Move canned_fs_config into libcutils

It's no longer specific to make_ext4fs, will be used for mksquashfs as
well.

BUG: 27467028
Change-Id: I41b8c2b168ada45c8378dee522391edfb8f6b9a6
Signed-off-by: Mohamad Ayyash <mkayyash@google.com>

include/private/canned_fs_config.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+#ifndef _CANNED_FS_CONFIG_H
+#define _CANNED_FS_CONFIG_H
+
+#include <inttypes.h>
+
+int load_canned_fs_config(const char* fn);
+void canned_fs_config(const char* path, int dir, const char* target_out_path,
+                      unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities);
+
+#endif

libcutils/Android.mk

@@ -20,6 +20,7 @@ libcutils_common_sources := \
         atomic.c.arm \
         config_utils.c \
         fs_config.c \
+        canned_fs_config.c \
         hashmap.c \
         iosched_policy.c \
         load_file.c \

libcutils/canned_fs_config.c

@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2014 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 <inttypes.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#include <private/android_filesystem_config.h>
+#include <private/canned_fs_config.h>
+
+typedef struct {
+	const char* path;
+	unsigned uid;
+	unsigned gid;
+	unsigned mode;
+	uint64_t capabilities;
+} Path;
+
+static Path* canned_data = NULL;
+static int canned_alloc = 0;
+static int canned_used = 0;
+
+static int path_compare(const void* a, const void* b) {
+	return strcmp(((Path*)a)->path, ((Path*)b)->path);
+}
+
+int load_canned_fs_config(const char* fn) {
+	FILE* f = fopen(fn, "r");
+	if (f == NULL) {
+		fprintf(stderr, "failed to open %s: %s\n", fn, strerror(errno));
+		return -1;
+	}
+
+	char line[PATH_MAX + 200];
+	while (fgets(line, sizeof(line), f)) {
+		while (canned_used >= canned_alloc) {
+			canned_alloc = (canned_alloc+1) * 2;
+			canned_data = (Path*) realloc(canned_data, canned_alloc * sizeof(Path));
+		}
+		Path* p = canned_data + canned_used;
+		p->path = strdup(strtok(line, " "));
+		p->uid = atoi(strtok(NULL, " "));
+		p->gid = atoi(strtok(NULL, " "));
+		p->mode = strtol(strtok(NULL, " "), NULL, 8);   // mode is in octal
+		p->capabilities = 0;
+
+		char* token = NULL;
+		do {
+			token = strtok(NULL, " ");
+			if (token && strncmp(token, "capabilities=", 13) == 0) {
+				p->capabilities = strtoll(token+13, NULL, 0);
+				break;
+			}
+		} while (token);
+
+		canned_used++;
+	}
+
+	fclose(f);
+
+	qsort(canned_data, canned_used, sizeof(Path), path_compare);
+	printf("loaded %d fs_config entries\n", canned_used);
+
+	return 0;
+}
+
+static const int kDebugCannedFsConfig = 0;
+
+void canned_fs_config(const char* path, int dir, const char* target_out_path,
+					  unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities) {
+	Path key;
+    key.path = path;
+    if (path[0] == '/')
+        key.path++;   // canned paths lack the leading '/'
+	Path* p = (Path*) bsearch(&key, canned_data, canned_used, sizeof(Path), path_compare);
+	if (p == NULL) {
+		fprintf(stderr, "failed to find [%s] in canned fs_config\n", path);
+		exit(1);
+	}
+	*uid = p->uid;
+	*gid = p->gid;
+	*mode = p->mode;
+	*capabilities = p->capabilities;
+
+	if (kDebugCannedFsConfig) {
+		// for debugging, run the built-in fs_config and compare the results.
+
+		unsigned c_uid, c_gid, c_mode;
+		uint64_t c_capabilities;
+		fs_config(path, dir, target_out_path, &c_uid, &c_gid, &c_mode, &c_capabilities);
+
+		if (c_uid != *uid) printf("%s uid %d %d\n", path, *uid, c_uid);
+		if (c_gid != *gid) printf("%s gid %d %d\n", path, *gid, c_gid);
+		if (c_mode != *mode) printf("%s mode 0%o 0%o\n", path, *mode, c_mode);
+		if (c_capabilities != *capabilities)
+			printf("%s capabilities %" PRIx64 " %" PRIx64 "\n",
+				path,
+				*capabilities,
+				c_capabilities);
+        }
+}