Magisk/core/jni/utils/file.c

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/* file.c - Contains all files related utilities
*/
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
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#include <errno.h>
#include <string.h>
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#include <libgen.h>
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#include <sys/sendfile.h>
#include <sys/mman.h>
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#include <linux/fs.h>
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#ifdef SELINUX
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#include <selinux/selinux.h>
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#endif
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#include "utils.h"
char **excl_list = NULL;
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static int is_excl(const char *name) {
if (excl_list)
for (int i = 0; excl_list[i]; ++i)
if (strcmp(name, excl_list[i]) == 0)
return 1;
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return 0;
}
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int fd_getpath(int fd, char *path, size_t size) {
snprintf(path, size, "/proc/self/fd/%d", fd);
if (xreadlink(path, path, size) == -1)
return -1;
return 0;
}
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int mkdir_p(const char *pathname, mode_t mode) {
char *path = strdup(pathname), *p;
errno = 0;
for (p = path + 1; *p; ++p) {
if (*p == '/') {
*p = '\0';
if (mkdir(path, mode) == -1) {
if (errno != EEXIST)
return -1;
}
*p = '/';
}
}
if (mkdir(path, mode) == -1) {
if (errno != EEXIST)
return -1;
}
free(path);
return 0;
}
void in_order_walk(int dirfd, void (*callback)(int, struct dirent*)) {
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struct dirent *entry;
int newfd;
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DIR *dir = fdopendir(dirfd);
if (dir == NULL) return;
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while ((entry = xreaddir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
if (is_excl(entry->d_name))
continue;
if (entry->d_type == DT_DIR) {
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newfd = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC);
in_order_walk(newfd, callback);
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close(newfd);
}
callback(dirfd, entry);
}
}
static void rm_cb(int dirfd, struct dirent *entry) {
switch (entry->d_type) {
case DT_DIR:
unlinkat(dirfd, entry->d_name, AT_REMOVEDIR);
break;
default:
unlinkat(dirfd, entry->d_name, 0);
break;
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}
}
void rm_rf(const char *path) {
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int fd = open(path, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
if (fd >= 0) {
frm_rf(fd);
close(fd);
}
remove(path);
}
void frm_rf(int dirfd) {
in_order_walk(dirfd, rm_cb);
}
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/* This will only on the same file system */
void mv_f(const char *source, const char *destination) {
struct stat st;
xlstat(source, &st);
int src, dest;
struct file_attr a;
if (S_ISDIR(st.st_mode)) {
xmkdir_p(destination, st.st_mode & 0777);
src = xopen(source, O_RDONLY | O_CLOEXEC);
dest = xopen(destination, O_RDONLY | O_CLOEXEC);
fclone_attr(src, dest);
mv_dir(src, dest);
close(src);
close(dest);
} else{
getattr(source, &a);
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xrename(source, destination);
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setattr(destination, &a);
}
rmdir(source);
}
/* This will only on the same file system */
void mv_dir(int src, int dest) {
struct dirent *entry;
DIR *dir;
int newsrc, newdest;
struct file_attr a;
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dir = xfdopendir(src);
while ((entry = xreaddir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
if (is_excl(entry->d_name))
continue;
getattrat(src, entry->d_name, &a);
switch (entry->d_type) {
case DT_DIR:
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xmkdirat(dest, entry->d_name, a.st.st_mode & 0777);
newsrc = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
newdest = xopenat(dest, entry->d_name, O_RDONLY | O_CLOEXEC);
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fsetattr(newdest, &a);
mv_dir(newsrc, newdest);
close(newsrc);
close(newdest);
unlinkat(src, entry->d_name, AT_REMOVEDIR);
break;
case DT_LNK:
case DT_REG:
renameat(src, entry->d_name, dest, entry->d_name);
setattrat(dest, entry->d_name, &a);
break;
}
}
}
void cp_afc(const char *source, const char *destination) {
int src, dest;
struct file_attr a;
getattr(source, &a);
if (S_ISDIR(a.st.st_mode)) {
xmkdir_p(destination, a.st.st_mode & 0777);
src = xopen(source, O_RDONLY | O_CLOEXEC);
