source: mainline/uspace/lib/c/generic/vfs/vfs.c@ 007e6efa

/*
 * Copyright (c) 2008 Jakub Jermar 
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libc
 * @{
 */
/** @file
 */

#include <vfs/vfs.h>
#include <vfs/canonify.h>
#include <macros.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <ipc/ns.h>
#include <async.h>
#include <fibril_synch.h>
#include <errno.h>
#include <assert.h>
#include <str.h>
#include <devmap.h>
#include <ipc/vfs.h>
#include <ipc/devmap.h>

static async_sess_t vfs_session;

static FIBRIL_MUTEX_INITIALIZE(vfs_phone_mutex);
static int vfs_phone = -1;

static FIBRIL_MUTEX_INITIALIZE(cwd_mutex);

static int cwd_fd = -1;
static char *cwd_path = NULL;
static size_t cwd_size = 0;

char *absolutize(const char *path, size_t *retlen)
{
        char *ncwd_path;
        char *ncwd_path_nc;

        fibril_mutex_lock(&cwd_mutex);
        size_t size = str_size(path);
        if (*path != '/') {
                if (!cwd_path) {
                        fibril_mutex_unlock(&cwd_mutex);
                        return NULL;
                }
                ncwd_path_nc = malloc(cwd_size + 1 + size + 1);
                if (!ncwd_path_nc) {
                        fibril_mutex_unlock(&cwd_mutex);
                        return NULL;
                }
                str_cpy(ncwd_path_nc, cwd_size + 1 + size + 1, cwd_path);
                ncwd_path_nc[cwd_size] = '/';
                ncwd_path_nc[cwd_size + 1] = '\0';
        } else {
                ncwd_path_nc = malloc(size + 1);
                if (!ncwd_path_nc) {
                        fibril_mutex_unlock(&cwd_mutex);
                        return NULL;
                }
                ncwd_path_nc[0] = '\0';
        }
        str_append(ncwd_path_nc, cwd_size + 1 + size + 1, path);
        ncwd_path = canonify(ncwd_path_nc, retlen);
        if (!ncwd_path) {
                fibril_mutex_unlock(&cwd_mutex);
                free(ncwd_path_nc);
                return NULL;
        }
        /*
         * We need to clone ncwd_path because canonify() works in-place and thus
         * the address in ncwd_path need not be the same as ncwd_path_nc, even
         * though they both point into the same dynamically allocated buffer.
         */
        ncwd_path = str_dup(ncwd_path);
        free(ncwd_path_nc);
        if (!ncwd_path) {
                fibril_mutex_unlock(&cwd_mutex);
                return NULL;
        }
        fibril_mutex_unlock(&cwd_mutex);
        return ncwd_path;
}

/** Connect to VFS service and create session. */
static void vfs_connect(void)
{
        while (vfs_phone < 0)
                vfs_phone = service_connect_blocking(SERVICE_VFS, 0, 0);
        
        async_session_create(&vfs_session, vfs_phone, 0);
}

/** Start an async exchange on the VFS session.
 *
 * @return              New phone to be used during the exchange.
 */
static int vfs_exchange_begin(void)
{
        fibril_mutex_lock(&vfs_phone_mutex);
        if (vfs_phone < 0)
                vfs_connect();
        fibril_mutex_unlock(&vfs_phone_mutex);

        return async_exchange_begin(&vfs_session);
}

/** End an async exchange on the VFS session.
 *
 * @param phone         Phone used during the exchange.
 */
static void vfs_exchange_end(int phone)
{
        async_exchange_end(&vfs_session, phone);
}

int mount(const char *fs_name, const char *mp, const char *fqdn,
    const char *opts, unsigned int flags)
{
        int null_id = -1;
        char null[DEVMAP_NAME_MAXLEN];
        
        if (str_cmp(fqdn, "") == 0) {
                /* No device specified, create a fresh
                   null/%d device instead */
                null_id = devmap_null_create();
                
                if (null_id == -1)
                        return ENOMEM;
                
                snprintf(null, DEVMAP_NAME_MAXLEN, "null/%d", null_id);
                fqdn = null;
        }
        
        devmap_handle_t devmap_handle;
        int res = devmap_device_get_handle(fqdn, &devmap_handle, flags);
        if (res != EOK) {
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                return res;
        }
        
        size_t mpa_size;
        char *mpa = absolutize(mp, &mpa_size);
        if (!mpa) {
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                return ENOMEM;
        }
        
        int vfs_phone = vfs_exchange_begin();

        sysarg_t rc_orig;
        aid_t req = async_send_2(vfs_phone, VFS_IN_MOUNT, devmap_handle, flags, NULL);
        sysarg_t rc = async_data_write_start(vfs_phone, (void *) mpa, mpa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(mpa);
                async_wait_for(req, &rc_orig);
                
