fuse.c

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/*
  plpfuse: Expose EPOC's file system via FUSE
  Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
  Copyright (C) 2007-2024 Reuben Thomas <rrt@sc3d.org>
  Copyright (C) 2026 Syed Shahrukh Hussain <syed.shahrukh@ossrevival.org>
 
  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/
 
#include "config.h"
 
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <syslog.h>
#ifdef HAVE_ATTR_XATTR_H
#include <attr/xattr.h>
#elif defined(HAVE_SYS_XATTR_H)
#include <sys/xattr.h>
#endif
 
#ifndef ENOATTR
#define ENOATTR ENODATA
#endif
#ifdef HAVE_ATTR_ATTRIBUTES_H
#include <attr/attributes.h>
#endif
 
#include "plpfuse.h"
#include "rfsv_api.h"
 
/* Name of our extended attribute */
#define XATTR_NAME "user.epoc"
 
/* Maximum length of a generated psion xattr string */
#define XATTR_MAXLEN 3
 
#ifndef ENOMEDIUM
#define ENOMEDIUM ENODEV
#endif
 
int debug;
 
void
debuglog(const char *fmt, ...)
{
    va_list ap;
    char *buf;
 
    if (!debug)
        return;
    va_start(ap, fmt);
    if (vasprintf(&buf, fmt, ap) == -1)
        syslog(LOG_DEBUG, "vasprintf error in debuglog");
    else {
        syslog(LOG_DEBUG, "%s", buf);
        free(buf);
    }
    va_end(ap);
}
 
static void
xattr2pattr(long *psisattr, long *psidattr, const char *oxattr, const char *nxattr)
{
    if ((strchr(oxattr, 'a') == NULL) != (strchr(nxattr, 'a') == NULL)) { /* a = archive */
        if (strchr(nxattr, 'a'))
            *psisattr |= PSI_A_ARCHIVE;
        else
            *psidattr |= PSI_A_ARCHIVE;
    }
    if ((strchr(oxattr, 'h') == NULL) != (strchr(nxattr, 'h') == NULL)) { /* h = hidden */
        if (strchr(nxattr, 'h'))
            *psisattr |= PSI_A_HIDDEN;
        else
            *psidattr |= PSI_A_HIDDEN;
    }
    if ((strchr(oxattr, 's') == NULL) != (strchr(nxattr, 's') == NULL)) { /* s = system */
        if (strchr(nxattr, 's'))
            *psisattr |= PSI_A_SYSTEM;
        else
            *psidattr |= PSI_A_SYSTEM;
    }
}
 
static void
attr2pattr(long oattr, long nattr, char *oxattr, char *nxattr, long *psisattr, long *psidattr)
{
    *psisattr = *psidattr = 0;
    if ((oattr & 0400) != (nattr & 0400)) {
        if (nattr & 0400) /* readable */
            *psisattr |= PSI_A_READ;
        else
            *psidattr |= PSI_A_READ;
    }
    if ((oattr & 0200) != (nattr & 0200)) {
        if (nattr & 0200) /* Not writable   -> readonly */
            *psidattr |= PSI_A_RDONLY;
        else
            *psisattr |= PSI_A_RDONLY;
    }
    xattr2pattr(psisattr, psidattr, oxattr, nxattr);
}
 
static void
pattr2xattr(long psiattr, char *xattr)
{
    *xattr = '\0';
 
    if (psiattr & PSI_A_HIDDEN)
        strcat(xattr, "h");
    if (psiattr & PSI_A_SYSTEM)
        strcat(xattr, "s");
    if (psiattr & PSI_A_ARCHIVE)
        strcat(xattr, "a");
}
 
static void
pattr2attr(long psiattr, long size, long ftime, struct stat *st, char *xattr)
{
    struct fuse_context *ct = fuse_get_context();
 
    memset(st, 0, sizeof(*st));
    st->st_uid = ct->uid;
    st->st_gid = ct->gid;
 
