[U-Boot] [PATCH] env: Provide programmatic equivalent to 'setenv -f'

[Simon Goldschmidt]

Heinrich Schuchardt <xypron.glpk at gmx.de> schrieb am Di., 19. Nov. 2019,
21:56:

> On 11/19/19 9:30 PM, Simon Goldschmidt wrote:
> > Am 19.11.2019 um 18:31 schrieb James Byrne:
> >> Add env_force() to provide an equivalent to 'setenv -f' that can be used
> >> programmatically.
> >>
> >> Also tighten up the definition of argv in _do_env_set() so that
> >> 'const char *' pointers are used.
> >>
> >> Signed-off-by: James Byrne <james.byrne at origamienergy.com>
> >
> > OK, I'm on CC, so I'll give my two cent:
> >
> > I always thought this code to be messed up a bit: I think it's better
> > programming style to have the "string argument parsing" code call real C
> > functions with typed arguments. The env code instead does it the other
> > way round (here, you add do_programmatic_env_set() that sets up an
> > argv[] array to call another function).
> >
> > I'm not a maintainer for the ENV code, but maybe that should be sorted
> > out instead of adding yet more code that goes this way?
>
> There is no maintainer for the ENV code. Simon makes a valid point here.
> By creating a function for setting variables and separating it from
> parsing arguments you get the function you need for forcing the value of
> a variable for free.
>

Right. I thought someone had volunteered but a look at the maintainers file
proves me wrong.

In any way, I'd be more open to review a cleanup patch than a patch
continuing this messy code flow.

Regards,
Simon


> Best regards
>
> Heinrich
>
> >
> > Regards,
> > Simon
> >
> >>
> >> ---
> >>
> >>   cmd/nvedit.c  | 43 +++++++++++++++++++++++++++++--------------
> >>   include/env.h | 13 +++++++++++++
> >>   2 files changed, 42 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/cmd/nvedit.c b/cmd/nvedit.c
> >> index 99a3bc57b1..1f363ba9f4 100644
> >> --- a/cmd/nvedit.c
> >> +++ b/cmd/nvedit.c
> >> @@ -221,10 +221,12 @@ DONE:
> >>    * Set a new environment variable,
> >>    * or replace or delete an existing one.
> >>    */
> >> -static int _do_env_set(int flag, int argc, char * const argv[], int
> >> env_flag)
> >> +static int _do_env_set(int flag, int argc, const char * const argv[],
> >> +               int env_flag)
> >>   {
> >>       int   i, len;
> >> -    char  *name, *value, *s;
> >> +    const char *name;
> >> +    char *value, *s;
> >>       struct env_entry e, *ep;
> >>       debug("Initial value for argc=%d\n", argc);
> >> @@ -235,7 +237,7 @@ static int _do_env_set(int flag, int argc, char *
> >> const argv[], int env_flag)
> >>   #endif
> >>       while (argc > 1 && **(argv + 1) == '-') {
> >> -        char *arg = *++argv;
> >> +        const char *arg = *++argv;
> >>           --argc;
> >>           while (*++arg) {
> >> @@ -277,7 +279,7 @@ static int _do_env_set(int flag, int argc, char *
> >> const argv[], int env_flag)
> >>           return 1;
> >>       }
> >>       for (i = 2, s = value; i < argc; ++i) {
> >> -        char *v = argv[i];
> >> +        const char *v = argv[i];
> >>           while ((*s++ = *v++) != '\0')
> >>               ;
> >> @@ -299,18 +301,30 @@ static int _do_env_set(int flag, int argc, char
> >> * const argv[], int env_flag)
> >>       return 0;
> >>   }
> >> -int env_set(const char *varname, const char *varvalue)
> >> +static int do_programmatic_env_set(int argc, const char * const argv[])
> >>   {
> >> -    const char * const argv[4] = { "setenv", varname, varvalue, NULL };
> >> -
> >>       /* before import into hashtable */
> >>       if (!(gd->flags & GD_FLG_ENV_READY))
> >>           return 1;
> >> -    if (varvalue == NULL || varvalue[0] == '\0')
> >> -        return _do_env_set(0, 2, (char * const *)argv, H_PROGRAMMATIC);
> >> -    else
> >> -        return _do_env_set(0, 3, (char * const *)argv, H_PROGRAMMATIC);
> >> +    if (!argv[argc - 1] || argv[argc - 1][0] == '\0')
> >> +        argc--;
> >> +
> >> +    return _do_env_set(0, argc, argv, H_PROGRAMMATIC);
> >> +}
> >> +
> >> +int env_set(const char *varname, const char *varvalue)
> >> +{
> >> +    const char * const argv[4] = {"setenv", varname, varvalue, NULL};
> >> +
> >> +    return do_programmatic_env_set(3, argv);
> >> +}
> >> +
> >> +int env_force(const char *varname, const char *varvalue)
> >> +{
> >> +    const char * const argv[5] = {"setenv", "-f", varname, varvalue,
> >> NULL};
> >> +
> >> +    return do_programmatic_env_set(4, argv);
> >>   }
> >>   /**
> >> @@ -382,7 +396,8 @@ static int do_env_set(cmd_tbl_t *cmdtp, int flag,
> >> int argc, char * const argv[])
> >>       if (argc < 2)
> >>           return CMD_RET_USAGE;
> >> -    return _do_env_set(flag, argc, argv, H_INTERACTIVE);
> >> +    return _do_env_set(flag, argc, (const char * const *)argv,
> >> +               H_INTERACTIVE);
> >>   }
> >>   /*
> >> @@ -643,12 +658,12 @@ static int do_env_edit(cmd_tbl_t *cmdtp, int
> >> flag, int argc,
> >>       if (buffer[0] == '\0') {
> >>           const char * const _argv[3] = { "setenv", argv[1], NULL };
> >> -        return _do_env_set(0, 2, (char * const *)_argv, H_INTERACTIVE);
> >> +        return _do_env_set(0, 2, _argv, H_INTERACTIVE);
> >>       } else {
> >>           const char * const _argv[4] = { "setenv", argv[1], buffer,
> >>               NULL };
> >> -        return _do_env_set(0, 3, (char * const *)_argv, H_INTERACTIVE);
> >> +        return _do_env_set(0, 3, _argv, H_INTERACTIVE);
> >>       }
> >>   }
> >>   #endif /* CONFIG_CMD_EDITENV */
> >> diff --git a/include/env.h b/include/env.h
> >> index b72239f6a5..37bbf1117d 100644
> >> --- a/include/env.h
> >> +++ b/include/env.h
> >> @@ -145,6 +145,19 @@ int env_get_yesno(const char *var);
> >>    */
> >>   int env_set(const char *varname, const char *value);
> >> +/**
> >> + * env_force() - forcibly set an environment variable
> >> + *
> >> + * This sets or deletes the value of an environment variable. It is
> >> the same
> >> + * as env_set(), except that the variable will be forcibly
> >> updated/deleted,
> >> + * even if it has access protection flags set.
> >> + *
> >> + * @varname: Variable to adjust
> >> + * @value: Value to set for the variable, or NULL or "" to delete the
> >> variable
> >> + * @return 0 if OK, 1 on error
> >> + */
> >> +int env_force(const char *varname, const char *varvalue);
> >> +
> >>   /**
> >>    * env_get_ulong() - Return an environment variable as an integer
> value
> >>    *
> >>
> >
> >
>
>