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        
        rc = async_data_write_start(vfs_phone, (void *) opts, str_size(opts));
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(mpa);
                async_wait_for(req, &rc_orig);
                
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        
        rc = async_data_write_start(vfs_phone, (void *) fs_name, str_size(fs_name));
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(mpa);
                async_wait_for(req, &rc_orig);
                
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        
        /* Ask VFS whether it likes fs_name. */
        rc = async_req_0_0(vfs_phone, IPC_M_PING);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(mpa);
                async_wait_for(req, &rc_orig);
                
                if (null_id != -1)
                        devmap_null_destroy(null_id);
                
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        
        vfs_exchange_end(vfs_phone);
        free(mpa);
        async_wait_for(req, &rc);
        
        if ((rc != EOK) && (null_id != -1))
                devmap_null_destroy(null_id);
        
        return (int) rc;
}

int unmount(const char *mp)
{
        sysarg_t rc;
        sysarg_t rc_orig;
        aid_t req;
        size_t mpa_size;
        char *mpa;
        
        mpa = absolutize(mp, &mpa_size);
        if (!mpa)
                return ENOMEM;
        
        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_0(vfs_phone, VFS_IN_UNMOUNT, NULL);
        rc = async_data_write_start(vfs_phone, (void *) mpa, mpa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(mpa);
                async_wait_for(req, &rc_orig);
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        

        vfs_exchange_end(vfs_phone);
        free(mpa);
        async_wait_for(req, &rc);
        
        return (int) rc;
}

static int open_internal(const char *abs, size_t abs_size, int lflag, int oflag)
{
        int vfs_phone = vfs_exchange_begin();
        
        ipc_call_t answer;
        aid_t req = async_send_3(vfs_phone, VFS_IN_OPEN, lflag, oflag, 0, &answer);
        sysarg_t rc = async_data_write_start(vfs_phone, abs, abs_size);
        
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);
                
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        
        vfs_exchange_end(vfs_phone);
        async_wait_for(req, &rc);
        
        if (rc != EOK)
            return (int) rc;
        
        return (int) IPC_GET_ARG1(answer);
}

int open(const char *path, int oflag, ...)
{
        size_t abs_size;
        char *abs = absolutize(path, &abs_size);
        if (!abs)
                return ENOMEM;
        
        int ret = open_internal(abs, abs_size, L_FILE, oflag);
        free(abs);
        
        return ret;
}

int open_node(fdi_node_t *node, int oflag)
{
        int vfs_phone = vfs_exchange_begin();
        
        ipc_call_t answer;
        aid_t req = async_send_4(vfs_phone, VFS_IN_OPEN_NODE, node->fs_handle,
            node->devmap_handle, node->index, oflag, &answer);
        
        vfs_exchange_end(vfs_phone);

        sysarg_t rc;
        async_wait_for(req, &rc);
        
        if (rc != EOK)
                return (int) rc;
        
        return (int) IPC_GET_ARG1(answer);
}

int close(int fildes)
{
        sysarg_t rc;
        
        int vfs_phone = vfs_exchange_begin();
        
        rc = async_req_1_0(vfs_phone, VFS_IN_CLOSE, fildes);
        
        vfs_exchange_end(vfs_phone);
        
        return (int)rc;
}

ssize_t read(int fildes, void *buf, size_t nbyte) 
{
        sysarg_t rc;
        ipc_call_t answer;
        aid_t req;

        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_1(vfs_phone, VFS_IN_READ, fildes, &answer);
        rc = async_data_read_start(vfs_phone, (void *)buf, nbyte);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);

                if (rc_orig == EOK)
                        return (ssize_t) rc;
                else
                        return (ssize_t) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        async_wait_for(req, &rc);
        if (rc == EOK)
                return (ssize_t) IPC_GET_ARG1(answer);
        else
                return rc;
}

ssize_t write(int fildes, const void *buf, size_t nbyte) 
{
        sysarg_t rc;
        ipc_call_t answer;
        aid_t req;