    if (psiattr & PSI_A_DIR) {
        st->st_mode = 0700 | S_IFDIR;
        st->st_blocks = 1;
        st->st_size = BLOCKSIZE;
        st->st_nlink = 2; /* Call getlinks for more accurate count */
    } else {
        st->st_blocks = (size + BLOCKSIZE - 1) / BLOCKSIZE;
        st->st_size = size;
        st->st_nlink = 1;
        st->st_mode = S_IFREG;
 
        if (psiattr & PSI_A_READ)
            st->st_mode |= 0400;        /* File readable */
        if (!(psiattr & PSI_A_RDONLY))
            st->st_mode |= 0200;        /* File writeable  */
    }
    st->st_mtime = st->st_ctime = st->st_atime = ftime;
    pattr2xattr(psiattr, xattr);
}
 
static device *devices;
 
static int
query_devices(void)
{
    device *dp, *np;
    int link_count = 2;        /* set the root link count */
 
    for (dp = devices; dp; dp = np) {
        np = dp->next;
        free(dp->name);
        free(dp);
    }
    devices = NULL;
    if (rfsv_drivelist(&link_count, &devices))
        return 1;
    return 0;
}
 
static char *
dirname(const char *dir)
{
    static char *namebuf = NULL;
    if (namebuf)
        free(namebuf);
    if (asprintf(&namebuf, "%s\\", dir) == -1)
        return NULL;
    return namebuf;
}
 
static const char *
filname(const char *dir)
{
    char *p;
    if ((p = (char *) rindex(dir, '\\')))
        return p + 1;
    else
        return dir;
}
 
static int
dircount(const char *path, long *count)
{
  dentry *e = NULL;
    long ret = 0;
 
    *count = 0;
    debuglog("dircount: %s", path);
    debuglog("RFSV dir %s", path);
    if ((ret = rfsv_dir(dirname(path), &e)) != 0)
        return ret;
    while (e) {
        struct stat st;
        dentry *o = e;
        char xattr[XATTR_MAXLEN + 1];
        pattr2attr(e->attr, e->size, e->time, &st, xattr);
        free(e->name);
        e = e->next;
        free(o);
        if (st.st_nlink > 1)
            (*count)++;
    }
 
    debuglog("count %d", *count);
    return ret;
}
 
static int getlinks(const char *path, struct stat *st)
{
    long dcount;
    int ret = dircount(path, &dcount);
    if (ret == 0)
        st->st_nlink = dcount + 2;
    return ret;
}
#if FUSE_USE_VERSION >= 30
static int plp_getattr(const char *path, struct stat *st, struct fuse_file_info *fi)
#else
static int plp_getattr(const char *path, struct stat *st)
#endif
{
    char xattr[XATTR_MAXLEN + 1];
    int ret = 0;
#if FUSE_USE_VERSION >= 30
    (void)fi;
#endif
    debuglog("plp_getattr `%s'", ++path);
 
    if (strcmp(path, "") == 0) {
        pattr2attr(PSI_A_DIR, 0, 0, st, xattr);
        if (!query_devices()) {
            device *dp;
 
            for (dp = devices; dp; dp = dp->next)
                st->st_nlink++;
            debuglog("root has %d links", st->st_nlink);
        } else
            return rfsv_isalive() ? -ENOENT : -ENOMEDIUM;
    } else {
        long pattr, psize, ptime;
 
        if (strlen(path) == 2 && path[1] == ':') {
            debuglog("getattr: device");
            if (!query_devices()) {
                device *dp;
 
                for (dp = devices; dp; dp = dp->next) {
                    debuglog("cmp '%c', '%c'", dp->letter, path[0]);
                    if (dp->letter == path[0])
                        break;
                }
                debuglog("device: %s", dp ? "exists" : "does not exist");
                pattr2attr(PSI_A_DIR, 0, 0, st, xattr);
                return getlinks(path, st);
            } else
                return rfsv_isalive() ? -ENOENT : -ENOMEDIUM;
        }
 
    debuglog("getattr: fileordir");
    if ((ret = rfsv_getattr(path, &pattr, &psize, &ptime)) == 0) {
        pattr2attr(pattr, psize, ptime, st, xattr);
        debuglog(" attrs Psion: %x %d %d, UNIX modes: %o, xattrs: %s", pattr, psize, ptime, st->st_mode, xattr);
        if (st->st_nlink > 1)
            ret = getlinks(path, st);
        }
    }
 
    debuglog("getattr: returned %d", ret);
    return ret;
}
 
static int plp_access(const char *path, int mask)
{
    (void)mask;
    debuglog("plp_access `%s'", ++path);
    return 0;
}
 
static int plp_readlink(const char *path, char *buf, size_t size)
{
    (void)buf;
    (void)size;
    debuglog("plp_readlink `%s'", ++path);
    return -EINVAL;
}
 
