4 files changed, 53 insertions, 35 deletions

diff --git a/src/cli/cli.cpp b/src/cli/cli.cpp
index f23c3574d..e3ff2a75f 100644
--- a/src/cli/cli.cpp
+++ b/src/cli/cli.cpp
@@ -21,10 +21,14 @@ Command::Command(const std::string& cmd_spec) : m_spec(cmd_spec)
 
 Command::~Command() { /* for unique_ptr */ }
 
+std::string Command::cmd_name() const
+   {
+   return m_spec.substr(0, m_spec.find(' '));
+   }
+
 std::string Command::help_text() const
    {
-   return "Usage: " + m_spec +
-      "\n\nAll commands support --verbose --help --output= --error-output= --rng-type= --drbg-seed=";
+   return "Usage: " + m_spec;
    }
 
 int Command::run(const std::vector<std::string>& params)
@@ -68,7 +72,7 @@ int Command::run(const std::vector<std::string>& params)
          }
 
       this->go();
-      return 0;
+      return m_return_code;
       }
    catch(CLI_Usage_Error& e)
       {
diff --git a/src/cli/cli.h b/src/cli/cli.h
index 75de33515..d096617a3 100644
--- a/src/cli/cli.h
+++ b/src/cli/cli.h
@@ -93,18 +93,18 @@ class Command
          return m_spec;
          }
 
-      std::string cmd_name() const
-         {
-         return m_spec.substr(0, m_spec.find(' '));
-         }
+      std::string cmd_name() const;
 
    protected:
 
       /*
-      * The actual functionality of the cli command implemented in subclas
+      * The actual functionality of the cli command implemented in subclas.
+      * The return value from main will be zero.
       */
       virtual void go() = 0;
 
+      void set_return_code(int rc) { m_return_code = rc; }
+
       std::ostream& output();
 
       std::ostream& error_output();
@@ -172,6 +172,9 @@ class Command
 
       std::unique_ptr<Botan::RandomNumberGenerator> m_rng;
 
+      // possibly set by calling set_return_code()
+      int m_return_code = 0;
+
    public:
       // the registry interface:
 
diff --git a/src/cli/main.cpp b/src/cli/main.cpp
index 6b0024465..167052c9d 100644
--- a/src/cli/main.cpp
+++ b/src/cli/main.cpp
@@ -5,41 +5,20 @@
 */
 
 #include "cli.h"
-
 #include <botan/version.h>
-#include <sstream>
 #include <iostream>
 
-namespace {
-
-std::string main_help()
-   {
-   std::ostringstream oss;
-
-   oss << "Usage: botan <cmd> <cmd-options>\n";
-   oss << "Available commands:\n";
-
-   for(const auto& cmd_name : Botan_CLI::Command::registered_cmds())
-      {
-      std::unique_ptr<Botan_CLI::Command> cmd = Botan_CLI::Command::get_cmd(cmd_name);
-      oss << cmd->cmd_spec() << "\n";
-      }
-
-   return oss.str();
-   }
-
-}
-
 int main(int argc, char* argv[])
    {
    std::cerr << Botan::runtime_version_check(BOTAN_VERSION_MAJOR, BOTAN_VERSION_MINOR, BOTAN_VERSION_PATCH);
 
-   const std::string cmd_name = (argc <= 1) ? "help" : argv[1];
+   std::string cmd_name = "help";
 
-   if(cmd_name == "help" || cmd_name == "--help" || cmd_name == "-h")
+   if(argc >= 2)
       {
-      std::cout << main_help();
-      return 1;
+      cmd_name = argv[1];
+      if(cmd_name == "--help" || cmd_name == "-h")
+         cmd_name = "help";
       }
 
    std::unique_ptr<Botan_CLI::Command> cmd(Botan_CLI::Command::get_cmd(cmd_name));
@@ -50,6 +29,6 @@ int main(int argc, char* argv[])
       return 1;
       }
 
-   std::vector<std::string> args(argv + 2, argv + argc);
+   std::vector<std::string> args(argv + std::min(argc, 2), argv + argc);
    return cmd->run(args);
    }
diff --git a/src/cli/utils.cpp b/src/cli/utils.cpp
index 1e2ddf42e..602035c8c 100644
--- a/src/cli/utils.cpp
+++ b/src/cli/utils.cpp
@@ -14,6 +14,7 @@
 #include <botan/cpuid.h>
 #include <botan/hex.h>
 #include <botan/parsing.h>
+#include <sstream>
 
 #if defined(BOTAN_HAS_BASE64_CODEC)
    #include <botan/base64.h>
@@ -29,6 +30,37 @@
 
 namespace Botan_CLI {
 
+class Print_Help final : public Command
+   {
+   public:
+      Print_Help() : Command("help") {}
+
+      std::string help_text() const override
+         {
+         std::ostringstream oss;
+
+         oss << "Usage: botan <cmd> <cmd-options>\n\n";
+         oss << "All commands support --verbose --help --output= --error-output= --rng-type= --drbg-seed=\n\n";
+         oss << "Available commands:\n";
+
+         for(const auto& cmd_name : Command::registered_cmds())
+            {
+            std::unique_ptr<Command> cmd = Command::get_cmd(cmd_name);
+            oss << "  " << cmd->cmd_spec() << "\n";
+            }
+
+         return oss.str();
+         }
+
+      void go() override
+         {
+         this->set_return_code(1);
+         output() << help_text();
+         }
+   };
+
+BOTAN_REGISTER_COMMAND("help", Print_Help);
+
 class Config_Info final : public Command
    {
    public: