Open jobs for finishing GNU libc:
---------------------------------
-Status: January 1997
+Status: February 2001
If you have time and talent to take over any of the jobs below please
-contact <bug-glibc@prep.ai.mit.edu>
+contact <bug-glibc@gnu.org>.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\f
users can immediately benefit from this.
Take a look at the matrix in
- ftp://prep.ai.mit.edu/pub/gnu/ABOUT-NLS
- for the current status (of course better use a mirror of prep).
+ ftp://ftp.gnu.org/pub/gnu/ABOUT-NLS
+ for the current status (of course better use a mirror of ftp.gnu.org).
-[ 5] Write wordexp() function; this is described in POSIX.2, the
- header <wordexp.h> already exists.
+[ 6] Write `long double' versions of the math functions.
- Implementation idea: use some functions from bash.
-
-**** Somebody is working on this. Help may or may not be appreciated.
-
-
-[ 6] Write `long double' versions of the math functions. This should be
- done in collaboration with the NetBSD and FreeBSD people.
-
- The libm is in fact fdlibm (not the same as in Linux libc).
+ The libm is in fact fdlibm (not the same as in Linux libc 5).
**** Partly done. But we need someone with numerical experiences for
the rest.
[ 7] Several math functions have to be written:
- exp2
- - log2
- each with float, double, and long double arguments. Writing these
- functions should be possible when following the implementation of
- the existing exp/log functions for other bases.
+ with long double arguments.
Beside this most of the complex math functions which are new in
- ISO C 9X. gcc already has support for numbers of complex type so the
- implementation should be possible today. I mention here the names
- and the way to write them (argument is z = x + iy):
-
- - cexp(z) = e^x (cos y + i sin y)
- - sin(z) = 1/(2i) (e^(iz) - e^-(iz)) = sin(x) cosh(y) + i cos(x) sinh(y)
- - cos(z) = 1/2 (e^(iz) + e^-(iz)) = cos(x) cosh(y) - i sin(x) sinh(y)
- - tan(z) = 1/i (e^(iz) - e^-(iz))/(e^(iz) + e^-(iz))
- - cot(z) = i (e^(iz) + e^-(iz))/(e^(iz) - e^-(iz))
- - asin(z) = -i ln(iz + sqrt(1-z^2))
- - acos(z) = -i ln(z + sqrt(z^2-1))
- - atan(z) = 1/(2i) ln((1+iz)/(1-iz))
- - acot(z) = -1/(2i) ln((iz+1)/(iz-1))
- - sinh(z) = 1/2 (e^z - e^-z)
- - cosh(z) = 1/2 (e^z + e^-z)
- - tanh(z) = (e^z - e^-z)/(e^z + e^-z)
- - coth(z) = (e^z + e^-z)/(e^z - e^-z)
-
- All functions should we written with all the parallelism in mind.
- And assembler versions are highly expreciated since, e.g., the ix87
- FPU provides an `fsincos' instructions which is certainly useful for
- the `sin' function. The implementations for the normal math functions
- shows other optimization techniques.
+ ISO C99 should be improved. Writing some of them in assembler is
+ useful to exploit the parallelism which often is available.
[ 8] If you enjoy assembler programming (as I do --drepper :-) you might
work.
-[ 9] Write nftw() function. Perhaps it might be good to reimplement the
- ftw() function as well to share most of the code.
+[10] Extend regex and/or rx to work with wide characters and complete
+ implementation of character class and collation class handling.
-**** Almost done!
+ It is planned to do a complete rewrite.
+*** We have now multibyte character support. But a rewrite is still
+ necessary.
-[10] Write AVL-tree based tsearch() et.al. functions. Currently only
- a very simple algorithm is used.
- There is a public domain version but using this would cause problems
- with the assignment.
+[11] Write access function for netmasks, bootparams, and automount
+ databases for nss_files and nss_db module.
+ The functions should be embedded in the nss scheme. This is not
+ hard and not all services must be supported at once.
-[11] Extend regex and/or rx to work with wide characters and complete
- implementation of character class and collation class handling.
- It is planed to do a complete rewrite.
+[15] Cleaning up the header files. Ideally, each header style should
+ follow the "good examples". Each variable and function should have
+ a short description of the function and its parameters. The prototypes
+ should always contain variable names which can help to identify their
+ meaning; better than
+
+ int foo (int, int, int, int);
+
+ Blargh!
+
+*** The conformtest.pl tool helps cleaning the namespace. As far as
+ known the prototypes all contain parameter names. But maybe some
+ comments can be improved.
-[12] Write access function for netmasks, bootparams, and automount
- databases for nss_files and nss_db module.
