From 40e55df46354536990e5f1e0f0a5026aa7b2b7de Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Arne=20Vestb=C3=B8?= <torarnv@gmail.com>
Date: Mon, 29 Jul 2013 23:01:12 +0200
Subject: [PATCH] Add sparsebundle_fatal_error function for unifying fatal
 errors

The function is marked with the printf archetype, so that the compiler
will not complain that we're passing non-string-literals to vfprintf.
---
 sparsebundlefs.cpp | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/sparsebundlefs.cpp b/sparsebundlefs.cpp
index a600feb..168c2a3 100644
--- a/sparsebundlefs.cpp
+++ b/sparsebundlefs.cpp
@@ -26,6 +26,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <syslog.h>
@@ -381,6 +382,23 @@ static int sparsebundle_release(const char * /* path */, struct fuse_file_info *
     return 0;
 }
 
+__attribute__((noreturn, format(printf, 1, 2))) static void sparsebundle_fatal_error(const char *message, ...)
+{
+    fprintf(stderr, "sparsebundlefs: ");
+
+    va_list args;
+    va_start(args, message);
+    vfprintf(stderr, message, args);
+    va_end(args);
+
+    if (errno)
+        fprintf(stderr, ": %s", strerror(errno));
+
+    fprintf(stderr, "\n");
+
+    exit(EXIT_FAILURE);
+}
+
 static int sparsebundle_show_usage(char *program_name)
 {
     fprintf(stderr, "usage: %s [-o options] [-s] [-f] [-D] <sparsebundle> <mountpoint>\n", program_name);
@@ -416,10 +434,8 @@ static int sparsebundle_opt_proc(void *data, const char *arg, int key, struct fu
 static off_t read_size(const string &str)
 {
     uintmax_t value = strtoumax(str.c_str(), 0, 10);
-    if (errno == ERANGE || value > uintmax_t(numeric_limits<off_t>::max())) {
-        fprintf(stderr, "Disk image too large to be mounted (%s bytes)\n", str.c_str());
-        exit(EXIT_FAILURE);
-    }
+    if (errno == ERANGE || value > uintmax_t(numeric_limits<off_t>::max()))
+        sparsebundle_fatal_error("disk image too large (%s bytes)", str.c_str());
 
     return value;
 }
@@ -453,10 +469,8 @@ int main(int argc, char **argv)
     sparsebundle.path = abs_path;
 
     char *plist_path;
-    if (asprintf(&plist_path, "%s/Info.plist", sparsebundle.path) == -1) {
-        perror("Failed to resolve Info.plist path");
-        return EXIT_FAILURE;
-    }
+    if (asprintf(&plist_path, "%s/Info.plist", sparsebundle.path) == -1)
+        sparsebundle_fatal_error("could not resolve Info.plist path");
 
     ifstream plist_file(plist_path);
     stringstream plist_data;