ebf96daacc67b7f5951c95dab94b30d230241c37
[util-vserver.git] / util-vserver / lib / syscall.c
1 // $Id$
2
3 // Copyright (C) 2003 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de>
4 // based on syscall.cc by Jacques Gelinas
5 //  
6 // This program is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 2, or (at your option)
9 // any later version.
10 //  
11 // This program is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 //  
16 // You should have received a copy of the GNU General Public License
17 // along with this program; if not, write to the Free Software
18 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19
20 /*
21         This tells the system call number for new_s_context and set_ipv4root
22         using /proc/self/status. This helps until the vserver project is
23         included officially in the kernel (and has its own syscall).
24
25         We rely on /proc/self/status to find the syscall number.
26
27         If it is not there, we rely on adm/unistd.h.
28
29         If this file does not have those system calls (not a patched kernel source)
30         we rely on static values in this file.
31 */
32 #include <stdio.h>
33 #include <string.h>
34 #include <stdlib.h>
35 #include <errno.h>
36 #include <syscall.h>
37 #include <asm/unistd.h>
38
39 #include "vserver.h"
40
41 // Here is the trick. We keep a copy of the define, then undef it
42 // and then later, we try to locate the value reading /proc/self/status
43 // If this fails, we have the old preserved copy.
44 static int def_NR_set_ipv4root = 227;
45 #undef __NR_set_ipv4root
46
47 static int __NR_set_ipv4root_rev0;
48 static int __NR_set_ipv4root_rev1;
49 static int __NR_set_ipv4root_rev2;
50 static int __NR_set_ipv4root_rev3;
51 static int rev_ipv4root=0;
52
53
54 static _syscall1(int, set_ipv4root_rev0, unsigned long, ip)
55 static _syscall2(int, set_ipv4root_rev1, unsigned long, ip, unsigned long, bcast)
56 static _syscall3(int, set_ipv4root_rev2, unsigned long *, ip, int, nb, unsigned long, bcast)
57 static _syscall4(int, set_ipv4root_rev3, unsigned long *, ip, int, nb, unsigned long, bcast, unsigned long *, mask)
58
59 static int def_NR_new_s_context = 226;
60 #undef __NR_new_s_context
61 static int __NR_new_s_context_rev0;
62 static int __NR_new_s_context_rev1;
63 static int rev_s_context=0;
64
65 static _syscall3(int, new_s_context_rev0, int, newctx, int, remove_cap, int, flags)
66 static _syscall4(int, new_s_context_rev1, int, nbctx, int *, ctxs, int, remove_cap, int, flags)
67
68 #undef __NR_set_ctxlimit
69 static int __NR_set_ctxlimit=-1;
70 static int rev_set_ctxlimit=-1;
71
72 static _syscall2 (int, set_ctxlimit, int, resource, long, limit)
73
74 #undef __NR_chrootsafe
75 static int __NR_chrootsafe=-1;
76 static int rev_chrootsafe=-1;
77
78 static _syscall1 (int, chrootsafe, const char *, dir)
79
80 static void init()
81 {
82         static int is_init = 0;
83         if (!is_init){
84                 FILE *fin = fopen ("/proc/self/status","r");
85                 __NR_set_ipv4root_rev0 = def_NR_set_ipv4root;
86                 __NR_set_ipv4root_rev1 = def_NR_set_ipv4root;
87                 __NR_set_ipv4root_rev2 = def_NR_set_ipv4root;
88                 __NR_set_ipv4root_rev3 = def_NR_set_ipv4root;
89                 __NR_new_s_context_rev1 = def_NR_new_s_context;
90                 if (fin != NULL){
91                         char line[100];
92                         while (fgets(line,sizeof(line)-1,fin)!=NULL){
93                                 int num;
94                                 char title[100],rev[100];
95                                 rev[0] = '\0';
96                                 if (sscanf(line,"%s %d %s",title,&num,rev)>=2){
97                                         if (strcmp(title,"__NR_set_ipv4root:")==0){
98                                                 __NR_set_ipv4root_rev0 = num;
99                                                 __NR_set_ipv4root_rev1 = num;
100                                                 __NR_set_ipv4root_rev2 = num;
101                                                 __NR_set_ipv4root_rev3 = num;
102                                                 if (strncmp(rev,"rev",3)==0){
103                                                         rev_ipv4root = atoi(rev+3);
104                                                 }
105                                         }else if (strcmp(title,"__NR_set_ctxlimit:")==0){
106                                                 __NR_set_ctxlimit = num;
