suckless-quark/resp.c
Laslo Hunhold cb7a1f6390
Replace off_t with size_t
While off_t might be better suited for file-offsets and -sizes, the
IEEE Computer Society was unable to mandate limits (min, max) for it
in the POSIX specification in the last 32 years. Because it's impossible
to portably determine these numbers for signed integers, I decided
to switch to size_t for the offsets to be able to pass proper values
to strtonum(), because C99 is sane and has defined limits for size_t
(i.e. SIZE_MIN and SIZE_MAX).

On my system, long long and off_t have the same size, so it didn't
trigger any bugs, but strtonum() could pass a bigger number to
lower and upper than they can handle and make them overflow.

The rationale for switching to size_t is actually given by the fact that
functions like mmap() blur the border between memory and filesystem.
Another point is that glibc has a horrible define _FILE_OFFSET_BITS
you need to set to 64 to actually get decent values for off_t, which
was a huge headache in sbase until we found that out.

Signed-off-by: Laslo Hunhold <dev@frign.de>
2020-08-05 18:59:55 +02:00

245 lines
5.3 KiB
C

/* See LICENSE file for copyright and license details. */
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#include "http.h"
#include "resp.h"
#include "util.h"
static int
compareent(const struct dirent **d1, const struct dirent **d2)
{
int v;
v = ((*d2)->d_type == DT_DIR ? 1 : -1) -
((*d1)->d_type == DT_DIR ? 1 : -1);
if (v) {
return v;
}
return strcmp((*d1)->d_name, (*d2)->d_name);
}
static char *
suffix(int t)
{
switch (t) {
case DT_FIFO: return "|";
case DT_DIR: return "/";
case DT_LNK: return "@";
case DT_SOCK: return "=";
}
return "";
}
static void
html_escape(const char *src, char *dst, size_t dst_siz)
{
const struct {
char c;
char *s;
} escape[] = {
{ '&', "&amp;" },
{ '<', "&lt;" },
{ '>', "&gt;" },
{ '"', "&quot;" },
{ '\'', "&#x27;" },
};
size_t i, j, k, esclen;
for (i = 0, j = 0; src[i] != '\0'; i++) {
for (k = 0; k < LEN(escape); k++) {
if (src[i] == escape[k].c) {
break;
}
}
if (k == LEN(escape)) {
/* no escape char at src[i] */
if (j == dst_siz - 1) {
/* silent truncation */
break;
} else {
dst[j++] = src[i];
}
} else {
/* escape char at src[i] */
esclen = strlen(escape[k].s);
if (j >= dst_siz - esclen) {
/* silent truncation */
break;
} else {
memcpy(&dst[j], escape[k].s, esclen);
j += esclen;
}
}
}
dst[j] = '\0';
}
enum status
resp_dir(int fd, const char *name, const struct request *req)
{
enum status sendstatus;
struct dirent **e;
struct response res = {
.status = S_OK,
.field[RES_CONTENT_TYPE] = "text/html; charset=utf-8",
};
size_t i;
int dirlen;
char esc[PATH_MAX /* > NAME_MAX */ * 6]; /* strlen("&...;") <= 6 */
/* read directory */
if ((dirlen = scandir(name, &e, NULL, compareent)) < 0) {
return http_send_status(fd, S_FORBIDDEN);
}
/* send header as late as possible */
if ((sendstatus = http_send_header(fd, &res)) != res.status) {
res.status = sendstatus;
goto cleanup;
}
if (req->method == M_GET) {
/* listing header */
html_escape(name, esc, sizeof(esc));
if (dprintf(fd,
"<!DOCTYPE html>\n<html>\n\t<head>"
"<title>Index of %s</title></head>\n"
"\t<body>\n\t\t<a href=\"..\">..</a>",
esc) < 0) {
res.status = S_REQUEST_TIMEOUT;
goto cleanup;
}
/* listing */
for (i = 0; i < (size_t)dirlen; i++) {
/* skip hidden files, "." and ".." */
if (e[i]->d_name[0] == '.') {
continue;
}
/* entry line */
html_escape(e[i]->d_name, esc, sizeof(esc));
if (dprintf(fd, "<br />\n\t\t<a href=\"%s%s\">%s%s</a>",
esc,
(e[i]->d_type == DT_DIR) ? "/" : "",
esc,
suffix(e[i]->d_type)) < 0) {
res.status = S_REQUEST_TIMEOUT;
goto cleanup;
}
}
/* listing footer */
if (dprintf(fd, "\n\t</body>\n</html>\n") < 0) {
res.status = S_REQUEST_TIMEOUT;
goto cleanup;
}
}
cleanup:
while (dirlen--) {
free(e[dirlen]);
}
free(e);
return res.status;
}
enum status
resp_file(int fd, const char *name, const struct request *req,
const struct stat *st, const char *mime, size_t lower,
size_t upper)
{
FILE *fp;
enum status sendstatus;
struct response res = {
.status = (req->field[REQ_RANGE][0] != '\0') ?
S_PARTIAL_CONTENT : S_OK,
.field[RES_ACCEPT_RANGES] = "bytes",
};
ssize_t bread, bwritten;
size_t remaining;
static char buf[BUFSIZ], *p;
/* open file */
if (!(fp = fopen(name, "r"))) {
res.status = http_send_status(fd, S_FORBIDDEN);
goto cleanup;
}
/* seek to lower bound */
if (fseek(fp, lower, SEEK_SET)) {
res.status = http_send_status(fd, S_INTERNAL_SERVER_ERROR);
goto cleanup;
}
/* build header */
if (esnprintf(res.field[RES_CONTENT_LENGTH],
sizeof(res.field[RES_CONTENT_LENGTH]),
"%zu", upper - lower + 1)) {
return http_send_status(fd, S_INTERNAL_SERVER_ERROR);
}
if (req->field[REQ_RANGE][0] != '\0') {
if (esnprintf(res.field[RES_CONTENT_RANGE],
sizeof(res.field[RES_CONTENT_RANGE]),
"bytes %zd-%zd/%zu", lower, upper,
st->st_size)) {
return http_send_status(fd, S_INTERNAL_SERVER_ERROR);
}
}
if (esnprintf(res.field[RES_CONTENT_TYPE],
sizeof(res.field[RES_CONTENT_TYPE]),
"%s", mime)) {
return http_send_status(fd, S_INTERNAL_SERVER_ERROR);
}
if (timestamp(res.field[RES_LAST_MODIFIED],
sizeof(res.field[RES_LAST_MODIFIED]),
st->st_mtim.tv_sec)) {
return http_send_status(fd, S_INTERNAL_SERVER_ERROR);
}
/* send header as late as possible */
if ((sendstatus = http_send_header(fd, &res)) != res.status) {
res.status = sendstatus;
goto cleanup;
}
if (req->method == M_GET) {
/* write data until upper bound is hit */
remaining = upper - lower + 1;
while ((bread = fread(buf, 1, MIN(sizeof(buf),
remaining), fp))) {
if (bread < 0) {
res.status = S_INTERNAL_SERVER_ERROR;
goto cleanup;
}
remaining -= bread;
p = buf;
while (bread > 0) {
bwritten = write(fd, p, bread);
if (bwritten <= 0) {
res.status = S_REQUEST_TIMEOUT;
goto cleanup;
}
bread -= bwritten;
p += bwritten;
}
}
}
cleanup:
if (fp) {
fclose(fp);
}
return res.status;
}