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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/stat.h>
#include "memory.h"
#include "plugin.h"
#include "util.h"
#include "buffer.h"
#include "mime.h"
// Will only be set once in the registration function, which is before any threading is done
static char *static_file_dir = NULL;
static bool path_allowed(const char *path) {
char last = '\0';
for (size_t i = 0; path[i]; i++) {
// no unprintable characters
if (path[i] < 32 || path[i] >= 127) return false;
// no hidden files or magic directory items like ".."
if (last == '/' && path[i] == '.') return false;
last = path[i];
}
return true;
}
static char* make_relative_path(const char *path) {
char *rel = malloc(strlen(static_file_dir) + 1 + strlen(path) + 1, char);
sprintf(rel, "%s/%s", static_file_dir, path);
return rel;
}
// If an error occurs, returns -1 and sets errno
static ssize_t query_file_size(const char *path) {
struct stat st;
memset(&st, 0, sizeof st);
if (stat(path, &st) < 0) {
return -1;
}
if (st.st_mode & S_IFREG) {
return st.st_size;
} else {
errno = EISDIR;
return -1;
}
}
static struct buffer build_response_headers(const char *status, const char *content_type, size_t body_len) {
struct buffer buffer = buffer_make(200 + body_len);
buffer_append_str(&buffer, "HTTP/1.1 ");
buffer_append_str(&buffer, status);
buffer_append_str(&buffer, "\r\n");
if (content_type) {
buffer_append_str(&buffer, "Content-Type: ");
buffer_append_str(&buffer, content_type);
buffer_append_str(&buffer, "\r\n");
}
char tempbuf[128]; // size_t is at most 20 chars long
sprintf(tempbuf, "Content-Length: %zu\r\n", body_len);
buffer_append_str(&buffer, tempbuf);
buffer_append_str(&buffer, "Server: cserver\r\n\r\n");
return buffer;
}
static void send_404(int sock) {
const char *body = "404 Not found";
struct buffer buffer = build_response_headers("404 Not found", "text/plain", strlen(body));
buffer_append_str(&buffer, body);
sendall(sock, buffer.buf, buffer.len);
}
static void send_500(int sock) {
const char *body = "500 Internal server error";
struct buffer buffer = build_response_headers("500 Internal server error", "text/plain", strlen(body));
buffer_append_str(&buffer, body);
sendall(sock, buffer.buf, buffer.len);
}
static Handler_ret_t connection_handler(int sock, Headers *headers) {
char *path = NULL;
struct buffer buffer;
buffer.buf = NULL;
if (!path_allowed(headers->url)) {
send_404(sock);
goto cleanup_return;
}
path = make_relative_path(headers->url);
ssize_t size = query_file_size(path);
if (size < 0) {
if (errno == ENOENT || errno == EISDIR) {
send_404(sock);
goto cleanup_return;
} else {
send_500(sock);
goto cleanup_return;
}
}
const char *mimetype = mime_detect(path);
if (!mimetype) mimetype = "application/octet-stream";
buffer = build_response_headers("200 OK", mimetype, size);
if (!buffer_append_file(&buffer, path)) {
send_500(sock);
goto cleanup_return;
}
sendall(sock, buffer.buf, buffer.len);
cleanup_return:
if (buffer.buf) buffer_free(buffer);
if (path) free(path);
return HR_HANDLED;
}
void plugin_register_yourself(register_callback_t callback) {
static_file_dir = getenv("STATIC_DIR");
if (!static_file_dir || access(static_file_dir, R_OK | X_OK) < 0) {
fprintf(stderr, "cserver: static: Environment variable $STATIC_DIR not set or directory not readable\n");
exit(1);
}
mime_init();
callback("static", &connection_handler);
}
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