        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_1(vfs_phone, VFS_IN_WRITE, fildes, &answer);
        rc = async_data_write_start(vfs_phone, (void *)buf, nbyte);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);

                if (rc_orig == EOK)
                        return (ssize_t) rc;
                else
                        return (ssize_t) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        async_wait_for(req, &rc);
        if (rc == EOK)
                return (ssize_t) IPC_GET_ARG1(answer);
        else
                return -1;
}

int fsync(int fildes)
{
        int vfs_phone = vfs_exchange_begin();
        
        sysarg_t rc = async_req_1_0(vfs_phone, VFS_IN_SYNC, fildes);
        
        vfs_exchange_end(vfs_phone);
        
        return (int) rc;
}

off64_t lseek(int fildes, off64_t offset, int whence)
{
        int vfs_phone = vfs_exchange_begin();
        
        sysarg_t newoff_lo;
        sysarg_t newoff_hi;
        sysarg_t rc = async_req_4_2(vfs_phone, VFS_IN_SEEK, fildes,
            LOWER32(offset), UPPER32(offset), whence,
            &newoff_lo, &newoff_hi);
        
        vfs_exchange_end(vfs_phone);
        
        if (rc != EOK)
                return (off64_t) -1;
        
        return (off64_t) MERGE_LOUP32(newoff_lo, newoff_hi);
}

int ftruncate(int fildes, aoff64_t length)
{
        sysarg_t rc;
        
        int vfs_phone = vfs_exchange_begin();
        
        rc = async_req_3_0(vfs_phone, VFS_IN_TRUNCATE, fildes,
            LOWER32(length), UPPER32(length));
        vfs_exchange_end(vfs_phone);
        
        return (int) rc;
}

int fstat(int fildes, struct stat *stat)
{
        sysarg_t rc;
        aid_t req;

        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_1(vfs_phone, VFS_IN_FSTAT, fildes, NULL);
        rc = async_data_read_start(vfs_phone, (void *) stat, sizeof(struct stat));
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);

                if (rc_orig == EOK)
                        return (ssize_t) rc;
                else
                        return (ssize_t) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        async_wait_for(req, &rc);

        return rc;
}

int stat(const char *path, struct stat *stat)
{
        sysarg_t rc;
        sysarg_t rc_orig;
        aid_t req;
        
        size_t pa_size;
        char *pa = absolutize(path, &pa_size);
        if (!pa)
                return ENOMEM;
        
        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_0(vfs_phone, VFS_IN_STAT, NULL);
        rc = async_data_write_start(vfs_phone, pa, pa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(pa);
                async_wait_for(req, &rc_orig);
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        rc = async_data_read_start(vfs_phone, stat, sizeof(struct stat));
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(pa);
                async_wait_for(req, &rc_orig);
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        free(pa);
        async_wait_for(req, &rc);
        return rc;
}

DIR *opendir(const char *dirname)
{
        DIR *dirp = malloc(sizeof(DIR));
        if (!dirp)
                return NULL;
        
        size_t abs_size;
        char *abs = absolutize(dirname, &abs_size);
        if (!abs) {
                free(dirp);
                return NULL;
        }
        
        int ret = open_internal(abs, abs_size, L_DIRECTORY, 0);
        free(abs);
        
        if (ret < 0) {
                free(dirp);
                return NULL;
        }
        
        dirp->fd = ret;
        return dirp;
}

struct dirent *readdir(DIR *dirp)
{
        ssize_t len = read(dirp->fd, &dirp->res.d_name[0], NAME_MAX + 1);
        if (len <= 0)
                return NULL;
        return &dirp->res;
}

void rewinddir(DIR *dirp)
{
        (void) lseek(dirp->fd, 0, SEEK_SET);
}

int closedir(DIR *dirp)
{
        (void) close(dirp->fd);
        free(dirp);
        return 0;
}

int mkdir(const char *path, mode_t mode)
{
        sysarg_t rc;
        aid_t req;
        
        size_t pa_size;
        char *pa = absolutize(path, &pa_size);
        if (!pa)
                return ENOMEM;
        
