function in vmlinux");
cur->vm_addr = vsym->sym.st_value;
@ -256,33 +286,6 @@ int main(int argc, char **argv)
patches_nr++;
}
#if 0
/* lookup non-exported globals and insert vmlinux address */
for_each_sym(&symlist, cur) {
if (GELF_ST_TYPE(cur->sym.st_info) != STT_NOTYPE ||
GELF_ST_BIND(cur->sym.st_info) != STB_GLOBAL)
continue;
printf("found global symbol %s\n", cur->name);
sprintf(name, "__kstrtab_%s", cur->name);
vsym = find_symbol_by_name(&symlistv, name);
if (vsym) {
printf("symbol is exported by the kernel\n");
continue;
}
vsym = find_symbol_by_name(&symlistv, cur->name);
if (!vsym)
ERROR("couldn't find global function in vmlinux");
cur->vm_addr = vsym->sym.st_value;
cur->vm_len = vsym->sym.st_size;
cur->action = LINK;
printf("original symbol at address %016lx (length %d)\n",
cur->vm_addr, cur->vm_len);
}
#endif
elf_end(elfv.elf);
close(elfv.fd);
@ -363,17 +366,6 @@ int main(int argc, char **argv)
data = elf_getdata(scn, NULL);
if (!data)
ERROR("elf_getdata");
#if 0
/* update LINK symbols */
for_each_sym(&symlist, cur) {
if (cur->action != LINK)
continue;
cur->sym.st_value = cur->vm_addr;
cur->sym.st_info = GELF_ST_INFO(STB_LOCAL,STT_FUNC);
cur->sym.st_shndx = SHN_ABS;
gelf_update_sym(data, cur->index, &cur->sym);
}
#endif
/* add new section symbols to symtab */
len = sizeof(GElf_Sym) * 2;

11
kpatch-build/link-vmlinux-syms.c
View File

@ -171,12 +171,6 @@ static void create_symlist(struct elf *elf, struct symlist *symlist)
if (!data)
ERROR("elf_getdata");
/*
* find (local) function symbols
* NOTE: If the function symbol is in the kpatch-gen file, it needs
* to be patched. If the function didn't need to be patched,
* it wouldn't have been incldued in the kpatch-gen file.
*/
symlist->len = sh->sh_size / sh->sh_entsize;
for (i = 0; i < symlist->len; i++) {
if (!gelf_getsym(data, i, &sym))
@ -200,6 +194,11 @@ static struct sym *find_symbol_by_name(struct symlist *list, char *name)
return NULL;
}
/*
* TODO: de-dup common code above these point with code
* in add-patches-section.c
*/
int main(int argc, char **argv)
{
struct symlist symlist, symlistv;