9f6ef391d2992fe9109b5df7e5b64fedab353698
[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 "compat.h"
40 #include "vserver.h"
41
42 // Here is the trick. We keep a copy of the define, then undef it
43 // and then later, we try to locate the value reading /proc/self/status
44 // If this fails, we have the old preserved copy.
45 static int def_NR_set_ipv4root = 227;
46 #undef __NR_set_ipv4root
47
48 static int __NR_set_ipv4root_rev0;
49 static int __NR_set_ipv4root_rev1;
50 static int __NR_set_ipv4root_rev2;
51 static int __NR_set_ipv4root_rev3;
52 static int rev_ipv4root=0;
53
54
55 static _syscall1(int, set_ipv4root_rev0, unsigned long, ip)
56 static _syscall2(int, set_ipv4root_rev1, unsigned long, ip, unsigned long, bcast)
57 static _syscall3(int, set_ipv4root_rev2, unsigned long *, ip, int, nb, unsigned long, bcast)
58 static _syscall4(int, set_ipv4root_rev3, unsigned long *, ip, int, nb, unsigned long, bcast, unsigned long *, mask)
59
60 static int def_NR_new_s_context = 226;
61 #undef __NR_new_s_context
62 static int __NR_new_s_context_rev0;
63 static int __NR_new_s_context_rev1;
64 static int rev_s_context=0;
65
66 static _syscall3(int, new_s_context_rev0, int, newctx, int, remove_cap, int, flags)
67 static _syscall4(int, new_s_context_rev1, int, nbctx, int *, ctxs, int, remove_cap, int, flags)
68
69 #undef __NR_set_ctxlimit
70 static int __NR_set_ctxlimit=-1;
71 static int rev_set_ctxlimit=-1;
72
73 static _syscall2 (int, set_ctxlimit, int, resource, long, limit)
74
75 #undef __NR_chrootsafe
76 static int __NR_chrootsafe=-1;
77 static int rev_chrootsafe=-1;
78
79 static _syscall1 (int, chrootsafe, const char *, dir)
80
81 static void init()
82 {
83         static int is_init = 0;
84         if (!is_init){
85                 FILE *fin = fopen ("/proc/self/status","r");
86                 __NR_set_ipv4root_rev0 = def_NR_set_ipv4root;
87                 __NR_set_ipv4root_rev1 = def_NR_set_ipv4root;
88                 __NR_set_ipv4root_rev2 = def_NR_set_ipv4root;
89                 __NR_set_ipv4root_rev3 = def_NR_set_ipv4root;
90                 __NR_new_s_context_rev1 = def_NR_new_s_context;
91                 if (fin != NULL){
92                         char line[100];
93                         while (fgets(line,sizeof(line)-1,fin)!=NULL){
94                                 int num;
95                                 char title[100],rev[100];
96                                 rev[0] = '\0';
97                                 if (sscanf(line,"%s %d %s",title,&num,rev)>=2){
98                                         if (strcmp(title,"__NR_set_ipv4root:")==0){
99                                                 __NR_set_ipv4root_rev0 = num;
100                                                 __NR_set_ipv4root_rev1 = num;
101                                                 __NR_set_ipv4root_rev2 = num;
102                                                 __NR_set_ipv4root_rev3 = num;
103                                                 if (strncmp(rev,"rev",3)==0){
104                                                         rev_ipv4root = atoi(rev+3);
105                                                 }
106                                         }else if (strcmp(title,"__NR_set_ctxlimit:")==0){
107                                                 __NR_set_ctxlimit = num;
108                                                 if (strncmp(rev,"rev",3)==0){
109                                                         rev_set_ctxlimit = atoi(rev+3);
110                                                 }
111                                         }else if (strcmp(title,"__NR_chrootsafe:")==0){
112                                                 __NR_chrootsafe = num;
113                                                 if (strncmp(rev,"rev",3)==0){
114                                                         rev_chrootsafe = atoi(rev+3);
115                                                 }
116                                         }else if (strcmp(title,"__NR_new_s_context:")==0){
117                                                 __NR_new_s_context_rev0 = num;
118                                                 __NR_new_s_context_rev1 = num;
119                                                 if (strncmp(rev,"rev",3)==0){
120                                                         rev_s_context = atoi(rev+3);
121                                                 }
122                                         }
123                                 }
124                         }
125                         fclose (fin);
126                 }
127                 is_init = 1;
128         }
129 }
130
131 void vserver_init()
132 {
133         init();
134 }
135
136 int call_new_s_context(int nbctx, int ctxs[], int remove_cap, int flags)
137 {
138         int ret = -1;
139         init();
140         if (rev_s_context == 0){
141                 if (nbctx > 1){
142                         errno = EINVAL;
143                         fprintf (stderr,"The current kernel does not support new_s_context revision 1\n");
144                 }else if (nbctx == 0){
145                         ret = new_s_context_rev0(-2,remove_cap,flags);
146                 }else if (nbctx == 1){
147                         ret = new_s_context_rev0(ctxs[0],remove_cap,flags);
148                 }
149         }else{
150 fprintf (stderr,"new_s_context rev1 %d %d\n",nbctx,ctxs[0]);
151                 ret = new_s_context_rev1(nbctx,ctxs,remove_cap,flags);
152         }
153         return ret;
154 }
155
156 int call_set_ipv4root (
157         unsigned long ip[],
158         int nb,
159         unsigned long bcast,
160         unsigned long mask[])
161 {
162         init();
163         if (rev_ipv4root == 0){
164                 if (nb > 1){
165                         fprintf (stderr,"set_ipv4root: Several IP number specified, but this kernel only supports one. Ignored\n");
166                 }
167                 return set_ipv4root_rev0 (ip[0]);
168         }else if (rev_ipv4root == 1){
169                 if (nb > 1){
170                         fprintf (stderr,"set_ipv4root: Several IP number specified, but this kernel only supports one. Ignored\n");
171                 }
172                 return set_ipv4root_rev1 (ip[0],bcast);
173         }else if (rev_ipv4root == 2){
174                 return set_ipv4root_rev2 (ip,nb,bcast);
175         }else if (rev_ipv4root == 3){
176                 return set_ipv4root_rev3 (ip,nb,bcast,mask);
177         }
178         errno = EINVAL;
179         return -1;
180 }
181
182 int call_chrootsafe (const char *dir)
183 {
184         init();
185         if (rev_chrootsafe == -1){
186                 fprintf (stderr,"chrootsafe: Unsupported system call, update kernel\n");
187         }else if (rev_chrootsafe == 0){
188                 return chrootsafe (dir);
189         }else{
190                 fprintf (stderr,"chrootsafe: kernel support version %d, application expects version 0\n"
191                         ,rev_chrootsafe);
192         }
193         errno = EINVAL;
194         return -1;
195 }
196
197 /*
198         Return != 0 if chrootsafe is available
199 */
200 int has_chrootsafe()
201 {
202         init();
203         return rev_chrootsafe != -1;
204 }
205
206 int call_set_ctxlimit (int res, long limit)
207 {
208         init();
209         if (rev_set_ctxlimit == -1){
210                 fprintf (stderr,"set_ctxlimit: Unsupported system call, update kernel\n");
211         }else if (rev_set_ctxlimit == 0){
212                 return set_ctxlimit (res,limit);
213         }else{
214                 fprintf (stderr,"set_ctxlimit: kernel support version %d, application expects version 0\n"
215                         ,rev_set_ctxlimit);
216         }
217         errno = EINVAL;
218         return -1;
219 }
220
221