#if FUSE_USE_VERSION >= 30
static int plp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                       off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags)
#else
static int plp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                       off_t offset, struct fuse_file_info *fi)
#endif
{
    device *dp;
    dentry *e = NULL;
    char xattr[XATTR_MAXLEN + 1];
#if FUSE_USE_VERSION >= 30
    enum fuse_fill_dir_flags fill_flags = FUSE_FILL_DIR_DEFAULTS;
 
    if (flags & FUSE_READDIR_PLUS) {
        fill_flags |= FUSE_FILL_DIR_PLUS;
    }
#endif
    debuglog("plp_readdir `%s'", ++path);
 
    (void)offset;
    (void)fi;
 
    if (strcmp(path, "") == 0) {
        debuglog("readdir root");
        if (query_devices() == 0) {
            for (dp = devices; dp; dp = dp->next) {
              struct stat st;
              unsigned char name[3];
 
              name[0] = dp->letter;
              name[1] = ':';
              name[2] = '\0';
              pattr2attr(dp->attrib, 1, 0, &st, xattr);
#if FUSE_USE_VERSION >= 30
              if (filler(buf, (char *)name, &st, 0, fill_flags))
#else
              if (filler(buf, (char *)name, &st, 0))
#endif
                  break;
            }
        }
    } else {
        int ret;
        debuglog("RFSV dir `%s'", dirname(path));
        if ((ret = rfsv_dir(dirname(path), &e)) != 0)
            return ret;
 
        debuglog("scanning contents");
        while (e) {
            dentry *o;
            struct stat st;
            const char *name = filname(e->name);
 
            pattr2attr(e->attr, e->size, e->time, &st, xattr);
            debuglog("  %s %o %d %d", name, st.st_mode, st.st_size, st.st_mtime);
#if FUSE_USE_VERSION >= 30
            if (filler(buf, name, &st, 0, fill_flags))
#else
            if (filler(buf, name, &st, 0))
#endif
                break;
            free(e->name);
            o = e;
            e = e->next;
            free(o);
        }
    }
 
    debuglog("readdir OK");
    return 0;
}
 
static int plp_mknod(const char *path, mode_t mode, dev_t dev)
{
    int ret = -EINVAL;
 
    debuglog("plp_mknod `%s' %o", ++path, mode);
 
    if (S_ISREG(mode) && dev == 0) {
        uint32_t phandle;
        if ((ret = rfsv_fcreate(0x200, path, &phandle)) == 0)
            rfsv_fclose(phandle);
    }
 
    return ret;
}
 
static int plp_mkdir(const char *path, mode_t mode)
{
    debuglog("plp_mkdir `%s' %o", ++path, mode);
    return rfsv_mkdir(path);
}
 
static int plp_unlink(const char *path)
{
    debuglog("plp_unlink `%s'", ++path);
    return rfsv_remove(path);
}
 
static int plp_rmdir(const char *path)
{
    debuglog("plp_rmdir `%s'", ++path);
    return rfsv_rmdir(path);
}
 
static int plp_symlink(const char *from, const char *to)
{
    debuglog("plp_symlink `%s' -> `'%s'", ++from, ++to);
    return -EPERM;
}
 
#if FUSE_USE_VERSION >= 30
static int plp_rename(const char *from, const char *to, unsigned int flag)
#else
static int plp_rename(const char *from, const char *to)
#endif
{
#if FUSE_USE_VERSION >= 30
    (void)flag;
#endif
    debuglog("plp_rename `%s' -> `%s'", ++from, ++to);
    rfsv_remove(to);
    return rfsv_rename(from, to);
}
 
static int plp_link(const char *from, const char *to)
{
    debuglog("plp_link `%s' -> `%s'", ++from, ++to);
    return -EPERM;
}
 
#if FUSE_USE_VERSION >= 30
static int plp_chmod(const char *path, mode_t mode,  struct fuse_file_info *fi)
#else
static int plp_chmod(const char *path, mode_t mode)
#endif
{
    int ret;
    long psisattr, psidattr, pattr, psize, ptime;
    struct stat st;
    char xattr[XATTR_MAXLEN + 1];
 
#if FUSE_USE_VERSION >= 30
    (void)fi;
#endif
    debuglog("plp_chmod `%s'", ++path);
 
    if ((ret = rfsv_getattr(path, &pattr, &psize, &ptime)) == 0) {
        pattr2attr(pattr, psize, ptime, &st, xattr);
        attr2pattr(st.st_mode, mode, "", "", &psisattr, &psidattr);
        debuglog("  UNIX old, new: %o, %o; Psion set, clear: %x, %x", st.st_mode, mode, psisattr, psidattr);
        if ((ret = rfsv_setattr(path, psisattr, psidattr)) == 0)
            debuglog("chmod succeeded");
    }
 
    return ret;
}
 
static int plp_getxattr(const char *path, const char *name, char *value, size_t size
#ifdef __APPLE__
                        , _GL_UNUSED uint32_t position
#endif
                        )
{
    debuglog("plp_getxattr `%s' %s", ++path, name);
    if (strcmp(name, XATTR_NAME) == 0) {
        if (size >= XATTR_MAXLEN) {
            long pattr, psize, ptime;
            int ret;
            if ((ret = rfsv_getattr(path, &pattr, &psize, &ptime)) == 0) {
                pattr2xattr(pattr, value);
                debuglog("getxattr succeeded: %s", value);
                return strlen(value);
            } else
                return ret;
        } else {
            debuglog("only gave %d bytes, need %d", size, XATTR_MAXLEN);
            return XATTR_MAXLEN;
        }
    }
    return 0;
}
 
static int plp_setxattr(const char *path, const char *name, const char *value, size_t size, int flags
#ifdef __APPLE__
                        , _GL_UNUSED uint32_t position
#endif
                        )
{
    debuglog("plp_setxattr `%s'", ++path);
    if (strcmp(name, XATTR_NAME) == 0) {
        int ret;
        long psisattr, psidattr;
        char oxattr[XATTR_MAXLEN + 1], nxattr[XATTR_MAXLEN + 1];
 
#ifdef XATTR_CREATE
        if (flags & XATTR_CREATE)
            return -EEXIST;
#endif
 
        strncpy(nxattr, value, size < XATTR_MAXLEN ? size : XATTR_MAXLEN);
        nxattr[XATTR_MAXLEN] = '\0';
        /* Need to undo earlier increment of path when calling plp_getxattr */
        plp_getxattr(path - 1, name, oxattr, XATTR_MAXLEN
#ifdef __APPLE__
                    , 0
#endif
                    );
        psisattr = psidattr = 0;
        xattr2pattr(&psisattr, &psidattr, oxattr, value);
        debuglog("attrs set %x delete %x; %s, %s", psisattr, psidattr, oxattr, value);
        if ((ret = rfsv_setattr(path, psisattr, psidattr)) != 0)
            return ret;
 
        debuglog("setxattr succeeded");
        return 0;
    } else {
#ifdef XATTR_REPLACE
        if (flags & XATTR_REPLACE)
            return -ENOATTR;
        else
#endif
            return -ENOTSUP;
    }
}
 
static int plp_listxattr(const char *path, char *list, size_t size)
{
    debuglog("plp_listxattr `%s'", ++path);
    if (size > sizeof(XATTR_NAME))
        strcpy(list, XATTR_NAME);
    return sizeof(XATTR_NAME);
}
 
static int plp_removexattr(const char *path, const char *name)
{
    debuglog("plp_removexattr `%s'", ++path);
    (void)name;
    return -ENOTSUP;
}
 
#if FUSE_USE_VERSION >= 30
static int plp_chown(const char *path, uid_t uid, gid_t gid, struct fuse_file_info *fi)
#else
static int plp_chown(const char *path, uid_t uid, gid_t gid)
#endif
{
    (void)uid;
    (void)gid;
#if FUSE_USE_VERSION >= 30
    (void)fi;
#endif
    debuglog("plp_chown `%s'", ++path);
    return -EPERM;
}
 
#if FUSE_USE_VERSION >= 30
static int plp_truncate(const char *path, off_t size, struct fuse_file_info *fi)
#else
static int plp_truncate(const char *path, off_t size)
#endif
{
#if FUSE_USE_VERSION >= 30
    (void)fi;
#endif
    debuglog("plp_truncate `%s'", ++path);
    return rfsv_setsize(path, size);
}
 
#if FUSE_USE_VERSION >= 30
static int plp_utimens(const char *path, const struct timespec ts[2], struct fuse_file_info *fi)
#else
static int plp_utimens(const char *path, const struct timespec ts[2])
#endif
{
#if FUSE_USE_VERSION >= 30
    (void)fi;
#endif
    debuglog("plp_utimens `%s'", ++path);
    return rfsv_setmtime(path, ts[1].tv_sec);
}
 
static int plp_open(const char *path, struct fuse_file_info *fi)
{
    debuglog("plp_open `%s'", ++path);
    (void)fi;
    return 0;
}
 
static int plp_read(const char *path, char *buf, size_t size, off_t offset,
                    struct fuse_file_info *fi)
{
    long read;
 
    (void)fi;
    debuglog("plp_read `%s' offset %lld size %ld", ++path, offset, size);
    read = rfsv_read(buf, (long)offset, size, path);
    debuglog("read returned %ld", read);
    return read;
}
 
static int plp_write(const char *path, const char *buf, size_t size,
                     off_t offset, struct fuse_file_info *fi)
{
    long written;
 
    (void)fi;
    debuglog("plp_write `%s' offset %lld size %ld", ++path, offset, size);
    written = rfsv_write(buf, offset, size, path);
    debuglog("write returned %ld", written);
    return written;
}
 
static int plp_statfs(const char *path, struct statvfs *stbuf)
{
    device *dp;
 
    (void)path;
    debuglog("plp_statfs");
 
    stbuf->f_bsize = BLOCKSIZE;
    stbuf->f_frsize = BLOCKSIZE;
    if (query_devices() == 0) {
        for (dp = devices; dp; dp = dp->next) {
            stbuf->f_blocks += (dp->total + BLOCKSIZE - 1) / BLOCKSIZE;
            stbuf->f_bfree += (dp->free + BLOCKSIZE - 1) / BLOCKSIZE;
        }
    }
    stbuf->f_bavail = stbuf->f_bfree;
 
    /* Don't have numbers for these */
    stbuf->f_files = 0;
    stbuf->f_ffree = stbuf->f_favail = 0;
 
    stbuf->f_fsid = FID;
    stbuf->f_flag = 0;    /* don't have mount flags */
    stbuf->f_namemax = 255; /* KDMaxFileNameLen% */
 
    return 0;
}
 
struct fuse_operations plp_oper = {
    .getattr     = plp_getattr,
    .access      = plp_access,
    .readlink    = plp_readlink,
    .readdir     = plp_readdir,
    .mknod       = plp_mknod,
    .mkdir       = plp_mkdir,
    .symlink     = plp_symlink,
    .unlink      = plp_unlink,
    .rmdir       = plp_rmdir,
    .rename      = plp_rename,
    .link        = plp_link,
    .chmod       = plp_chmod,
    .setxattr    = plp_setxattr,
    .getxattr    = plp_getxattr,
    .listxattr   = plp_listxattr,
    .removexattr = plp_removexattr,
    .chown       = plp_chown,
    .truncate    = plp_truncate,
    .utimens     = plp_utimens,
    .open        = plp_open,
    .read        = plp_read,
    .write       = plp_write,
    .statfs      = plp_statfs,
};