MarcoBuster/Magisk
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Introduce new boot flow to handle SAR 2SI

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The existing method for handling legacy SAR is:
1. Mount /sbin tmpfs overlay
2. Dump all patched/new files into /sbin
3. Magic mount root dir and re-exec patched stock init

With Android 11 removing the /sbin folder, it is quite obvious that
things completely break down right in step 1.

To overcome this issue, we have to find a way to swap out the init
binary AFTER we re-exec stock init. This is where 2SI comes to rescue!

2SI normal boot procedure is:
1st stage -> Load sepolicy -> 2nd stage -> boot continue...

2SI Magisk boot procedure is:
MagiskInit 1st stage -> Stock 1st stage -> MagiskInit 2nd Stage ->
-> Stock init load sepolicy -> Stock 2nd stage -> boot continue...

As you can see, the trick is to make stock 1st stage init re-exec back
into MagiskInit so we can do our setup. This is possible by manipulating
some ramdisk files on initramfs based 2SI devices (old ass non SAR
devices AND super modern devices like Pixel 3/4), but not possible
on device that are stuck using legacy SAR (device that are not that
modern but not too old, like Pixel 1/2. Fucking Google logic!!)

This commit introduces a new way to intercept stock init re-exec flow:
ptrace init with forked tracer, monitor PTRACE_EVENT_EXEC, then swap
out the init file with bind mounts right before execv returns!

Going through this flow however will lose some necessary backup files,
so some bookkeeping has to be done by making the tracer hold these
files in memory and act as a daemon. 2nd stage MagiskInit will ack the
daemon to release these files at the correct time.

It just works™  ¯\_(ツ)_/¯
This commit is contained in:
topjohnwu 2020-04-01 04:39:28 -07:00
parent 543ce937ec
commit 5f1174de27
8 changed files with 361 additions and 154 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
native/jni/Android.mk
View File

@ -82,6 +82,7 @@ LOCAL_SRC_FILES := \
init/mount.cpp \ init/mount.cpp \
init/rootdir.cpp \ init/rootdir.cpp \
init/getinfo.cpp \ init/getinfo.cpp \
init/twostage.cpp \
magiskpolicy/api.cpp \ magiskpolicy/api.cpp \
magiskpolicy/magiskpolicy.cpp \ magiskpolicy/magiskpolicy.cpp \
magiskpolicy/rules.cpp \ magiskpolicy/rules.cpp \

11
native/jni/init/init.cpp
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@ -217,16 +217,19 @@ int main(int argc, char *argv[]) {
// This will also mount /sys and /proc // This will also mount /sys and /proc
load_kernel_info(&cmd); load_kernel_info(&cmd);
if (cmd.force_normal_boot) { if (access("/apex", F_OK) == 0) {
init = make_unique<ABFirstStageInit>(argv, &cmd); if (cmd.force_normal_boot)
init = make_unique<ForcedFirstStageInit>(argv, &cmd);
else if (cmd.skip_initramfs)
init = make_unique<SARFirstStageInit>(argv, &cmd);
else
init = make_unique<FirstStageInit>(argv, &cmd);
} else if (cmd.skip_initramfs) { } else if (cmd.skip_initramfs) {
init = make_unique<SARInit>(argv, &cmd); init = make_unique<SARInit>(argv, &cmd);
} else { } else {
decompress_ramdisk(); decompress_ramdisk();
if (access("/sbin/recovery", F_OK) == 0 || access("/system/bin/recovery", F_OK) == 0) if (access("/sbin/recovery", F_OK) == 0 || access("/system/bin/recovery", F_OK) == 0)
init = make_unique<RecoveryInit>(argv, &cmd); init = make_unique<RecoveryInit>(argv, &cmd);
else if (access("/apex", F_OK) == 0)
init = make_unique<AFirstStageInit>(argv, &cmd);
else else
init = make_unique<RootFSInit>(argv, &cmd); init = make_unique<RootFSInit>(argv, &cmd);
} }

