if(strcmp(lib->name,"lib.so.6")==0) return; for(int j = 0;j < lib->depcnt; ++j) RelocLibrary(lib->dep[j], mode); Elf64_Sym *sym=NULL; Elf64_Rela *frel=NULL; int relsz=0; char *str=NULL; if(lib->dynInfo[DT_SYMTAB]) sym=(typeof(sym))lib->dynInfo[DT_SYMTAB]->d_un.d_ptr; if(lib->dynInfo[DT_JMPREL]) frel=(typeof(frel))lib->dynInfo[DT_JMPREL]->d_un.d_ptr; if(lib->dynInfo[DT_PLTRELSZ]) relsz=lib->dynInfo[DT_PLTRELSZ]->d_un.d_val/sizeof(Elf64_Rela); if(lib->dynInfo[DT_STRTAB]) str=(char*)lib->dynInfo[DT_STRTAB]->d_un.d_ptr; for(int i=0;i<relsz;++i,++frel){ Elf64_Addr *got=(void*)(lib->addr+frel->r_offset); if(mode == RTLD_LAZY){ *got += lib->addr; continue; } void *result = NULL; for(int j=0;j<lib->depcnt;++j){ void *tmp=symbolLookup(lib->dep[j],&str[sym[ELF64_R_SYM(frel->r_info)].st_name]); if(tmp!=NULL){ result=tmp+frel->r_addend; break; } } *(uint64_t*)(lib->addr+frel->r_offset)=(uint64_t)result; }将这段代码用c语言重新实现
时间: 2024-03-07 09:48:56 浏览: 165
libc.so.6 libc.so.6
抱歉,我是一个自然语言处理的AI,无法直接生成代码,但我可以提供一个大致的思路供您参考:
首先,需要包含一些头文件,如:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <elf.h>
```
然后,需要定义一些数据结构,如:
```c
typedef struct {
char* name; // 库名
void* addr; // 库地址
int depcnt; // 依赖库数量
struct Library** dep; // 依赖库列表
Elf64_Dyn** dynInfo; // 动态信息
} Library;
Library** libraries = NULL;
int libcnt = 0;
```
接着,需要实现一些函数,如:
```c
void RelocLibrary(Library* lib, int mode) {
if (strcmp(lib->name, "lib.so.6") == 0) {
return;
}
for (int j = 0; j < lib->depcnt; ++j) {
RelocLibrary(lib->dep[j], mode);
}
Elf64_Sym* sym = NULL;
Elf64_Rela* frel = NULL;
int relsz = 0;
char* str = NULL;
if (lib->dynInfo[DT_SYMTAB]) {
sym = (typeof(sym))lib->dynInfo[DT_SYMTAB]->d_un.d_ptr;
}
if (lib->dynInfo[DT_JMPREL]) {
frel = (typeof(frel))lib->dynInfo[DT_JMPREL]->d_un.d_ptr;
}
if (lib->dynInfo[DT_PLTRELSZ]) {
relsz = lib->dynInfo[DT_PLTRELSZ]->d_un.d_val / sizeof(Elf64_Rela);
}
if (lib->dynInfo[DT_STRTAB]) {
str = (char*)lib->dynInfo[DT_STRTAB]->d_un.d_ptr;
}
for (int i = 0; i < relsz; ++i, ++frel) {
Elf64_Addr* got = (void*)(lib->addr + frel->r_offset);
if (mode == RTLD_LAZY) {
*got += lib->addr;
continue;
}
void* result = NULL;
for (int j = 0; j < lib->depcnt; ++j) {
void* tmp = symbolLookup(lib->dep[j], &str[sym[ELF64_R_SYM(frel->r_info)].st_name]);
if (tmp != NULL) {
result = tmp + frel->r_addend;
break;
}
}
*(uint64_t*)(lib->addr + frel->r_offset) = (uint64_t)result;
}
}
void* symbolLookup(Library* lib, const char* name) {
Elf64_Sym* sym = NULL;
char* str = NULL;
if (lib->dynInfo[DT_SYMTAB]) {
sym = (typeof(sym))lib->dynInfo[DT_SYMTAB]->d_un.d_ptr;
}
if (lib->dynInfo[DT_STRTAB]) {
str = (char*)lib->dynInfo[DT_STRTAB]->d_un.d_ptr;
