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mc/vfs/sfs.c

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C
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/*
* Single File fileSystem
*
* Copyright 1998 Pavel Machek, distribute under GPL
*
* This defines whole class of filesystems which contain single file
* inside. It is somehow similar to extfs, except that extfs makes
* whole virtual trees and we do only single virtual files.
*
* If you want to gunzip something, you should open it with #ugz
* suffix, DON'T try to gunzip it yourself.
*
* Namespace: exports vfs_sfs_ops, shell (FIXME) */
#include <config.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include "utilvfs.h"
#include "vfs.h"
#include "local.h"
/* This is needed, or libvfs.so will lack symbol shell. Should look up who requires it */
char *shell = "/bin/sh";
struct cachedfile {
char *name, *cache;
uid_t uid;
struct cachedfile *next;
};
static struct cachedfile *head;
#define MAXFS 32
static int sfs_no = 0;
static char *sfs_prefix[ MAXFS ];
static char *sfs_command[ MAXFS ];
static int sfs_flags[ MAXFS ];
#define F_1 1
#define F_2 2
#define F_NOLOCALCOPY 4
#define F_FULLMATCH 8
static int uptodate (char *name, char *cache)
{
return 1;
}
static int vfmake (vfs *me, char *name, char *cache)
{
char *inpath, *op;
int w;
char pad [10240];
char *s, *t = pad;
int was_percent = 0;
vfs_split (name, &inpath, &op);
if ((w = (*me->which) (me, op)) == -1)
vfs_die ("This cannot happen... Hopefully.\n");
if ((sfs_flags[w] & F_1) || (!strcmp (name, "/"))) ; else return -1;
/* if ((sfs_flags[w] & F_2) || (!inpath) || (!*inpath)); else return -1; */
if (!(sfs_flags[w] & F_NOLOCALCOPY))
name = mc_getlocalcopy (name);
else
name = g_strdup (name);
s = sfs_command[w];
#define COPY_CHAR if (t-pad>10200) return -1; else *t++ = *s;
#define COPY_STRING(a) if ((t-pad)+strlen(a)>10200) return -1; else { strcpy (t, a); t+= strlen(a); }
while (*s) {
if (was_percent) {
switch (*s) {
case '1': COPY_STRING (name); break;
case '2': COPY_STRING (op + strlen (sfs_prefix[w])); break;
case '3': COPY_STRING (cache); break;
case '%': COPY_CHAR; break;
}
was_percent = 0;
} else {
if (*s == '%')
was_percent = 1;
else
COPY_CHAR;
}
s++;
}
g_free (name);
if (my_system (EXECUTE_AS_SHELL | EXECUTE_SETUID | EXECUTE_WAIT, "/bin/sh", pad)) {
return -1;
}
return 0; /* OK */
}
static char *
redirect (vfs *me, char *name)
{
struct cachedfile *cur = head;
uid_t uid = vfs_uid;
char *cache, *xname;
int handle;
while (cur){
if ((!strcmp (name, cur->name)) &&
(uid == cur->uid) &&
(uptodate (cur->name, cur->cache)))
/* FIXME: when not uptodate, we might want to kill cache
* file immediately, not to wait until timeout. */ {
vfs_stamp (&vfs_sfs_ops, cur);
return cur->cache;
}
cur = cur->next;
}
cache = tempnam (NULL, "sfs");
handle = open (cache, O_RDWR | O_CREAT | O_EXCL, 0600);
if (handle == -1)
return "/SOMEONE_PLAYING_DIRTY_TMP_TRICKS_ON_US";
close (handle);
xname = g_strdup (name);
if (!vfmake (me, name, cache)){
cur = g_new (struct cachedfile, 1);
cur->name = xname;
cur->cache = cache;
cur->uid = uid;
cur->next = head;
head = cur;
vfs_add_noncurrent_stamps (&vfs_sfs_ops, (vfsid) head, NULL);
vfs_rm_parents (NULL);
return cache;
} else {
g_free(xname);
}
return "/I_MUST_NOT_EXIST";
}
static void *
sfs_open (vfs *me, char *path, int flags, int mode)
{
int *sfs_info;
int fd;
path = redirect (me, path);
fd = open (path, flags, mode);
if (fd == -1)
return 0;
sfs_info = g_new (int, 1);
*sfs_info = fd;
return sfs_info;
}
static int sfs_stat (vfs *me, char *path, struct stat *buf)
{
path = redirect (me, path);
return stat (path, buf);
}
static int sfs_lstat (vfs *me, char *path, struct stat *buf)
{
path = redirect (me, path);
#ifndef HAVE_STATLSTAT
return lstat (path,buf);
#else
return statlstat (path, buf);
#endif
}
static int sfs_chmod (vfs *me, char *path, int mode)
{
path = redirect (me, path);
return chmod (path, mode);
}
