ref: a14f9efa6848f167f54dea3e3823b31dae1461c9
dir: /sys/src/libauth/newns.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <auth.h>
#include <authsrv.h>
#include "authlocal.h"
enum
{
NARG = 15, /* max number of arguments */
MAXARG = 10*ANAMELEN, /* max length of an argument */
};
static int setenv(char*, char*);
static char *expandarg(char*, char*);
static int splitargs(char*, char*[], char*, int);
static int nsfile(char*, Biobuf *, AuthRpc *, int);
static int nsop(char*, int, char*[], AuthRpc*, int);
static int catch(void*, char*);
int newnsdebug;
static int
freecloserpc(AuthRpc *rpc)
{
if(rpc){
close(rpc->afd);
auth_freerpc(rpc);
}
return -1;
}
static int
buildns(int newns, char *user, char *file)
{
Biobuf *b;
char home[4*ANAMELEN];
int afd, cdroot, dfd;
char *path;
AuthRpc *rpc;
rpc = nil;
/* try for factotum now because later is impossible */
afd = open("/mnt/factotum/rpc", ORDWR|OCEXEC);
if(afd < 0 && newnsdebug)
fprint(2, "open /mnt/factotum/rpc: %r\n");
if(afd >= 0){
rpc = auth_allocrpc(afd);
if(rpc == nil)
close(afd);
}
/* rpc != nil iff afd >= 0 */
dfd = open("#c/drivers", OWRITE|OCEXEC);
if(dfd < 0 && newnsdebug)
fprint(2, "open #c/drivers: %r\n");
if(file == nil){
if(!newns){
close(dfd);
werrstr("no namespace file specified");
return freecloserpc(rpc);
}
file = "/lib/namespace";
}
b = Bopen(file, OREAD|OCEXEC);
if(b == nil){
close(dfd);
werrstr("can't open %s: %r", file);
return freecloserpc(rpc);
}
if(newns){
rfork(RFENVG|RFCNAMEG);
setenv("user", user);
snprint(home, sizeof home, "/usr/%s", user);
setenv("home", home);
}
cdroot = nsfile(newns ? "newns" : "addns", b, rpc, dfd);
close(dfd);
Bterm(b);
freecloserpc(rpc);
/* make sure we managed to cd into the new name space */
if(newns && !cdroot){
path = malloc(1024);
if(path == nil || getwd(path, 1024) == 0 || chdir(path) < 0)
chdir("/");
if(path != nil)
free(path);
}
return 0;
}
static int
nsfile(char *fn, Biobuf *b, AuthRpc *rpc, int dfd)
{
int argc;
char *cmd, *argv[NARG+1], argbuf[MAXARG*NARG];
int cdroot;
cdroot = 0;
atnotify(catch, 1);
while(cmd = Brdline(b, '\n')){
cmd[Blinelen(b)-1] = '\0';
while(*cmd==' ' || *cmd=='\t')
cmd++;
if(*cmd == '#')
continue;
argc = splitargs(cmd, argv, argbuf, NARG);
if(argc)
cdroot |= nsop(fn, argc, argv, rpc, dfd);
}
atnotify(catch, 0);
return cdroot;
}
int
newns(char *user, char *file)
{
return buildns(1, user, file);
}
int
addns(char *user, char *file)
{
return buildns(0, user, file);
}
static int
famount(int fd, AuthRpc *rpc, char *mntpt, int flags, char *aname)
{
int afd;
AuthInfo *ai;
int ret;
afd = fauth(fd, aname);
if(afd >= 0){
ai = fauth_proxy(afd, rpc, amount_getkey, "proto=p9any role=client");
if(ai != nil)
auth_freeAI(ai);
}
ret = mount(fd, afd, mntpt, flags, aname);
if(ret == -1)
close(fd);
if(afd >= 0)
close(afd);
return ret;
}
static int
nsop(char *fn, int argc, char *argv[], AuthRpc *rpc, int dfd)
{
char *argv0;
ulong flags;
char *devop;
int fd, i;
Biobuf *b;
int cdroot;
cdroot = 0;
flags = 0;
devop = "&";
argv0 = nil;
if(newnsdebug){
for (i = 0; i < argc; i++)
fprint(2, "%s ", argv[i]);
fprint(2, "\n");
}
ARGBEGIN{
case 'a':
flags |= MAFTER;
break;
case 'b':
flags |= MBEFORE;
break;
case 'c':
flags |= MCREATE;
break;
case 'C':
flags |= MCACHE;
break;
case 'r':
devop = "&~";
break;
case 'n':
devop = "~";
break;
}ARGEND
if(!(flags & (MAFTER|MBEFORE)))
flags |= MREPL;
if(strcmp(argv0, ".") == 0 && argc == 1){
b = Bopen(argv[0], OREAD|OCEXEC);
if(b == nil)
return 0;
cdroot |= nsfile(fn, b, rpc, dfd);
Bterm(b);
}else if(strcmp(argv0, "clear") == 0 && argc == 0){
rfork(RFCNAMEG);
}else if(strcmp(argv0, "bind") == 0 && argc == 2){
if(bind(argv[0], argv[1], flags) == -1 && newnsdebug)
fprint(2, "%s: bind: %s %s: %r\n", fn, argv[0], argv[1]);
}else if(strcmp(argv0, "unmount") == 0){
if(argc == 1)
unmount(nil, argv[0]);
else if(argc == 2)
unmount(argv[0], argv[1]);
}else if(strcmp(argv0, "mount") == 0){
fd = open(argv[0], ORDWR);
if(fd < 0){
if(newnsdebug)
fprint(2, "%s: mount: %s: %r\n", fn, argv[0]);
return 0;
}
if(argc == 2){
if(famount(fd, rpc, argv[1], flags, "") == -1 && newnsdebug)
fprint(2, "%s: mount: %s %s: %r\n", fn, argv[0], argv[1]);
}else if(argc == 3){
if(famount(fd, rpc, argv[1], flags, argv[2]) == -1 && newnsdebug)
fprint(2, "%s: mount: %s %s %s: %r\n", fn, argv[0], argv[1], argv[2]);
} else {
close(fd);
}
}else if(strcmp(argv0, "cd") == 0 && argc == 1){
if(chdir(argv[0]) == 0 && *argv[0] == '/')
cdroot = 1;
}else if(strcmp(argv0, "chdev") == 0){
//We should not silently fail if we can not honor a chdev
//due to the parent namespace missing #c/drivers.
