freebsd-dev/lib/libc/gen/getvfsent.c
Garrett Wollman 6335830372 Fix for vfsload(3):
- Don't allow non-root users to specify LKMDIR.
- Don't allow any users to specify TMPDIR.
- Call /sbin/modload using execl() rather than execlp().
1996-05-17 15:35:13 +00:00

249 lines
3.8 KiB
C

/*
* getvfsent.c - get a listing of installed filesystems
* Written September 1994 by Garrett A. Wollman
* This file is in the public domain.
*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <paths.h>
#define _PATH_MODLOAD "/sbin/modload" /* XXX should be in header file */
static struct vfsconf *_vfslist = 0;
static struct vfsconf _vfsconf;
static size_t _vfslistlen = 0;
static int _vfs_keeplist = 0;
static int _vfs_index = 0;
static int
initvfs(void)
{
int mib[2] = { CTL_VFS, VFS_VFSCONF };
size_t size = 0;
int rv;
rv = sysctl(mib, 2, (void *)0, &size, (void *)0, (size_t)0);
if(rv < 0)
return 0;
if(_vfslist)
free(_vfslist);
_vfslist = malloc(size);
if(!_vfslist)
return 0;
rv = sysctl(mib, 2, _vfslist, &size, (void *)0, (size_t)0);
if(rv < 0) {
free(_vfslist);
_vfslist = 0;
return 0;
}
_vfslistlen = size / sizeof _vfslist[0];
return 1;
}
struct vfsconf *
getvfsent(void)
{
if(!_vfslist && !initvfs()) {
return 0;
}
do {
if(_vfs_index > _vfslistlen) {
return 0;
}
_vfsconf = _vfslist[_vfs_index++];
} while(!_vfsconf.vfc_vfsops);
if(!_vfs_keeplist) {
free(_vfslist);
_vfslist = 0;
}
return &_vfsconf;
}
struct vfsconf *
getvfsbyname(const char *name)
{
int i;
if(!_vfslist && !initvfs()) {
return 0;
}
for(i = 0; i < _vfslistlen; i++) {
if( ! strcmp(_vfslist[i].vfc_name, name) )
break;
}
if(i < _vfslistlen) {
_vfsconf = _vfslist[i];
}
if(!_vfs_keeplist) {
free(_vfslist);
_vfslist = 0;
}
if(i < _vfslistlen) {
return &_vfsconf;
} else {
return 0;
}
}
struct vfsconf *
getvfsbytype(int type)
{
int i;
if(!_vfslist && !initvfs()) {
return 0;
}
for(i = 0; i < _vfslistlen; i++) {
if(_vfslist[i].vfc_index == type)
break;
}
if(i < _vfslistlen) {
_vfsconf = _vfslist[i];
}
if(!_vfs_keeplist) {
free(_vfslist);
_vfslist = 0;
}
if(i < _vfslistlen) {
return &_vfsconf;
} else {
return 0;
}
}
void
setvfsent(int keep)
{
if(_vfslist && !keep) {
free(_vfslist);
_vfslist = 0;
}
_vfs_keeplist = keep;
_vfs_index = 0;
}
void
endvfsent(void)
{
if(_vfslist) {
free(_vfslist);
_vfslist = 0;
}
_vfs_index = 0;
}
static const char *vfs_lkmdirs[] = {
"/lkm",
"/usr/lkm",
0,
0
};
#define NLKMDIRS ((sizeof vfs_lkmdirs) / (sizeof vfs_lkmdirs[0]))
static const char *
vfspath(const char *name)
{
static char pnbuf[MAXPATHLEN];
char *userdir = getenv("LKMDIR");
int i;
if(userdir && getuid() == geteuid() && getuid() == 0) {
vfs_lkmdirs[NLKMDIRS - 2] = userdir;
}
for(i = 0; vfs_lkmdirs[i]; i++) {
snprintf(pnbuf, sizeof pnbuf, "%s/%s_mod.o", vfs_lkmdirs[i], name);
if( ! access(pnbuf, R_OK) )
return pnbuf;
}
return 0;
}
int
vfsisloadable(const char *name)
{
int fd;
fd = open("/dev/lkm", O_RDWR, 0);
if(fd < 0) {
return 0;
}
close(fd);
return !!vfspath(name);
}
int
vfsload(const char *name)
{
const char *path = vfspath(name);
char name_mod[sizeof("_mod") + strlen(name)];
pid_t pid;
int status;
if(!path) {
errno = ENOENT;
return -1;
}
pid = fork();
if(pid < 0)
return -1;
if(pid > 0) {
waitpid(pid, &status, 0);
if(WIFEXITED(status)) {
errno = WEXITSTATUS(status);
return errno ? -1 : 0;
}
errno = EINVAL; /* not enough errno values, >sigh< */
return -1;
}
status = -1;
unsetenv("TMPDIR");
if(status) {
status = chdir(_PATH_VARTMP);
}
if(status) {
status = chdir(_PATH_TMP);
}
if(status) {
exit(errno);
}
snprintf(name_mod, sizeof name_mod, "%s%s", name, "_mod");
status = execl(_PATH_MODLOAD, "modload", "-e", name_mod, "-o",
name_mod, "-u", "-q", path, (const char *)0);
exit(status ? errno : 0);
}