build: Fix clobbering of FUSE_PREFIX

pkg_check_modules(FUSE ...) in fuse.cmake tells CMake's pkg-config
module to use FUSE as the variable prefix. pkg-config then populates
FUSE_PREFIX with the install prefix of libfuse (i.e., usr). This
overwrote the FUSE_PREFIX cache variable set to /tmp/ouroboros in
global.cmake.

IRMd was calling mkdir("/usr", 0777) on startup and rmdir("/usr") on
shutdown. The rmdir only fails because usr isn't empty — if it ever
were (e.g., in a minimal container), it would deleted /usr.

The fix renames the pkg-config prefix from FUSE to FUSE_PKG, so
pkg-config populates FUSE_PKG_PREFIX (harmless) instead of clobbering
FUSE_PREFIX.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 14 insertions, 13 deletions

diff --git a/cmake/dependencies/system/fuse.cmake b/cmake/dependencies/system/fuse.cmake
index 7de12b31..ffd9e92e 100644
--- a/cmake/dependencies/system/fuse.cmake
+++ b/cmake/dependencies/system/fuse.cmake
@@ -1,28 +1,29 @@
 # Try pkg-config first, fall back to find_library
+# Use FUSE_PKG prefix to avoid collision with FUSE_PREFIX
 if(PkgConfig_FOUND)
-  pkg_check_modules(FUSE QUIET IMPORTED_TARGET fuse>=2.6)
-  if(FUSE_FOUND AND NOT TARGET Fuse::Fuse)
-    add_library(Fuse::Fuse ALIAS PkgConfig::FUSE)
+  pkg_check_modules(FUSE_PKG QUIET IMPORTED_TARGET fuse>=2.6)
+  if(FUSE_PKG_FOUND AND NOT TARGET Fuse::Fuse)
+    add_library(Fuse::Fuse ALIAS PkgConfig::FUSE_PKG)
   endif()
 endif()
 
-if(NOT FUSE_FOUND)
-  find_library(FUSE_LIBRARIES fuse QUIET)
-  if(FUSE_LIBRARIES)
-    set(FUSE_FOUND TRUE)
+if(NOT FUSE_PKG_FOUND)
+  find_library(FUSE_PKG_LIBRARIES fuse QUIET)
+  if(FUSE_PKG_LIBRARIES)
+    set(FUSE_PKG_FOUND TRUE)
     if(NOT TARGET Fuse::Fuse)
       add_library(Fuse::Fuse UNKNOWN IMPORTED)
       set_target_properties(Fuse::Fuse PROPERTIES
-        IMPORTED_LOCATION "${FUSE_LIBRARIES}")
+        IMPORTED_LOCATION "${FUSE_PKG_LIBRARIES}")
     endif()
   endif()
 endif()
 
-if(FUSE_FOUND)
+if(FUSE_PKG_FOUND)
   set(DISABLE_FUSE FALSE CACHE BOOL "Disable FUSE support")
   if(NOT DISABLE_FUSE)
-    if(FUSE_VERSION)
-      message(STATUS "FUSE support enabled (version ${FUSE_VERSION})")
+    if(FUSE_PKG_VERSION)
+      message(STATUS "FUSE support enabled (version ${FUSE_PKG_VERSION})")
     else()
       message(STATUS "FUSE support enabled")
     endif()
@@ -38,7 +39,7 @@ else()
 endif()
 
 if(NOT HAVE_FUSE)
-  set(FUSE_LIBRARIES "")
+  set(FUSE_PKG_LIBRARIES "")
 endif()
 
-mark_as_advanced(FUSE_LIBRARIES)
+mark_as_advanced(FUSE_PKG_LIBRARIES)