Magisk/native/jni/utils/file.cpp
2020-04-11 04:05:34 -07:00

404 lines
9.7 KiB
C++

#include <sys/sendfile.h>
#include <linux/fs.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <libgen.h>
#include <utils.hpp>
#include <selinux.hpp>
using namespace std;
ssize_t fd_path(int fd, char *path, size_t size) {
snprintf(path, size, "/proc/self/fd/%d", fd);
return xreadlink(path, path, size);
}
int fd_pathat(int dirfd, const char *name, char *path, size_t size) {
if (fd_path(dirfd, path, size) < 0)
return -1;
auto len = strlen(path);
path[len] = '/';
strlcpy(path + len + 1, name, size - len - 1);
return 0;
}
int mkdirs(string path, mode_t mode) {
errno = 0;
for (char *p = path.data() + 1; *p; ++p) {
if (*p == '/') {
*p = '\0';
if (mkdir(path.data(), mode) == -1) {
if (errno != EEXIST)
return -1;
}
*p = '/';
}
}
if (mkdir(path.data(), mode) == -1) {
if (errno != EEXIST)
return -1;
}
return 0;
}
#define SKIP_DOTS {\
if (entry->d_name == "."sv || entry->d_name == ".."sv) \
continue;\
}
static void post_order_walk(int dirfd, const function<int(int, dirent *)> &&fn) {
auto dir = xopen_dir(dirfd);
if (!dir) return;
for (dirent *entry; (entry = xreaddir(dir.get()));) {
SKIP_DOTS
if (entry->d_type == DT_DIR)
post_order_walk(xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC), std::move(fn));
fn(dirfd, entry);
}
}
static int remove_at(int dirfd, struct dirent *entry) {
return unlinkat(dirfd, entry->d_name, entry->d_type == DT_DIR ? AT_REMOVEDIR : 0);
}
void rm_rf(const char *path) {
struct stat st;
if (lstat(path, &st) < 0)
return;
if (S_ISDIR(st.st_mode))
frm_rf(xopen(path, O_RDONLY | O_CLOEXEC));
remove(path);
}
void frm_rf(int dirfd) {
post_order_walk(dirfd, remove_at);
}
void mv_path(const char *src, const char *dest) {
file_attr a;
getattr(src, &a);
if (S_ISDIR(a.st.st_mode)) {
xmkdirs(dest, 0);
setattr(dest, &a);
mv_dir(xopen(src, O_RDONLY | O_CLOEXEC), xopen(dest, O_RDONLY | O_CLOEXEC));
} else{
xrename(src, dest);
}
rmdir(src);
}
void mv_dir(int src, int dest) {
auto dir = xopen_dir(src);
run_finally f([&]{ close(dest); });
for (dirent *entry; (entry = xreaddir(dir.get()));) {
SKIP_DOTS
switch (entry->d_type) {
case DT_DIR:
if (faccessat(dest, entry->d_name, F_OK, 0) == 0) {
// Destination folder exists, needs recursive move
int newsrc = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
int newdest = xopenat(dest, entry->d_name, O_RDONLY | O_CLOEXEC);
mv_dir(newsrc, newdest);
unlinkat(src, entry->d_name, AT_REMOVEDIR);
break;
}
// Else fall through
case DT_LNK:
case DT_REG:
renameat(src, entry->d_name, dest, entry->d_name);
break;
}
}
}
void cp_afc(const char *src, const char *dest) {
file_attr a;
getattr(src, &a);
if (S_ISDIR(a.st.st_mode)) {
xmkdirs(dest, 0);
clone_dir(xopen(src, O_RDONLY | O_CLOEXEC), xopen(dest, O_RDONLY | O_CLOEXEC));
} else{
unlink(dest);
if (S_ISREG(a.st.st_mode)) {
int sfd = xopen(src, O_RDONLY | O_CLOEXEC);
int dfd = xopen(dest, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0);
xsendfile(dfd, sfd, nullptr, a.st.st_size);
close(sfd);
close(dfd);
} else if (S_ISLNK(a.st.st_mode)) {
char buf[4096];
xreadlink(src, buf, sizeof(buf));
xsymlink(buf, dest);
}
}
setattr(dest, &a);
}
void clone_dir(int src, int dest) {
auto dir = xopen_dir(src);
run_finally f([&]{ close(dest); });
for (dirent *entry; (entry = xreaddir(dir.get()));) {
SKIP_DOTS
file_attr a;
getattrat(src, entry->d_name, &a);
switch (entry->d_type) {
case DT_DIR: {
xmkdirat(dest, entry->d_name, 0);
setattrat(dest, entry->d_name, &a);
int sfd = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
int dst = xopenat(dest, entry->d_name, O_RDONLY | O_CLOEXEC);
clone_dir(sfd, dst);
break;
}
case DT_REG: {
int sfd = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
int dfd = xopenat(dest, entry->d_name, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC, 0);
xsendfile(dfd, sfd, nullptr, a.st.st_size);
fsetattr(dfd, &a);
close(dfd);
close(sfd);
break;
}
case DT_LNK: {
char buf[4096];
xreadlinkat(src, entry->d_name, buf, sizeof(buf));
xsymlinkat(buf, dest, entry->d_name);
setattrat(dest, entry->d_name, &a);
break;
}
}
}
}
void link_path(const char *src, const char *dest) {
link_dir(xopen(src, O_RDONLY | O_CLOEXEC), xopen(dest, O_RDONLY | O_CLOEXEC));
}
void link_dir(int src, int dest) {
auto dir = xopen_dir(src);
run_finally f([&]{ close(dest); });
