fish: help command return error for non-existent commands (RHBZ#597145).

With this change, the exit status indicates error for non-existent
commands.

$ guestfish -h foo
foo: command not known, use -h to list all commands
$ echo $?
1
$ guestfish help foo
foo: command not known, use -h to list all commands
$ echo $?
1

3 files changed, 62 insertions, 28 deletions

diff --git a/fish/fish.c b/fish/fish.c
index 557a6ac9..470c6251 100644
--- a/fish/fish.c
+++ b/fish/fish.c
@@ -304,14 +304,18 @@ main (int argc, char *argv[])
       file = optarg;
       break;
 
-    case 'h':
+    case 'h': {
+      int r = 0;
+
       if (optarg)
-        display_command (optarg);
+        r = display_command (optarg);
       else if (argv[optind] && argv[optind][0] != '-')
-        display_command (argv[optind++]);
+        r = display_command (argv[optind++]);
       else
         list_commands ();
-      exit (EXIT_SUCCESS);
+
+      exit (r == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+    }
 
     case 'i':
       inspector = 1;
@@ -957,11 +961,11 @@ issue_command (const char *cmd, char *argv[], const char *pipecmd)
 
   /* Otherwise execute it locally. */
   else if (STRCASEEQ (cmd, "help")) {
-    if (argc == 0)
+    if (argc == 0) {
       list_commands ();
-    else
-      display_command (argv[0]);
-    r = 0;
+      r = 0;
+    } else
+      r = display_command (argv[0]);
   }
   else if (STRCASEEQ (cmd, "quit") ||
            STRCASEEQ (cmd, "exit") ||
@@ -1058,13 +1062,13 @@ list_builtin_commands (void)
   /* actions are printed after this (see list_commands) */
 }
 
-void
+int
 display_builtin_command (const char *cmd)
 {
   /* help for actions is auto-generated, see display_command */
 
   if (STRCASEEQ (cmd, "alloc") ||
-      STRCASEEQ (cmd, "allocate"))
+      STRCASEEQ (cmd, "allocate")) {
     printf (_("alloc - allocate an image\n"
               "     alloc <filename> <size>\n"
               "\n"
@@ -1075,14 +1079,18 @@ display_builtin_command (const char *cmd)
               "\n"
               "    Size can be specified using standard suffixes, eg. '1M'.\n"
               ));
-  else if (STRCASEEQ (cmd, "echo"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "echo")) {
     printf (_("echo - display a line of text\n"
               "     echo [<params> ...]\n"
               "\n"
               "    This echos the parameters to the terminal.\n"));
+    return 0;
+  }
   else if (STRCASEEQ (cmd, "edit") ||
            STRCASEEQ (cmd, "vi") ||
-           STRCASEEQ (cmd, "emacs"))
+           STRCASEEQ (cmd, "emacs")) {
     printf (_("edit - edit a file in the image\n"
               "     edit <filename>\n"
               "\n"
@@ -1096,32 +1104,42 @@ display_builtin_command (const char *cmd)
               "\n"
               "    NOTE: This will not work reliably for large files\n"
               "    (> 2 MB) or binary files containing \\0 bytes.\n"));
-  else if (STRCASEEQ (cmd, "lcd"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "lcd")) {
     printf (_("lcd - local change directory\n"
               "    lcd <directory>\n"
               "\n"
               "    Change guestfish's current directory. This command is\n"
               "    useful if you want to download files to a particular\n"
               "    place.\n"));
-  else if (STRCASEEQ (cmd, "glob"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "glob")) {
     printf (_("glob - expand wildcards in command\n"
               "    glob <command> [<args> ...]\n"
               "\n"
               "    Glob runs <command> with wildcards expanded in any\n"
               "    command args.  Note that the command is run repeatedly\n"
               "    once for each expanded argument.\n"));
+    return 0;
+  }
   else if (STRCASEEQ (cmd, "man") ||
-           STRCASEEQ (cmd, "manual"))
+           STRCASEEQ (cmd, "manual")) {
     printf (_("man - read the manual\n"
               "    man\n"
               "\n"
               "    Opens the manual page for guestfish.\n"));
-  else if (STRCASEEQ (cmd, "help"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "help")) {
     printf (_("help - display a list of commands or help on a command\n"
               "     help cmd\n"
               "     help\n"));
+    return 0;
+  }
   else if (STRCASEEQ (cmd, "more") ||
-           STRCASEEQ (cmd, "less"))
+           STRCASEEQ (cmd, "less")) {
     printf (_("more - view a file in the pager\n"
               "     more <filename>\n"
               "\n"
@@ -1135,19 +1153,25 @@ display_builtin_command (const char *cmd)
               "\n"
               "    NOTE: This will not work reliably for large files\n"
               "    (> 2 MB) or binary files containing \\0 bytes.\n"));
+    return 0;
+  }
   else if (STRCASEEQ (cmd, "quit") ||
            STRCASEEQ (cmd, "exit") ||
-           STRCASEEQ (cmd, "q"))
+           STRCASEEQ (cmd, "q")) {
     printf (_("quit - quit guestfish\n"
               "     quit\n"));
-  else if (STRCASEEQ (cmd, "reopen"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "reopen")) {
     printf (_("reopen - close and reopen the libguestfs handle\n"
               "     reopen\n"
               "\n"
               "Close and reopen the libguestfs handle.  It is not necessary to use\n"
               "this normally, because the handle is closed properly when guestfish\n"
               "exits.  However this is occasionally useful for testing.\n"));
-  else if (STRCASEEQ (cmd, "sparse"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "sparse")) {
     printf (_("sparse - allocate a sparse image file\n"
               "     sparse <filename> <size>\n"
               "\n"
@@ -1166,7 +1190,9 @@ display_builtin_command (const char *cmd)
               "\n"
               "    Size can be specified using standard suffixes, eg. '1M'.\n"
               ));
-  else if (STRCASEEQ (cmd, "supported"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "supported")) {
     printf (_("supported - list supported groups of commands\n"
               "     supported\n"
               "\n"
@@ -1176,15 +1202,21 @@ display_builtin_command (const char *cmd)
               "\n"
               "    See also guestfs(3) section AVAILABILITY.\n"
               ));
-  else if (STRCASEEQ (cmd, "time"))
+    return 0;
+  }
+  else if (STRCASEEQ (cmd, "time")) {
     printf (_("time - measure time taken to run command\n"
               "    time <command> [<args> ...]\n"
               "\n"
               "    This runs <command> as usual, and prints the elapsed\n"
               "    time afterwards.\n"));
-  else
+    return 0;
+  }
+  else {
     fprintf (stderr, _("%s: command not known, use -h to list all commands\n"),
              cmd);
+    return -1;
+  }
 }
 
