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de4c5d3d8

Denis Vlasenko

2007-08-23

FAILED Duration: 16s

Subject

httpd: code shrink of dir indexer example

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Commit Diff GitHub →

networking/httpd_indexcgi.c +196 -185

networking/httpd_indexcgi.c+196 -185

@@ -5,7 +5,7 @@
	*/

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

@@ -23,14 +23,16 @@ i486-linux-uclibc-gcc \
	-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
-
-	Size (approximate):
-	text data bss dec hex filename
-	22642 160 3052 25854 64fe index.cgi
	*/

-	/* TODO: get rid of printf's: printf code is more than 50%
-	* of the entire executable when built against static uclibc */
+	/* 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, approximate):
+	* text data bss dec hex filename
+	* 13036 44 3052 16132 3f04 index.cgi
+	* 2576 4 2048 4628 1214 index.cgi.o
+	*/

	#include <sys/types.h>
	#include <sys/stat.h>
@@ -47,172 +49,165 @@ Size (approximate):
	* formatting code uses <TAG class=CLASS> to apply style
	* to elements. Edit stylesheet to your liking and recompile. */

-	static const char str_header[] =
-	"" /* Additional headers (currently none) */
-	"\r\n" /* Mandatory empty line after headers */
-	"<html><head><title>Index of %s</title>" "\n"
-	"<style>" "\n"
-	"table {" "\n"
-	" width: 100%%;" "\n"
-	" background-color: #fff5ee;" "\n"
-	" border-width: 1px;" /* 1px 1px 1px 1px; */ "\n"
-	" border-spacing: 2px;" "\n"
-	" border-style: solid;" /* solid solid solid solid; */ "\n"
-	" border-color: black;" /* black black black black; */ "\n"
-	" border-collapse: collapse;" "\n"
-	"}" "\n"
-	"th {" "\n"
-	" border-width: 1px;" /* 1px 1px 1px 1px; */ "\n"
-	" padding: 1px;" /* 1px 1px 1px 1px; */ "\n"
-	" border-style: solid;" /* solid solid solid solid; */ "\n"
-	" border-color: black;" /* black black black black; */ "\n"
-	"}" "\n"
-	"td {" "\n"
-	/* top right bottom left */
-	" border-width: 0px 1px 0px 1px;" "\n"
-	" padding: 1px;" /* 1px 1px 1px 1px; */ "\n"
-	" border-style: solid;" /* solid solid solid solid; */ "\n"
-	" border-color: black;" /* black black black black; */ "\n"
-	"}" "\n"
-	"tr.hdr { background-color:#eee5de; }" "\n"
-	"tr.o { background-color:#ffffff; }" "\n"
-	/* tr.e { ... } - for even rows (currently none) */
-	"tr.foot { background-color:#eee5de; }" "\n"
-	"th.cnt { text-align:left; }" "\n"
-	"th.sz { text-align:right; }" "\n"
-	"th.dt { text-align:right; }" "\n"
-	"td.sz { text-align:right; }" "\n"
-	"td.dt { text-align:right; }" "\n"
-	"col.nm { width: 98%%; }" "\n"
-	"col.sz { width: 1%%; }" "\n"
-	"col.dt { width: 1%%; }" "\n"
-	"</style>" "\n"
-	"</head>" "\n"
-	"<body>" "\n"
-	"<h1>Index of %s</h1>" "\n"
-	"" "\n"
-	"<table>" "\n"
-	"<col class=nm><col class=sz><col class=dt>" "\n"
-	"<tr class=hdr><th class=cnt>Name<th class=sz>Size<th class=dt>Last modified" "\n"
-	;
+	#define STYLE_STR \
+	"<style>" "\n"\
+	"table {" "\n"\
+	"width:100%;" "\n"\
+	"background-color:#fff5ee;" "\n"\
+	"border-width:1px;" /* 1px 1px 1px 1px; */ "\n"\
+	"border-spacing:2px;" "\n"\
+	"border-style:solid;" /* solid solid solid solid; */ "\n"\
+	"border-color:black;" /* black black black black; */ "\n"\
+	"border-collapse:collapse;" "\n"\
+	"}" "\n"\
+	"th {" "\n"\
+	"border-width:1px;" /* 1px 1px 1px 1px; */ "\n"\
+	"padding:1px;" /* 1px 1px 1px 1px; */ "\n"\
+	"border-style:solid;" /* solid solid solid solid; */ "\n"\
+	"border-color:black;" /* black black black black; */ "\n"\
+	"}" "\n"\
+	"td {" "\n"\
+	/* top right bottom left */ \
+	"border-width:0px 1px 0px 1px;" "\n"\
+	"padding:1px;" /* 1px 1px 1px 1px; */ "\n"\
+	"border-style:solid;" /* solid solid solid solid; */ "\n"\
+	"border-color:black;" /* black black black black; */ "\n"\
+	"white-space:nowrap;" "\n"\
+	"}" "\n"\
+	"tr.hdr { background-color:#eee5de; }" "\n"\
+	"tr.o { background-color:#ffffff; }" "\n"\
+	/* tr.e { ... } - for even rows (currently none) */ \
+	"tr.foot { background-color:#eee5de; }" "\n"\
+	"th.cnt { text-align:left; }" "\n"\
+	"th.sz { text-align:right; }" "\n"\
+	"th.dt { text-align:right; }" "\n"\
+	"td.sz { text-align:right; }" "\n"\
+	"td.dt { text-align:right; }" "\n"\
+	"col.nm { width:98%; }" "\n"\
+	"col.sz { width:1%; }" "\n"\
+	"col.dt { width:1%; }" "\n"\
+	"</style>" "\n"\

