lvm: Updates lvcreate to wipe signatures if supported, fallbacks to old command if not.

src/lxc/storage/lvm.c

@@ -55,6 +55,7 @@ struct lvcreate_args {
 	const char *lv;
 	const char *thinpool;
 	const char *fstype;
+	bool sigwipe;
 
 	/* snapshot specific arguments */
 	const char *source_lv;
@@ -76,12 +77,19 @@ static int lvm_create_exec_wrapper(void *data)
 
 	(void)setenv("LVM_SUPPRESS_FD_WARNINGS", "1", 1);
 	if (args->thinpool)
-		execlp("lvcreate", "lvcreate", "-qq", "--thinpool", args->thinpool,
-		       "-V", args->size, args->vg, "-n", args->lv,
-		       (char *)NULL);
+		if(args->sigwipe)
+			execlp("lvcreate", "lvcreate", "-Wy", "--yes", "--thinpool", args->thinpool,
+			       "-V", args->size, args->vg, "-n", args->lv, (char *)NULL);
+		else
+			execlp("lvcreate", "lvcreate", "-qq", "--thinpool", args->thinpool,
+			       "-V", args->size, args->vg, "-n", args->lv, (char *)NULL);
 	else
-		execlp("lvcreate", "lvcreate", "-qq", "-L", args->size, args->vg, "-n",
-		       args->lv, (char *)NULL);
+		if(args->sigwipe)
+			execlp("lvcreate", "lvcreate", "-Wy", "--yes", "-L", args->size, args->vg, "-n",
+			       args->lv, (char *)NULL);
+		else
+			execlp("lvcreate", "lvcreate", "-qq", "-L", args->size, args->vg, "-n",
+			       args->lv, (char *)NULL);
 
 	return -1;
 }
@@ -177,11 +185,22 @@ static int do_lvm_create(const char *path, uint64_t size, const char *thinpool)
 	cmd_args.vg = vg;
 	cmd_args.lv = lv;
 	cmd_args.size = sz;
+	cmd_args.sigwipe = true;
 	TRACE("Creating new lvm storage volume \"%s\" on volume group \"%s\" "
 	      "of size \"%s\"", lv, vg, sz);
-	ret = run_command(cmd_output, sizeof(cmd_output),
+	ret = run_command_status(cmd_output, sizeof(cmd_output),
 			  lvm_create_exec_wrapper, (void *)&cmd_args);
-	if (ret < 0) {
+
+	/* If lvcreate is old and doesn't support signature wiping, try again without it.
+	 * Test for exit code EINVALID_CMD_LINE(3) of lvcreate command.
+	 */
+	if (WIFEXITED(ret) && WEXITSTATUS(ret) == 3) {
+		cmd_args.sigwipe = false;
+		ret = run_command(cmd_output, sizeof(cmd_output),
+			      lvm_create_exec_wrapper, (void *)&cmd_args);
+	}
+
+	if (ret != 0) {
 		ERROR("Failed to create logical volume \"%s\": %s", lv,
 		      cmd_output);
 		free(pathdup);

src/lxc/utils.c

@@ -1585,7 +1585,7 @@ pop_stack:
 	return umounts;
 }
 
-int run_command(char *buf, size_t buf_size, int (*child_fn)(void *), void *args)
+int run_command_internal(char *buf, size_t buf_size, int (*child_fn)(void *), void *args, bool wait_status)
 {
 	pid_t child;
 	int ret, fret, pipefd[2];
@@ -1642,13 +1642,27 @@ int run_command(char *buf, size_t buf_size, int (*child_fn)(void *), void *args)
 			buf[bytes - 1] = '\0';
 	}
 
-	fret = wait_for_pid(child);
+	if (wait_status)
+		fret = lxc_wait_for_pid_status(child);
+	else
+		fret = wait_for_pid(child);
+
 	/* close the read-end of the pipe */
 	close(pipefd[0]);
 
 	return fret;
 }
 
+int run_command(char *buf, size_t buf_size, int (*child_fn)(void *), void *args)
+{
+    return run_command_internal(buf, buf_size, child_fn, args, false);
+}
+
+int run_command_status(char *buf, size_t buf_size, int (*child_fn)(void *), void *args)
+{
+    return run_command_internal(buf, buf_size, child_fn, args, true);
+}
+
 bool lxc_nic_exists(char *nic)
 {
 #define __LXC_SYS_CLASS_NET_LEN 15 + IFNAMSIZ + 1

src/lxc/utils.h

@@ -200,6 +200,21 @@ extern int lxc_unstack_mountpoint(const char *path, bool lazy);
 extern int run_command(char *buf, size_t buf_size, int (*child_fn)(void *),
 		       void *args);
 
+/*
+ * run_command runs a command and collect it's std{err,out} output in buf, returns exit status.
+ *
+ * @param[out] buf     The buffer where the commands std{err,out] output will be
+ *                     read into. If no output was produced, buf will be memset
+ *                     to 0.
+ * @param[in] buf_size The size of buf. This function will reserve one byte for
+ *                     \0-termination.
+ * @param[in] child_fn The function to be run in the child process. This
+ *                     function must exec.
+ * @param[in] args     Arguments to be passed to child_fn.
+ */
+extern int run_command_status(char *buf, size_t buf_size, int (*child_fn)(void *),
+		       void *args);
+
 /* Concatenate all passed-in strings into one path. Do not fail. If any piece
  * is not prefixed with '/', add a '/'.
  */