if(dfd <= 0)
sysfatal("chdev requested, but could not open #c/drivers");
if(argc == 0 && devop[0] == '~'){
if(fprint(dfd, "chdev ~") < 0 && newnsdebug)
fprint(2, "%s: chdev ~: %r\n", fn);
}else if(argc == 1){
if(fprint(dfd, "chdev %s %s", devop, argv[0]) < 0 && newnsdebug)
fprint(2, "%s: chdev %s %s: %r\n", fn, devop, argv[0]);
}
}
return cdroot;
}
static char *wocp = "sys: write on closed pipe";
static int
catch(void *x, char *m)
{
USED(x);
return strncmp(m, wocp, strlen(wocp)) == 0;
}
static char*
unquote(char *s)
{
char *r, *w;
int inquote;
inquote = 0;
for(r=w=s; *r; r++){
if(*r != '\''){
*w++ = *r;
continue;
}
if(inquote){
if(*(r+1) == '\''){
*w++ = '\'';
r++;
}else
inquote = 0;
}else
inquote = 1;
}
*w = 0;
return s;
}
static int
splitargs(char *p, char *argv[], char *argbuf, int nargv)
{
char *q;
int i, n;
n = gettokens(p, argv, nargv, " \t\r");
if(n == nargv)
return 0;
for(i = 0; i < n; i++){
q = argv[i];
argv[i] = argbuf;
argbuf = expandarg(q, argbuf);
if(argbuf == nil)
return 0;
unquote(argv[i]);
}
return n;
}
static char*
nextdollar(char *arg)
{
char *p;
int inquote;
inquote = 0;
for(p=arg; *p; p++){
if(*p == '\'')
inquote = !inquote;
if(*p == '$' && !inquote)
return p;
}
return nil;
}
/*
* copy the arg into the buffer,
* expanding any environment variables.
* environment variables are assumed to be
* names (ie. < ANAMELEN long)
* the entire argument is expanded to be at
* most MAXARG long and null terminated
* the address of the byte after the terminating null is returned
* any problems cause a 0 return;
*/
static char *
expandarg(char *arg, char *buf)
{
char env[3+ANAMELEN], *p, *x;
int fd, n, len;
n = 0;
while(p = nextdollar(arg)){
len = p - arg;
if(n + len + ANAMELEN >= MAXARG-1)
return 0;
memmove(&buf[n], arg, len);
n += len;
p++;
arg = strpbrk(p, "/.!'$");
if(arg == nil)
arg = p+strlen(p);
len = arg - p;
if(len == 0 || len >= ANAMELEN)
continue;
strcpy(env, "#e/");
strncpy(env+3, p, len);
env[3+len] = '\0';
fd = open(env, OREAD|OCEXEC);
if(fd >= 0){
len = read(fd, &buf[n], ANAMELEN - 1);
/* some singleton environment variables have trailing NULs */
/* lists separate entries with NULs; we arbitrarily take the first element */
if(len > 0){
x = memchr(&buf[n], 0, len);
if(x != nil)
len = x - &buf[n];
n += len;
}
close(fd);
}
}
len = strlen(arg);
if(n + len >= MAXARG - 1)
return 0;
strcpy(&buf[n], arg);
return &buf[n+len+1];
}
static int
setenv(char *name, char *val)
{
int f;
char ename[ANAMELEN+6];
long s;
sprint(ename, "#e/%s", name);
f = create(ename, OWRITE|OCEXEC, 0664);
if(f < 0)
return -1;
s = strlen(val);
if(write(f, val, s) != s){
close(f);
return -1;
}
close(f);
return 0;
}