1 files changed, 117 insertions, 0 deletions
diff --git a/usage.c b/usage.c
new file mode 100644
index 0000000000..79856a2b9f
--- /dev/null
+++ b/usage.c
@@ -0,0 +1,117 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#include "git-compat-util.h"
+
+static void report(const char *prefix, const char *err, va_list params)
+{
+	char msg[4096];
+	vsnprintf(msg, sizeof(msg), err, params);
+	fprintf(stderr, "%s%s\n", prefix, msg);
+}
+
+static NORETURN void usage_builtin(const char *err, va_list params)
+{
+	report("usage: ", err, params);
+	exit(129);
+}
+
+static NORETURN void die_builtin(const char *err, va_list params)
+{
+	report("fatal: ", err, params);
+	exit(128);
+}
+
+static void error_builtin(const char *err, va_list params)
+{
+	report("error: ", err, params);
+}
+
+static void warn_builtin(const char *warn, va_list params)
+{
+	report("warning: ", warn, params);
+}
+
+/* If we are in a dlopen()ed .so write to a global variable would segfault
+ * (ugh), so keep things static. */
+static NORETURN_PTR void (*usage_routine)(const char *err, va_list params) = usage_builtin;
+static NORETURN_PTR void (*die_routine)(const char *err, va_list params) = die_builtin;
+static void (*error_routine)(const char *err, va_list params) = error_builtin;
+static void (*warn_routine)(const char *err, va_list params) = warn_builtin;
+
+void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params))
+{
+	die_routine = routine;
+}
+
+void usagef(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	usage_routine(err, params);
+	va_end(params);
+}
+
+void usage(const char *err)
+{
+	usagef("%s", err);
+}
+
+void die(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	die_routine(err, params);
+	va_end(params);
+}
+
+void die_errno(const char *fmt, ...)
+{
+	va_list params;
+	char fmt_with_err[1024];
+	char str_error[256], *err;
+	int i, j;
+
+	err = strerror(errno);
+	for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) {
+		if ((str_error[j++] = err[i++]) != '%')
+			continue;
+		if (j < sizeof(str_error) - 1) {
+			str_error[j++] = '%';
+		} else {
+			/* No room to double the '%', so we overwrite it with
+			 * '\0' below */
+			j--;
+			break;
+		}
+	}
+	str_error[j] = 0;
+	snprintf(fmt_with_err, sizeof(fmt_with_err), "%s: %s", fmt, str_error);
+
+	va_start(params, fmt);
+	die_routine(fmt_with_err, params);
+	va_end(params);
+}
+
+int error(const char *err, ...)
+{
+	va_list params;
+
+	va_start(params, err);
+	error_routine(err, params);
+	va_end(params);
+	return -1;
+}
+
+void warning(const char *warn, ...)
+{
+	va_list params;
+
+	va_start(params, warn);
+	warn_routine(warn, params);
+	va_end(params);
+}