libfstools: extroot: simplify kmodloader invocation

[project/fstools.git] / libfstools / extroot.c

diff --git a/libfstools/extroot.c b/libfstools/extroot.c
index a8c1028..73ceae8 100644 (file)
--- a/libfstools/extroot.c
+++ b/libfstools/extroot.c
@@ -19,13 +19,19 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <libgen.h>
 
 #include "libfstools.h"
 
 char const *extroot_prefix = NULL;
 
+/*
+ * This will execute "block extroot" and make use of mounted extroot or return
+ * an error.
+ */
 int mount_extroot(void)
 {
+       char ldlib_path[32];
        char block_path[32];
        char kmod_loader[64];
        struct stat s;
@@ -34,13 +40,31 @@ int mount_extroot(void)
        if (!extroot_prefix)
                return -1;
 
-       sprintf(block_path, "%s/sbin/block", extroot_prefix);
+       /* try finding the library directory */
+       snprintf(ldlib_path, sizeof(ldlib_path), "%s/upper/lib", extroot_prefix);
+
+       if (stat(ldlib_path, &s) || !S_ISDIR(s.st_mode))
+               snprintf(ldlib_path, sizeof(ldlib_path), "%s/lib", extroot_prefix);
+
+       /* try finding the block executable */
+       snprintf(block_path, sizeof(block_path), "%s/upper/sbin/block", extroot_prefix);
 
-       if (stat(block_path, &s))
+       if (stat(block_path, &s) || !S_ISREG(s.st_mode))
+               snprintf(block_path, sizeof(block_path), "%s/sbin/block", extroot_prefix);
+
+       if (stat(block_path, &s) || !S_ISREG(s.st_mode))
+               snprintf(block_path, sizeof(block_path), "/sbin/block");
+
+       if (stat(block_path, &s) || !S_ISREG(s.st_mode))
                return -1;
 
-       sprintf(kmod_loader, "/sbin/kmodloader %s/etc/modules-boot.d/ %s", extroot_prefix, extroot_prefix);
-       system(kmod_loader);
+       /* set LD_LIBRARY_PATH env var and load kmods from overlay if we found a lib directory there */
+       if (!stat(ldlib_path, &s) && S_ISDIR(s.st_mode)) {
+               setenv("LD_LIBRARY_PATH", ldlib_path, 1);
+               snprintf(kmod_loader, sizeof(kmod_loader),
+                        "/sbin/kmodloader %s/etc/modules-boot.d/", dirname(ldlib_path));
+               system(kmod_loader);
+       }
 
        pid = fork();
        if (!pid) {