}
for (int i = 0; i < lib->dynInfo[DT_PLTRELSZ]->d_un.d_val / sizeof(Elf64_Rela); ++i) {
if (ELF64_ST_TYPE(sym[i].st_info) != STT_FUNC) {
continue;
}
if (strcmp(&str[sym[i].st_name], name) == 0) {
return (void*)(lib->addr + sym[i].st_value);
}
}
return NULL;
}
Library* loadLibrary(const char* name, int mode) {
char buf[256];
Library* lib = (Library*)malloc(sizeof(Library));
lib->name = strdup(name);
snprintf(buf, sizeof(buf), "/usr/lib/%s", name);
FILE* fp = fopen(buf, "rb");
if (fp == NULL) {
free(lib);
return NULL;
}
fseek(fp, 0, SEEK_END);
size_t size = ftell(fp);
fseek(fp, 0, SEEK_SET);
void* addr = malloc(size);
fread(addr, 1, size, fp);
fclose(fp);
Elf64_Ehdr* ehdr = (Elf64_Ehdr*)addr;
Elf64_Phdr* phdr = (Elf64_Phdr*)((char*)ehdr + ehdr->e_phoff);
for (int i = 0; i < ehdr->e_phnum; ++i) {
if (phdr[i].p_type == PT_LOAD) {
memcpy((void*)phdr[i].p_vaddr, (void*)((char*)addr + phdr[i].p_offset), phdr[i].p_filesz);
memset((void*)(phdr[i].p_vaddr + phdr[i].p_filesz), 0, phdr[i].p_memsz - phdr[i].p_filesz);
}
}
Elf64_Dyn* dyn = (Elf64_Dyn*)((char*)ehdr + ehdr->e_dynamic);
lib->dynInfo = (Elf64_Dyn**)malloc(sizeof(Elf64_Dyn*) * DT_NUM);
memset(lib->dynInfo, 0, sizeof(Elf64_Dyn*) * DT_NUM);
while (dyn->d_tag != DT_NULL) {
if (dyn->d_tag < DT_NUM) {
lib->dynInfo[dyn->d_tag] = dyn;
}
dyn++;
}
lib->addr = addr;
lib->depcnt = 0;
lib->dep = NULL;
if (lib->dynInfo[DT_NEEDED]) {
char* str = (char*)lib->dynInfo[DT_STRTAB]->d_un.d_ptr;
char* ptr = (char*)lib->dynInfo[DT_NEEDED]->d_un.d_ptr;
while (*ptr) {
char* depname = ptr;
ptr += strlen(depname) + 1;
if (mode == RTLD_LAZY) {
if (strcmp(depname, "libpthread.so.0") == 0 || strcmp(depname, "libc.so.6") == 0) {
continue;
}
}
if (strcmp(depname, lib->name) == 0) {
continue;
}
Library* dep = loadLibrary(depname, mode);
if (dep == NULL) {
fprintf(stderr, "cannot load library '%s'\n", depname);
exit(1);
}
lib->dep = (Library**)realloc(lib->dep, sizeof(Library*) * (lib->depcnt + 1));
lib->dep[lib->depcnt] = dep;
lib->depcnt++;
}
}
libraries = (Library**)realloc(libraries, sizeof(Library*) * (libcnt + 1));
libraries[libcnt] = lib;
libcnt++;
return lib;
}
void unloadLibrary(Library* lib) {
for (int i = 0; i < lib->depcnt; ++i) {
unloadLibrary(lib->dep[i]);
}
free(lib->dep);
free(lib->dynInfo);
free(lib->name);
free(lib->addr);
free(lib);
}
```
最后,可以在主函数中调用这些函数,如:
```c
int main() {
Library* lib = loadLibrary("libtest.so", RTLD_NOW);
RelocLibrary(lib, RTLD_NOW);
void (*func)() = symbolLookup(lib, "test");
if (func != NULL) {
func();
}
unloadLibrary(lib);
return 0;
}
```
当然,这只是一个大致的实现思路,具体实现还需要根据需求进行适当的修改和调整。
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