From de4c5d3d8c77f0c1f68b72fff3d7e3be0dc2dec2 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Thu, 23 Aug 2007 10:43:18 +0000 Subject: httpd: code shrink of dir indexer example --- networking/httpd_indexcgi.c | 381 +++++++++++++++++++++++--------------------- 1 file changed, 196 insertions(+), 185 deletions(-) diff --git a/networking/httpd_indexcgi.c b/networking/httpd_indexcgi.c index def8632..fd64af3 100644 --- a/networking/httpd_indexcgi.c +++ b/networking/httpd_indexcgi.c @@ -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 #include @@ -47,172 +49,165 @@ Size (approximate): * formatting code uses 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 */ -"Index of %s" "\n" -"" "\n" -"" "\n" -"" "\n" -"

Index of %s

" "\n" -"" "\n" -"" "\n" -"" "\n" -"

Name	Size	Last modified" "\n" -; +#define STYLE_STR \ +"" "\n"\ -static const char str_footer[] = -"
Files: %u, directories: %u	%llu	" "\n" -/* "

" - 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[2*1024 > sizeof(STYLE_STR) ? 2*1024 : 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 */ + "Index of "); + /* Guard against directories with &, > etc */ + fmt_html(QUERY_STRING); + fmt_str( + "\n" + STYLE_STR + "" "\n" + "" "\n" + "

Index of "); + fmt_html(QUERY_STRING); + fmt_str( + "

" "\n" + "" "\n" + "" "\n" + "

Name	Size	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("
"); + fmt_html(cdir->dl_name); /* < etc / + if (S_ISDIR(cdir->dl_mode)) + dst++ = '/'; + fmt_str("	"); + if (S_ISREG(cdir->dl_mode)) + fmt_ull(cdir->dl_size); + fmt_str("	"); 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("
%s%s	%s	%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("
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("	"); + fmt_ull(size_total); + fmt_str("	\n"); + /* "

" - why bother? */ + guarantee(BUFFER_SIZE * 2); /* flush */ + return 0; } -- cgit v1.1