Modified the file index graphical interface to be similar to the nginx interface, Original reference: networking/httpd_indexcgi.c

busybox_httpd_indexcgi.c

/*
 * Copyright (c) 2007 Denys Vlasenko <vda.linux@googlemail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

/*
 * This program is a CGI application. It outputs directory index page.
 * Put it into cgi-bin/index.cgi and chmod 0755.
 */

/* Build a-la
i486-linux-uclibc-gcc \
-static -static-libgcc \
-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 \
-Wall -Wshadow -Wwrite-strings -Wundef -Wstrict-prototypes -Werror \
-Wold-style-definition -Wdeclaration-after-statement -Wno-pointer-sign \
-Wmissing-prototypes -Wmissing-declarations \
-Os -fno-builtin-strlen -finline-limit=0 -fomit-frame-pointer \
-ffunction-sections -fdata-sections -fno-guess-branch-probability \
-funsigned-char \
-falign-functions=1 -falign-jumps=1 -falign-labels=1 -falign-loops=1 \
-march=i386 -mpreferred-stack-boundary=2 \
-Wl,-Map -Wl,link.map -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \
httpd_indexcgi.c -o index.cgi
*/

/* We don't use printf, as it pulls in >12 kb of code from uclibc (i386). */
/* Currently malloc machinery is the biggest part of libc we pull in. */
/* We have only one realloc and one strdup, any idea how to do without? */

/* Size (i386, static uclibc, approximate):
 *   text    data     bss     dec     hex filename
 *  13036      44    3052   16132    3f04 index.cgi
 *   2576       4    2048    4628    1214 index.cgi.o
 */

#define _GNU_SOURCE 1  /* for strchrnul */
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <dirent.h>
#include <time.h>

/* Appearance of the table is controlled by style sheet *ONLY*,
 * formatting code uses <TAG class=CLASS> to apply style
 * to elements. Edit stylesheet to your liking and recompile. */

typedef struct dir_list_t {
	char  *dl_name;
	mode_t dl_mode;
	off_t  dl_size;
	time_t dl_mtime;
} dir_list_t;

static int compare_dl(dir_list_t *a, dir_list_t *b)
{
	/* ".." is 'less than' any other dir entry */
	if (strcmp(a->dl_name, "..") == 0) {
		return -1;
	}
	if (strcmp(b->dl_name, "..") == 0) {
		return 1;
	}
	if (S_ISDIR(a->dl_mode) != S_ISDIR(b->dl_mode)) {
		/* 1 if b is a dir (and thus a is 'after' b, a > b),
		 * else -1 (a < b) */
		return (S_ISDIR(b->dl_mode) != 0) ? 1 : -1;
	}
	return strcmp(a->dl_name, b->dl_name);
}

/* NB: formatters do not store terminating NUL! */

static int fmt_fill_space(unsigned len)
{
	static const char spaces[] = "                    ";
	int ret_len = len;
	for(;len > sizeof(spaces) - 1; len -= sizeof(spaces) - 1) {
		write(STDOUT_FILENO, spaces, sizeof(spaces) - 1);
	}
	write(STDOUT_FILENO, spaces, len);
	return ret_len;
}

static int fmt_str(const char *src)
{
	unsigned len = strlen(src);
	write(STDOUT_FILENO, src, len);
	return len;
}

static int fmt_char(char c)
{
	write(STDOUT_FILENO, &c, 1);
	return 1;
}

static int fmt_url(/*char *dst,*/ const char *name)
{
	int ret_len = 0;
	while (*name) {
		unsigned c = *name++;
		if ((c - '0') > 9 /* not a digit */
		 && ((c|0x20) - 'a') > ('z' - 'a') /* not A-Z or a-z */
		 && !strchr("._-+@", c)
		) {
			ret_len += fmt_char('%');
			ret_len += fmt_char("0123456789ABCDEF"[c >> 4]);
			ret_len += fmt_char("0123456789ABCDEF"[c & 0xf]);
		} else {
			ret_len += fmt_char(c);
		}
	}
	return ret_len;
}

/* HEADROOM bytes are available after dst after this call */
static int fmt_html(/*char *dst,*/ const char *name)
{
	int ret_len = 0;
	while (*name) {
		char c = *name++;
		if (c == '<')
			ret_len += fmt_str("&lt;");
		else if (c == '>')
			ret_len += fmt_str("&gt;");
		else if (c == '&') {
			ret_len += fmt_str("&amp;");
		} else {
			ret_len += fmt_char(c);
			continue;
		}
	}
	return ret_len;
}

/* HEADROOM bytes are available after dst after this call */
static int fmt_ull(/*char *dst,*/ unsigned long long n)
{
	char buf[sizeof(n)*3 + 2];
	char *p;

	p = buf + sizeof(buf) - 1;
	*p = '\0';
	do {
		*--p = (n % 10) + '0';
		n /= 10;
	} while (n);
	return fmt_str(p);
}

