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#define _GNU_SOURCE
#include <stdio.h>
#include <getopt.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <ext2fs/ext2fs.h>
#include "perms.h"
#include "base_fs.h"
#include "block_list.h"
#include "basefs_allocator.h"
#include "create_inode.h"
#ifndef UID_GID_MAP_MAX_EXTENTS
/*
* The value is defined in linux/user_namspace.h.
* The value is (arbitrarily) 5 in 4.14 and earlier, or 340 in 4.15 and later.
* Here, the bigger value is taken. See also man user_namespace(7).
*/
#define UID_GID_MAP_MAX_EXTENTS 340
#endif
static char *prog_name = "e2fsdroid";
static char *in_file;
static char *block_list;
static char *basefs_out;
static char *basefs_in;
static char *mountpoint = "";
static time_t fixed_time = -1;
static char *fs_config_file;
static struct selinux_opt seopt_file[8];
static int max_nr_opt = (int)sizeof(seopt_file) / sizeof(seopt_file[0]);
static char *product_out;
static char *src_dir;
static int android_configure;
static int android_sparse_file = 1;
static void usage(int ret)
{
fprintf(stderr, "%s [-B block_list] [-D basefs_out] [-T timestamp]\n"
"\t[-C fs_config] [-S file_contexts] [-p product_out]\n"
"\t[-a mountpoint] [-d basefs_in] [-f src_dir] [-e] [-s]\n"
"\t[-u uid-mapping] [-g gid-mapping] image\n",
prog_name);
exit(ret);
}
static char *absolute_path(const char *file)
{
char *ret;
char cwd[PATH_MAX];
if (file[0] != '/') {
if (getcwd(cwd, PATH_MAX) == NULL) {
fprintf(stderr, "Failed to getcwd\n");
exit(EXIT_FAILURE);
}
ret = malloc(strlen(cwd) + 1 + strlen(file) + 1);
if (ret)
sprintf(ret, "%s/%s", cwd, file);
} else
ret = strdup(file);
return ret;
}
static int parse_ugid_map_entry(char* line, struct ugid_map_entry* result)
{
char *token, *token_saveptr;
size_t num_tokens;
unsigned int *parsed[] = {&result->child_id,
&result->parent_id,
&result->length};
for (token = strtok_r(line, " ", &token_saveptr), num_tokens = 0;
token && num_tokens < 3;
token = strtok_r(NULL, " ", &token_saveptr), ++num_tokens) {
char* endptr = NULL;
unsigned long t = strtoul(token, &endptr, 10);
if ((t == ULONG_MAX && errno) || (t > UINT_MAX) || *endptr) {
fprintf(stderr, "Malformed u/gid mapping line\n");
return 0;
}
*parsed[num_tokens] = (unsigned int) t;
}
if (num_tokens < 3 || strtok_r(NULL, " ", &token_saveptr) != NULL) {
fprintf(stderr, "Malformed u/gid mapping line\n");
return 0;
}
if (result->child_id + result->length < result->child_id ||
result->parent_id + result->length < result->parent_id) {
fprintf(stderr, "u/gid mapping overflow\n");
return 0;
}
return 1;
}
/*
* Returns 1 if [begin1, begin1+length1) and [begin2, begin2+length2) have
* overlapping range. Otherwise 0.
*/
static int is_overlapping(unsigned int begin1, unsigned int length1,
unsigned int begin2, unsigned int length2)
{
unsigned int end1 = begin1 + length1;
unsigned int end2 = begin2 + length2;
return !(end1 <= begin2 || end2 <= begin1);
}
/*
* Verifies if the given mapping works.
* - Checks if the number of entries is less than or equals to
* UID_GID_MAP_MAX_EXTENTS.
* - Checks if there is no overlapped ranges.
* Returns 1 if valid, otherwise 0.
*/
static int is_valid_ugid_map(const struct ugid_map* mapping)
{
size_t i, j;
if (mapping->size > UID_GID_MAP_MAX_EXTENTS) {
fprintf(stderr, "too many u/gid mapping entries\n");
return 0;
}
for (i = 0; i < mapping->size; ++i) {
const struct ugid_map_entry *entry1 = &mapping->entries[i];
for (j = i + 1; j < mapping->size; ++j) {
const struct ugid_map_entry *entry2 =
&mapping->entries[j];
if (is_overlapping(entry1->child_id, entry1->length,
entry2->child_id, entry2->length)) {
fprintf(stderr,
"Overlapping child u/gid: [%d %d %d],"
" [%d %d %d]\n",
entry1->child_id, entry1->parent_id,
entry1->length, entry2->child_id,
entry2->parent_id, entry2->length);
return 0;
}
if (is_overlapping(entry1->parent_id, entry1->length,
entry2->parent_id, entry2->length)) {
fprintf(stderr,
"Overlapping parent u/gid: [%d %d %d],"
" [%d %d %d]\n",
entry1->child_id, entry1->parent_id,
entry1->length, entry2->child_id,
entry2->parent_id, entry2->length);
return 0;
}
}
}
return 1;
}
/*
* Parses the UID/GID mapping argument. The argument could be a multi-line
* string (separated by '\n', no trailing '\n' is allowed). Each line must
* contain exact three integer tokens; the first token is |child_id|,
* the second is |parent_id|, and the last is |length| of the mapping range.
* See also user_namespace(7) man page.
* On success, the parsed entries are stored in |result|, and it returns 1.
* Otherwise, returns 0.
