libc: Fix a few bugs in the xlocale collation code.

[markj]

Summary

• Fix checks for mmap() failures.
• Set the "map" and "maplen" fields of struct xlocale_collate so that the destructor actually works.
• Free an already-mapped collation file before loading a new one into the global table.
• Harmonize the prototype and definition of __collate_load_tables_l() by adding the "static" qualifier to the latter.

PR: 243195

[markj]

Defer the unmap until we are sure that __collate_load_tables_l() won't fail.

[yuripv]

I wonder if we could instead check if we have the table already loaded and return without doing everything over and over again. Something like the following right at the start:

if (table->__collate_load_error == 0 && table->header != NULL && strcmp(table->header.locale, encoding) == 0)
    return (_LDP_LOADED);

Not completely sure about the table->header check here as we already checked that the table was loaded, but it's just an idea.

(P.S. I think encoding is really a wrong argument name here, as it's full locale name.)

[yuripv]

In D23109#506462, @yuripv wrote:

I wonder if we could instead check if we have the table already loaded and return without doing everything over and over again. Something like the following right at the start:

if (table->__collate_load_error == 0 && table->header != NULL && strcmp(table->header.locale, encoding) == 0)
    return (_LDP_LOADED);

Not completely sure about the table->header check here as we already checked that the table was loaded, but it's just an idea.

(P.S. I think encoding is really a wrong argument name here, as it's full locale name.)

Nevermind me, I obviously can't read several lines up :)

[markj]

In D23109#506463, @yuripv wrote:

In D23109#506462, @yuripv wrote:

I wonder if we could instead check if we have the table already loaded and return without doing everything over and over again. Something like the following right at the start:

if (table->__collate_load_error == 0 && table->header != NULL && strcmp(table->header.locale, encoding) == 0)
    return (_LDP_LOADED);

Not completely sure about the table->header check here as we already checked that the table was loaded, but it's just an idea.

(P.S. I think encoding is really a wrong argument name here, as it's full locale name.)

Nevermind me, I obviously can't read several lines up :)

Hmm, I don't see what lines you are referring to. Indeed, this function does not handle the case where a table is already loaded. I'd prefer to fix that separately though.