28
native/jni/init/init.hpp
View File

@ -1,4 +1,6 @@
#include <sys/mount.h> #include <sys/mount.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h> #include <unistd.h>
#include <stdlib.h> #include <stdlib.h>
#include <vector> #include <vector>
@ -66,9 +68,11 @@ public:
class SARBase : public MagiskInit { class SARBase : public MagiskInit {
protected: protected:
raw_data config; raw_data config;
std::vector<raw_file> overlays;
void backup_files(const char *self_path); void backup_files();
void patch_rootdir(); void patch_rootdir();
void mount_system_root();
public: public:
SARBase(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) { SARBase(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {
persist_dir = MIRRDIR "/persist/magisk"; persist_dir = MIRRDIR "/persist/magisk";
@ -84,28 +88,41 @@ public:
* 2 Stage Init * 2 Stage Init
* *************/ * *************/
class ABFirstStageInit : public BaseInit { class ForcedFirstStageInit : public BaseInit {
private: private:
void prepare(); void prepare();
public: public:
ABFirstStageInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {}; ForcedFirstStageInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
void start() override { void start() override {
prepare(); prepare();
exec_init("/system/bin/init"); exec_init("/system/bin/init");
} }
}; };
class AFirstStageInit : public BaseInit { class FirstStageInit : public BaseInit {
private: private:
void prepare(); void prepare();
public: public:
AFirstStageInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {}; FirstStageInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
void start() override { void start() override {
prepare(); prepare();
exec_init(); exec_init();
} }
}; };
class SARFirstStageInit : public SARBase {
private:
void traced_exec_init();
protected:
void early_mount() override;
public:
SARFirstStageInit(char *argv[], cmdline *cmd) : SARBase(argv, cmd) {};
void start() override {
early_mount();
traced_exec_init();
}
};
class SecondStageInit : public SARBase { class SecondStageInit : public SARBase {
protected: protected:
void early_mount() override; void early_mount() override;
@ -152,3 +169,4 @@ int dump_magisk(const char *path, mode_t mode);
int magisk_proxy_main(int argc, char *argv[]); int magisk_proxy_main(int argc, char *argv[]);
void setup_klog(); void setup_klog();
void mount_sbin(); void mount_sbin();
socklen_t setup_sockaddr(struct sockaddr_un *sun);

49
native/jni/init/mount.cpp
View File

@ -183,27 +183,15 @@ void RootFSInit::early_mount() {
mount_list.emplace_back("/dev/mnt/cache"); mount_list.emplace_back("/dev/mnt/cache");
} }
void SARBase::backup_files(const char *self_path) { void SARBase::backup_files() {
if (access("/overlay.d", F_OK) == 0) if (access("/overlay.d", F_OK) == 0)
cp_afc("/overlay.d", "/dev/overlay.d"); backup_folder("/overlay.d", overlays);
full_read(self_path, self.buf, self.sz); full_read("/proc/self/exe", self.buf, self.sz);
full_read("/.backup/.magisk", config.buf, config.sz); full_read("/.backup/.magisk", config.buf, config.sz);
} }
void SARInit::early_mount() { void SARBase::mount_system_root() {
// Make dev writable
xmkdir("/dev", 0755);
xmount("tmpfs", "/dev", "tmpfs", 0, "mode=755");
mount_list.emplace_back("/dev");
backup_files("/init");
LOGD("Cleaning rootfs\n");
int root = xopen("/", O_RDONLY | O_CLOEXEC);
frm_rf(root, { "proc", "sys", "dev" });
close(root);
LOGD("Early mount system_root\n"); LOGD("Early mount system_root\n");
sprintf(partname, "system%s", cmd->slot); sprintf(partname, "system%s", cmd->slot);
strcpy(block_dev, "/dev/root"); strcpy(block_dev, "/dev/root");
@ -221,6 +209,22 @@ void SARInit::early_mount() {
xmkdir("/system_root", 0755); xmkdir("/system_root", 0755);
if (xmount("/dev/root", "/system_root", "ext4", MS_RDONLY, nullptr)) if (xmount("/dev/root", "/system_root", "ext4", MS_RDONLY, nullptr))
xmount("/dev/root", "/system_root", "erofs", MS_RDONLY, nullptr); xmount("/dev/root", "/system_root", "erofs", MS_RDONLY, nullptr);
}
void SARInit::early_mount() {
// Make dev writable
xmkdir("/dev", 0755);
xmount("tmpfs", "/dev", "tmpfs", 0, "mode=755");
mount_list.emplace_back("/dev");
backup_files();
LOGD("Cleaning rootfs\n");
int root = xopen("/", O_RDONLY | O_CLOEXEC);
frm_rf(root, { "proc", "sys", "dev" });
close(root);
mount_system_root();
switch_root("/system_root"); switch_root("/system_root");
mount_root(vendor); mount_root(vendor);
@ -228,14 +232,21 @@ void SARInit::early_mount() {
mount_root(odm); mount_root(odm);
} }
void SecondStageInit::early_mount() { void SARFirstStageInit::early_mount() {
// Early mounts should already be done by first stage init backup_files();
mount_system_root();
switch_root("/system_root");
}
backup_files("/system/bin/init"); void SecondStageInit::early_mount() {
backup_files();
rm_rf("/system"); rm_rf("/system");
rm_rf("/.backup"); rm_rf("/.backup");
rm_rf("/overlay.d"); rm_rf("/overlay.d");
umount2("/system/bin/init", MNT_DETACH);
if (access("/system_root", F_OK) == 0)
switch_root("/system_root"); switch_root("/system_root");
} }

