From 4017d8237e56a531f880ada608db2a67f46c8096 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 3 Jan 2017 18:59:12 -0500
Subject: [PATCH] Add System::executable_path()

---
 src/core/System.cc | 24 +++++++++++++++++++++++-
 src/core/System.h  |  5 ++++-
 src/jes.cc         |  2 +-
 test/src/main.cc   |  2 +-
 4 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/core/System.cc b/src/core/System.cc
index 14a7924..a999694 100644
--- a/src/core/System.cc
+++ b/src/core/System.cc
@@ -3,13 +3,15 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <stdint.h>
+#include <fcntl.h>
 
 unsigned long System::page_size;
 unsigned int System::page_size_log;
 unsigned long System::page_base_mask;
 unsigned long System::page_offset_mask;
+static std::string Executable_Path;
 
-bool System::init()
+bool System::init(char * argv[])
 {
     long sc_page_size = sysconf(_SC_PAGESIZE);
     if (sc_page_size < 0)
@@ -41,6 +43,21 @@ bool System::init()
         return false;
     }
 
+#if defined(PLATFORM_LINUX)
+    char link_buffer[1000];
+    ssize_t len = readlink("/proc/self/exe", link_buffer, sizeof(link_buffer));
+    if ((len > 0) && (len < (ssize_t)sizeof(link_buffer)))
+    {
+        Executable_Path = std::string(link_buffer, len);
+    }
+    else
+    {
+        return false;
+    }
+#elif defined(PLATFORM_WINDOWS)
+    Executable_Path = argv[0];
+#endif
+
     return true;
 }
 
@@ -59,3 +76,8 @@ void System::free_pages(void * addr, int num)
 {
     (void)munmap(addr, num << System::page_size_log);
 }
+
+std::string System::executable_path()
+{
+    return Executable_Path;
+}
diff --git a/src/core/System.h b/src/core/System.h
index 764bac9..49586d8 100644
--- a/src/core/System.h
+++ b/src/core/System.h
@@ -1,12 +1,15 @@
 #ifndef SYSTEM_H
 #define SYSTEM_H
 
+#include <string>
+
 class System
 {
 public:
-    static bool init();
+    static bool init(char * argv[]);
     static void * alloc_pages(int num);
     static void free_pages(void * addr, int num);
+    static std::string executable_path();
 
     static unsigned long page_size;
     static unsigned int page_size_log;
diff --git a/src/jes.cc b/src/jes.cc
index e3d0899..56b460a 100644
--- a/src/jes.cc
+++ b/src/jes.cc
@@ -6,7 +6,7 @@
 
 int main(int argc, char * argv[])
 {
-    if (!System::init())
+    if (!System::init(argv))
     {
         return 1;
     }
diff --git a/test/src/main.cc b/test/src/main.cc
index dc6d270..ecb91e3 100644
--- a/test/src/main.cc
+++ b/test/src/main.cc
@@ -6,7 +6,7 @@
 int main(int argc, char * argv[])
 {
     ::testing::InitGoogleTest(&argc, argv);
-    System::init();
+    System::init(argv);
     mkdir("test/tmp", 0777);
     return RUN_ALL_TESTS();
 }