1 files changed, 53 insertions, 0 deletions
diff --git a/pager.c b/pager.c
new file mode 100644
index 0000000000..9a30939016
--- /dev/null
+++ b/pager.c
@@ -0,0 +1,53 @@
+#include "cache.h"
+
+/*
+ * This is split up from the rest of git so that we might do
+ * something different on Windows, for example.
+ */
+
+static void run_pager(const char *pager)
+{
+	execlp(pager, pager, NULL);
+	execl("/bin/sh", "sh", "-c", pager, NULL);
+}
+
+void setup_pager(void)
+{
+	pid_t pid;
+	int fd[2];
+	const char *pager = getenv("PAGER");
+
+	if (!isatty(1))
+		return;
+	if (!pager)
+		pager = "less";
+	else if (!*pager || !strcmp(pager, "cat"))
+		return;
+
+	if (pipe(fd) < 0)
+		return;
+	pid = fork();
+	if (pid < 0) {
+		close(fd[0]);
+		close(fd[1]);
+		return;
+	}
+
+	/* return in the child */
+	if (!pid) {
+		dup2(fd[1], 1);
+		close(fd[0]);
+		close(fd[1]);
+		return;
+	}
+
+	/* The original process turns into the PAGER */
+	dup2(fd[0], 0);
+	close(fd[0]);
+	close(fd[1]);
+
+	setenv("LESS", "-S", 0);
+	run_pager(pager);
+	die("unable to execute pager '%s'", pager);
+	exit(255);
+}