mdopen: add sbin path to env PATH when call system("modprobe md_mod")

During the boot process if mdadm is called in udev context, sbin paths
like /sbin, /usr/sbin, /usr/local/sbin normally not defined in PATH env
variable, calling system("modprobe md_mod") in create_named_array() may
fail with 'sh: modprobe: command not found' error message.

We don't want to move modprobe binary into udev private directory, so
setting the PATH env is a more proper method to avoid the above issue.

This patch sets PATH env variable with "/sbin:/usr/sbin:/usr/local/sbin"
before calling system("modprobe md_mod"). The change only takes effect
within the udev worker context, not seen by global udev environment.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Mariusz Tkaczyk <mtkaczyk@kernel.org>

diff --git a/mdopen.c b/mdopen.c
index 26f0c716d92b693dcea9a04532568e1db1b1d289..57252b646137ce0616ee2c24ad134e36f15d8e5a 100644 (file)
--- a/mdopen.c
+++ b/mdopen.c
@@ -39,6 +39,24 @@ int create_named_array(char *devnm)
 
        fd = open(new_array_file, O_WRONLY);
        if (fd < 0 && errno == ENOENT) {
+               char buf[PATH_MAX] = {0};
+               char *env_ptr;
+
+               env_ptr = getenv("PATH");
+               /*
+                * When called by udev worker context, path of modprobe
+                * might not be in env PATH. Set sbin paths into PATH
+                * env to avoid potential failure when run modprobe here.
+                */
+               if (env_ptr)
+                       snprintf(buf, PATH_MAX - 1, "%s:%s", env_ptr,
+                                "/sbin:/usr/sbin:/usr/local/sbin");
+               else
+                       snprintf(buf, PATH_MAX - 1, "%s",
+                                "/sbin:/usr/sbin:/usr/local/sbin");
+
+               setenv("PATH", buf, 1);
+
                if (system("modprobe md_mod") == 0)
                        fd = open(new_array_file, O_WRONLY);
        }