Split implementation into two files.

- also fix threadings bugs: threads could leak (if the join loop exited
  due to some error) or non existent threads could be joined (we add the
  created struct member to avoid this)

Makefile

@@ -1,3 +1,5 @@
 .PHONY: all
 
 all: erm
+
+erm: erm.c remove.c | erm.h

erm.c

@@ -1,7 +1,4 @@
-#define _XOPEN_SOURCE 500 /* nftw */
 #include <errno.h>
-#include <ftw.h>
-#include <pthread.h>
 #include <stdbool.h>
 #include <stdnoreturn.h>
 #include <stdio.h>
@@ -9,41 +6,7 @@
 #include <string.h>
 #include <unistd.h>
 
-static int ftw_cb(const char *fpath, const struct stat *sb,
-		int typeflag, struct FTW *ftwbuf)
-{
-	if (typeflag == FTW_D || typeflag == FTW_DP) return rmdir(fpath);
-	else return unlink(fpath);
-}
-
-struct task {
-	pthread_t thread;
-	const char *path;
-	int rv;
-} *task_list = NULL;
-
-void *run_ftw(void *arg)
-{
-	struct task *t = arg;
-	t->rv = nftw(t->path, ftw_cb, 20, FTW_DEPTH|FTW_PHYS);
-	return NULL;
-}
-static int recurse_into(const char *path, int c)
-{
-	task_list[c].path = path;
-	return pthread_create(&task_list[c].thread, NULL, run_ftw, &task_list[c]);
-}
-static int join_thread(const char *path, int c)
-{
-	pthread_join(task_list[c].thread, NULL);
-	return task_list[c].rv;
-}
-
-static int single_file(const char *path, int c)
-{
-	(void)c;
-	return remove(path);
-}
+#include "erm.h"
 
 noreturn static void usage(int s)
 {
@@ -73,16 +36,18 @@ int main(int argc, char **argv)
 	}
 	argc -= optind;
 	argv += optind;
+	if (argc == 0) {
+		usage(1);
+	}
 
 	if (recursive) {
-		task_list = calloc(sizeof(*task_list), argc);
-		if (!task_list) {
+		if (!malloc_task_list(argc)) {
 			perror("malloc");
 			return 5;
 		}
 	}
-	int (*action)(const char *, int) = recursive ? recurse_into : single_file;
-	int (*callback)(const char *, int) = recursive ? join_thread : NULL;
+	file_action action = recursive ? recurse_into : single_file;
+	file_action callback = recursive ? join_thread : NULL;
 	const char *err_fmt = recursive ?
 		"failed to delve into '%s': %s\n" : "failed to remove '%s': %s\n";
 
@@ -103,11 +68,7 @@ int main(int argc, char **argv)
 			const char *path = argv[i];
 			if (callback(path, i)) {
 				fprintf(stderr, err_fmt, path, strerror(errno));
-				if (stop_at_error) {
-					return 1;
-				} else {
-					rv = 1;
-				}
+				rv = 1;
 			}
 		}
 	}

erm.h

@@ -0,0 +1,8 @@
+typedef int (*file_action)(const char *path, int position);
+struct task;
+
+/* remove.c */
+struct task *malloc_task_list(size_t);
+int recurse_into(const char *, int);
+int join_thread(const char *, int);
+int single_file(const char *, int);

remove.c

@@ -0,0 +1,60 @@
+#define _XOPEN_SOURCE 500 /* nftw */
+#include <errno.h>
+#include <ftw.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "erm.h"
+
+struct task {
+	pthread_t thread;
+	const char *path;
+	int rv;
+	int created;
+} *task_list = NULL;
+
+struct task *malloc_task_list(size_t n)
+{
+	return task_list = calloc(sizeof(struct task), n);
+}
+
+static int ftw_cb(const char *fpath, const struct stat *sb,
+		int typeflag, struct FTW *ftwbuf)
+{
+	if (typeflag == FTW_D || typeflag == FTW_DP) return rmdir(fpath);
+	else return unlink(fpath);
+}
+static void *run_ftw(void *arg)
+{
+	struct task *t = arg;
+	t->rv = nftw(t->path, ftw_cb, 20, FTW_DEPTH|FTW_PHYS) ? errno : 0;
+	return NULL;
+}
+
+int recurse_into(const char *path, int c)
+{
+	task_list[c].path = path;
+	int rv = pthread_create(&task_list[c].thread, NULL, run_ftw, &task_list[c]);
+	if (!rv) task_list[c].created = 1;
+	return rv;
+}
+
+int join_thread(const char *path, int c)
+{
+	if (!task_list[c].created) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	pthread_join(task_list[c].thread, NULL);
+	errno = task_list[c].rv;
+	return errno ? -1 : 0;
+}
+
+int single_file(const char *path, int c)
+{
+	(void)c;
+	return remove(path);
+}