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samba-mirror/source4/smbwrapper/shared.c
Andrew Tridgell ef2e26c91b first public release of samba4 code
(This used to be commit b0510b5428)
2003-08-13 01:53:07 +00:00

204 lines
4.5 KiB
C

/*
Unix SMB/CIFS implementation.
SMB wrapper functions - shared variables
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
static int shared_fd;
static char *variables;
static int shared_size;
/*****************************************************
setup the shared area
*******************************************************/
void smbw_setup_shared(void)
{
int fd;
pstring name, s;
slprintf(name,sizeof(name)-1, "%s/smbw.XXXXXX",tmpdir());
fd = smb_mkstemp(name);
if (fd == -1) goto failed;
unlink(name);
shared_fd = set_maxfiles(SMBW_MAX_OPEN);
while (shared_fd && dup2(fd, shared_fd) != shared_fd) shared_fd--;
if (shared_fd == 0) goto failed;
close(fd);
DEBUG(4,("created shared_fd=%d\n", shared_fd));
slprintf(s,sizeof(s)-1,"%d", shared_fd);
setenv("SMBW_HANDLE", s, 1);
return;
failed:
perror("Failed to setup shared variable area ");
exit(1);
}
static int locked;
/*****************************************************
lock the shared variable area
*******************************************************/
static void lockit(void)
{
if (shared_fd == 0) {
char *p = getenv("SMBW_HANDLE");
if (!p) {
DEBUG(0,("ERROR: can't get smbw shared handle\n"));
exit(1);
}
shared_fd = atoi(p);
}
if (locked==0 &&
fcntl_lock(shared_fd,SMB_F_SETLKW,0,1,F_WRLCK)==False) {
DEBUG(0,("ERROR: can't get smbw shared lock (%s)\n", strerror(errno)));
exit(1);
}
locked++;
}
/*****************************************************
unlock the shared variable area
*******************************************************/
static void unlockit(void)
{
locked--;
if (locked == 0) {
fcntl_lock(shared_fd,SMB_F_SETLK,0,1,F_UNLCK);
}
}
/*****************************************************
get a variable from the shared area
*******************************************************/
char *smbw_getshared(const char *name)
{
int i;
struct stat st;
char *var;
lockit();
/* maybe the area has changed */
if (fstat(shared_fd, &st)) goto failed;
if (st.st_size != shared_size) {
var = (char *)Realloc(variables, st.st_size);
if (!var) goto failed;
else variables = var;
shared_size = st.st_size;
lseek(shared_fd, 0, SEEK_SET);
if (read(shared_fd, variables, shared_size) != shared_size) {
goto failed;
}
}
unlockit();
i=0;
while (i < shared_size) {
char *n, *v;
int l1, l2;
l1 = SVAL(&variables[i], 0);
l2 = SVAL(&variables[i], 2);
n = &variables[i+4];
v = &variables[i+4+l1];
i += 4+l1+l2;
if (strcmp(name,n)) {
continue;
}
return v;
}
return NULL;
failed:
DEBUG(0,("smbw: shared variables corrupt (%s)\n", strerror(errno)));
exit(1);
return NULL;
}
/*****************************************************
set a variable in the shared area
*******************************************************/
void smbw_setshared(const char *name, const char *val)
{
int l1, l2;
char *var;
/* we don't allow variable overwrite */
if (smbw_getshared(name)) return;
lockit();
l1 = strlen(name)+1;
l2 = strlen(val)+1;
var = (char *)Realloc(variables, shared_size + l1+l2+4);
if (!var) {
DEBUG(0,("out of memory in smbw_setshared\n"));
exit(1);
}
variables = var;
SSVAL(&variables[shared_size], 0, l1);
SSVAL(&variables[shared_size], 2, l2);
pstrcpy(&variables[shared_size] + 4, name);
pstrcpy(&variables[shared_size] + 4 + l1, val);
shared_size += l1+l2+4;
lseek(shared_fd, 0, SEEK_SET);
if (write(shared_fd, variables, shared_size) != shared_size) {
DEBUG(0,("smbw_setshared failed (%s)\n", strerror(errno)));
exit(1);
}
unlockit();
}
/*****************************************************************
return true if the passed fd is the SMBW_HANDLE
*****************************************************************/
int smbw_shared_fd(int fd)
{
return (shared_fd && shared_fd == fd);
}