144
native/jni/init/rootdir.cpp
View File

@ -67,22 +67,24 @@ static void patch_init_rc(FILE *rc) {
fprintf(rc, magiskrc, pfd_svc, pfd_svc, ls_svc, bc_svc, bc_svc); fprintf(rc, magiskrc, pfd_svc, pfd_svc, ls_svc, bc_svc, bc_svc);
} }
static void load_overlay_rc(int dirfd) { static void load_overlay_rc(const char *overlay) {
auto dir = open_dir(overlay);
if (!dir) return;
int dfd = dirfd(dir.get());
// Do not allow overwrite init.rc // Do not allow overwrite init.rc
unlinkat(dirfd, "init.rc", 0); unlinkat(dfd, "init.rc", 0);
DIR *dir = fdopendir(dirfd); for (dirent *entry; (entry = readdir(dir.get()));) {
for (dirent *entry; (entry = readdir(dir));) {
if (strend(entry->d_name, ".rc") == 0) { if (strend(entry->d_name, ".rc") == 0) {
LOGD("Found rc script [%s]\n", entry->d_name); LOGD("Found rc script [%s]\n", entry->d_name);
int rc = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC); int rc = xopenat(dfd, entry->d_name, O_RDONLY | O_CLOEXEC);
raw_data data; raw_data data;
fd_full_read(rc, data.buf, data.sz); fd_full_read(rc, data.buf, data.sz);
close(rc); close(rc);
rc_list.push_back(std::move(data)); rc_list.push_back(std::move(data));
unlinkat(dirfd, entry->d_name, 0); unlinkat(dfd, entry->d_name, 0);
} }
} }
rewinddir(dir);
} }
void RootFSInit::setup_rootfs() { void RootFSInit::setup_rootfs() {
@ -102,13 +104,10 @@ void RootFSInit::setup_rootfs() {
} }
// Handle overlays // Handle overlays
int fd = open("/overlay.d", O_RDONLY | O_CLOEXEC); if (access("/overlay.d", F_OK) == 0) {
if (fd >= 0) {
LOGD("Merge overlay.d\n"); LOGD("Merge overlay.d\n");
load_overlay_rc(fd); load_overlay_rc("/overlay.d");
mv_dir(fd, root); mv_f("/overlay.d", "/");
close(fd);
rmdir("/overlay.d");
} }
// Patch init.rc // Patch init.rc
@ -127,7 +126,7 @@ void RootFSInit::setup_rootfs() {
close(sbin); close(sbin);
// Dump magiskinit as magisk // Dump magiskinit as magisk
fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755); int fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, self.buf, self.sz); write(fd, self.buf, self.sz);
close(fd); close(fd);
} }
@ -336,21 +335,26 @@ void SARBase::patch_rootdir() {
patch_sepolicy(PATCHPOLICY); patch_sepolicy(PATCHPOLICY);
// Handle overlay // Handle overlay
if ((src = xopen("/dev/overlay.d", O_RDONLY | O_CLOEXEC)) >= 0) { struct sockaddr_un sun{};
load_overlay_rc(src); socklen_t len = setup_sockaddr(&sun);
if (int fd = xopen("/dev/overlay.d/sbin", O_RDONLY | O_CLOEXEC); fd >= 0) { int socketfd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
dest = xopen("/sbin", O_RDONLY | O_CLOEXEC); if (connect(socketfd, (struct sockaddr*) &sun, len) == 0) {
clone_dir(fd, dest); LOGD("ACK init tracer to write backup files\n");
close(fd); int ack;
close(dest); // Wait for init tracer finish copying files