dest = xopen(destination, O_RDONLY | O_CLOEXEC);
fsetattr(dest, &a);
clone_dir(src, dest);
close(src);
close(dest);
} else{
unlink(destination);
if (S_ISREG(a.st.st_mode)) {
src = xopen(source, O_RDONLY);
dest = xopen(destination, O_WRONLY | O_CREAT | O_TRUNC);
xsendfile(dest, src, NULL, a.st.st_size);
fsetattr(src, &a);
close(src);
close(dest);
} else if (S_ISLNK(a.st.st_mode)) {
char buf[PATH_MAX];
xreadlink(source, buf, sizeof(buf));
xsymlink(buf, destination);
setattr(destination, &a);
}
}
}
void clone_dir(int src, int dest) {
struct dirent *entry;
DIR *dir;
int srcfd, destfd, newsrc, newdest;
char buf[PATH_MAX];
struct file_attr a;
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dir = xfdopendir(src);
while ((entry = xreaddir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
if (is_excl(entry->d_name))
continue;
getattrat(src, entry->d_name, &a);
switch (entry->d_type) {
case DT_DIR:
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xmkdirat(dest, entry->d_name, a.st.st_mode & 0777);
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setattrat(dest, entry->d_name, &a);
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newsrc = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
newdest = xopenat(dest, entry->d_name, O_RDONLY | O_CLOEXEC);
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clone_dir(newsrc, newdest);
close(newsrc);
close(newdest);
break;
case DT_REG:
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destfd = xopenat(dest, entry->d_name, O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC);
srcfd = xopenat(src, entry->d_name, O_RDONLY | O_CLOEXEC);
xsendfile(destfd, srcfd, 0, a.st.st_size);
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fsetattr(destfd, &a);
close(destfd);
close(srcfd);
break;
case DT_LNK:
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xreadlinkat(src, entry->d_name, buf, sizeof(buf));
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symlinkat(buf, dest, entry->d_name);
setattrat(dest, entry->d_name, &a);
break;
}
}
}
int getattr(const char *path, struct file_attr *a) {
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if (xlstat(path, &a->st) == -1)
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return -1;
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#ifdef SELINUX
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char *con = "";
if (lgetfilecon(path, &con) == -1)
return -1;
strcpy(a->con, con);
freecon(con);
#else
a->con[0] = '\0';
#endif
return 0;
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}
int getattrat(int dirfd, const char *pathname, struct file_attr *a) {
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int fd = xopenat(dirfd, pathname, O_PATH | O_NOFOLLOW | O_CLOEXEC);
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if (fd < 0)
return -1;
int ret = fgetattr(fd, a);
close(fd);
return ret;
}
int fgetattr(int fd, struct file_attr *a) {
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#ifdef SELINUX
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char path[PATH_MAX];
fd_getpath(fd, path, sizeof(path));
return getattr(path, a);
#else
if (fstat(fd, &a->st) == -1)
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return -1;
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a->con[0] = '\0';
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return 0;
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#endif
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}
int setattr(const char *path, struct file_attr *a) {
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if (chmod(path, a->st.st_mode & 0777) < 0)
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return -1;
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if (chown(path, a->st.st_uid, a->st.st_gid) < 0)
return -1;
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#ifdef SELINUX
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if (strlen(a->con) && lsetfilecon(path, a->con) < 0)
return -1;
#endif
return 0;
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}
int setattrat(int dirfd, const char *pathname, struct file_attr *a) {
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int fd = xopenat(dirfd, pathname, O_PATH | O_NOFOLLOW | O_CLOEXEC);
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if (fd < 0)
return -1;
int ret = fsetattr(fd, a);
close(fd);
return ret;
}
int fsetattr(int fd, struct file_attr *a) {
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#ifdef SELINUX
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char path[PATH_MAX];
fd_getpath(fd, path, sizeof(path));
return setattr(path, a);
#else
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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;
return 0;
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#endif