 /* This is printed when the user types in an unknown command for the
diff --git a/fish/fish.h b/fish/fish.h
index b98faf02..9f64979e 100644
--- a/fish/fish.h
+++ b/fish/fish.h
@@ -55,7 +55,7 @@ extern int command_num;
 extern int issue_command (const char *cmd, char *argv[], const char *pipe);
 extern void pod2text (const char *name, const char *shortdesc, const char *body);
 extern void list_builtin_commands (void);
-extern void display_builtin_command (const char *cmd);
+extern int display_builtin_command (const char *cmd);
 extern void free_strings (char **argv);
 extern int count_strings (char *const *argv);
 extern void print_strings (char *const *argv);
@@ -71,7 +71,7 @@ extern void extended_help_message (void);
 
 /* in cmds.c (auto-generated) */
 extern void list_commands (void);
-extern void display_command (const char *cmd);
+extern int display_command (const char *cmd);
 extern int run_action (const char *cmd, int argc, char *argv[]);
 
 /* in completion.c (auto-generated) */
diff --git a/src/generator.ml b/src/generator.ml
index 2c33049d..571ea3a0 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -7575,7 +7575,7 @@ and generate_fish_cmds () =
   pr "\n";
 
   (* display_command function, which implements guestfish -h cmd *)
-  pr "void display_command (const char *cmd)\n";
+  pr "int display_command (const char *cmd)\n";
   pr "{\n";
   List.iter (
     fun (name, style, _, flags, _, shortdesc, longdesc) ->
@@ -7623,15 +7623,17 @@ and generate_fish_cmds () =
         pr " || STRCASEEQ (cmd, \"%s\")" name2;
       if name <> alias then
         pr " || STRCASEEQ (cmd, \"%s\")" alias;
-      pr ")\n";
+      pr ") {\n";
       pr "    pod2text (\"%s\", _(\"%s\"), %S);\n"
         name2 shortdesc
         ("=head1 SYNOPSIS\n\n " ^ synopsis ^ "\n\n" ^
          "=head1 DESCRIPTION\n\n" ^
          longdesc ^ warnings ^ describe_alias);
+      pr "    return 0;\n";
+      pr "  }\n";
       pr "  else\n"
   ) all_functions;
-  pr "    display_builtin_command (cmd);\n";
+  pr "    return display_builtin_command (cmd);\n";
   pr "}\n";
   pr "\n";