vshost-util-vserver

getvserverctx.c (5129B)

---

 // $Id$    --*- c -*--
 
 // Copyright (C) 2003 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
 //  
 // 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; version 2 of the License.
 //  
 // 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 
 #ifdef HAVE_CONFIG_H
 #  include <config.h>
 #endif
 
 #include "vserver.h"
 #include "pathconfig.h"
 #include "compat-c99.h"
 #include "lib_internal/util.h"
 #include "internal.h"
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
 
 #ifdef VC_ENABLE_API_COMPAT
 #include <fcntl.h>
 
 static xid_t
 extractLegacyXID(char const *dir, char const *basename)
 {
   size_t	l1 = strlen(dir);
   size_t	l2 = strlen(basename);
   char		path[l1 + l2 + sizeof("/.ctx")];
   char *	ptr = path;
   int		fd;
   ssize_t	len;
   xid_t		result = VC_NOXID;
 
   ptr    = Xmemcpy(ptr, dir, l1);
   *ptr++ = '/';
   ptr    = Xmemcpy(ptr, basename, l2);
   ptr    = Xmemcpy(ptr, ".ctx",    5);
 
   fd = open(path, O_RDONLY);
   if (fd==-1) return VC_NOXID;
 
   len = lseek(fd, 0, SEEK_END);
 
   if (len!=-1 && lseek(fd, 0, SEEK_SET)!=-1) {
     char	buf[len+2];
     char const	*pos = 0;
 
     buf[0] = '\n';
     
     if (read(fd, buf+1, len+1)==len) {
       buf[len+1] = '\0';
       pos        = strstr(buf, "\nS_CONTEXT=");
     }
 
     if (pos) pos += 11;
     if (*pos>='1' && *pos<='9')
       result = atoi(pos);
   }
 
   close(fd);
   return result;
 }
 #else
 static xid_t
 extractLegacyXID(char const UNUSED *dir, char const UNUSED *basename)
 {
   return VC_NOXID;
 }
 #endif
 
 
 static xid_t
 getCtxFromFile(char const *pathname)
 {
   int		fd;
   off_t		len;
 
   fd = open(pathname, O_RDONLY);
 
   if (fd==-1) return VC_NOCTX;
   if ((len=lseek(fd, 0, SEEK_END))==-1 ||
       (len>50) ||
       (lseek(fd, 0, SEEK_SET)==-1)) {
     close(fd);
     return VC_NOCTX;
   }
 
   {
   char		buf[len+1];
   char		*errptr;
   xid_t		res;
   
   if (TEMP_FAILURE_RETRY(read(fd, buf, len+1))!=len) res = VC_NOCTX;
   else {
     buf[len] = '\0';
 
     res = strtol(buf, &errptr, 10);
     if (*errptr!='\0' && *errptr!='\n') res = VC_NOCTX;
   }
 
   close(fd);
   return res;
   }
 }
 
 xid_t
 vc_getVserverCtx(char const *id, vcCfgStyle style, bool honor_static, bool *is_running,
 		 vcCtxType type)
 {
   size_t		l1 = strlen(id);
   char			buf[sizeof(CONFDIR "//") + l1 + sizeof("/ncontext")];
 			    
   if (style==vcCFG_NONE || style==vcCFG_AUTO)
     style = vc_getVserverCfgStyle(id);
 
   if (is_running) *is_running = false;
 
   switch (style) {
     case vcCFG_NONE		:  return VC_NOCTX;
     case vcCFG_LEGACY		:
       return extractLegacyXID(DEFAULT_PKGSTATEDIR, id);
     case vcCFG_RECENT_SHORT	:
     case vcCFG_RECENT_FULL	: {
       size_t		idx = 0;
       xid_t		res = 0;
 
       if (style==vcCFG_RECENT_SHORT) {
 	memcpy(buf, CONFDIR "/", sizeof(CONFDIR "/")-1);
 	idx  = sizeof(CONFDIR "/") - 1;
       }
       memcpy(buf+idx, id, l1);    idx += l1;
       memcpy(buf+idx, "/run", 5);	// appends '\0' too
       
       res = getCtxFromFile(buf);
 
 	// when context information could be read, we have to verify that
 	// it belongs to a running vserver and the both vservers are
 	// identically
       if (res!=VC_NOCTX && type == vcCTX_XID) {
 	char			*cur_name;
 	struct vc_vx_info	info;
 
 	  // determine the vserver which is associated with the xid resp. skip
 	  // this step when the context does not exist. When checking whether
 	  // the context exists, do not rely on the success of
 	  // vc_get_vx_info() alone but check 'errno' for ESRCH also. Else,
 	  // wrong results will be caused e.g. for xid 1 which will fail with
 	  // ENOSYS.
 	cur_name = (vc_get_vx_info(res, &info)!=-1 || errno!=ESRCH ?
 		    vc_getVserverByCtx_Internal(res, &style, 0, false) :
 		    0);
 
 	buf[idx] = '\0';	// cut off the '/run' from the vserver name
 	
 	res      = ((cur_name!=0 &&
 		     vc_compareVserverById(buf,      vcCFG_RECENT_FULL,
 					  cur_name, vcCFG_RECENT_FULL)==0)
 		    ? res
 		    : VC_NOCTX);	// correct the value of 'res'
 	  
 	free(cur_name);
 
 	if (is_running)			// fill 'is_running' information...
 	  *is_running = res!=VC_NOCTX;
       }
       else if (is_running)
 	*is_running = false;
 
       if (res==VC_NOCTX && honor_static) {
 check_static:
 	switch (type) {
 	  case vcCTX_XID:
 	    memcpy(buf+idx, "/context", 9);	// appends '\0' too
 	    break;
 	  case vcCTX_NID:
 	    memcpy(buf+idx, "/ncontext", 10);
 	    break;
 	  case vcCTX_TAG:
 	    memcpy(buf+idx, "/tag", 5);
 	    break;
 	}
 
 	res = getCtxFromFile(buf);
 	if (res==VC_NOCTX && type!=vcCTX_XID) {
 	  type = vcCTX_XID;
 	  goto check_static;
 	}
       }
 
       return res;
     }
     default			:  return VC_NOCTX;
   }
 }