-	static const char str_footer[] =
-	"<tr class=foot><th class=cnt>Files: %u, directories: %u<th class=sz>%llu<th class=dt> " "\n"
-	/* "</table></body></html>" - why bother? */
-	;
+	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 bad_url_char(unsigned c)
+	static int compare_dl(dir_list_t a, dir_list_t b)
	{
-	return (c - '0') > 9 /* not a digit */
-	&& ((c\|0x20) - 'a') > 26 /* not A-Z or a-z */
-	&& !strchr("._-+@", c);
+	/* ".." 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);
	}

-	static char url_encode(const char name)
-	{
-	int i;
-	int size = 0;
-	int len = strlen(name);
-	char p, result;
-
-	i = 0;
-	while (name[i]) {
-	if (bad_url_char((unsigned)name[i]))
-	size++;
-	i++;
-	}
+	static char buffer[21024 > sizeof(STYLE_STR) ? 21024 : sizeof(STYLE_STR)];
+	static char *dst = buffer;
+	enum {
+	BUFFER_SIZE = sizeof(buffer),
+	HEADROOM = 64,
+	};

-	/* No %xx needed! */
-	if (!size)
-	return (char*)name;
+	/* After this call, you have at least size + HEADROOM bytes available
+	* ahead of dst */
+	static void guarantee(int size)
+	{
+	if (buffer + (BUFFER_SIZE-HEADROOM) - dst >= size)
+	return;
+	write(1, buffer, dst - buffer);
+	dst = buffer;
+	}

-	/* Each %xx requires 2 additional chars */
-	size = size * 2 + len + 1;
-	p = result = malloc(size);
+	/* NB: formatters do not store terminating NUL! */

-	i = 0;
-	while (name[i]) {
-	*p = name[i];
-	if (bad_url_char((unsigned)name[i])) {
-	*p++ = '%';
-	*p++ = "0123456789ABCDEF"[(uint8_t)(name[i]) >> 4];
-	*p = "0123456789ABCDEF"[(uint8_t)(name[i]) & 0xf];
-	}
-	p++;
-	i++;
-	}
-	*p = 0;
-	return result;
+	/* HEADROOM bytes are available after dst after this call */
+	static void fmt_str(/char dst,/ const char src)
+	{
+	unsigned len = strlen(src);
+	guarantee(len);
+	memcpy(dst, src, len);
+	dst += len;
	}