- The functions should be embedded in the nss scheme. This is not
- hard and not all services must be supported at once.
+[16] The libio stream file functions should be extended in a way to use
+ mmap to map the file and use it as the buffer to user sees. For
+ read-only streams this should be rather easy and it avoids all read()
+ calls.
+
+ A more sophisticated solution would use mmap also for writing. The
+ standards do not demand that the file on the disk is always in the
+ correct form so it would be possible to enlarge it always according
+ to the page size and install the correct length only for fclose() and
+ fflush() calls.
+
+
+[18] Based on the sprof program we need tools to analyze the output. The
+ result should be a link map which specifies in which order the .o
+ files are placed in the shared object. This should help to improve
+ code locality and result in a smaller foorprint (in code and data
+ memory) since less pages are only used in small parts.
+
+
+[19] A user-level STREAMS implementation should be available if the
+ kernel does not provide the support.
+
+*** This is a much lower priority job now that STREAMS are optional in
+ XPG.
+
+
+[20] More conversion modules for iconv(3). Existing modules should be
+ extended to do things like transliteration if this is wanted.
+ For often used conversion a direct conversion function should be
+ available.
-[13] Rewrite utmp/wtmp functions to use database functions. This is much
- better than the normal flat file format.
+[21] The nscd program and the stubs in the libc should be changed so
+ that each program uses only one socket connect. Take a look at
+ http://www.cygnus.com/~drepper/nscd.html
-**** There are plans for a new approach to this problem. Please contact
- bug-glibc@prep.ai.mit.edu before starting to work.)
+ An alternative approach is to use an mmap()ed file. The idea is
+ the following:
+ - the nscd creates the hash tables and the information it stores
+ in it in a mmap()ed region. This means no pointers must be
+ used, only offsets.
+ OR
+ if POSIX shared memory is available use a named shared memory
+ region to put the data in
+ - each program using NSS functionality tries to open the file
+ with the data.
+ - by checking some timestamp (which the nscd renews frequently)
+ the programs can test whether the file is still valid
+ - if the file is valid look through the nscd and locate the
+ appropriate hash table for the database and lookup the data.
+ If it is included we are set.
+ - if the data is not yet in the database we contact the nscd using
+ the currently implemented methods.
-[14] Several more or less small functions have to be written:
+[22] It should be possible to have the information gconv-modules in
+ a simple cache which is faster to access. Using libdb is probably
+ overkill and loading it would probably be slower than reading the
+ plain text file. But a file format with a simple hash table and
+ some data it points to should be fine. Probably it should be
+ two tables, one for the aliases, one for the mappings. The code
+ should start similar to this:
- + tcgetid() and waitid() from XPG4.2
- + grantpt(), ptsname(), unlockpt() from XPG4.2
- + getdate() from XPG4.2
- + fmtmsg() from SVID
+ if (stat ("gconv-modules", &stp) == 0
+ && stat ("gconv-modules.db", &std) == 0
+ && stp.st_mtime < std.st_mtime)
+ {
+ ... use the cache ...
+ {
+ else
+ {
+ ... use the plain file if it exists, otherwise the db ...
+ }
- More information are available on request.
+[23] The `strptime' function needs to be completed. This includes among
+ other things that it must get teached about timezones. The solution
+ envisioned is to extract the timezones from the ADO timezone
+ specifications. Special care must be given names which are used
+ multiple times. Here the precedence should (probably) be according
+ to the geograhical distance. E.g., the timezone EST should be
+ treated as the `Eastern Australia Time' instead of the US `Eastern
+ Standard Time' if the current TZ variable is set to, say,
+ Australia/Canberra or if the current locale is en_AU.
+
+
+[25] Sun's nscd version implements a feature where the nscd keeps N entries
+ for each database current. I.e., if an entries lifespan is over and
+ it is one of the N entries to be kept the nscd updates the information
+ instead of removing the entry.
-[15] We need to write a library for on-the-fly transformation of streams
- of text. In fact, this would be a recode-library (you know, GNU recode).
- This is needed in several places in the GNU libc and I already have
- rather concrete plans but so far no possibility to start this.
+ How to decide about which N entries to keep has to be examined.
+ Factors should be number of uses (of course), influenced by aging.
+ Just imagine a computer used by several people. The IDs of the current
+ user should be preferred even if the last user spent more time.
+
+
+[26] ...done
+
+
+[27] We need a second test suite with tests which cannot run during a normal
+ `make check' run. This test suite can require root priviledges and
+ can test things like DNS (i.e., require network access),
+ user-interaction, networking in general, and probably many other things.
projects / platform / upstream / glibc.git / blobdiff