glibc/misc/hsearch_r.c
Ulrich Drepper d68171edce update from main archive 960927
Sat Sep 28 03:02:49 1996  Ulrich Drepper  <drepper@cygnus.com>
	* dirent/Makefile (routines): Add readdir_r.
	* dirent/readdir_r.c: New file.  Wrapper around readdir.c.
	* dirent/dirent.h: Add prototype for readdir_r.
	* misc/hsearch_r.c (ENTRY): Make field `used' of type `unsigned int'
	to prevent warnings.
	* sysdeps/unix/sysv/linux/getsysstats.c (get_proc_path):
 	Initialize `result'.

Sat Sep 28 01:16:42 1996  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/generic/strsep.c: Rename to __strsep and make strsep
	weak alias.
	* string/string.h: Add prototype for __strsep.
	* misc/mntent_r.c: Use __strsep instead of strsep to keep
	namespace clean.

	* sysdeps/stub/nanosleep.c: Rename to __libc_nanosleep and make
	__nanosleep and nanosleep weak aliases.
	* sysdeps/unix/sysv/linux/syscalls.list: Add __nanosleep as weak
	alias.
	* sysdeps/unix/sysv/linux/sleep.c: Call __nanosleep instead of
	nanosleep to keep namespace clean.

	* sysdeps/posix/ttyname.c (ttyname): Add cast to prevent warning.
	* sysdeps/posix/ttyname_r.c (ttyname_r): Likewise.
	* sysdeps/posix/getcwd.c (__getcwd): Likewise.

	* sysdeps/unix/nlist.c: Use ISO C definition since we don't always
	have prototype.

	* login/Makefile (headers): Add pty.h.
	* login/pty.h: New file.
	* sysdeps/generic/pty.h: Include <pty.h>.
	* login/pututline_r.c: Add cast to prevent warning.

	* gmon/gmon.c: Add prototype for __profile_frequency.
	(monstartup): Add cast to prevent warning.
	* sysdeps/generic/prof-freq.c: Change to use ISO C style definition.

	* locale/programs/ld-time.c (time_output): Write `era' information
	in correct order.

Sat Sep 28 00:11:08 1996  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/syscalls.list: Add weak alias
	`adjtimex'.
	Set caller for mlock, mlockall, mremap, munlock, and munlockall
	to EXTRA.
	Reported by Matthias Urlichs <smurf@smurf.noris.de>.

1996-09-27  Paul Eggert  <eggert@twinsun.com>

	* strftime.c (strftime): Output incomplete formats like %E
	at end of string.

1996-09-27  Paul Eggert  <eggert@twinsun.com>

	* strftime.c (strftime): Add support for %EC and %Ey.
	Fix support for %EY.  This uses the new _nl_get_era_entry function.

Fri Sep 27 14:12:27 1996  Ulrich Drepper  <drepper@cygnus.com>

	Security related patch by Elliot Lee <sopwith@redhat.com> and
	David Holland <dholland@eecs.harvard.edu>.

	* inet/rexec.c (rexec): Increase size of `num' array from 8 to 32.
	* inet/ruserpass.c (ruserpass): Don't allow $HOME envvar to not exist.

	* sysdeps/generic/getenv.c (__secure_getenv): New function.  Return
	NULL when programs runs with SUID or SGID enabled.
	* sysdeps/stub/getenv.c: Make __secure_getenv an alias of getenv.
	* stdlib/stdlib.h: Add prototype for __secure_getenv.

	* locale/setlocale.c: Use __secure_getenv.
	* resolv/res_init.c: Likewise.
	* resolv/res_query.c: Likewise.
	* inet/ruserpass.c: Likewise.
	* sysdeps/posix/tempname.c: Likewise.
	* malloc/mtrace.c: Likewise.
	* catgets/catgets.c: Likewise.

	Make temporary file handling functions reentrant.

	* stdio-common/tmpnam.c: Rewrite to have own buffer to write
	result to.  The called __stdio_gen_tempname function must be
	thread safe.
	* stdio-common/tmpnam_r.c: New file.
	* stdio/stdio.h: Add prototype for `tmpnam_r'.
	Change prototype for __stdio_gen_tempname.
	* stdio/libio.h: Likewise.
	* sysdeps/posix/tempname.c: Add new parameters and use them instead
	of static buffer.
	Don't reset `indeces' when PID changed between calls.
	Don't fail for long running programs when index counter once
	reached the limit.
	* sysdeps/stub/tempname.c: Likewise.
	* stdio-common/tempnam.c: Provide local buffer as extra argument
	to __stdio_gen_tempname.  This makes this function reentrant.
	* stdio-common/tmpfile.c: Likewise.
	* stdio-common/temptest.c: Provide extra argument to
	__stdio_gen_tempname.
	* manual/filesys.texi: Describe tmpnam_r and add comments about
	reentrancy of the functions.

	* inet/rcmd.c: Fixed address length handling.

	* sysdeps/posix/mk-stdiolim.c: Count final \0 byte in L_tmpnam value.

	* time/strftime.c: Remove unused variables alt_digits and
 	end_alt_digits.