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}
void clone_attr(const char *source, const char *target) {
struct file_attr a;
getattr(source, &a);
setattr(target, &a);
}
void fclone_attr(const int sourcefd, const int targetfd) {
struct file_attr a;
fgetattr(sourcefd, &a);
fsetattr(targetfd, &a);
}
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#ifdef SELINUX
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#define UNLABEL_CON "u:object_r:unlabeled:s0"
#define SYSTEM_CON "u:object_r:system_file:s0"
void restorecon(int dirfd, int force) {
struct dirent *entry;
DIR *dir;
int fd;
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char path[PATH_MAX], *con;
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fd_getpath(dirfd, path, sizeof(path));
lgetfilecon(path, &con);
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if (force || strlen(con) == 0 || strcmp(con, UNLABEL_CON) == 0)
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lsetfilecon(path, SYSTEM_CON);
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freecon(con);
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dir = xfdopendir(dirfd);
while ((entry = xreaddir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
if (entry->d_type == DT_DIR) {
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fd = xopenat(dirfd, entry->d_name, O_RDONLY | O_CLOEXEC);
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restorecon(fd, force);
} else {
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fd = xopenat(dirfd, entry->d_name, O_PATH | O_NOFOLLOW | O_CLOEXEC);
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fd_getpath(fd, path, sizeof(path));
lgetfilecon(path, &con);
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if (force || strlen(con) == 0 || strcmp(con, UNLABEL_CON) == 0)
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lsetfilecon(path, SYSTEM_CON);
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freecon(con);
}
close(fd);
}
}
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#endif // SELINUX
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static int _mmap(int rw, const char *filename, void **buf, size_t *size) {
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struct stat st;
int fd = xopen(filename, rw ? O_RDWR : O_RDONLY);
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fstat(fd, &st);
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if (S_ISBLK(st.st_mode))
ioctl(fd, BLKGETSIZE64, size);
else
*size = st.st_size;
*buf = *size > 0 ? xmmap(NULL, *size, PROT_READ | (rw ? PROT_WRITE : 0), MAP_SHARED, fd, 0) : NULL;
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close(fd);
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return S_ISBLK(st.st_mode);
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}
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int mmap_ro(const char *filename, void **buf, size_t *size) {
return _mmap(0, filename, buf, size);
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}
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int mmap_rw(const char *filename, void **buf, size_t *size) {
return _mmap(1, filename, buf, size);
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}
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);
xxread(fd, *buf, *size);
}
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void full_read(const char *filename, void **buf, size_t *size) {
int fd = xopen(filename, O_RDONLY);
if (fd < 0) {
*buf = NULL;
*size = 0;
return;
}
fd_full_read(fd, buf, size);
close(fd);
}
void full_read_at(int dirfd, const char *filename, void **buf, size_t *size) {
int fd = xopenat(dirfd, filename, O_RDONLY);
if (fd < 0) {
*buf = NULL;
*size = 0;
return;
}
fd_full_read(fd, buf, size);
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close(fd);
}
void stream_full_read(int fd, void **buf, size_t *size) {
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size_t cap = 1 << 20;
uint8_t tmp[1 << 20];
*buf = xmalloc(cap);
ssize_t read;
*size = 0;
while (1) {
read = xread(fd, tmp, sizeof(tmp));
if (read <= 0)
break;
if (*size + read > cap) {
cap *= 2;
*buf = realloc(*buf, cap);
}
memcpy(*buf + *size, tmp, read);
*size += read;
}
}
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void write_zero(int fd, size_t size) {
size_t pos = lseek(fd, 0, SEEK_CUR);
ftruncate(fd, pos + size);
lseek(fd, pos + size, SEEK_SET);
}
void mem_align(size_t *pos, size_t align) {
size_t mask = align - 1;
if (*pos & mask) {
*pos += align - (*pos & mask);
}
}
void file_align(int fd, size_t align, int out) {
size_t pos = lseek(fd, 0, SEEK_CUR);
size_t mask = align - 1;
size_t off;
if (pos & mask) {
off = align - (pos & mask);
if (out) {
write_zero(fd, off);
} else {
lseek(fd, pos + off, SEEK_SET);
}
}
}