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/*
* Copyright 2023, Vincent Douillet <vincent@vdouillet.fr>
*
* 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 copyright holder 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 COPYRIGHT HOLDER OR CONTRIBUTORS 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.
*/
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "cgi.h"
#include "config.h"
#include "download.h"
#include "file.h"
#include "http.h"
#include "url.h"
#include "util.h"
/*
* download url = r->pname / DOWNLOAD_URL / file->path / file->name
*/
size_t
build_download_url(struct kreq * r, struct file * file)
{
char action_url[PATH_MAX];
size_t action_url_len;
/* don't download directories */
if (file->is_dir)
return 0;
action_url_len = url_build(action_url, PATH_MAX, r->pname, DOWNLOAD_URL,
file->path, file->name, NULL);
if (action_url_len == 0 || action_url_len >= PATH_MAX) {
kutil_warn(r, NULL,
"download: action URL overflow: %s", action_url);
return 0;
}
file->action_url = strndup(action_url, action_url_len);
if (file->action_url == NULL) {
kutil_warn(r, NULL,
"download: unable to allocate file url buffer: %s",
action_url);
return 0;
}
return action_url_len;
}
static char *
strsplit(char *str, char c)
{
char *right, *result;
size_t right_len;
right = strrchr(str, c);
if (!right || right == str)
return NULL;
/* move right part to new buffer */
right_len = strlen(right);
result = malloc(sizeof(char) * right_len);
if (result == NULL)
return NULL;
if (strlcpy(result, right + 1, right_len) >= right_len) {
free(result);
return NULL;
}
/* remove right part from src buffer */
*right = '\0';
return result;
}
struct http_ret
download(struct kreq * r)
{
char *file_name;
void *buffer;
struct file *f;
int fd;
char file_path[PATH_MAX], request_path[PATH_MAX];
size_t path_size;
struct http_ret ret;
/* initialize empty file and return struct to success */
f = NULL;
ret = (struct http_ret) {
KHTTP_200, ""
};
/* check that the requested URL can be safely processed */
if (strlen(r->path) == 0 || !check_request_path(r->path, r->suffix)) {
ret = (struct http_ret) {
KHTTP_400,
"download: invalid request path"
};
goto end;
}
/* build requested file path, with suffix or without */
if (strlen(r->suffix) > 0) {
if (snprintf(request_path, sizeof(request_path), "%s.%s", r->path, r->suffix)
>= (int) sizeof(request_path)) {
ret = (struct http_ret) {
KHTTP_414,
"download: request too long"
};
goto end;
}
} else {
if (snprintf(request_path, sizeof(request_path), "%s", r->path)
>= (int) sizeof(request_path)) {
ret = (struct http_ret) {
KHTTP_414,
"download: request too long"
};
goto end;
}
}
path_size = url_build(file_path, PATH_MAX, DATA_DIR, request_path,
NULL);
if (path_size == 0) {
ret = (struct http_ret) {
KHTTP_404,
"download: unable to build file path"
};
goto end;
}
if (path_size >= PATH_MAX) {
ret = (struct http_ret) {
KHTTP_414,
"download: request too long"
};
goto end;
}
/* build file metadata */
file_name = strsplit(request_path, '/');
if (file_name == NULL)
f = file_new("/", 1, request_path, strlen(request_path)); /* ROOT file */
else {
f = file_new(request_path, strlen(request_path), file_name,
strlen(file_name));
free(file_name);/* copied in file_new */
}
if (f == NULL) {
ret = (struct http_ret) {
KHTTP_404,
"download: file metadata failure"
};
goto end;
}
/* memory map the file */
fd = open(file_path, O_RDONLY);
if (fd < 0) {
ret = (struct http_ret) {
KHTTP_404,
"download: unable to open file"
};
goto end;
}
/* mmap does not work with empty file: st_size = 0 */
if (f->size > 0) {
buffer = mmap(NULL, f->size, PROT_READ, MAP_PRIVATE, fd, 0);
if (buffer == MAP_FAILED) {
ret = (struct http_ret) {
KHTTP_500,
"download: mmap failed"
};
goto end;
}
}
/* write the file */
http_open_file(r, KHTTP_200, f);
if (f->size > 0)
K_OK(khttp_write(r, (const char *) buffer, f->size), r);
/* cleanup */
end:
if (f != NULL && f->size > 0)
munmap(buffer, f->size);
if (f != NULL)
free(f);
return ret;
}
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