[PATCH] command line: report if runscript file is missing

[Justin Cinkelj]

Previously, if runscript file was missing, std::instream constructor
silently failed to open the file. The filebuf descriptor likely remained
at 0, and then we were reading from stdin, never reaching EOF.

This is fixed now by extra checking all error bits with .good().

In addition, empty runscript files are permitted now. Previously, the
"runscript /filename" part was not removed from command line, so loader
tried to execut binary named runscript with argv /filename.

Fixes #849

Signed-off-by: Justin Cinkelj <justin.cink...@xlab.si>
---
 core/commands.cc | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/core/commands.cc b/core/commands.cc
index c8d6031..7bddfbb 100644
--- a/core/commands.cc
+++ b/core/commands.cc
@@ -158,10 +158,12 @@ ok flag is set to false on parse error, and left 
unchanged otherwise.
 
 If cmd doesn't start with runscript, then vector with size 0 is returned.
 */
-std::vector<std::vector<std::string>> runscript_expand(const 
std::vector<std::string>& cmd, bool &ok)
+std::vector<std::vector<std::string>>
+runscript_expand(const std::vector<std::string>& cmd, bool &ok, bool 
&is_runscript)
 {
     std::vector<std::vector<std::string> > result2, result3;
     if (cmd[0] == "runscript") {
+        is_runscript = true;
         /*
         The cmd vector ends with additional ";" or "\0" element.
         */
@@ -173,6 +175,11 @@ std::vector<std::vector<std::string>> 
runscript_expand(const std::vector<std::st
         auto fn = cmd[1];
 
         std::ifstream in(fn);
+        if (!in.good()) {
+            printf("Failed to open runscript file '%s'.\n", fn.c_str());
+            ok = false;
+            return result2;
+        }
         std::string line;
         size_t line_num = 0;
         while (!in.eof()) {
@@ -192,6 +199,9 @@ std::vector<std::vector<std::string>> 
runscript_expand(const std::vector<std::st
             line_num++;
         }
     }
+    else {
+        is_runscript = false;
+    }
     return result2;
 }
 
@@ -207,13 +217,16 @@ parse_command_line(const std::string line,  bool &ok)
     */
     std::vector<std::vector<std::string>>::iterator cmd_iter;
     for (cmd_iter=result.begin(); ok && cmd_iter!=result.end(); ) {
-        result2 = runscript_expand(*cmd_iter, ok);
-        if (result2.size() > 0) {
+        bool is_runscript;
+        result2 = runscript_expand(*cmd_iter, ok, is_runscript);
+        if (is_runscript) {
             cmd_iter = result.erase(cmd_iter);
-            int pos;
-            pos = cmd_iter - result.begin();
-            result.insert(cmd_iter, result2.begin(), result2.end());
-            cmd_iter = result.begin() + pos + result2.size();
+            if (result2.size() > 0) {
+                int pos;
+                pos = cmd_iter - result.begin();
+                result.insert(cmd_iter, result2.begin(), result2.end());
+                cmd_iter = result.begin() + pos + result2.size();
+            }
         }
         else {
             cmd_iter++;
-- 
2.9.3

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