xmkdir(ROOTOVL "/sbin", 0); // Prevent copying read(socketfd, &ack, sizeof(ack));
} else {
LOGD("Restore backup files locally\n");
restore_folder(ROOTOVL, overlays);
overlays.clear();
} }
dest = xopen(ROOTOVL, O_RDONLY | O_CLOEXEC); close(socketfd);
clone_dir(src, dest, false); if (access(ROOTOVL "/sbin", F_OK) == 0) {
rmdir(ROOTOVL "/sbin"); file_attr a;
close(src); getattr("/sbin", &a);
close(dest); cp_afc(ROOTOVL "/sbin", "/sbin");
rm_rf("/dev/overlay.d"); rm_rf(ROOTOVL "/sbin");
setattr("/sbin", &a);
} }
// Patch init.rc // Patch init.rc
@ -366,90 +370,6 @@ void SARBase::patch_rootdir() {
close(dest); close(dest);
} }
static void patch_fstab(const string &fstab) {
string patched = fstab + ".p";
FILE *fp = xfopen(patched.data(), "we");
file_readline(fstab.data(), [=](string_view l) -> bool {
if (l[0] == '#' || l.length() == 1)
return true;
char *line = (char *) l.data();
int src0, src1, mnt0, mnt1, type0, type1, opt0, opt1, flag0, flag1;
sscanf(line, "%n%*s%n %n%*s%n %n%*s%n %n%*s%n %n%*s%n",
&src0, &src1, &mnt0, &mnt1, &type0, &type1, &opt0, &opt1, &flag0, &flag1);
const char *src, *mnt, *type, *opt, *flag;
src = &line[src0];
line[src1] = '\0';
mnt = &line[mnt0];
line[mnt1] = '\0';
type = &line[type0];
line[type1] = '\0';
opt = &line[opt0];
line[opt1] = '\0';
flag = &line[flag0];
line[flag1] = '\0';
// Redirect system to system_root
if (mnt == "/system"sv)
mnt = "/system_root";
fprintf(fp, "%s %s %s %s %s\n", src, mnt, type, opt, flag);
return true;
});
fclose(fp);
// Replace old fstab
clone_attr(fstab.data(), patched.data());
rename(patched.data(), fstab.data());
}
#define FSR "/first_stage_ramdisk"
void ABFirstStageInit::prepare() {
// It is actually possible to NOT have FSR, create it just in case
xmkdir(FSR, 0755);
if (auto dir = xopen_dir(FSR); dir) {
string fstab(FSR "/");
for (dirent *de; (de = xreaddir(dir.get()));) {
if (strstr(de->d_name, "fstab")) {
fstab += de->d_name;
break;
}
}
if (fstab.length() == sizeof(FSR))
return;
patch_fstab(fstab);
} else {
return;
}
// Move stuffs for next stage
xmkdir(FSR "/system", 0755);
xmkdir(FSR "/system/bin", 0755);
rename("/init", FSR "/system/bin/init");
symlink("/system/bin/init", FSR "/init");
xmkdir(FSR "/.backup", 0);
rename("/.backup/.magisk", FSR "/.backup/.magisk");
rename("/overlay.d", FSR "/overlay.d");
}
void AFirstStageInit::prepare() {
auto dir = xopen_dir("/");
for (dirent *de; (de = xreaddir(dir.get()));) {
if (strstr(de->d_name, "fstab")) {
patch_fstab(de->d_name);
break;
}
}
// Move stuffs for next stage
xmkdir("/system", 0755);
xmkdir("/system/bin", 0755);
rename("/init", "/system/bin/init");
rename("/.backup/init", "/init");
}
int magisk_proxy_main(int argc, char *argv[]) { int magisk_proxy_main(int argc, char *argv[]) {
setup_klog(); setup_klog();

