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libisofs/src/fs_local.c

518 lines
11 KiB

/*
* Copyright (c) 2007 Vreixo Formoso
*
* This file is part of the libisofs project; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. See COPYING file for details.
*/
/*
* Filesystem/FileSource implementation to access the local filesystem.
*/
#include "fsource.h"
#include "error.h"
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <libgen.h>
#include <string.h>
#define ISO_LOCAL_FS_ID 1
/*
* We can share a local filesystem object, as it has no private atts.
*/
IsoFilesystem *lfs = NULL;
typedef struct
{
/* IsoFilesystem *fs; It seems not needed */
char *path;
unsigned int openned:2; /* 0: not openned, 1: file, 2:dir */
union {
int fd;
DIR *dir;
} info;
} _LocalFsFileSource;
static
const char* lfs_get_path(IsoFileSource *src)
{
_LocalFsFileSource *data;
data = src->data;
return data->path;
}
static
char* lfs_get_name(IsoFileSource *src)
{
char *name, *p;
_LocalFsFileSource *data;
data = src->data;
p = strdup(data->path); /* because basename() might modify its arg */
name = strdup(basename(p));
free(p);
return name;
}
static
int lfs_lstat(IsoFileSource *src, struct stat *info)
{
_LocalFsFileSource *data;
if (src == NULL || info == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
if (lstat(data->path, info) != 0) {
int err;
/* error, choose an appropriate return code */
switch(errno) {
case EACCES:
err = ISO_FILE_ACCESS_DENIED;
break;
case ENOTDIR:
case ENAMETOOLONG:
case ELOOP:
err = ISO_FILE_BAD_PATH;
break;
case ENOENT:
err = ISO_FILE_DOESNT_EXIST;
break;
case EFAULT:
case ENOMEM:
err = ISO_MEM_ERROR;
break;
default:
err = ISO_FILE_ERROR;
break;
}
return err;
}
return ISO_SUCCESS;
}
static
int lfs_stat(IsoFileSource *src, struct stat *info)
{
_LocalFsFileSource *data;
if (src == NULL || info == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
if (stat(data->path, info) != 0) {
int err;
/* error, choose an appropriate return code */
switch(errno) {
case EACCES:
err = ISO_FILE_ACCESS_DENIED;
break;
case ENOTDIR:
case ENAMETOOLONG:
case ELOOP:
err = ISO_FILE_BAD_PATH;
break;
case ENOENT:
err = ISO_FILE_DOESNT_EXIST;
break;
case EFAULT:
case ENOMEM:
err = ISO_MEM_ERROR;
break;
default:
err = ISO_FILE_ERROR;
break;
}
return err;
}
return ISO_SUCCESS;
}
static
int lfs_open(IsoFileSource *src)
{
int err;
struct stat info;
_LocalFsFileSource *data;
if (src == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
if (data->openned) {
return ISO_FILE_ALREADY_OPENNED;
}
/* is a file or a dir ? */
err = lfs_stat(src, &info);
if (err < 0) {
return err;
}
if (S_ISDIR(info.st_mode)) {
data->info.dir = opendir(data->path);
data->openned = data->info.dir ? 2 : 0;
} else {
data->info.fd = open(data->path, O_RDONLY);
data->openned = data->info.fd != -1 ? 1 : 0;
}
/*
* check for possible errors, note that many of possible ones are
* parsed in the lstat call above
*/
if (data->openned == 0) {
switch(errno) {
case EACCES:
err = ISO_FILE_ACCESS_DENIED;
break;
case EFAULT:
case ENOMEM:
err = ISO_MEM_ERROR;
break;
default:
err = ISO_FILE_ERROR;
break;
}
return err;
}
return ISO_SUCCESS;
}
static
int lfs_close(IsoFileSource *src)
{
int ret;
_LocalFsFileSource *data;
if (src == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
switch(data->openned) {
case 1: /* not dir */
ret = close(data->info.fd) == 0 ? ISO_SUCCESS : ISO_FILE_ERROR;
break;
case 2: /* directory */
ret = closedir(data->info.dir) == 0 ? ISO_SUCCESS : ISO_FILE_ERROR;
break;
default:
ret = ISO_FILE_NOT_OPENNED;
break;
}
if (ret == ISO_SUCCESS) {
data->openned = 0;
}
return ret;
}
static
int lfs_read(IsoFileSource *src, void *buf, size_t count)
{
_LocalFsFileSource *data;
if (src == NULL || buf == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
switch(data->openned) {
case 1: /* not dir */
{
int ret;
ret = read(data->info.fd, buf, count);
if (ret < 0) {
/* error on read */
switch(errno) {
case EINTR:
ret = ISO_INTERRUPTED;
break;
case EFAULT:
ret = ISO_MEM_ERROR;
break;
case EIO:
ret = ISO_FILE_READ_ERROR;
break;
default:
ret = ISO_FILE_ERROR;
break;
}
}
return ret;
}
case 2: /* directory */
return ISO_FILE_IS_DIR;
default:
return ISO_FILE_NOT_OPENNED;