        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_1(vfs_phone, VFS_IN_MKDIR, mode, NULL);
        rc = async_data_write_start(vfs_phone, pa, pa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(pa);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);

                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        free(pa);
        async_wait_for(req, &rc);
        return rc;
}

static int _unlink(const char *path, int lflag)
{
        sysarg_t rc;
        aid_t req;
        
        size_t pa_size;
        char *pa = absolutize(path, &pa_size);
        if (!pa)
                return ENOMEM;

        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_0(vfs_phone, VFS_IN_UNLINK, NULL);
        rc = async_data_write_start(vfs_phone, pa, pa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(pa);

                sysarg_t rc_orig;
                async_wait_for(req, &rc_orig);

                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        free(pa);
        async_wait_for(req, &rc);
        return rc;
}

int unlink(const char *path)
{
        return _unlink(path, L_NONE);
}

int rmdir(const char *path)
{
        return _unlink(path, L_DIRECTORY);
}

int rename(const char *old, const char *new)
{
        sysarg_t rc;
        sysarg_t rc_orig;
        aid_t req;
        
        size_t olda_size;
        char *olda = absolutize(old, &olda_size);
        if (!olda)
                return ENOMEM;

        size_t newa_size;
        char *newa = absolutize(new, &newa_size);
        if (!newa) {
                free(olda);
                return ENOMEM;
        }

        int vfs_phone = vfs_exchange_begin();
        
        req = async_send_0(vfs_phone, VFS_IN_RENAME, NULL);
        rc = async_data_write_start(vfs_phone, olda, olda_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(olda);
                free(newa);
                async_wait_for(req, &rc_orig);
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        rc = async_data_write_start(vfs_phone, newa, newa_size);
        if (rc != EOK) {
                vfs_exchange_end(vfs_phone);
                free(olda);
                free(newa);
                async_wait_for(req, &rc_orig);
                if (rc_orig == EOK)
                        return (int) rc;
                else
                        return (int) rc_orig;
        }
        vfs_exchange_end(vfs_phone);
        free(olda);
        free(newa);
        async_wait_for(req, &rc);
        return rc;
}

int chdir(const char *path)
{
        size_t abs_size;
        char *abs = absolutize(path, &abs_size);
        if (!abs)
                return ENOMEM;
        
        int fd = open_internal(abs, abs_size, L_DIRECTORY, O_DESC);
        
        if (fd < 0) {
                free(abs);
                return ENOENT;
        }
        
        fibril_mutex_lock(&cwd_mutex);
        
        if (cwd_fd >= 0)
                close(cwd_fd);
        
        
        if (cwd_path)
                free(cwd_path);
        
        cwd_fd = fd;
        cwd_path = abs;
        cwd_size = abs_size;
        
        fibril_mutex_unlock(&cwd_mutex);
        return EOK;
}

char *getcwd(char *buf, size_t size)
{
        if (size == 0)
                return NULL;
        
        fibril_mutex_lock(&cwd_mutex);
        
        if ((cwd_size == 0) || (size < cwd_size + 1)) {
                fibril_mutex_unlock(&cwd_mutex);
                return NULL;
        }
        
        str_cpy(buf, size, cwd_path);
        fibril_mutex_unlock(&cwd_mutex);
        
        return buf;
}

int fd_phone(int fildes)
{
        struct stat stat;
        int rc;

        rc = fstat(fildes, &stat);

        if (!stat.device)
                return -1;
        
        return devmap_device_connect(stat.device, 0);
}

int fd_node(int fildes, fdi_node_t *node)
{
        struct stat stat;
        int rc;

        rc = fstat(fildes, &stat);
        
        if (rc == EOK) {
                node->fs_handle = stat.fs_handle;
                node->devmap_handle = stat.devmap_handle;
                node->index = stat.index;
        }
        
        return rc;
}

int dup2(int oldfd, int newfd)
{
        int vfs_phone = vfs_exchange_begin();
        
        sysarg_t ret;
        sysarg_t rc = async_req_2_1(vfs_phone, VFS_IN_DUP, oldfd, newfd, &ret);
        
        vfs_exchange_end(vfs_phone);
        
        if (rc == EOK)
                return (int) ret;
        
        return (int) rc;
}

/** @}
 */