4a80d9d029
devproc assumes that when we hold the Proc.debug qlock, the process will be prevented from exiting. but there is another race where the process has already exited and the Proc* slot gets reused. to solve this, on process creation we also have to acquire the debug qlock while initializing the fields of the process. this also means newproc() should only initialize fields *not* protected by the debug qlock. always acquire the Proc.debug qlock when changing strings in the proc structure to avoid doublefree on concurrent update. for changing the user string, we add a procsetuser() function that does this for auth.c and devcap. remove pgrpnote() from pgrp.c and replace by static postnotepg() in devproc. avoid the assumption that the Proc* entries returned by proctab() are continuous. fixed devproc permission issues: - make sure only eve can access /proc/trace - none should only be allowed to read its own /proc/n/text - move Proc.kp checks into procopen() pid reuse was not handled correctly, as we where only checking if a pid had a living process, but there still could be processes expecting a particular parentpid or noteid. this is now addressed with reference counted Pid structures which are organized in a hash table. read access to the hash table does not require locks which will be usefull for dtracy later.
166 lines
2.6 KiB
C
166 lines
2.6 KiB
C
#include "u.h"
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#include "../port/lib.h"
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#include "mem.h"
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#include "dat.h"
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#include "fns.h"
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#include "../port/error.h"
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#include <authsrv.h>
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char *eve;
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char hostdomain[DOMLEN];
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/*
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* return true if current user is eve
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*/
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int
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iseve(void)
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{
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return strcmp(eve, up->user) == 0;
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}
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uintptr
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sysfversion(va_list list)
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{
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int msize, arglen, fd;
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char *vers;
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Chan *c;
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fd = va_arg(list, int);
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msize = va_arg(list, int);
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vers = va_arg(list, char*);
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arglen = va_arg(list, int);
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validaddr((uintptr)vers, arglen, 1);
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/* check there's a NUL in the version string */
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if(arglen <= 0 || memchr(vers, 0, arglen) == nil)
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error(Ebadarg);
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c = fdtochan(fd, ORDWR, 0, 1);
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if(waserror()){
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cclose(c);
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nexterror();
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}
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msize = mntversion(c, vers, msize, arglen);
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cclose(c);
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poperror();
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return msize;
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}
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uintptr
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sys_fsession(va_list list)
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{
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int fd;
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char *str;
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uint len;
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/* deprecated; backwards compatibility only */
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fd = va_arg(list, int);
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str = va_arg(list, char*);
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len = va_arg(list, uint);
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if(len == 0)
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error(Ebadarg);
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validaddr((uintptr)str, len, 1);
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*str = '\0';
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USED(fd);
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return 0;
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}
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uintptr
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sysfauth(va_list list)
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{
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Chan *c, *ac;
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char *aname;
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int fd;
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fd = va_arg(list, int);
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aname = va_arg(list, char*);
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validaddr((uintptr)aname, 1, 0);
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aname = validnamedup(aname, 1);
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if(waserror()){
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free(aname);
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nexterror();
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}
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c = fdtochan(fd, ORDWR, 0, 1);
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if(waserror()){
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cclose(c);
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nexterror();
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}
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ac = mntauth(c, aname);
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/* at this point ac is responsible for keeping c alive */
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poperror(); /* c */
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cclose(c);
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poperror(); /* aname */
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free(aname);
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if(waserror()){
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cclose(ac);
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nexterror();
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}
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fd = newfd(ac);
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if(fd < 0)
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error(Enofd);
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poperror(); /* ac */
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/* always mark it close on exec */
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ac->flag |= CCEXEC;
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return (uintptr)fd;
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}
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/*
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* called by devcons() for user device
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*
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* anyone can become none
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*/
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long
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userwrite(char *a, int n)
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{
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if(n!=4 || strncmp(a, "none", 4)!=0)
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error(Eperm);
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procsetuser(up, "none");
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return n;
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}
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/*
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* called by devcons() for host owner/domain
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*
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* writing hostowner also sets user
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*/
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long
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hostownerwrite(char *a, int n)
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{
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char buf[KNAMELEN];
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if(!iseve())
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error(Eperm);
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if(n <= 0)
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error(Ebadarg);
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if(n >= sizeof buf)
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error(Etoolong);
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memmove(buf, a, n);
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buf[n] = 0;
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renameuser(eve, buf);
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srvrenameuser(eve, buf);
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shrrenameuser(eve, buf);
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kstrdup(&eve, buf);
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procsetuser(up, buf);
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return n;
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}
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long
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hostdomainwrite(char *a, int n)
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{
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char buf[DOMLEN];
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if(!iseve())
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error(Eperm);
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if(n <= 0 || n >= DOMLEN)
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error(Ebadarg);
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memset(buf, 0, DOMLEN);
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strncpy(buf, a, n);
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if(buf[0] == 0)
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error(Ebadarg);
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memmove(hostdomain, buf, DOMLEN);
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return n;
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}
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