fs_config.c revision 74a81e6633276d92337749a5ee9d921207814dd4 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19#include <sys/stat.h>
20#include <errno.h>
21#include <unistd.h>
22#include <string.h>
23#include <inttypes.h>
24
25#include <selinux/selinux.h>
26#include <selinux/label.h>
27#include <selinux/android.h>
28
29#include "private/android_filesystem_config.h"
30
31// This program takes a list of files and directories (indicated by a
32// trailing slash) on the stdin, and prints to stdout each input
33// filename along with its desired uid, gid, and mode (in octal).
34// The leading slash should be stripped from the input.
35//
36// After the first 4 columns, optional key=value pairs are emitted
37// for each file.  Currently, the following keys are supported:
38// * -S: selabel=[selinux_label]
39// * -C: capabilities=[hex capabilities value]
40//
41// Example input:
42//
43//      system/etc/dbus.conf
44//      data/app/
45//
46// Output:
47//
48//      system/etc/dbus.conf 1002 1002 440
49//      data/app 1000 1000 771
50//
51//   or if, for example, -S is used:
52//
53//      system/etc/dbus.conf 1002 1002 440 selabel=u:object_r:system_file:s0
54//      data/app 1000 1000 771 selabel=u:object_r:apk_data_file:s0
55//
56// Note that the output will omit the trailing slash from
57// directories.
58
59static struct selabel_handle* get_sehnd(const char* context_file) {
60  struct selinux_opt seopts[] = { { SELABEL_OPT_PATH, context_file } };
61  struct selabel_handle* sehnd = selabel_open(SELABEL_CTX_FILE, seopts, 1);
62
63  if (!sehnd) {
64    perror("error running selabel_open");
65    exit(EXIT_FAILURE);
66  }
67  return sehnd;
68}
69
70static void usage() {
71  fprintf(stderr, "Usage: fs_config [-D product_out_path] [-S context_file] [-C]\n");
72}
73
74int main(int argc, char** argv) {
75  char buffer[1024];
76  const char* context_file = NULL;
77  const char* product_out_path = NULL;
78  struct selabel_handle* sehnd = NULL;
79  int print_capabilities = 0;
80  int opt;
81  while((opt = getopt(argc, argv, "CS:D:")) != -1) {
82    switch(opt) {
83    case 'C':
84      print_capabilities = 1;
85      break;
86    case 'S':
87      context_file = optarg;
88      break;
89    case 'D':
90      product_out_path = optarg;
91      break;
92    default:
93      usage();
94      exit(EXIT_FAILURE);
95    }
96  }
97
98  if (context_file != NULL) {
99    sehnd = get_sehnd(context_file);
100  }
101
102  while (fgets(buffer, 1023, stdin) != NULL) {
103    int is_dir = 0;
104    int i;
105    for (i = 0; i < 1024 && buffer[i]; ++i) {
106      switch (buffer[i]) {
107        case '\n':
108          buffer[i-is_dir] = '\0';
109          i = 1025;
110          break;
111        case '/':
112          is_dir = 1;
113          break;
114        default:
115          is_dir = 0;
116          break;
117      }
118    }
119
120    unsigned uid = 0, gid = 0, mode = 0;
121    uint64_t capabilities;
122    fs_config(buffer, is_dir, product_out_path, &uid, &gid, &mode, &capabilities);
123    printf("%s %d %d %o", buffer, uid, gid, mode);
124
125    if (sehnd != NULL) {
126      size_t buffer_strlen = strnlen(buffer, sizeof(buffer));
127      if (buffer_strlen >= sizeof(buffer)) {
128        fprintf(stderr, "non null terminated buffer, aborting\n");
129        exit(EXIT_FAILURE);
130      }
131      size_t full_name_size = buffer_strlen + 2;
132      char* full_name = (char*) malloc(full_name_size);
133      if (full_name == NULL) {
134        perror("malloc");
135        exit(EXIT_FAILURE);
136      }
137
138      full_name[0] = '/';
139      strncpy(full_name + 1, buffer, full_name_size - 1);
140      full_name[full_name_size - 1] = '\0';
141
142      char* secontext;
143      if (selabel_lookup(sehnd, &secontext, full_name, ( mode | (is_dir ? S_IFDIR : S_IFREG)))) {
144        secontext = strdup("u:object_r:unlabeled:s0");
145      }
146
147      printf(" selabel=%s", secontext);
148      free(full_name);
149      freecon(secontext);
150    }
151
152    if (print_capabilities) {
153      printf(" capabilities=0x%" PRIx64, capabilities);
154    }
155
156    printf("\n");
157  }
158  return 0;
159}
160