Add an installd command to link files

Given a pair of absolute paths {from_path, to_path} , check that
they are both valid apk subpaths (eg. /data/app/package/foo) and
link(2) to_path to from_path. This is required by staged installs,
where we link existing apks and oat files to their staging location.

bug: 20889739
Change-Id: I3b5e3b43677af68be59308121a4409caaa6a72f0
This commit is contained in:
Narayan Kamath 2015-06-04 13:20:27 +01:00
parent 13b1604018
commit d845c96128
4 changed files with 51 additions and 9 deletions

View File

@ -1778,6 +1778,31 @@ int rm_package_dir(const char* apk_path)
return delete_dir_contents(apk_path, 1 /* also_delete_dir */ , NULL /* exclusion_predicate */);
}
int link_file(const char* relative_path, const char* from_base, const char* to_base) {
char from_path[PKG_PATH_MAX];
char to_path[PKG_PATH_MAX];
snprintf(from_path, PKG_PATH_MAX, "%s/%s", from_base, relative_path);
snprintf(to_path, PKG_PATH_MAX, "%s/%s", to_base, relative_path);
if (validate_apk_path_subdirs(from_path)) {
ALOGE("invalid app data sub-path '%s' (bad prefix)\n", from_path);
return -1;
}
if (validate_apk_path_subdirs(to_path)) {
ALOGE("invalid app data sub-path '%s' (bad prefix)\n", to_path);
return -1;
}
const int ret = link(from_path, to_path);
if (ret < 0) {
ALOGE("link(%s, %s) failed : %s", from_path, to_path, strerror(errno));
return -1;
}
return 0;
}
int calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir, const char *apk_path,
const char *instruction_set) {
char *file_name_start;

View File

@ -179,6 +179,12 @@ static int do_rm_package_dir(char **arg, char reply[REPLY_MAX] __unused)
return rm_package_dir(arg[0]);
}
static int do_link_file(char **arg, char reply[REPLY_MAX] __unused)
{
/* relative_path, from_base, to_base */
return link_file(arg[0], arg[1], arg[2]);
}
struct cmdinfo {
const char *name;
unsigned numargs;
@ -210,6 +216,7 @@ struct cmdinfo cmds[] = {
{ "restorecondata", 4, do_restorecon_data },
{ "createoatdir", 2, do_create_oat_dir },
{ "rmpackagedir", 1, do_rm_package_dir },
{ "linkfile", 3, do_link_file }
};
static int readx(int s, void *_buf, int count)

View File

@ -203,6 +203,7 @@ int get_path_from_string(dir_rec_t* rec, const char* path);
int copy_and_append(dir_rec_t* dst, const dir_rec_t* src, const char* suffix);
int validate_apk_path(const char *path);
int validate_apk_path_subdirs(const char *path);
int append_and_increment(char** dst, const char* src, size_t* dst_size);
@ -254,3 +255,4 @@ int calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir, const
const char *instruction_set);
int move_package_dir(char path[PKG_PATH_MAX], const char *oat_dir, const char *apk_path,
const char *instruction_set);
int link_file(const char *relative_path, const char *from_base, const char *to_base);

View File

@ -1043,15 +1043,13 @@ int copy_and_append(dir_rec_t* dst, const dir_rec_t* src, const char* suffix) {
}
/**
* Check whether path points to a valid path for an APK file. Only one level of
* subdirectory names is allowed. Returns -1 when an invalid path is encountered
* and 0 when a valid path is encountered.
* Check whether path points to a valid path for an APK file. The path must
* begin with a whitelisted prefix path and must be no deeper than |maxSubdirs| within
* that path. Returns -1 when an invalid path is encountered and 0 when a valid path
* is encountered.
*/
int validate_apk_path(const char *path)
{
static int validate_apk_path_internal(const char *path, int maxSubdirs) {
const dir_rec_t* dir = NULL;
int maxSubdirs = 1;
if (!strncmp(path, android_app_dir.path, android_app_dir.len)) {
dir = &android_app_dir;
} else if (!strncmp(path, android_app_private_dir.path, android_app_private_dir.len)) {
@ -1060,7 +1058,9 @@ int validate_apk_path(const char *path)
dir = &android_asec_dir;
} else if (!strncmp(path, android_mnt_expand_dir.path, android_mnt_expand_dir.len)) {
dir = &android_mnt_expand_dir;
if (maxSubdirs < 2) {
maxSubdirs = 2;
}
} else {
return -1;
}
@ -1068,6 +1068,14 @@ int validate_apk_path(const char *path)
return validate_path(dir, path, maxSubdirs);
}
int validate_apk_path(const char* path) {
return validate_apk_path_internal(path, 1 /* maxSubdirs */);
}
int validate_apk_path_subdirs(const char* path) {
return validate_apk_path_internal(path, 3 /* maxSubdirs */);
}
int append_and_increment(char** dst, const char* src, size_t* dst_size) {
ssize_t ret = strlcpy(*dst, src, *dst_size);
if (ret < 0 || (size_t) ret >= *dst_size) {