3 files changed, 48 insertions, 7 deletions

diff --git a/list.h b/list.h
index a226a870dc..eb601192f4 100644
--- a/list.h
+++ b/list.h
@@ -163,4 +163,42 @@ static inline void list_replace_init(struct list_head *old,
 	INIT_LIST_HEAD(old);
 }
 
+/*
+ * This is exactly the same as a normal list_head, except that it can be
+ * declared volatile (e.g., if you have a list that may be accessed from signal
+ * handlers).
+ */
+struct volatile_list_head {
+	volatile struct volatile_list_head *next, *prev;
+};
+
+#define VOLATILE_LIST_HEAD(name) \
+	volatile struct volatile_list_head name = { &(name), &(name) }
+
+static inline void __volatile_list_del(volatile struct volatile_list_head *prev,
+				       volatile struct volatile_list_head *next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+static inline void volatile_list_del(volatile struct volatile_list_head *elem)
+{
+	__volatile_list_del(elem->prev, elem->next);
+}
+
+static inline int volatile_list_empty(volatile struct volatile_list_head *head)
+{
+	return head == head->next;
+}
+
+static inline void volatile_list_add(volatile struct volatile_list_head *newp,
+				     volatile struct volatile_list_head *head)
+{
+	head->next->prev = newp;
+	newp->next = head->next;
+	newp->prev = head;
+	head->next = newp;
+}
+
 #endif /* LIST_H */
diff --git a/tempfile.c b/tempfile.c
index e655e28477..11bda824cf 100644
--- a/tempfile.c
+++ b/tempfile.c
@@ -55,14 +55,16 @@
 #include "tempfile.h"
 #include "sigchain.h"
 
-static struct tempfile *volatile tempfile_list;
+static VOLATILE_LIST_HEAD(tempfile_list);
 
 static void remove_tempfiles(int in_signal_handler)
 {
 	pid_t me = getpid();
-	struct tempfile *volatile p;
+	volatile struct volatile_list_head *pos;
+
+	list_for_each(pos, &tempfile_list) {
+		struct tempfile *p = list_entry(pos, struct tempfile, list);
 
-	for (p = tempfile_list; p; p = p->next) {
 		if (!is_tempfile_active(p) || p->owner != me)
 			continue;
 
@@ -95,7 +97,7 @@ static void remove_tempfiles_on_signal(int signo)
  */
 static void prepare_tempfile_object(struct tempfile *tempfile)
 {
-	if (!tempfile_list) {
+	if (volatile_list_empty(&tempfile_list)) {
 		/* One-time initialization */
 		sigchain_push_common(remove_tempfiles_on_signal);
 		atexit(remove_tempfiles_on_exit);
@@ -110,8 +112,7 @@ static void prepare_tempfile_object(struct tempfile *tempfile)
 		tempfile->active = 0;
 		tempfile->owner = 0;
 		strbuf_init(&tempfile->filename, 0);
-		tempfile->next = tempfile_list;
-		tempfile_list = tempfile;
+		volatile_list_add(&tempfile->list, &tempfile_list);
 		tempfile->on_list = 1;
 	} else if (tempfile->filename.len) {
 		/* This shouldn't happen, but better safe than sorry. */
diff --git a/tempfile.h b/tempfile.h
index d30663182d..2ee24f4380 100644
--- a/tempfile.h
+++ b/tempfile.h
@@ -1,6 +1,8 @@
 #ifndef TEMPFILE_H
 #define TEMPFILE_H
 
+#include "list.h"
+
 /*
  * Handle temporary files.
  *
@@ -81,7 +83,7 @@
  */
 
 struct tempfile {
-	struct tempfile *volatile next;
+	volatile struct volatile_list_head list;
 	volatile sig_atomic_t active;
 	volatile int fd;
 	FILE *volatile fp;