/* Does not call guarantee - eats into headroom instead */
static int fmt_02u(/*char *dst,*/ unsigned n)
{
	/* n %= 100; - not needed, callers don't pass big n */
	fmt_char((n / 10) + '0');
	fmt_char((n % 10) + '0');
	return 2;
}

/* Does not call guarantee - eats into headroom instead */
static int fmt_04u(/*char *dst,*/ unsigned n)
{
	/* n %= 10000; - not needed, callers don't pass big n */
	fmt_02u(n / 100);
	fmt_02u(n % 100);
	return 4;
}

int main(int argc, char **argv)
{
	dir_list_t *dir_list;
	dir_list_t *cdir;
	unsigned dir_list_count;
	unsigned count_dirs;
	unsigned count_files;
	unsigned long long size_total;
	DIR *dirp;
	char *location;

	location = getenv("REQUEST_URI");
	if (!location)
		return 1;

	/* drop URL arguments if any */
	strchrnul(location, '?')[0] = '\0';

	if (location[0] != '/'
	 || strstr(location, "//")
	 || strstr(location, "/../")
	 || strcmp(strrchr(location, '/'), "/..") == 0
	) {
		return 1;
	}

	if (chdir("..")
	 || (location[1] && chdir(location + 1))
	) {
		return 1;
	}

	dirp = opendir(".");
	if (!dirp)
		return 1;
	dir_list = NULL;
	dir_list_count = 0;
	while (1) {
		struct dirent *dp;
		struct stat sb;

		dp = readdir(dirp);
		if (!dp)
			break;
		if (dp->d_name[0] == '.' && !dp->d_name[1])
			continue;
		if (stat(dp->d_name, &sb) != 0)
			continue;
		dir_list = realloc(dir_list, (dir_list_count + 1) * sizeof(dir_list[0]));
		dir_list[dir_list_count].dl_name = strdup(dp->d_name);
		dir_list[dir_list_count].dl_mode = sb.st_mode;
		dir_list[dir_list_count].dl_size = sb.st_size;
		dir_list[dir_list_count].dl_mtime = sb.st_mtime;
		dir_list_count++;
	}
	closedir(dirp);

	qsort(dir_list, dir_list_count, sizeof(dir_list[0]), (void*)compare_dl);

	fmt_str(
		"" /* Additional headers (currently none) */
		"\r\n" /* Mandatory empty line after headers */
		"<html><head><title>Index of ");
	/* Guard against directories with &, > etc */
	fmt_html(location);
	fmt_str(
		"</title>\n"
		"</head>" "\n"
		"<body>" "\n"
		"<h1>Index of ");
	fmt_html(location);
	fmt_str(
		"</h1>" "\n"
		"<hr>" "\n"
		"<pre>" "\n"
	);

	count_dirs = 0;
	count_files = 0;
	size_total = 0;
	cdir = dir_list;

	while (dir_list_count--) {
		if (S_ISDIR(cdir->dl_mode)) {
			count_dirs++;
		} else if (S_ISREG(cdir->dl_mode)) {
			count_files++;
			size_total += cdir->dl_size;
		} else
			goto next;

		fmt_str("<a href='");
		fmt_url(cdir->dl_name); /* %20 etc */
		if (S_ISDIR(cdir->dl_mode))
			fmt_char('/');
		fmt_str("'>");
		fmt_html(cdir->dl_name); /* &lt; etc */
		int cur_text_position = strlen(cdir->dl_name);
		if (S_ISDIR(cdir->dl_mode)) {
			fmt_char('/');
			cur_text_position += 1;
		}
		fmt_str("</a>");

		if (strstr(cdir->dl_name, "..")) {
			fmt_char('\n');
			goto next;
		}

		// FILENAME_LENGTH_LIMIT refers to the display length of nginx
		const unsigned FILENAME_LENGTH_LIMIT = 51;

		if (cur_text_position < FILENAME_LENGTH_LIMIT ) {
			fmt_fill_space(FILENAME_LENGTH_LIMIT - cur_text_position);
		}
		struct tm cur_tm;
		localtime_r(&cdir->dl_mtime, &cur_tm);
		fmt_04u(1900 + cur_tm.tm_year); fmt_char('-');
		fmt_02u(cur_tm.tm_mon + 1); fmt_char('-');
		fmt_02u(cur_tm.tm_mday); fmt_char(' ');
		fmt_02u(cur_tm.tm_hour); fmt_char(':');
		fmt_02u(cur_tm.tm_min); fmt_char(':');
		fmt_02u(cur_tm.tm_sec);

		fmt_str("                   ");
		if (S_ISREG(cdir->dl_mode))
			fmt_ull(cdir->dl_size);
		else
			fmt_str("-");

		fmt_char('\n');
 next:
		cdir++;
	}

	fmt_str(
		"</pre>" "\n"
		"<hr>" "\n"
	);

	fmt_str("Files: ");
	fmt_ull(count_files);
	/* count_dirs - 1: we don't want to count ".." */
	fmt_str(", directories: ");
	fmt_ull(count_dirs - 1);
	fmt_str(", total size: ");
	fmt_ull(size_total);
	/* "</body></html>" - why bother? */

	return 0;
}