182
native/jni/init/twostage.cpp Normal file
View File

@ -0,0 +1,182 @@
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <utils.hpp>
#include <logging.hpp>
#include "init.hpp"
using namespace std;
static void patch_fstab(const string &fstab) {
string patched = fstab + ".p";
FILE *fp = xfopen(patched.data(), "we");
file_readline(fstab.data(), [=](string_view l) -> bool {
if (l[0] == '#' || l.length() == 1)
return true;
char *line = (char *) l.data();
int src0, src1, mnt0, mnt1, type0, type1, opt0, opt1, flag0, flag1;
sscanf(line, "%n%*s%n %n%*s%n %n%*s%n %n%*s%n %n%*s%n",
&src0, &src1, &mnt0, &mnt1, &type0, &type1, &opt0, &opt1, &flag0, &flag1);
const char *src, *mnt, *type, *opt, *flag;
src = &line[src0];
line[src1] = '\0';
mnt = &line[mnt0];
line[mnt1] = '\0';
type = &line[type0];
line[type1] = '\0';
opt = &line[opt0];
line[opt1] = '\0';
flag = &line[flag0];
line[flag1] = '\0';
// Redirect system to system_root
if (mnt == "/system"sv)
mnt = "/system_root";
fprintf(fp, "%s %s %s %s %s\n", src, mnt, type, opt, flag);
return true;
});
fclose(fp);
// Replace old fstab
clone_attr(fstab.data(), patched.data());
rename(patched.data(), fstab.data());
}
#define FSR "/first_stage_ramdisk"
void ForcedFirstStageInit::prepare() {
// It is actually possible to NOT have FSR, create it just in case
xmkdir(FSR, 0755);
if (auto dir = xopen_dir(FSR); dir) {
string fstab(FSR "/");
for (dirent *de; (de = xreaddir(dir.get()));) {
if (strstr(de->d_name, "fstab")) {
fstab += de->d_name;
break;
}
}
if (fstab.length() == sizeof(FSR))
return;
patch_fstab(fstab);
} else {
return;
}
// Move stuffs for next stage
xmkdir(FSR "/system", 0755);
xmkdir(FSR "/system/bin", 0755);
rename("/init", FSR "/system/bin/init");
symlink("/system/bin/init", FSR "/init");
xmkdir(FSR "/.backup", 0);
rename("/.backup/.magisk", FSR "/.backup/.magisk");
rename("/overlay.d", FSR "/overlay.d");
}
void FirstStageInit::prepare() {
auto dir = xopen_dir("/");
for (dirent *de; (de = xreaddir(dir.get()));) {
if (strstr(de->d_name, "fstab")) {
patch_fstab(de->d_name);
break;
}
}
// Move stuffs for next stage
xmkdir("/system", 0755);
xmkdir("/system/bin", 0755);
rename("/init", "/system/bin/init");
rename("/.backup/init", "/init");
}
static inline long xptrace(int request, pid_t pid, void *addr, void *data) {
long ret = ptrace(request, pid, addr, data);
if (ret < 0)
PLOGE("ptrace %d", pid);
return ret;
}
static inline long xptrace(int request, pid_t pid, void *addr = nullptr, intptr_t data = 0) {
return xptrace(request, pid, addr, reinterpret_cast<void *>(data));
}
#define INIT_SOCKET "MAGISKINIT"
socklen_t setup_sockaddr(struct sockaddr_un *sun) {
sun->sun_family = AF_LOCAL;
strcpy(sun->sun_path + 1, INIT_SOCKET);
return sizeof(sa_family_t) + sizeof(INIT_SOCKET);
}
void SARFirstStageInit::traced_exec_init() {
int pid = getpid();
// Block SIGUSR1
sigset_t block, old;
sigemptyset(&block);
sigaddset(&block, SIGUSR1);
sigprocmask(SIG_BLOCK, &block, &old);
if (int child = xfork(); child) {
LOGD("init tracer [%d]\n", child);
// Wait for children to attach
int sig;
sigwait(&block, &sig);
// Restore sigmask
sigprocmask(SIG_BLOCK, &old, nullptr);
// Re-exec init
exec_init();
} else {
// Close all file descriptors and stop logging
no_logging();
for (int i = 0; i < 20; ++i)
close(i);
// Attach to parent to trace exec
xptrace(PTRACE_ATTACH, pid);
waitpid(pid, nullptr, __WALL | __WNOTHREAD);
xptrace(PTRACE_SETOPTIONS, pid, nullptr, PTRACE_O_TRACEEXEC);
xptrace(PTRACE_CONT, pid, 0, SIGUSR1);
// Wait for execve
waitpid(pid, nullptr, __WALL | __WNOTHREAD);
// Swap out init with bind mount
xmount("tmpfs", "/dev", "tmpfs", 0, "mode=755");
int init = xopen("/dev/magisk", O_CREAT | O_WRONLY, 0750);
write(init, self.buf, self.sz);
close(init);
xmount("/dev/magisk", "/init", nullptr, MS_BIND, nullptr);
xumount2("/dev", MNT_DETACH);
xptrace(PTRACE_DETACH, pid);
// Start daemon for 2nd stage preparation
struct sockaddr_un sun{};
auto len = setup_sockaddr(&sun);
int sockfd = xsocket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
xbind(sockfd, (struct sockaddr*) &sun, len);
xlisten(sockfd, 1);
// Wait for second stage ack
int client = xaccept4(sockfd, nullptr, nullptr, SOCK_CLOEXEC);
// Write backup files
int cfg = xopen(MAGISKTMP "/config", O_WRONLY | O_CREAT, 0000);
xwrite(cfg, config.buf, config.sz);
close(cfg);
restore_folder(ROOTOVL, overlays);
// Ack and bail out!
write(sockfd, &sockfd, sizeof(sockfd));
close(client);
close(sockfd);
exit(0);
}
}

