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 <private/android_filesystem_config.h>
18 #include <private/canned_fs_config.h>
19 #include <private/fs_config.h>
20
21 #include <errno.h>
22 #include <inttypes.h>
23 #include <limits.h>
24 #include <stdbool.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28
29 typedef struct {
30 const char* path;
31 unsigned uid;
32 unsigned gid;
33 unsigned mode;
34 uint64_t capabilities;
35 } Path;
36
37 static Path* canned_data = NULL;
38 static int canned_alloc = 0;
39 static int canned_used = 0;
40
path_compare(const void * a,const void * b)41 static int path_compare(const void* a, const void* b) {
42 return strcmp(((Path*)a)->path, ((Path*)b)->path);
43 }
44
load_canned_fs_config(const char * fn)45 int load_canned_fs_config(const char* fn) {
46 char buf[PATH_MAX + 200];
47 FILE* f;
48
49 f = fopen(fn, "r");
50 if (f == NULL) {
51 fprintf(stderr, "failed to open %s: %s\n", fn, strerror(errno));
52 return -1;
53 }
54
55 while (fgets(buf, sizeof(buf), f)) {
56 Path* p;
57 char* token;
58 char* line = buf;
59 bool rootdir;
60
61 while (canned_used >= canned_alloc) {
62 canned_alloc = (canned_alloc+1) * 2;
63 canned_data = (Path*) realloc(canned_data, canned_alloc * sizeof(Path));
64 }
65 p = canned_data + canned_used;
66 if (line[0] == '/') line++;
67 rootdir = line[0] == ' ';
68 p->path = strdup(rootdir ? "" : strtok(line, " "));
69 p->uid = atoi(strtok(rootdir ? line : NULL, " "));
70 p->gid = atoi(strtok(NULL, " "));
71 p->mode = strtol(strtok(NULL, " "), NULL, 8); // mode is in octal
72 p->capabilities = 0;
73
74 do {
75 token = strtok(NULL, " ");
76 if (token && strncmp(token, "capabilities=", 13) == 0) {
77 p->capabilities = strtoll(token+13, NULL, 0);
78 break;
79 }
80 } while (token);
81
82 canned_used++;
83 }
84
85 fclose(f);
86
87 qsort(canned_data, canned_used, sizeof(Path), path_compare);
88 printf("loaded %d fs_config entries\n", canned_used);
89
90 return 0;
91 }
92
93 static const int kDebugCannedFsConfig = 0;
94
canned_fs_config(const char * path,int dir,const char * target_out_path,unsigned * uid,unsigned * gid,unsigned * mode,uint64_t * capabilities)95 void canned_fs_config(const char* path, int dir, const char* target_out_path,
96 unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities) {
97 Path key, *p;
98
99 key.path = path;
100 if (path[0] == '/') key.path++; // canned paths lack the leading '/'
101 p = (Path*) bsearch(&key, canned_data, canned_used, sizeof(Path), path_compare);
102 if (p == NULL) {
103 fprintf(stderr, "failed to find [%s] in canned fs_config\n", path);
104 exit(1);
105 }
106 *uid = p->uid;
107 *gid = p->gid;
108 *mode = p->mode;
109 *capabilities = p->capabilities;
110
111 if (kDebugCannedFsConfig) {
112 // for debugging, run the built-in fs_config and compare the results.
113
114 unsigned c_uid, c_gid, c_mode;
115 uint64_t c_capabilities;
116
117 fs_config(path, dir, target_out_path, &c_uid, &c_gid, &c_mode, &c_capabilities);
118
119 if (c_uid != *uid) printf("%s uid %d %d\n", path, *uid, c_uid);
120 if (c_gid != *gid) printf("%s gid %d %d\n", path, *gid, c_gid);
121 if (c_mode != *mode) printf("%s mode 0%o 0%o\n", path, *mode, c_mode);
122 if (c_capabilities != *capabilities) {
123 printf("%s capabilities %" PRIx64 " %" PRIx64 "\n",
124 path,
125 *capabilities,
126 c_capabilities);
127 }
128 }
129 }
130