*/
static int parse_ugid_map(char* arg, struct ugid_map* result)
{
int i;
char *line, *line_saveptr;
size_t current_index;
/* Count the number of lines. */
result->size = 1;
for (i = 0; arg[i]; ++i) {
if (arg[i] == '\n')
++result->size;
}
/* Allocate memory for entries. */
result->entries = malloc(sizeof(struct ugid_map_entry) * result->size);
if (!result->entries) {
result->size = 0;
return 0;
}
/* Parse each line */
for (line = strtok_r(arg, "\n", &line_saveptr), current_index = 0;
line;
line = strtok_r(NULL, "\n", &line_saveptr), ++current_index) {
if (!parse_ugid_map_entry(
line, &result->entries[current_index])) {
return 0;
}
}
return is_valid_ugid_map(result);
}
int main(int argc, char *argv[])
{
int c;
char *p;
int flags = EXT2_FLAG_RW;
errcode_t retval;
io_manager io_mgr;
ext2_filsys fs = NULL;
struct fs_ops_callbacks fs_callbacks = { NULL, NULL };
char *token;
int nr_opt = 0;
ext2_ino_t inodes_count;
ext2_ino_t free_inodes_count;
blk64_t blocks_count;
blk64_t free_blocks_count;
struct ugid_map uid_map = { 0, NULL }, gid_map = { 0, NULL };
add_error_table(&et_ext2_error_table);
while ((c = getopt (argc, argv, "T:C:S:p:a:D:d:B:f:esu:g:")) != EOF) {
switch (c) {
case 'T':
fixed_time = strtoul(optarg, &p, 0);
android_configure = 1;
break;
case 'C':
fs_config_file = absolute_path(optarg);
android_configure = 1;
break;
case 'S':
token = strtok(optarg, ",");
while (token) {
if (nr_opt == max_nr_opt) {
fprintf(stderr, "Expected at most %d selinux opts\n",
max_nr_opt);
exit(EXIT_FAILURE);
}
seopt_file[nr_opt].type = SELABEL_OPT_PATH;
seopt_file[nr_opt].value = absolute_path(token);
nr_opt++;
token = strtok(NULL, ",");
}
android_configure = 1;
break;
case 'p':
product_out = absolute_path(optarg);
android_configure = 1;
break;
case 'a':
mountpoint = strdup(optarg);
break;
case 'D':
basefs_out = absolute_path(optarg);
break;
case 'd':
basefs_in = absolute_path(optarg);
break;
case 'B':
block_list = absolute_path(optarg);
break;
case 'f':
src_dir = absolute_path(optarg);
break;
case 'e':
android_sparse_file = 0;
break;
case 's':
flags |= EXT2_FLAG_SHARE_DUP;
break;
case 'u':
if (!parse_ugid_map(optarg, &uid_map))
exit(EXIT_FAILURE);
android_configure = 1;
break;
case 'g':
if (!parse_ugid_map(optarg, &gid_map))
exit(EXIT_FAILURE);
android_configure = 1;
break;
default:
usage(EXIT_FAILURE);
}
}
if (optind >= argc) {
fprintf(stderr, "Expected filename after options\n");
exit(EXIT_FAILURE);
}
if (android_sparse_file) {
io_mgr = sparse_io_manager;
if (asprintf(&in_file, "(%s)", argv[optind]) == -1) {
fprintf(stderr, "Failed to allocate file name\n");
exit(EXIT_FAILURE);
}
} else {
io_mgr = unix_io_manager;
in_file = strdup(argv[optind]);
}
retval = ext2fs_open(in_file, flags, 0, 0, io_mgr, &fs);
if (retval) {
com_err(prog_name, retval, "while opening file %s\n", in_file);
return retval;
}
if (src_dir) {
ext2fs_read_bitmaps(fs);
if (basefs_in) {
retval = base_fs_alloc_load(fs, basefs_in, mountpoint,
src_dir);
if (retval) {
com_err(prog_name, retval, "%s",
"while reading base_fs file");
exit(1);
}
fs_callbacks.create_new_inode =
base_fs_alloc_set_target;
fs_callbacks.end_create_new_inode =
base_fs_alloc_unset_target;
}
retval = populate_fs2(fs, EXT2_ROOT_INO, src_dir,
EXT2_ROOT_INO, &fs_callbacks);
if (retval) {
com_err(prog_name, retval, "%s",
"while populating file system");
exit(1);
}
if (basefs_in)
base_fs_alloc_cleanup(fs);
}
if (android_configure) {
retval = android_configure_fs(
fs, src_dir, product_out, mountpoint, seopt_file,
nr_opt, fs_config_file, fixed_time, &uid_map, &gid_map);
if (retval) {
com_err(prog_name, retval, "%s",
"while configuring the file system");
exit(1);
}
}
if (block_list) {
retval = fsmap_iter_filsys(fs, &block_list_format, block_list,
mountpoint);
if (retval) {
com_err(prog_name, retval, "%s",
"while creating the block_list");
exit(1);
}
}
if (basefs_out) {
retval = fsmap_iter_filsys(fs, &base_fs_format,
basefs_out, mountpoint);
if (retval) {
com_err(prog_name, retval, "%s",
"while creating the basefs file");
exit(1);
}
}
inodes_count = fs->super->s_inodes_count;
free_inodes_count = fs->super->s_free_inodes_count;
blocks_count = ext2fs_blocks_count(fs->super);
free_blocks_count = ext2fs_free_blocks_count(fs->super);
retval = ext2fs_close_free(&fs);
if (retval) {
com_err(prog_name, retval, "%s",
"while writing superblocks");
exit(1);
}
printf("Created filesystem with %u/%u inodes and %llu/%llu blocks\n",
inodes_count - free_inodes_count, inodes_count,
blocks_count - free_blocks_count, blocks_count);
remove_error_table(&et_ext2_error_table);
return 0;
}