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/**
* @file file.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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.
*
* @section DESCRIPTION
*
* File I/O module.
*
* Synopsis:
* file_read(string filename)
*
* Variables:
* string (empty) - file contents
*
* Description:
* Reads the contents of a file. Reports an error if something goes wrong.
* WARNING: this uses fopen/fread/fclose, blocking the entire interpreter while
* the file is being read. For this reason, you should only use this
* to read small local files which will be read quickly, and especially
* not files on network mounts.
*
* Synopsis:
* file_write(string filename, string contents)
*
* Description:
* Writes a file, possibly overwriting an existing one. Reports an error if something
* goes wrong.
* WARNING: this is not an atomic operation; other programs may see the file in an
* inconsistent state while it is being written. Similarly, if writing
* fails, the file may remain in an inconsistent state indefinitely.
* If this is a problem, you should write the new contents to a temporary
* file and rename this temporary file to the live file.
* WARNING: this uses fopen/fwrite/fclose, blocking the entire interpreter while
* the file is being written. For this reason, you should only use this
* to write small local files which will be written quickly, and especially
* not files on network mounts.
*
* Synopsis:
* file_stat(string filename)
* file_lstat(string filename)
*
* Description:
* Retrieves information about a file.
* file_stat() follows symlinks; file_lstat() does not and allows retrieving information
* about a symlink.
* WARNING: this blocks the interpreter
*
* Variables:
* succeeded - whether the stat operation succeeded (true/false). If false, all other
* variables obtain the value "failed".
* type - file, dir, chr, blk, fifo, link, socket, other, failed
* size - size of the file, or failed
*/
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <misc/read_file.h>
#include <misc/write_file.h>
#include <misc/parse_number.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_file.h>
struct read_instance {
NCDModuleInst *i;
uint8_t *file_data;
size_t file_len;
};
struct stat_instance {
NCDModuleInst *i;
int succeeded;
struct stat result;
};
static void read_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct read_instance *o = vo;
o->i = i;
// read arguments
NCDValRef filename_arg;
if (!NCDVal_ListRead(params->args, 1, &filename_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsStringNoNulls(filename_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail0;
}
// get null terminated name
NCDValNullTermString filename_nts;
if (!NCDVal_StringNullTerminate(filename_arg, &filename_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail0;
}
// read file
int res = read_file(filename_nts.data, &o->file_data, &o->file_len);
NCDValNullTermString_Free(&filename_nts);
if (!res) {
ModuleLog(i, BLOG_ERROR, "failed to read file");
goto fail0;
}
// signal up
NCDModuleInst_Backend_Up(i);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void read_func_die (void *vo)
{
struct read_instance *o = vo;
// free data
free(o->file_data);
NCDModuleInst_Backend_Dead(o->i);
}
static int read_func_getvar2 (void *vo, NCD_string_id_t name, NCDValMem *mem, NCDValRef *out)
{
struct read_instance *o = vo;
if (name == NCD_STRING_EMPTY) {
*out = NCDVal_NewStringBin(mem, o->file_data, o->file_len);
return 1;
}
return 0;
}
static void write_func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
// read arguments
NCDValRef filename_arg;
NCDValRef contents_arg;
if (!NCDVal_ListRead(params->args, 2, &filename_arg, &contents_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsStringNoNulls(filename_arg) || !NCDVal_IsString(contents_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail0;
}
// get null terminated name
NCDValNullTermString filename_nts;
if (!NCDVal_StringNullTerminate(filename_arg, &filename_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail0;
}
// write file
int res = write_file(filename_nts.data, NCDVal_StringMemRef(contents_arg));
NCDValNullTermString_Free(&filename_nts);
if (!res) {
ModuleLog(i, BLOG_ERROR, "failed to write file");
goto fail0;
}
// signal up
NCDModuleInst_Backend_Up(i);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void stat_func_new_common (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params, int is_lstat)
{
struct stat_instance *o = vo;
o->i = i;
NCDValRef filename_arg;
if (!NCDVal_ListRead(params->args, 1, &filename_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsString(filename_arg)) {
ModuleLog(i, BLOG_ERROR, "wrong type");
goto fail0;
}
o->succeeded = 0;
if (!NCDVal_IsStringNoNulls(filename_arg)) {
goto out;
}
// null terminate filename
NCDValNullTermString filename_nts;
if (!NCDVal_StringNullTerminate(filename_arg, &filename_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail0;
}
int res;
if (is_lstat) {
res = lstat(filename_nts.data, &o->result);
} else {
res = stat(filename_nts.data, &o->result);
}
NCDValNullTermString_Free(&filename_nts);
if (res < 0) {
goto out;
}
o->succeeded = 1;
out:
NCDModuleInst_Backend_Up(i);
return;
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void stat_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
stat_func_new_common(vo, i, params, 0);
}
static void lstat_func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
stat_func_new_common(vo, i, params, 1);
}
static int stat_func_getvar2 (void *vo, NCD_string_id_t name, NCDValMem *mem, NCDValRef *out)
{
struct stat_instance *o = vo;
if (name == NCD_STRING_SUCCEEDED) {
*out = ncd_make_boolean(mem, o->succeeded);
return 1;
}
if (name == NCD_STRING_TYPE) {
const char *str;
if (!o->succeeded) {
str = "failed";
} else if (S_ISREG(o->result.st_mode)) {
str = "file";
} else if (S_ISDIR(o->result.st_mode)) {
str = "dir";
} else if (S_ISCHR(o->result.st_mode)) {
str = "chr";
} else if (S_ISBLK(o->result.st_mode)) {
str = "blk";
} else if (S_ISFIFO(o->result.st_mode)) {
str = "fifo";
} else if (S_ISLNK(o->result.st_mode)) {
str = "link";
} else if (S_ISSOCK(o->result.st_mode)) {
str = "socket";
} else {
str = "other";
}
*out = NCDVal_NewString(mem, str);
return 1;
}
if (name == NCD_STRING_SIZE) {
char str[50];
if (!o->succeeded) {
strcpy(str, "failed");
} else {
generate_decimal_repr_string((uintmax_t)o->result.st_size, str);
}
*out = NCDVal_NewString(mem, str);
return 1;
}
return 0;
}
static struct NCDModule modules[] = {
{
.type = "file_read",
.func_new2 = read_func_new,
.func_die = read_func_die,
.func_getvar2 = read_func_getvar2,
.alloc_size = sizeof(struct read_instance)
}, {
.type = "file_write",
.func_new2 = write_func_new
}, {
.type = "file_stat",
.func_new2 = stat_func_new,
.func_getvar2 = stat_func_getvar2,
.alloc_size = sizeof(struct stat_instance)
}, {
.type = "file_lstat",
.func_new2 = lstat_func_new,
.func_getvar2 = stat_func_getvar2,
.alloc_size = sizeof(struct stat_instance)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_file = {
.modules = modules
};