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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <inttypes.h>
#include <selinux/selinux.h>
#include <selinux/label.h>
#include "private/android_filesystem_config.h"
// This program takes a list of files and directories (indicated by a
// trailing slash) on the stdin, and prints to stdout each input
// filename along with its desired uid, gid, and mode (in octal).
// The leading slash should be stripped from the input.
//
// After the first 4 columns, optional key=value pairs are emitted
// for each file. Currently, the following keys are supported:
// * -S: selabel=[selinux_label]
// * -C: capabilities=[hex capabilities value]
//
// Example input:
//
// system/etc/dbus.conf
// data/app/
//
// Output:
//
// system/etc/dbus.conf 1002 1002 440
// data/app 1000 1000 771
//
// or if, for example, -S is used:
//
// system/etc/dbus.conf 1002 1002 440 selabel=u:object_r:system_file:s0
// data/app 1000 1000 771 selabel=u:object_r:apk_data_file:s0
//
// Note that the output will omit the trailing slash from
// directories.
static struct selabel_handle* get_sehnd(const char* context_file) {
struct selinux_opt seopts[] = { { SELABEL_OPT_PATH, context_file } };
struct selabel_handle* sehnd = selabel_open(SELABEL_CTX_FILE, seopts, 1);
if (!sehnd) {
perror("error running selabel_open");
exit(EXIT_FAILURE);
}
return sehnd;
}
static void usage() {
fprintf(stderr, "Usage: fs_config [-D product_out_path] [-S context_file] [-R root] [-C]\n");
}
int main(int argc, char** argv) {
char buffer[1024];
const char* context_file = NULL;
const char* product_out_path = NULL;
char* root_path = NULL;
struct selabel_handle* sehnd = NULL;
int print_capabilities = 0;
int opt;
while((opt = getopt(argc, argv, "CS:R:D:")) != -1) {
switch(opt) {
case 'C':
print_capabilities = 1;
break;
case 'S':
context_file = optarg;
break;
case 'R':
root_path = optarg;
break;
case 'D':
product_out_path = optarg;
break;
default:
usage();
exit(EXIT_FAILURE);
}
}
if (context_file != NULL) {
sehnd = get_sehnd(context_file);
}
if (root_path != NULL) {
size_t root_len = strlen(root_path);
/* Trim any trailing slashes from the root path. */
while (root_len && root_path[--root_len] == '/') {
root_path[root_len] = '\0';
}
}
while (fgets(buffer, 1023, stdin) != NULL) {
int is_dir = 0;
int i;
for (i = 0; i < 1024 && buffer[i]; ++i) {
switch (buffer[i]) {
case '\n':
buffer[i-is_dir] = '\0';
if (i == 0) {
is_dir = 1; // empty line is considered as root directory
}
i = 1025;
break;
case '/':
is_dir = 1;
break;
default:
is_dir = 0;
break;
}
}
unsigned uid = 0, gid = 0, mode = 0;
uint64_t capabilities;
fs_config(buffer, is_dir, product_out_path, &uid, &gid, &mode, &capabilities);
if (root_path != NULL && strcmp(buffer, root_path) == 0) {
/* The root of the filesystem needs to be an empty string. */
strcpy(buffer, "");
}
printf("%s %d %d %o", buffer, uid, gid, mode);
if (sehnd != NULL) {
size_t buffer_strlen = strnlen(buffer, sizeof(buffer));
if (buffer_strlen >= sizeof(buffer)) {
fprintf(stderr, "non null terminated buffer, aborting\n");
exit(EXIT_FAILURE);
}
size_t full_name_size = buffer_strlen + 2;
char* full_name = (char*) malloc(full_name_size);
if (full_name == NULL) {
perror("malloc");
exit(EXIT_FAILURE);
}
full_name[0] = '/';
strncpy(full_name + 1, buffer, full_name_size - 1);
full_name[full_name_size - 1] = '\0';
char* secontext;
if (selabel_lookup(sehnd, &secontext, full_name, ( mode | (is_dir ? S_IFDIR : S_IFREG)))) {
secontext = strdup("u:object_r:unlabeled:s0");
}
printf(" selabel=%s", secontext);
free(full_name);
freecon(secontext);
}
if (print_capabilities) {
printf(" capabilities=0x%" PRIx64, capabilities);
}
printf("\n");
}
return 0;
}