for (dirent *entry; (entry = xreaddir(dir.get()));) {
SKIP_DOTS
if (entry->d_type == DT_DIR) {
file_attr a;
getattrat(src, entry->d_name, &a);
xmkdirat(dest, entry->d_name, 0);
setattrat(dest, entry->d_name, &a);
int sfd = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
int dfd = xopenat(dest, entry->d_name, O_RDONLY | O_CLOEXEC);
link_dir(sfd, dfd);
} else {
xlinkat(src, entry->d_name, dest, entry->d_name, 0);
}
}
}
int getattr(const char *path, file_attr *a) {
if (xlstat(path, &a->st) == -1)
return -1;
char *con;
if (lgetfilecon(path, &con) == -1)
return -1;
strcpy(a->con, con);
freecon(con);
return 0;
}
int getattrat(int dirfd, const char *name, file_attr *a) {
char path[4096];
fd_pathat(dirfd, name, path, sizeof(path));
return getattr(path, a);
}
int fgetattr(int fd, file_attr *a) {
if (xfstat(fd, &a->st) < 0)
return -1;
char *con;
if (fgetfilecon(fd, &con) < 0)
return -1;
strcpy(a->con, con);
freecon(con);
return 0;
}
int setattr(const char *path, file_attr *a) {
if (chmod(path, a->st.st_mode & 0777) < 0)
return -1;
if (chown(path, a->st.st_uid, a->st.st_gid) < 0)
return -1;
if (a->con[0] && lsetfilecon(path, a->con) < 0)
return -1;
return 0;
}
int setattrat(int dirfd, const char *name, file_attr *a) {
char path[4096];
fd_pathat(dirfd, name, path, sizeof(path));
return setattr(path, a);
}
int fsetattr(int fd, file_attr *a) {
if (fchmod(fd, a->st.st_mode & 0777) < 0)
return -1;
if (fchown(fd, a->st.st_uid, a->st.st_gid) < 0)
return -1;
if (a->con[0] && fsetfilecon(fd, a->con) < 0)
return -1;
return 0;
}
void clone_attr(const char *src, const char *dest) {
file_attr a;
getattr(src, &a);
setattr(dest, &a);
}
void fclone_attr(int src, int dest) {
file_attr a;
fgetattr(src, &a);
fsetattr(dest, &a);
}
void *__mmap(const char *filename, size_t *size, bool rw) {
struct stat st;
void *buf;
int fd = xopen(filename, (rw ? O_RDWR : O_RDONLY) | O_CLOEXEC);
fstat(fd, &st);
if (S_ISBLK(st.st_mode))
ioctl(fd, BLKGETSIZE64, size);
else
*size = st.st_size;
buf = *size > 0 ? xmmap(nullptr, *size, PROT_READ | (rw ? PROT_WRITE : 0), MAP_SHARED, fd, 0) : nullptr;
close(fd);
return buf;
}
void fd_full_read(int fd, void **buf, size_t *size) {
*size = lseek(fd, 0, SEEK_END);
lseek(fd, 0, SEEK_SET);
*buf = xmalloc(*size + 1);
xxread(fd, *buf, *size);
((char *) *buf)[*size] = '\0';
}
void full_read(const char *filename, void **buf, size_t *size) {
int fd = xopen(filename, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
*buf = nullptr;
*size = 0;
return;
}
fd_full_read(fd, buf, size);
close(fd);
}
void write_zero(int fd, size_t size) {
char buf[4096] = {0};
size_t len;
while (size > 0) {
len = sizeof(buf) > size ? size : sizeof(buf);
write(fd, buf, len);
size -= len;
}
}
void file_readline(bool trim, const char *file, const function<bool(string_view)> &fn) {
FILE *fp = xfopen(file, "re");
if (fp == nullptr)
return;
size_t len = 1024;
char *buf = (char *) malloc(len);
char *start;
ssize_t read;
while ((read = getline(&buf, &len, fp)) >= 0) {
start = buf;
if (trim) {
while (read && (buf[read - 1] == '\n' || buf[read - 1] == ' '))
--read;
buf[read] = '\0';
while (*start == ' ')
++start;
}
if (!fn(start))
break;
}
fclose(fp);
free(buf);
}
void parse_prop_file(const char *file, const function<bool(string_view, string_view)> &&fn) {
file_readline(true, file, [&](string_view line_view) -> bool {
char *line = (char *) line_view.data();
if (line[0] == '#')
return true;
char *eql = strchr(line, '=');
if (eql == nullptr || eql == line)
return true;
*eql = '\0';
return fn(line, eql + 1);
});
}
void parse_mnt(const char *file, const function<bool(mntent*)> &fn) {
auto fp = sFILE(setmntent(file, "re"), endmntent);
if (fp) {
mntent mentry{};
char buf[4096];
while (getmntent_r(fp.get(), &mentry, buf, sizeof(buf))) {
if (!fn(&mentry))
break;
}
}
}
void backup_folder(const char *dir, vector<raw_file> &files) {
char path[4096];
xrealpath(dir, path);
int len = strlen(path);
post_order_walk(xopen(dir, O_RDONLY), [&](int dfd, dirent *entry) -> int {
int fd = xopenat(dfd, entry->d_name, O_RDONLY);
if (fd < 0)
return -1;
run_finally f([&]{ close(fd); });
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);
}
files.emplace_back(std::move(file));
return 0;
});
}
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(), "we");
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);
}
}