67
native/jni/utils/file.cpp
View File

@ -55,21 +55,18 @@ static bool is_excl(initializer_list<const char *> excl, const char *name) {
} }
static void post_order_walk(int dirfd, initializer_list<const char *> excl, static void post_order_walk(int dirfd, initializer_list<const char *> excl,
int (*fn)(int, struct dirent *)) { function<int(int, dirent *)> &&fn) {
struct dirent *entry; auto dir = xopen_dir(dirfd);
int newfd; if (!dir) return;
DIR *dir = fdopendir(dirfd);
if (dir == nullptr) return;
while ((entry = xreaddir(dir))) { for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0) if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue; continue;
if (is_excl(excl, entry->d_name)) if (is_excl(excl, entry->d_name))
continue; continue;
if (entry->d_type == DT_DIR) { if (entry->d_type == DT_DIR) {
newfd = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC); int newfd = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC);
post_order_walk(newfd, excl, fn); post_order_walk(newfd, excl, std::move(fn));
close(newfd);
} }
fn(dirfd, entry); fn(dirfd, entry);
} }
@ -84,15 +81,14 @@ void rm_rf(const char *path) {
if (lstat(path, &st) < 0) if (lstat(path, &st) < 0)
return; return;
if (S_ISDIR(st.st_mode)) { if (S_ISDIR(st.st_mode)) {
int fd = open(path, O_RDONLY | O_CLOEXEC); int fd = xopen(path, O_RDONLY | O_CLOEXEC);
frm_rf(fd); frm_rf(fd);
close(fd);
} }
remove(path); remove(path);
} }
void frm_rf(int dirfd, initializer_list<const char *> excl) { void frm_rf(int dirfd, initializer_list<const char *> excl) {
post_order_walk(dirfd, excl, remove_at); post_order_walk(dup(dirfd), excl, remove_at);
} }
/* This will only on the same file system */ /* This will only on the same file system */
@ -403,3 +399,50 @@ void parse_mnt(const char *file, const function<bool (mntent*)> &fn) {
} }
} }
} }
void backup_folder(const char *dir, vector<raw_file> &files) {
char path[4096];
realpath(dir, path);
int len = strlen(path);
int dirfd = xopen(dir, O_RDONLY);
post_order_walk(dirfd, {}, [&](int dfd, dirent *entry) -> int {
int fd = xopenat(dfd, entry->d_name, O_RDONLY);
if (fd < 0)
return -1;
if (fd_path(fd, path, sizeof(path)) < 0)
return -1;
raw_file file;
file.path = path + len + 1;
if (fgetattr(fd, &file.attr) < 0)
return -1;
if (entry->d_type == DT_REG) {
fd_full_read(fd, file.buf, file.sz);
} else if (entry->d_type == DT_LNK) {
xreadlinkat(dfd, entry->d_name, path, sizeof(path));
file.sz = strlen(path) + 1;
file.buf = (uint8_t *) xmalloc(file.sz);
memcpy(file.buf, path, file.sz);
}
close(fd);
files.emplace_back(std::move(file));
return 0;
});
close(dirfd);
}
void restore_folder(const char *dir, vector<raw_file> &files) {
string base(dir);
// Reversed post-order means folders will always be first
for (raw_file &file : reversed(files)) {
string path = base + "/" + file.path;
if (S_ISDIR(file.attr.st.st_mode)) {
mkdirs(path.data(), 0);
} else if (S_ISREG(file.attr.st.st_mode)) {
auto fp = xopen_file(path.data(), "w");
fwrite(file.buf, 1, file.sz, fp.get());
} else if (S_ISLNK(file.attr.st.st_mode)) {
symlink((char *)file.buf, path.data());
}
setattr(path.data(), &file.attr);
}
}

