devices file: rename unused system.devices

If lvm.conf has use_devicesfile=0 and /etc/lvm/device/system.devices
exists, then rename it to system.devices-unused.YYYYMMDD.HHMMSS.
This prevents an old, incorrect system.devices from being used in
the future if lvm.conf is changed to use_devicesfile=1.

diff --git a/lib/device/dev-cache.c b/lib/device/dev-cache.c
index d61185ff48308506a7c7158c4e5d4bca35bd8109..3e87ddc3a59ddc9914657ef89267eeb64f80e74b 100644 (file)
--- a/lib/device/dev-cache.c
+++ b/lib/device/dev-cache.c
@@ -29,6 +29,7 @@
 #include <unistd.h>
 #include <dirent.h>
 #include <locale.h>
+#include <time.h>
 /* coverity[unnecessary_header] needed for MuslC */
 #include <sys/file.h>
 
@@ -1812,7 +1813,51 @@ static int _setup_devices_file_dmeventd(struct cmd_context *cmd)
        (void) dm_strncpy(cmd->devices_file_path, path, sizeof(cmd->devices_file_path));
        return 1;
 }
-       
+
+/*
+ * When lvm.conf use_devicesfile=0, then an existing system.devices
+ * is renamed to system.devices-unused.<date>.<time>.  Because,
+ * if lvm.conf is later changed to use_devicesfile=1, then the
+ * old system.devices file would immediately be used again, and
+ * the old file may not longer be correct due to changes to the
+ * system while it was disabled.
+ */
+static void devices_file_rename_unused(struct cmd_context *cmd)
+{
+       char path[PATH_MAX];
+       char path2[PATH_MAX];
+       char datetime_str[48] = {0};
+       const char *filename;
+       time_t t;
+       struct tm *tm;
+       struct stat st;
+
+       filename = find_config_tree_str(cmd, devices_devicesfile_CFG, NULL);
+
+       if (!filename || !strlen(filename))
+               return;
+
+       if (dm_snprintf(path, sizeof(path), "%s/devices/%s", cmd->system_dir, filename) < 0)
+               return;
+
+       if (stat(path, &st))
+               return;
+
+       t = time(NULL);
+       if (!(tm = localtime(&t)))
+               return;
+       strftime(datetime_str, sizeof(datetime_str), "%Y%m%d.%H%M%S", tm);
+
+       if (dm_snprintf(path2, sizeof(path2), "%s/devices/%s-unused.%s", cmd->system_dir, filename, datetime_str) < 0)
+               return;
+
+       if (rename(path, path2) < 0) {
+               stack;
+               return;
+       }
+       log_debug("Devices file moved to %s", path2);
+}
+
 int setup_devices_file(struct cmd_context *cmd)
 {
        char dirpath[PATH_MAX];
@@ -1848,8 +1893,15 @@ int setup_devices_file(struct cmd_context *cmd)
                }
        }
 
-       if (!cmd->enable_devices_file)
+       if (!cmd->enable_devices_file) {
+               struct dm_config_tree *cft;
+               /* rename unused system.devices to system.devices.unused.<date>.<time> */
+               if (!cmd->devicesfile &&
+                   (cft = get_config_tree_by_source(cmd, CONFIG_MERGED_FILES)) &&
+                   !find_config_bool(cmd, cft, devices_use_devicesfile_CFG))
+                       devices_file_rename_unused(cmd);
                return 1;
+       }
 
        if (dm_snprintf(dirpath, sizeof(dirpath), "%s/devices", cmd->system_dir) < 0) {
                log_error("Failed to copy devices dir path");
@@ -1873,6 +1925,7 @@ int setup_devices_file(struct cmd_context *cmd)
                log_error("Failed to copy devices file path");
                return 0;
        }
+
        return 1;
 }
 

diff --git a/test/shell/devicesfile-basic.sh b/test/shell/devicesfile-basic.sh
index c96bab7bc63c483e8dff54ac091044114407a0c6..91a162059c479f0f7a65c0ca5865c6b7400a3121 100644 (file)
--- a/test/shell/devicesfile-basic.sh
+++ b/test/shell/devicesfile-basic.sh
@@ -42,6 +42,23 @@ DFDIR="$LVM_SYSTEM_DIR/devices"
 mkdir -p "$DFDIR" || true
 DF="$DFDIR/system.devices"
 
+#
+# Test that unused system.devices is renamed
+#
+
+aux lvmconf 'devices/use_devicesfile = 1'
+wipe_all
+rm -f "$DF"
+rm -f "$DF.unused.*"
+touch "$DF"
+pvcreate "$dev1"
+grep "$dev1" "$DF"
+aux lvmconf 'devices/use_devicesfile = 0'
+pvs "$dev1"
+not ls "$DF"
+ls "$DF"-unused*
+rm -f "$DF-unused.*"
+
 #
 # Test with use_devicesfile=0 (no devices file is being applied by default)
 #