libfstools: extroot: rework libdir and block tool discovery

Account for new upper/ directory component in recent overlayfs versions.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>

diff --git a/libfstools/extroot.c b/libfstools/extroot.c
index ca38ce132b8857c6295d8836fe2785eb20d13a23..4225d8b08752fa41c211d621227e6a19cb3049ef 100644 (file)
--- a/libfstools/extroot.c
+++ b/libfstools/extroot.c
@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <libgen.h>
 
 #include "libfstools.h"
 
@@ -32,29 +33,43 @@ int mount_extroot(void)
 {
        char ldlib_path[32];
        char block_path[32];
-       char kmod_loader[64];
+       char kmod_loader[128];
+       char *kmod_prefix;
        struct stat s;
        pid_t pid;
 
        if (!extroot_prefix)
                return -1;
 
-       sprintf(ldlib_path, "%s/lib", extroot_prefix);
-       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(block_path, &s)) {
-               sprintf(block_path, "/sbin/block");
-               if (stat(block_path, &s))
-                       return -1;
-       }
+       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) || !S_ISREG(s.st_mode))
+               snprintf(block_path, sizeof(block_path), "%s/sbin/block", extroot_prefix);
 
-       sprintf(kmod_loader, "/sbin/kmodloader %s/etc/modules-boot.d/ %s", extroot_prefix, extroot_prefix);
-       system(kmod_loader);
+       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;
+
+       /* 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);
+               kmod_prefix = dirname(ldlib_path);
+               sprintf(kmod_loader, "/sbin/kmodloader %s/etc/modules-boot.d/ %s", kmod_prefix, kmod_prefix);
+               system(kmod_loader);
+       }
 
        pid = fork();
        if (!pid) {
                mkdir("/tmp/extroot", 0755);
-               setenv("LD_LIBRARY_PATH", ldlib_path, 1);
                execl(block_path, block_path, "extroot", NULL);
                exit(-1);
        } else if (pid > 0) {