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#include <u.h>
#include <libc.h>
#include <auth.h>
static int debug;
static char cwd[8192];
static char *parts[256];
static int mflags[nelem(parts)];
static int nparts;
static void
binderr(char *new, char *old, int flag)
{
char dash[4] = { '-' };
if(debug){
if(flag & MCREATE)
dash[2] = 'c';
switch(flag){
case MCREATE|MREPL:
case MREPL:
dash[0] = ' ';
if(dash[2] == 'c')
dash[1] = '-';
else
dash[1] = ' ';
break;
case MBEFORE:
dash[1] = 'b';
break;
case MAFTER:
dash[1] = 'a';
break;
}
fprint(2, "bind %s %s %s\n", dash, new, old);
}
if(bind(new, old, flag) < 0)
sysfatal("bind %s: %r", new);
}
static void
resolvenames(char **names, int nname)
{
int i;
for(i = 0; i < nname; i++){
if(names[i] == nil)
continue;
cleanname(names[i]);
switch(names[i][0]){
case '#':
case '/':
break;
default:
names[i] = cleanname(smprint("%s/%s", cwd, names[i]));
}
}
}
static void
sandbox(char **names, int *flags, int nname)
{
char *parts[32];
char rootskel[128];
char src[8192], targ[8192], dir[8192], skel[8192];
char name[8192];
char *newroot;
Dir *d;
int i, j, n;
snprint(rootskel, sizeof rootskel, "/mnt/d/newroot.%d", getpid());
binderr(rootskel, "/", MBEFORE);
newroot = rootskel + strlen("/mnt/d");
for(j = 0; j < nname; j++){
if(names[j] == nil)
continue;
utfecpy(name, &name[sizeof name-1], names[j]);
n = gettokens(name, parts, nelem(parts), "/");
utfecpy(targ, &targ[sizeof targ-1], newroot);
memset(src, 0, sizeof src);
for(i = 0; i < n; i++){
utfecpy(dir, &dir[sizeof dir-1], targ);
snprint(targ, sizeof targ, "%s/%s", targ, parts[i]);
snprint(src, sizeof src, "%s/%s", src, parts[i]);
d = dirstat(targ);
if(d != nil){
free(d);
continue;
}
d = dirstat(src);
if(d == nil)
continue;
if(d->mode & DMDIR)
snprint(skel, sizeof skel, "/mnt/d/%s", parts[i]);
else
snprint(skel, sizeof skel, "/mnt/f/%s", parts[i]);
free(d);
binderr(skel, dir, MBEFORE);
}
if(flags[j] != -1)
binderr(names[j], targ, flags[j]);
}
binderr(newroot, "/", MREPL);
}
void
skelfs(void)
{
int p[2];
int dfd;
pipe(p);
switch(rfork(RFFDG|RFREND|RFPROC|RFNAMEG)){
case -1:
sysfatal("fork");
case 0:
close(p[1]);
dup(p[0], 0);
dup(p[0], 1);
execl("/bin/skelfs", "skelfs", debug > 1 ? "-Di" : "-i", nil);
sysfatal("exec /bin/skelfs: %r");
}
close(p[0]);
dfd = dup(p[1], -1);
if(mount(p[1], -1, "/mnt/f", MREPL, "file") < 0)
sysfatal("/mnt/f mount setup: %r");
if(mount(dfd, -1, "/mnt/d", MREPL, "dir") < 0)
sysfatal("/mnt/d mount setup: %r");
}
static void
push(char *path, int flag)
{
if(nparts == nelem(parts))
sysfatal("too many bound paths");
parts[nparts] = path;
mflags[nparts++] = flag;
}
void
usage(void)
{
fprint(2, "usage %s: [ -s ] [ -rc file ] [ -e devs ] command arg ...\n", argv0);
exits("usage");
}
void
main(int argc, char **argv)
{
char **argp, devs[128];
int i, narg, dfd;
char *a;
int sflag;
nparts = 0;
narg = 0;
memset(devs, 0, sizeof devs);
sflag = 0;
argp = argv;
ARGBEGIN{
case 'D':
debug++;
case 'd':
debug++;
break;
case 'r':
a = EARGF(usage());
push(a, MREPL);
break;
case 'c':
a = EARGF(usage());
push(a, MREPL|MCREATE);
break;
case 'e':
snprint(devs, sizeof devs, "%s%s", devs, EARGF(usage()));
break;
case 's':
sflag = 1;
break;
default:
usage();
break;
}ARGEND
if(argc == 0 && !sflag)
usage();
if(getwd(cwd, sizeof(cwd)) == nil)
sysfatal("getwd: %r");
push(cwd, -1);
if(sflag){
snprint(devs, sizeof devs, "%s%s", devs, "|d");
push("/srv", MREPL|MCREATE);
push("/env", MREPL|MCREATE);
push("/rc", MREPL);
push("/bin", MREPL);
argp[narg++] = "/bin/rc";
} else {
if(access(argv[0], AEXIST) == -1){
if((argv[0] = smprint("/bin/%s", argv[0])) == nil)
sysfatal("smprint: %r");
if(access(argv[0], AEXIST) == -1)
sysfatal("could not stat %s %r", argv[0]);
}
push(argv[0], MREPL);
}
for(i = 0; i < argc; i++)
argp[narg++] = argv[i];
argp[narg] = nil;
rfork(RFNAMEG|RFFDG);
skelfs();
dfd = open("/dev/drivers", OWRITE|OCEXEC);
if(dfd < 0)
sysfatal("could not /dev/drivers: %r");
resolvenames(parts, nparts);
sandbox(parts, mflags, nparts);
if(debug)
fprint(2, "chdev %s\n", devs);
if(devs[0] != '\0'){
if(fprint(dfd, "chdev & %s", devs) <= 0)
sysfatal("could not write chdev: %r");
} else {
if(fprint(dfd, "chdev ~") <= 0)
sysfatal("could not write chdev: %r");
}
close(dfd);
if(chdir(cwd) < 0)
sysfatal("chdir %s: %r", cwd);
exec(argp[0], argp);
sysfatal("exec: %r");
}
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