Bug#55873 short startup options do not work in 5.5

Before this fix, the server did not recognize 'short' (as in -a)
options but only 'long' (as in --ansi) options
in the startup command line, due to earlier changes in 5.5
introduced for the performance schema.

The root cause is that handle_options() did not honor the
my_getopt_skip_unknown flag when parsing 'short' options.

The fix changes handle_options(), so that my_getopt_skip_unknown is
honored in all cases.

Note that there are limitations to this,
see the added doxygen documentation in handle_options().

The current usage of handle_options() by the server to
parse early performance schema options fits within the limitations.
This has been enforced by an assert for PARSE_EARLY options, for safety.

1 files changed, 93 insertions, 7 deletions

diff --git a/mysys/my_getopt.c b/mysys/my_getopt.c
index 1c5bf0b6b1c..5689e0bafb5 100644
--- a/mysys/my_getopt.c
+++ b/mysys/my_getopt.c
@@ -98,6 +98,49 @@ void my_getopt_register_get_addr(my_getopt_value func_addr)
   matches with one of the options in struct 'my_option'.
   Check that option was given an argument if it requires one
   Call the optional 'get_one_option()' function once for each option.
+
+  Note that handle_options() can be invoked multiple times to
+  parse a command line in several steps.
+  In this case, use the global flag @c my_getopt_skip_unknown to indicate
+  that options unknown in the current step should be preserved in the
+  command line for later parsing in subsequent steps.
+
+  For 'long' options (--a_long_option), @c my_getopt_skip_unknown is
+  fully supported. Command line parameters such as:
+  - "--a_long_option"
+  - "--a_long_option=value"
+  - "--a_long_option value"
+  will be preserved as is when the option is not known.
+
+  For 'short' options (-S), support for @c my_getopt_skip_unknown
+  comes with some limitation, because several short options
+  can also be specified together in the same command line argument,
+  as in "-XYZ".
+
+  The first use case supported is: all short options are declared.
+  handle_options() will be able to interpret "-XYZ" as one of:
+  - an unknown X option
+  - "-X -Y -Z", three short options with no arguments
+  - "-X -YZ", where Y is a short option with argument Z
+  - "-XYZ", where X is a short option with argument YZ
+  based on the full short options specifications.
+
+  The second use case supported is: no short option is declared.
+  handle_options() will reject "-XYZ" as unknown, to be parsed later.
+
+  The use case that is explicitly not supported is to provide
+  only a partial list of short options to handle_options().
+  This function can not be expected to extract some option Y
+  in the middle of the string "-XYZ" in these conditions,
+  without knowing if X will be declared an option later.
+
+  Note that this limitation only impacts parsing of several
+  short options from the same command line argument,
+  as in "mysqld -anW5".
+  When each short option is properly separated out in the command line
+  argument, for example in "mysqld -a -n -w5", the code would actually
+  work even with partial options specs given at each stage.
+
   @param [in, out] argc      command line options (count)
   @param [in, out] argv      command line options (values)
   @param [in] longopts       descriptor of all valid options
@@ -464,14 +507,57 @@ int handle_options(int *argc, char ***argv,
 	  }
 	  if (!opt_found)
 	  {
-	    if (my_getopt_print_errors)
-              my_getopt_error_reporter(ERROR_LEVEL,
-                                       "%s: unknown option '-%c'", 
-                                       my_progname, *optend);
-	    return EXIT_UNKNOWN_OPTION;
+            if (my_getopt_skip_unknown)
+            {
+              /*
+                We are currently parsing a single argv[] argument
+                of the form "-XYZ", and parsing is done in multiple phases.
+                One or the argument found is not an option.
+              */
+              if (optend == cur_arg)
+              {
+                /*
+                  The first argument, "-X", is not an option
+                  In this case, the entire argument "-XYZ" is rejected
+                  from this phase, and preserved as is for later parsing.
+                */
+                (*argv)[argvpos++]= *pos;
+              }
+              else
+              {
+                /*
+                  We are in the middle of an "-XYZ" string already,
+                  "-X" has already been parsed, and "Y" (pointed by optend)
+                  is not an option.
+                  Hack the string "-XYZ" to make a "-YZ" substring in it,
+                  and push that to the next parsing phase.
+                */
+                DBUG_ASSERT(optend > *pos);
+                DBUG_ASSERT(optend > cur_arg);
+                DBUG_ASSERT(optend <= *pos + strlen(*pos));
+                DBUG_ASSERT(*optend);
+                optend--;
+                optend[0]= '-'; /* replace 'X' by '-' */
+                (*argv)[argvpos++]= optend;
+              }
+              /*
+                Do not continue to parse at the current "-XYZ" argument,
+                skip to the next argv[] argument instead.
+              */
+              optend= (char*) " ";
+            }
+            else
+            {
+              if (my_getopt_print_errors)
+                my_getopt_error_reporter(ERROR_LEVEL,
+                                         "%s: unknown option '-%c'",
+                                         my_progname, *optend);
+              return EXIT_UNKNOWN_OPTION;
+            }
 	  }
 	}
-	(*argc)--; /* option handled (short), decrease argument count */
+        if (opt_found)
+          (*argc)--; /* option handled (short), decrease argument count */
 	continue;
       }
       if ((error= setval(optp, value, argument, set_maximum_value)))
@@ -479,7 +565,7 @@ int handle_options(int *argc, char ***argv,
       if (get_one_option && get_one_option(optp->id, optp, argument))
         return EXIT_UNSPECIFIED_ERROR;
 
-      (*argc)--; /* option handled (short or long), decrease argument count */
+      (*argc)--; /* option handled (long), decrease argument count */
     }
     else /* non-option found */
       (*argv)[argvpos++]= cur_arg;