29
native/jni/utils/files.hpp
View File

@ -5,6 +5,8 @@
#include <mntent.h> #include <mntent.h>
#include <functional> #include <functional>
#include <string_view> #include <string_view>
#include <string>
#include <vector>
#include "xwrap.hpp" #include "xwrap.hpp"
@ -16,6 +18,27 @@ struct file_attr {
char con[128]; char con[128];
}; };
struct raw_file {
std::string path;
file_attr attr;
uint8_t *buf = nullptr;
size_t sz = 0;
raw_file() = default;
raw_file(const raw_file&) = delete;
raw_file(raw_file &&d) {
path = std::move(d.path);
attr = d.attr;
buf = d.buf;
sz = d.sz;
d.buf = nullptr;
d.sz = 0;
}
~raw_file() {
free(buf);
}
};
ssize_t fd_path(int fd, char *path, size_t size); ssize_t fd_path(int fd, char *path, size_t size);
int fd_pathat(int dirfd, const char *name, char *path, size_t size); int fd_pathat(int dirfd, const char *name, char *path, size_t size);
int mkdirs(const char *pathname, mode_t mode); int mkdirs(const char *pathname, mode_t mode);
@ -46,6 +69,8 @@ void *__mmap(const char *filename, size_t *size, bool rw);
void frm_rf(int dirfd, std::initializer_list<const char *> excl = {}); void frm_rf(int dirfd, std::initializer_list<const char *> excl = {});
void clone_dir(int src, int dest, bool overwrite = true); void clone_dir(int src, int dest, bool overwrite = true);
void parse_mnt(const char *file, const std::function<bool(mntent*)> &fn); void parse_mnt(const char *file, const std::function<bool(mntent*)> &fn);
void backup_folder(const char *dir, std::vector<raw_file> &files);
void restore_folder(const char *dir, std::vector<raw_file> &files);
template <typename T> template <typename T>
void full_read(const char *filename, T &buf, size_t &size) { void full_read(const char *filename, T &buf, size_t &size) {
@ -94,6 +119,10 @@ static inline sDIR xopen_dir(const char *path) {
return sDIR(xopendir(path), closedir); return sDIR(xopendir(path), closedir);
} }
static inline sDIR xopen_dir(int dirfd) {
return sDIR(xfdopendir(dirfd), closedir);
}
static inline sFILE open_file(const char *path, const char *mode) { static inline sFILE open_file(const char *path, const char *mode) {
return sFILE(fopen(path, mode), fclose); return sFILE(fopen(path, mode), fclose);
} }