init: create symlinks to block device nodes
eMMC block device names may change based on the detection order of
the eMMC device and any other SD bus devices, such as a removable SD
card.
This patch adds support to init for:
* Symlinks to block devices. When a block device uevent is
processed, if it starts with "/devices/platform", the platform
driver name is parsed out, and symlinks to the block device are
created in /dev/block/platform/<platform driver>/
* Symlinks based on partition name and number. If the uevent for
a block device contains information on the partition name or
number, symlinks are created under
/dev/block/platform/<platform driver>/by-num/p<partition>
and
/dev/block/platform/<platform driver>/by-name/<partition name>
init.rc can then use a device path like the following to mount an
eMMC device:
/dev/block/platform/<platform>/by-name/system /system ro
Change-Id: Id11bb7cdf1e2ada7752a5bd671cbf87237b34ae2
diff --git a/init/util.c b/init/util.c
index 6f9a12e..a56ba0d 100644
--- a/init/util.c
+++ b/init/util.c
@@ -299,3 +299,81 @@
return ts.tv_sec;
}
+
+int mkdir_recursive(const char *pathname, mode_t mode)
+{
+ char buf[128];
+ const char *slash;
+ const char *p = pathname;
+ int width;
+ int ret;
+ struct stat info;
+
+ while ((slash = strchr(p, '/')) != NULL) {
+ width = slash - pathname;
+ p = slash + 1;
+ if (width < 0)
+ break;
+ if (width == 0)
+ continue;
+ if ((unsigned int)width > sizeof(buf) - 1) {
+ ERROR("path too long for mkdir_recursive\n");
+ return -1;
+ }
+ memcpy(buf, pathname, width);
+ buf[width] = 0;
+ if (stat(buf, &info) != 0) {
+ ret = mkdir(buf, mode);
+ if (ret && errno != EEXIST)
+ return ret;
+ }
+ }
+ ret = mkdir(pathname, mode);
+ if (ret && errno != EEXIST)
+ return ret;
+ return 0;
+}
+
+void sanitize(char *s)
+{
+ if (!s)
+ return;
+ while (isalnum(*s))
+ s++;
+ *s = 0;
+}
+void make_link(const char *oldpath, const char *newpath)
+{
+ int ret;
+ char buf[256];
+ char *slash;
+ int width;
+
+ slash = strrchr(newpath, '/');
+ if (!slash)
+ return;
+ width = slash - newpath;
+ if (width <= 0 || width > (int)sizeof(buf) - 1)
+ return;
+ memcpy(buf, newpath, width);
+ buf[width] = 0;
+ ret = mkdir_recursive(buf, 0755);
+ if (ret)
+ ERROR("Failed to create directory %s: %s (%d)\n", buf, strerror(errno), errno);
+
+ ret = symlink(oldpath, newpath);
+ if (ret && errno != EEXIST)
+ ERROR("Failed to symlink %s to %s: %s (%d)\n", oldpath, newpath, strerror(errno), errno);
+}
+
+void remove_link(const char *oldpath, const char *newpath)
+{
+ char path[256];
+ ssize_t ret;
+ ret = readlink(newpath, path, sizeof(path) - 1);
+ if (ret <= 0)
+ return;
+ path[ret] = 0;
+ if (!strcmp(path, oldpath))
+ unlink(newpath);
+}