-	static char html_encode(const char name)
+	/* HEADROOM bytes after dst are available after this call */
+	static void fmt_url(/char dst,/ const char name)
	{
-	int i;
-	int size = 0;
-	int len = strlen(name);
-	char p, result;
-
-	i = 0;
-	while (name[i]) {
-	if (name[i] == '<'
-	\|\| name[i] == '>'
-	\|\| name[i] == '&'
+	while (*name) {
+	unsigned c = *name++;
+	guarantee(3);
+	*dst = c;
+	if ((c - '0') > 9 /* not a digit */
+	&& ((c\|0x20) - 'a') > 26 /* not A-Z or a-z */
+	&& !strchr("._-+@", c)
	) {
-	size++;
+	*dst++ = '%';
+	*dst++ = "0123456789ABCDEF"[c >> 4];
+	*dst = "0123456789ABCDEF"[c & 0xf];
	}
-	i++;
+	dst++;
	}
+	}

-	/* No < etc needed! */
-	if (!size)
-	return (char*)name;
-
-	/* & requires 4 additional chars */
-	size = size * 4 + len + 1;
-	p = result = malloc(size);
-
-	i = 0;
-	while (name[i]) {
-	char c;
-	*p = c = name[i++];
+	/* HEADROOM bytes are available after dst after this call */
+	static void fmt_html(/char dst,/ const char name)
+	{
+	while (*name) {
+	char c = *name++;
	if (c == '<')
-	strcpy(p, "<");
+	fmt_str("<");
	else if (c == '>')
-	strcpy(p, ">");
-	else if (c == '&')
-	strcpy(++p, "amp;");
-	else {
-	p++;
+	fmt_str(">");
+	else if (c == '&') {
+	fmt_str("&");
+	} else {
+	guarantee(1);
+	*dst++ = c;
	continue;
	}
-	p += 4;
	}
-	*p = 0;
-	return result;
	}

-	typedef struct dir_list_t {
-	char *dl_name;
-	mode_t dl_mode;
-	off_t dl_size;
-	time_t dl_mtime;
-	} dir_list_t;
+	/* HEADROOM bytes are available after dst after this call */
+	static void 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);
+	fmt_str(/dst,/ p);
+	}

-	static int compare_dl(dir_list_t a, dir_list_t b)
+	/* Does not call guarantee - eats into headroom instead */
+	static void fmt_02u(/char dst,*/ unsigned n)
	{
-	if (strcmp(a->dl_name, "..") == 0) {
-	/* ".." is 'less than' any other dir entry */
-	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);
+	/* n %= 100; - not needed, callers don't pass big n */
+	dst[0] = (n / 10) + '0';
+	dst[1] = (n % 10) + '0';
+	dst += 2;
+	}
+
+	/* Does not call guarantee - eats into headroom instead */
+	static void fmt_04u(/char dst,*/ unsigned n)
+	{
+	/* n %= 10000; - not needed, callers don't pass big n */
+	fmt_02u(n / 100);
+	fmt_02u(n % 100);
	}

	int main(void)
@@ -245,7 +240,6 @@ int main(void)
	dirp = opendir(".");
	if (!dirp)
	return 1;
-
	dir_list = NULL;
	dir_list_count = 0;
	while (1) {
@@ -266,66 +260,83 @@ int main(void)
	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);

