libcutils: add fs_config_generate
Bug: 19908228
Change-Id: Icb0e189a86758bb779b9bdf7c0d92216d297869f
diff --git a/libcutils/fs_config.c b/libcutils/fs_config.c
index bdb24dc..7fd66cd 100644
--- a/libcutils/fs_config.c
+++ b/libcutils/fs_config.c
@@ -63,6 +63,8 @@
return ((uint64_t) high << 32) | (uint64_t) low;
}
+#define ALIGN(x, alignment) ( ((x) + ((alignment) - 1)) & ~((alignment) - 1) )
+
/* Rules for directories.
** These rules are applied based on "first match", so they
** should start with the most specific path and work their
@@ -261,3 +263,22 @@
*mode = (*mode & (~07777)) | pc->mode;
*capabilities = pc->capabilities;
}
+
+ssize_t fs_config_generate(char *buffer, size_t length, const struct fs_path_config *pc)
+{
+ struct fs_path_config_from_file *p = (struct fs_path_config_from_file *)buffer;
+ size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t));
+
+ if ((length < len) || (len > UINT16_MAX)) {
+ return -ENOSPC;
+ }
+ memset(p, 0, len);
+ uint16_t host_len = len;
+ p->len = get2LE((const uint8_t *)&host_len);
+ p->mode = get2LE((const uint8_t *)&(pc->mode));
+ p->uid = get2LE((const uint8_t *)&(pc->uid));
+ p->gid = get2LE((const uint8_t *)&(pc->gid));
+ p->capabilities = get8LE((const uint8_t *)&(pc->capabilities));
+ strcpy(p->prefix, pc->prefix);
+ return len;
+}