static int sfs_chown (vfs *me, char *path, int owner, int group)
{
path = redirect (me, path);
return chown (path, owner, group);
}
static int sfs_utime (vfs *me, char *path, struct utimbuf *times)
{
path = redirect (me, path);
return utime (path, times);
}
static int sfs_readlink (vfs *me, char *path, char *buf, int size)
{
path = redirect (me, path);
return readlink (path, buf, size);
}
static vfsid sfs_getid (vfs *me, char *path, struct vfs_stamping **parent)
{ /* FIXME: what should I do? */
vfs *v;
vfsid id;
struct vfs_stamping *par;
struct cachedfile *cur = head;
while (cur) {
if ((!strcmp( path, cur->name )) &&
(vfs_uid == cur->uid))
break;
cur = cur->next;
}
if (!cur)
vfs_die( "sfs_getid of noncached thingie?" );
*parent = NULL;
{
char *path2 = g_strdup (path);
v = vfs_split (path2, NULL, NULL);
id = (*v->getid) (v, path2, &par);
g_free (path2);
}
if (id != (vfsid)-1) {
*parent = g_new (struct vfs_stamping, 1);
(*parent)->v = v;
(*parent)->id = id;
(*parent)->parent = par;
(*parent)->next = NULL;
}
return (vfsid) cur;
}
static void sfs_free (vfsid id)
{
struct cachedfile *which = (struct cachedfile *) id;
struct cachedfile *cur, *prev;
for (cur = head, prev = 0; cur && cur != which; prev = cur, cur = cur->next)
;
if (!cur)
vfs_die( "Free of thing which is unknown to me\n" );
unlink (cur->cache);
if (prev)
prev->next = cur->next;
else
head = cur->next;
}
static void sfs_fill_names (vfs *me, void (*func)(char *))
{
struct cachedfile *cur = head;
while (cur){
(*func)(cur->name);
cur = cur->next;
}
}
static int sfs_nothingisopen (vfsid id)
{
/* FIXME: Investigate whether have to guard this like in
the other VFSs (see fd_usage in extfs) -- Norbert */
return 1;
}
static char *sfs_getlocalcopy (vfs *me, char *path)
{
path = redirect (me, path);
return g_strdup (path);
}
static void sfs_ungetlocalcopy (vfs *me, char *path, char *local, int has_changed)
{
}
static int sfs_init (vfs *me)
{
FILE *cfg = fopen (LIBDIR "extfs/sfs.ini", "r");
if (!cfg){
fprintf (stderr, "Warning: " LIBDIR "extfs/sfs.ini not found\n");
return 0;
}
sfs_no = 0;
while (sfs_no < MAXFS){
char key[256];
char *c, *semi = NULL, flags = 0;
int i;
if (!fgets (key, 250, cfg))
break;
if (*key == '#')
continue;
for (i = 0; i < strlen (key); i++)
if ((key[i]==':') || (key[i]=='/')){
semi = key+i;
if (key [i] == '/'){
key [i] = 0;
flags |= F_FULLMATCH;
}
break;
}
if (!semi){
fprintf (stderr, "Warning: Invalid line %s in sfs.ini.\n", key);
continue;
}
c = semi + 1;
while ((*c != ' ') && (*c != 9)) {
switch (*c) {
case '1': flags |= F_1; break;
case '2': flags |= F_2; break;
case 'R': flags |= F_NOLOCALCOPY; break;
default:
fprintf (stderr, "Warning: Invalid flag %c in sfs.ini line %s.\n", *c, key);
}
c++;
}
c++;
*(semi+1) = 0;
if ((semi = strchr (c, '\n')))
*semi = 0;
sfs_prefix [sfs_no] = g_strdup (key);
sfs_command [sfs_no] = g_strdup (c);
sfs_flags [sfs_no] = flags;
sfs_no++;
}
fclose (cfg);
return 1;
}
static void
sfs_done (vfs *me)
{
int i;
for (i = 0; i < sfs_no; i++){
g_free (sfs_prefix [i]);
g_free (sfs_command [i]);
sfs_prefix [i] = sfs_command [i] = NULL;
}
sfs_no = 0;
}
static int
sfs_which (vfs *me, char *path)
{
int i;
for (i = 0; i < sfs_no; i++)
if (sfs_flags [i] & F_FULLMATCH) {
if (!strcmp (path, sfs_prefix [i]))
return i;
} else
if (!strncmp (path, sfs_prefix [i], strlen (sfs_prefix [i])))
return i;
return -1;
}
vfs vfs_sfs_ops = {
NULL, /* This is place of next pointer */
"Signle file filesystems",
F_EXEC, /* flags */
NULL, /* prefix */
NULL, /* data */
0, /* errno */
sfs_init,
sfs_done,
sfs_fill_names,
sfs_which,
sfs_open,
local_close,
local_read,
NULL,
NULL,
NULL,
NULL,
NULL,
NULL,
sfs_stat,
sfs_lstat,
local_fstat,
sfs_chmod,
sfs_chown,
sfs_utime,
sfs_readlink,
NULL,
NULL,
NULL,
NULL,
NULL,
local_errno,
local_lseek,
NULL,
sfs_getid,
sfs_nothingisopen,
sfs_free,
sfs_getlocalcopy,
sfs_ungetlocalcopy,
NULL,
NULL,
NULL,
NULL
#ifdef HAVE_MMAP
,local_mmap,
local_munmap
#endif
};
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