-	/* Guard against directories wit &, > etc */
-	QUERY_STRING = html_encode(QUERY_STRING);
-	printf(str_header, QUERY_STRING, QUERY_STRING);
+	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(QUERY_STRING);
+	fmt_str(
+	"</title>\n"
+	STYLE_STR
+	"</head>" "\n"
+	"<body>" "\n"
+	"<h1>Index of ");
+	fmt_html(QUERY_STRING);
+	fmt_str(
+	"</h1>" "\n"
+	"<table>" "\n"
+	"<col class=nm><col class=sz><col class=dt>" "\n"
+	"<tr class=hdr><th class=cnt>Name<th class=sz>Size<th class=dt>Last modified" "\n");

	odd = 0;
	count_dirs = 0;
	count_files = 0;
	size_total = 0;
-
	cdir = dir_list;
	while (dir_list_count--) {
-	char size_str[sizeof(long long) * 3];
-	const char *slash_if_dir;
	struct tm *tm;
-	char *href;
-	char *filename;
-	char datetime_str[sizeof("2000-02-02 02:02:02")];

-	slash_if_dir = "/";
	if (S_ISDIR(cdir->dl_mode)) {
	count_dirs++;
-	size_str[0] = '\0';
	} else if (S_ISREG(cdir->dl_mode)) {
	count_files++;
	size_total += cdir->dl_size;
-	slash_if_dir++; /* points to "" now */
-	sprintf(size_str, "%llu", (unsigned long long)(cdir->dl_size));
	} else
	goto next;
-	href = url_encode(cdir->dl_name); /* %20 etc */
-	filename = html_encode(cdir->dl_name); /* < etc */
+
+	fmt_str("<tr class=");
+	*dst++ = (odd ? 'o' : 'e');
+	fmt_str("><td class=nm><a href='");
+	fmt_url(cdir->dl_name); /* %20 etc */
+	if (S_ISDIR(cdir->dl_mode))
+	*dst++ = '/';
+	fmt_str("'>");
+	fmt_html(cdir->dl_name); /* < etc */
+	if (S_ISDIR(cdir->dl_mode))
+	*dst++ = '/';
+	fmt_str("</a><td class=sz>");
+	if (S_ISREG(cdir->dl_mode))
+	fmt_ull(cdir->dl_size);
+	fmt_str("<td class=dt>");
	tm = gmtime(&cdir->dl_mtime);
-	sprintf(datetime_str, "%04u-%02u-%02u %02u:%02u:%02u",
-	(unsigned)(1900 + tm->tm_year),
-	(unsigned)(tm->tm_mon + 1),
-	(unsigned)(tm->tm_mday),
-	(unsigned)(tm->tm_hour),
-	(unsigned)(tm->tm_min),
-	(unsigned)(tm->tm_sec)
-	);
-	printf("<tr class=%c><td class=nm><a href='%s%s'>%s%s</a><td class=sz>%s<td class=dt>%s\n",
-	odd ? 'o' : 'e',
-	href, slash_if_dir,
-	filename, slash_if_dir,
-	size_str,
-	datetime_str
-	);
-	if (cdir->dl_name != href)
-	free(href);
-	if (cdir->dl_name != filename)
-	free(filename);
+	fmt_04u(1900 + tm->tm_year); *dst++ = '-';
+	fmt_02u(tm->tm_mon + 1); *dst++ = '-';
+	fmt_02u(tm->tm_mday); *dst++ = ' ';
+	fmt_02u(tm->tm_hour); *dst++ = ':';
+	fmt_02u(tm->tm_min); *dst++ = ':';
+	fmt_02u(tm->tm_sec);
+	*dst++ = '\n';
+
	odd = 1 - odd;
	next:
	cdir++;
	}

+	fmt_str("<tr class=foot><th class=cnt>Files: ");
+	fmt_ull(count_files);
	/* count_dirs - 1: we don't want to count ".." */
-	printf(str_footer, count_files, count_dirs - 1, size_total);
+	fmt_str(", directories: ");
+	fmt_ull(count_dirs - 1);
+	fmt_str("<th class=sz>");
+	fmt_ull(size_total);
+	fmt_str("<th class=dt>\n");
+	/* "</table></body></html>" - why bother? */
+	guarantee(BUFFER_SIZE * 2); /* flush */
+
	return 0;
	}