Initial import

[samba] / source / smbwrapper / shared.c

diff --git a/source/smbwrapper/shared.c b/source/smbwrapper/shared.c
new file mode 100644 (file)
index 0000000..ca8df58
--- /dev/null
+++ b/source/smbwrapper/shared.c
@@ -0,0 +1,203 @@
+/* 
+   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);
+
+       safe_strcpy(&variables[shared_size] + 4, name, l1-1);
+       safe_strcpy(&variables[shared_size] + 4 + l1, val, l2-1);
+
+       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);
+}