107                                                 if (strncmp(rev,"rev",3)==0){
108                                                         rev_set_ctxlimit = atoi(rev+3);
109                                                 }
110                                         }else if (strcmp(title,"__NR_chrootsafe:")==0){
111                                                 __NR_chrootsafe = num;
112                                                 if (strncmp(rev,"rev",3)==0){
113                                                         rev_chrootsafe = atoi(rev+3);
114                                                 }
115                                         }else if (strcmp(title,"__NR_new_s_context:")==0){
116                                                 __NR_new_s_context_rev0 = num;
117                                                 __NR_new_s_context_rev1 = num;
118                                                 if (strncmp(rev,"rev",3)==0){
119                                                         rev_s_context = atoi(rev+3);
120                                                 }
121                                         }
122                                 }
123                         }
124                         fclose (fin);
125                 }
126                 is_init = 1;
127         }
128 }
129
130 void vserver_init()
131 {
132         init();
133 }
134
135 int call_new_s_context(int nbctx, int ctxs[], int remove_cap, int flags)
136 {
137         int ret = -1;
138         init();
139         if (rev_s_context == 0){
140                 if (nbctx > 1){
141                         errno = EINVAL;
142                         fprintf (stderr,"The current kernel does not support new_s_context revision 1\n");
143                 }else if (nbctx == 0){
144                         ret = new_s_context_rev0(-2,remove_cap,flags);
145                 }else if (nbctx == 1){
146                         ret = new_s_context_rev0(ctxs[0],remove_cap,flags);
147                 }
148         }else{
149 fprintf (stderr,"new_s_context rev1 %d %d\n",nbctx,ctxs[0]);
150                 ret = new_s_context_rev1(nbctx,ctxs,remove_cap,flags);
151         }
152         return ret;
153 }
154
155 int call_set_ipv4root (
156         unsigned long ip[],
157         int nb,
158         unsigned long bcast,
159         unsigned long mask[])
160 {
161         init();
162         if (rev_ipv4root == 0){
163                 if (nb > 1){
164                         fprintf (stderr,"set_ipv4root: Several IP number specified, but this kernel only supports one. Ignored\n");
165                 }
166                 return set_ipv4root_rev0 (ip[0]);
167         }else if (rev_ipv4root == 1){
168                 if (nb > 1){
169                         fprintf (stderr,"set_ipv4root: Several IP number specified, but this kernel only supports one. Ignored\n");
170                 }
171                 return set_ipv4root_rev1 (ip[0],bcast);
172         }else if (rev_ipv4root == 2){
173                 return set_ipv4root_rev2 (ip,nb,bcast);
174         }else if (rev_ipv4root == 3){
175                 return set_ipv4root_rev3 (ip,nb,bcast,mask);
176         }
177         errno = EINVAL;
178         return -1;
179 }
180
181 int call_chrootsafe (const char *dir)
182 {
183         init();
184         if (rev_chrootsafe == -1){
185                 fprintf (stderr,"chrootsafe: Unsupported system call, update kernel\n");
186         }else if (rev_chrootsafe == 0){
187                 return chrootsafe (dir);
188         }else{
189                 fprintf (stderr,"chrootsafe: kernel support version %d, application expects version 0\n"
190                         ,rev_chrootsafe);
191         }
192         errno = EINVAL;
193         return -1;
194 }
195
196 /*
197         Return != 0 if chrootsafe is available
198 */
199 int has_chrootsafe()
200 {
201         init();
202         return rev_chrootsafe != -1;
203 }
204
205 int call_set_ctxlimit (int res, long limit)
206 {
207         init();
208         if (rev_set_ctxlimit == -1){
209                 fprintf (stderr,"set_ctxlimit: Unsupported system call, update kernel\n");
210         }else if (rev_set_ctxlimit == 0){
211                 return set_ctxlimit (res,limit);
212         }else{
213                 fprintf (stderr,"set_ctxlimit: kernel support version %d, application expects version 0\n"
214                         ,rev_set_ctxlimit);
215         }
216         errno = EINVAL;
217         return -1;
218 }
219
220