}
}
static
int lfs_readdir(IsoFileSource *src, IsoFileSource **child)
{
_LocalFsFileSource *data;
if (src == NULL || child == NULL) {
return ISO_NULL_POINTER;
}
data = src->data;
switch(data->openned) {
case 1: /* not dir */
return ISO_FILE_IS_NOT_DIR;
case 2: /* directory */
{
char *path;
struct dirent *entry;
size_t a, b;
int ret;
/* while to skip "." and ".." dirs */
while (1) {
entry = readdir(data->info.dir);
if (entry == NULL) {
if (errno == EBADF)
return ISO_FILE_ERROR;
else
return 0; /* EOF */
}
if (strcmp(entry->d_name,".") && strcmp(entry->d_name,"..")) {
break;
}
}
/* constructs the new path */
a = strlen(data->path);
b = strlen(entry->d_name);
path = malloc(a + b + 2);
if (path == NULL) {
return ISO_MEM_ERROR;
}
strncpy(path, data->path, a);
path[a] = '/';
path[a + 1] = '\0';
strncat(path, entry->d_name, b);
/* create the new FileSrc */
ret = iso_file_source_new_lfs(path, child);
free(path);
return ret;
}
default:
return ISO_FILE_NOT_OPENNED;
}
}
static
int lfs_readlink(IsoFileSource *src, char *buf, size_t bufsiz)
{
int size;
_LocalFsFileSource *data;
if (src == NULL || buf == NULL) {
return ISO_NULL_POINTER;
}
if (bufsiz <= 0) {
return ISO_WRONG_ARG_VALUE;
}
data = src->data;
/*
* invoke readlink, with bufsiz -1 to reserve an space for
* the NULL character
*/
size = readlink(data->path, buf, bufsiz - 1);
if (size < 0) {
/* error */
switch(errno) {
case EACCES:
return ISO_FILE_ACCESS_DENIED;
case ENOTDIR:
case ENAMETOOLONG:
case ELOOP:
return ISO_FILE_BAD_PATH;
case ENOENT:
return ISO_FILE_DOESNT_EXIST;
case EINVAL:
return ISO_FILE_IS_NOT_SYMLINK;
case EFAULT:
case ENOMEM:
return ISO_MEM_ERROR;
default:
return ISO_FILE_ERROR;
}
}
/* NULL-terminate the buf */
buf[size] = '\0';
return ISO_SUCCESS;
}
static
IsoFilesystem* lfs_get_filesystem(IsoFileSource *src)
{
return src == NULL ? NULL : lfs;
}
static
void lfs_free(IsoFileSource *src)
{
_LocalFsFileSource *data;
data = src->data;
/* close the file if it is already openned */
if (data->openned) {
src->class->close(src);
}
free(data->path);
free(data);
iso_filesystem_unref(lfs);
}
IsoFileSourceIface lfs_class = {
lfs_get_path,
lfs_get_name,
lfs_lstat,
lfs_stat,
lfs_open,
lfs_close,
lfs_read,
lfs_readdir,
lfs_readlink,
lfs_get_filesystem,
lfs_free
};
/**
*
* @return
* 1 success, < 0 error
*/
int iso_file_source_new_lfs(const char *path, IsoFileSource **src)
{
IsoFileSource *lfs_src;
_LocalFsFileSource *data;
if (src == NULL) {
return ISO_NULL_POINTER;
}
if (lfs == NULL) {
/* this should never happen */
return ISO_ERROR;
}
/* allocate memory */
data = malloc(sizeof(_LocalFsFileSource));
if (data == NULL) {
return ISO_OUT_OF_MEM;
}
lfs_src = malloc(sizeof(IsoFileSource));
if (lfs_src == NULL) {
free(data);
return ISO_OUT_OF_MEM;
}
/* fill struct */
data->path = strdup(path);
{
/* remove trailing '/' */
int len = strlen(path);
if (len > 1) {
/* don't remove / for root! */
if (path[len-1] == '/') {
data->path[len-1] = '\0';
}
}
}
data->openned = 0;
lfs_src->refcount = 1;
lfs_src->data = data;
lfs_src->class = &lfs_class;
/* take a ref to local filesystem */
iso_filesystem_ref(lfs);
/* return */
*src = lfs_src;
return ISO_SUCCESS;
}
static
int lfs_get_root(IsoFilesystem *fs, IsoFileSource **root)
{
if (fs == NULL || root == NULL) {
return ISO_NULL_POINTER;
}
return iso_file_source_new_lfs("/", root);
}
static
int lfs_get_by_path(IsoFilesystem *fs, const char *path, IsoFileSource **file)
{
if (fs == NULL || path == NULL || file == NULL) {
return ISO_NULL_POINTER;
}
return iso_file_source_new_lfs(path, file);
}
static
unsigned int lfs_get_id(IsoFilesystem *fs)
{
return ISO_LOCAL_FS_ID;
}
static
void lfs_fs_free(IsoFilesystem *fs)
{
lfs = NULL;
}
int iso_local_filesystem_new(IsoFilesystem **fs)
{
if (fs == NULL) {
return ISO_NULL_POINTER;
}
if (lfs != NULL) {
/* just take a new ref */
iso_filesystem_ref(lfs);
} else {
lfs = malloc(sizeof(IsoFilesystem));
if (lfs == NULL) {
return ISO_OUT_OF_MEM;
}
/* fill struct */
lfs->refcount = 1;
lfs->data = NULL; /* we don't need private data */
lfs->get_root = lfs_get_root;
lfs->get_by_path = lfs_get_by_path;
lfs->get_id = lfs_get_id;
lfs->free = lfs_fs_free;
}
*fs = lfs;
return ISO_SUCCESS;
}