Magisk/native/jni/boot/cpio.cpp
2022-06-08 23:23:39 -07:00

241 lines
6.8 KiB
C++

#include <unistd.h>
#include <fcntl.h>
#include <algorithm>
#include <base.hpp>
#include "cpio.hpp"
using namespace std;
struct cpio_newc_header {
char magic[6];
char ino[8];
char mode[8];
char uid[8];
char gid[8];
char nlink[8];
char mtime[8];
char filesize[8];
char devmajor[8];
char devminor[8];
char rdevmajor[8];
char rdevminor[8];
char namesize[8];
char check[8];
} __attribute__((packed));
static uint32_t x8u(const char *hex) {
uint32_t val, inpos = 8, outpos;
char pattern[6];
while (*hex == '0') {
hex++;
if (!--inpos) return 0;
}
// Because scanf gratuitously treats %*X differently than printf does.
sprintf(pattern, "%%%dx%%n", inpos);
sscanf(hex, pattern, &val, &outpos);
if (inpos != outpos)
LOGE("bad cpio header\n");
return val;
}
cpio_entry::cpio_entry(uint32_t mode) : mode(mode), uid(0), gid(0), filesize(0), data(nullptr) {}
cpio_entry::cpio_entry(const cpio_newc_header *h) :
mode(x8u(h->mode)), uid(x8u(h->uid)), gid(x8u(h->gid)), filesize(x8u(h->filesize)), data(nullptr)
{}
void cpio::dump(const char *file) {
fprintf(stderr, "Dump cpio: [%s]\n", file);
dump(xfopen(file, "we"));
}
void cpio::rm(entry_map::iterator it) {
if (it == entries.end())
return;
fprintf(stderr, "Remove [%s]\n", it->first.data());
entries.erase(it);
}
void cpio::rm(const char *name, bool r) {
size_t len = strlen(name);
for (auto it = entries.begin(); it != entries.end();) {
if (it->first.compare(0, len, name) == 0 &&
((r && it->first[len] == '/') || it->first[len] == '\0')) {
auto tmp = it;
++it;
rm(tmp);
if (!r) return;
} else {
++it;
}
}
}
void cpio::extract_entry(const entry_map::value_type &e, const char *file) {
fprintf(stderr, "Extract [%s] to [%s]\n", e.first.data(), file);
unlink(file);
rmdir(file);
if (S_ISDIR(e.second->mode)) {
::mkdir(file, e.second->mode & 0777);
} else if (S_ISREG(e.second->mode)) {
int fd = creat(file, e.second->mode & 0777);
xwrite(fd, e.second->data, e.second->filesize);
fchown(fd, e.second->uid, e.second->gid);
close(fd);
} else if (S_ISLNK(e.second->mode)) {
auto target = strndup((char *) e.second->data, e.second->filesize);
symlink(target, file);
free(target);
}
}
void cpio::extract() {
for (auto &e : entries)
extract_entry(e, e.first.data());
}
bool cpio::extract(const char *name, const char *file) {
auto it = entries.find(name);
if (it != entries.end()) {
extract_entry(*it, file);
return true;
}
fprintf(stderr, "Cannot find the file entry [%s]\n", name);
return false;
}
bool cpio::exists(const char *name) {
return entries.count(name) != 0;
}
#define do_out(buf, len) pos += fwrite(buf, 1, len, out);
#define out_align() do_out(zeros, align_padding(pos, 4))
void cpio::dump(FILE *out) {
size_t pos = 0;
unsigned inode = 300000;
char header[111];
char zeros[4] = {0};
for (auto &e : entries) {
sprintf(header, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x",
inode++, // e->ino
e.second->mode,
e.second->uid,
e.second->gid,
1, // e->nlink
0, // e->mtime
e.second->filesize,
0, // e->devmajor
0, // e->devminor
0, // e->rdevmajor
0, // e->rdevminor
(uint32_t) e.first.size() + 1,
0 // e->check
);
do_out(header, 110);
do_out(e.first.data(), e.first.size() + 1);
out_align();
if (e.second->filesize) {
do_out(e.second->data, e.second->filesize);
out_align();
}
}
// Write trailer
sprintf(header, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x",
inode++, 0755, 0, 0, 1, 0, 0, 0, 0, 0, 0, 11, 0);
do_out(header, 110);
do_out("TRAILER!!!\0", 11);
out_align();
fclose(out);
}
void cpio::load_cpio(const char *file) {
fprintf(stderr, "Loading cpio: [%s]\n", file);
auto m = mmap_data(file);
load_cpio(reinterpret_cast<char *>(m.buf), m.sz);
}
void cpio::insert(string_view name, cpio_entry *e) {
auto it = entries.find(name);
if (it != entries.end()) {
it->second.reset(e);
} else {
entries.emplace(name, e);
}
}
void cpio::add(mode_t mode, const char *name, const char *file) {
auto m = mmap_data(file);
auto e = new cpio_entry(S_IFREG | mode);
e->filesize = m.sz;
e->data = xmalloc(m.sz);
memcpy(e->data, m.buf, m.sz);
insert(name, e);
fprintf(stderr, "Add entry [%s] (%04o)\n", name, mode);
}
void cpio::mkdir(mode_t mode, const char *name) {
insert(name, new cpio_entry(S_IFDIR | mode));
fprintf(stderr, "Create directory [%s] (%04o)\n", name, mode);
}
void cpio::ln(const char *target, const char *name) {
auto e = new cpio_entry(S_IFLNK);
e->filesize = strlen(target);
e->data = strdup(target);
insert(name, e);
fprintf(stderr, "Create symlink [%s] -> [%s]\n", name, target);
}
void cpio::mv(entry_map::iterator it, const char *name) {
fprintf(stderr, "Move [%s] -> [%s]\n", it->first.data(), name);
auto e = it->second.release();
entries.erase(it);
insert(name, e);
}
bool cpio::mv(const char *from, const char *to) {
auto it = entries.find(from);
if (it != entries.end()) {
mv(it, to);
return true;
}
fprintf(stderr, "Cannot find entry %s\n", from);
return false;
}
#define pos_align(p) p = align_to(p, 4)
void cpio::load_cpio(const char *buf, size_t sz) {
size_t pos = 0;
while (pos < sz) {
auto hdr = reinterpret_cast<const cpio_newc_header *>(buf + pos);
if (memcmp(hdr->magic, "070701", 6) != 0)
LOGE("bad cpio header\n");
pos += sizeof(cpio_newc_header);
string_view name(buf + pos);
pos += x8u(hdr->namesize);
pos_align(pos);
if (name == "." || name == "..")
continue;
if (name == "TRAILER!!!") {
// Android support multiple CPIO being concatenated
// Search for the next cpio header
auto next = static_cast<const char *>(memmem(buf + pos, sz - pos, "070701", 6));
if (next == nullptr)
break;
pos = next - buf;
continue;
}
auto entry = new cpio_entry(hdr);
entry->data = xmalloc(entry->filesize);
memcpy(entry->data, buf + pos, entry->filesize);
pos += entry->filesize;
insert(name, entry);
pos_align(pos);
}
}