1/*
2 * Copyright (C) 2014 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 <errno.h>
18#include <inttypes.h>
19#include <limits.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <string.h>
23
24#include <private/android_filesystem_config.h>
25#include <private/canned_fs_config.h>
26
27typedef struct {
28    const char* path;
29    unsigned uid;
30    unsigned gid;
31    unsigned mode;
32    uint64_t capabilities;
33} Path;
34
35static Path* canned_data = NULL;
36static int canned_alloc = 0;
37static int canned_used = 0;
38
39static int path_compare(const void* a, const void* b) {
40    return strcmp(((Path*)a)->path, ((Path*)b)->path);
41}
42
43int load_canned_fs_config(const char* fn) {
44    char line[PATH_MAX + 200];
45    FILE* f;
46
47    f = fopen(fn, "r");
48    if (f == NULL) {
49        fprintf(stderr, "failed to open %s: %s\n", fn, strerror(errno));
50        return -1;
51    }
52
53    while (fgets(line, sizeof(line), f)) {
54        Path* p;
55        char* token;
56
57        while (canned_used >= canned_alloc) {
58            canned_alloc = (canned_alloc+1) * 2;
59            canned_data = (Path*) realloc(canned_data, canned_alloc * sizeof(Path));
60        }
61        p = canned_data + canned_used;
62        p->path = strdup(strtok(line, " "));
63        p->uid = atoi(strtok(NULL, " "));
64        p->gid = atoi(strtok(NULL, " "));
65        p->mode = strtol(strtok(NULL, " "), NULL, 8);   // mode is in octal
66        p->capabilities = 0;
67
68        do {
69            token = strtok(NULL, " ");
70            if (token && strncmp(token, "capabilities=", 13) == 0) {
71                p->capabilities = strtoll(token+13, NULL, 0);
72                break;
73            }
74        } while (token);
75
76        canned_used++;
77    }
78
79    fclose(f);
80
81    qsort(canned_data, canned_used, sizeof(Path), path_compare);
82    printf("loaded %d fs_config entries\n", canned_used);
83
84    return 0;
85}
86
87static const int kDebugCannedFsConfig = 0;
88
89void canned_fs_config(const char* path, int dir, const char* target_out_path,
90                      unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities) {
91    Path key, *p;
92
93    key.path = path;
94    if (path[0] == '/') key.path++; // canned paths lack the leading '/'
95    p = (Path*) bsearch(&key, canned_data, canned_used, sizeof(Path), path_compare);
96    if (p == NULL) {
97        fprintf(stderr, "failed to find [%s] in canned fs_config\n", path);
98        exit(1);
99    }
100    *uid = p->uid;
101    *gid = p->gid;
102    *mode = p->mode;
103    *capabilities = p->capabilities;
104
105    if (kDebugCannedFsConfig) {
106        // for debugging, run the built-in fs_config and compare the results.
107
108        unsigned c_uid, c_gid, c_mode;
109        uint64_t c_capabilities;
110
111        fs_config(path, dir, target_out_path, &c_uid, &c_gid, &c_mode, &c_capabilities);
112
113        if (c_uid != *uid) printf("%s uid %d %d\n", path, *uid, c_uid);
114        if (c_gid != *gid) printf("%s gid %d %d\n", path, *gid, c_gid);
115        if (c_mode != *mode) printf("%s mode 0%o 0%o\n", path, *mode, c_mode);
116        if (c_capabilities != *capabilities) {
117            printf("%s capabilities %" PRIx64 " %" PRIx64 "\n",
118                path,
119                *capabilities,
120                c_capabilities);
121        }
122    }
123}
124