Re: [Libguestfs] [PATCH nbdkit v2 2/2] build: Replace ./nbdkit with a C program.

There are advantages to having the same code parse the options in the ./nbdkit wrapper as in the real nbdkit: - We can parse options in exactly the same way as the real program. - Use the more accurate ‘is_short_name’ test for unadorned plugin/filter names on the command line. - Fixes the FreeBSD problem with shebangs caused because FreeBSD refuses to use a shell script as a shebang path. Apart from the above, this is a straightforward translation of the original shell script into C and preserves all the existing features such as valgrind and gdb support. --- Makefile.am | 11 ++- README | 2 +- configure.ac | 2 - nbdkit.in | 160 ------------------------------- wrapper.c | 259 +++++++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 270 insertions(+), 164 deletions(-)

+ + /* If NBDKIT_VALGRIND=1 is set in the environment, then we run the + * program under valgrind. This is used by the tests. Similarly if + * NBDKIT_GDB=1 is set, we run the program under GDB, useful during + * development. + */ + s = getenv ("NBDKIT_VALGRIND"); + if (s && strcmp (s, "1") == 0) {

+ /* Option parsing. We don't really parse options here. We are only + * interested in which options have arguments and which need + * rewriting. + */ + for (;;) { + long_index = -1; + c = getopt_long (argc, argv, short_options, long_options, &long_index); + if (c == -1) + break; + + if (c == '?') /* getopt prints an error */ + exit (EXIT_FAILURE); + + /* long_index is only set if it's an actual long option. However + * in nbdkit all short options have long equivalents so we can + * associate those with a long_index, but we must do it ourselves. + * https://stackoverflow.com/a/34070441 + */ + is_long_option = long_index >= 0; + if (long_index == -1) { + for (i = 0; long_options[i].name != NULL; ++i) { + if (long_options[i].val == c) { + long_index = i; + break; + } + } + if (long_index == -1) + abort (); + }

+ /* Any short option. */ + else { + /* Short option which takes an argument. */ + if (long_options[long_index].has_arg) {

+ passthru_format ("-%c", c); + passthru (optarg); + } + /* Short option which takes no argument. */ + else + passthru_format ("-%c", c); + } + } +