	* sysdeps/unix/sysv/linux/sys/sysinfo.h: Correct prototype names
	for get_nprocs and get_nprocs_conf.
	* sysdeps/generic/sys/sysinfo.h: Likewise.

	* stdlib/test-canon.c: Finally do the right fix.

	* misc/Makefile: Only compile force-wrapper when compiling
	reentrant libc.
1996-09-28 03:24:10 +00:00

229 lines
6.3 KiB
C

/* Copyright (C) 1993, 1995, 1996 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <malloc.h>
#include <string.h>
#include <search.h>
/* [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
[Knuth] The Art of Computer Programming, part 3 (6.4) */
/* The reentrant version has no static variables to maintain the state.
Instead the interface of all functions is extended to take an argument
which describes the current status. */
typedef struct _ENTRY
{
unsigned int used;
ENTRY entry;
}
_ENTRY;
/* For the used double hash method the table size has to be a prime. To
correct the user given table size we need a prime test. This trivial
algorithm is adequate because
a) the code is (most probably) called a few times per program run and
b) the number is small because the table must fit in the core */
static int
isprime (unsigned int number)
{
/* no even number will be passed */
unsigned int div = 3;
while (div * div < number && number % div != 0)
div += 2;
return number % div != 0;
}
/* Before using the hash table we must allocate memory for it.
Test for an existing table are done. We allocate one element
more as the found prime number says. This is done for more effective
indexing as explained in the comment for the hsearch function.
The contents of the table is zeroed, especially the field used
becomes zero. */
int
hcreate_r (nel, htab)
unsigned int nel;
struct hsearch_data *htab;
{
/* Test for correct arguments. */
if (htab == NULL)
{
__set_errno (EINVAL);
return 0;
}
/* There is still another table active. Return with error. */
if (htab->table != NULL)
return 0;
/* Change nel to the first prime number not smaller as nel. */
nel |= 1; /* make odd */
while (!isprime (nel))
nel += 2;
htab->size = nel;
htab->filled = 0;
/* allocate memory and zero out */
htab->table = (_ENTRY *) calloc (htab->size + 1, sizeof (_ENTRY));
if (htab->table == NULL)
return 0;
/* everything went alright */
return 1;
}
/* After using the hash table it has to be destroyed. The used memory can
be freed and the local static variable can be marked as not used. */
void
hdestroy_r (htab)
struct hsearch_data *htab;
{
/* Test for correct arguments. */
if (htab == NULL)
{
__set_errno (EINVAL);
return;
}
if (htab->table != NULL)
/* free used memory */
free (htab->table);
/* the sign for an existing table is an value != NULL in htable */
htab->table = NULL;
}
/* This is the search function. It uses double hashing with open adressing.
The argument item.key has to be a pointer to an zero terminated, most
probably strings of chars. The function for generating a number of the
strings is simple but fast. It can be replaced by a more complex function
like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
We use an trick to speed up the lookup. The table is created by hcreate
with one more element available. This enables us to use the index zero
special. This index will never be used because we store the first hash
index in the field used where zero means not used. Every other value
means used. The used field can be used as a first fast comparison for
equality of the stored and the parameter value. This helps to prevent
unnecessary expensive calls of strcmp. */
int
hsearch_r (item, action, retval, htab)
ENTRY item;
ACTION action;
ENTRY **retval;
struct hsearch_data *htab;
{
unsigned int hval;
unsigned int count;
unsigned int len = strlen (item.key);
unsigned int idx;
/* If table is full and another entry should be entered return with
error. */
if (action == ENTER && htab->filled == htab->size)
{
__set_errno (ENOMEM);
*retval = NULL;
return 0;
}
/* Compute an value for the given string. Perhaps use a better method. */
hval = len;
count = len;
while (count-- > 0)
{
hval <<= 4;
hval += item.key[count];
}
/* First hash function: simply take the modul but prevent zero. */
hval %= htab->size;
if (hval == 0)
++hval;
/* The first index tried. */
idx = hval;
if (htab->table[idx].used)
{
/* Further action might be required according to the action value. */
unsigned hval2;
if (htab->table[idx].used == hval
&& strcmp (item.key, htab->table[idx].entry.key) == 0)
{
if (action == ENTER)
htab->table[idx].entry.data = item.data;
*retval = &htab->table[idx].entry;
return 1;
}
/* Second hash function, as suggested in [Knuth] */
hval2 = 1 + hval % (htab->size - 2);
do
{
/* Because SIZE is prime this guarantees to step through all
available indeces. */
if (idx <= hval2)
idx = htab->size + idx - hval2;
else
idx -= hval2;
/* If entry is found use it. */
if (htab->table[idx].used == hval
&& strcmp (item.key, htab->table[idx].entry.key) == 0)
{
if (action == ENTER)
htab->table[idx].entry.data = item.data;
*retval = &htab->table[idx].entry;
return 1;
}
}
while (htab->table[idx].used);
}
/* An empty bucket has been found. */
if (action == ENTER)
{
htab->table[idx].used = hval;
htab->table[idx].entry = item;
++htab->filled;
*retval = &htab->table[idx].entry;
return 1;
}
__set_errno (ESRCH);
*retval = NULL;
return 0;
}