networking/httpd_indexcgi.c

   1 /*
   2  * Copyright (c) 2007 Denys Vlasenko <vda.linux@googlemail.com>
   3  *
   4  * Licensed under GPLv2, see file LICENSE in this tarball for details.
   5  */
   6
   7 /*
   8  * This program is a CGI application. It outputs directory index page.
   9  * Put it into cgi-bin/index.cgi and chmod 0755.
  10  */
  11
  12 /* Build a-la
  13 i486-linux-uclibc-gcc \
  14 -static -static-libgcc \
  15 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 \
  16 -Wall -Wshadow -Wwrite-strings -Wundef -Wstrict-prototypes -Werror \
  17 -Wold-style-definition -Wdeclaration-after-statement -Wno-pointer-sign \
  18 -Wmissing-prototypes -Wmissing-declarations \
  19 -Os -fno-builtin-strlen -finline-limit=0 -fomit-frame-pointer \
  20 -ffunction-sections -fdata-sections -fno-guess-branch-probability \
  21 -funsigned-char \
  22 -falign-functions=1 -falign-jumps=1 -falign-labels=1 -falign-loops=1 \
  23 -march=i386 -mpreferred-stack-boundary=2 \
  24 -Wl,-Map -Wl,link.map -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \
  25 httpd_indexcgi.c -o index.cgi
  26 */
  27
  28 /* We don't use printf, as it pulls in >12 kb of code from uclibc (i386). */
  29 /* Currently malloc machinery is the biggest part of libc we pull in. */
  30 /* We have only one realloc and one strdup, any idea how to do without? */
  31 /* Size (i386, approximate):
  32  *   text    data     bss     dec     hex filename
  33  *  13036      44    3052   16132    3f04 index.cgi
  34  *   2576       4    2048    4628    1214 index.cgi.o
  35  */
  36
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39 #include <errno.h>
  40 #include <stdint.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <stdio.h>
  45 #include <dirent.h>
  46 #include <time.h>
  47
  48 /* Appearance of the table is controlled by style sheet *ONLY*,
  49  * formatting code uses <TAG class=CLASS> to apply style
  50  * to elements. Edit stylesheet to your liking and recompile. */
  51
  52 #define STYLE_STR \
  53 "<style>"                                               "\n"\
  54 "table {"                                               "\n"\
  55   "width:100%;"                                         "\n"\
  56   "background-color:#fff5ee;"                           "\n"\
  57   "border-width:1px;" /* 1px 1px 1px 1px; */            "\n"\
  58   "border-spacing:2px;"                                 "\n"\
  59   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  60   "border-color:black;" /* black black black black; */  "\n"\
  61   "border-collapse:collapse;"                           "\n"\
  62 "}"                                                     "\n"\
  63 "th {"                                                  "\n"\
  64   "border-width:1px;" /* 1px 1px 1px 1px; */            "\n"\
  65   "padding:1px;" /* 1px 1px 1px 1px; */                 "\n"\
  66   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  67   "border-color:black;" /* black black black black; */  "\n"\
  68 "}"                                                     "\n"\
  69 "td {"                                                  "\n"\
  70              /* top right bottom left */                    \
  71   "border-width:0px 1px 0px 1px;"                       "\n"\
  72   "padding:1px;" /* 1px 1px 1px 1px; */                 "\n"\
  73   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  74   "border-color:black;" /* black black black black; */  "\n"\
  75   "white-space:nowrap;"                                 "\n"\
  76 "}"                                                     "\n"\
  77 "tr.hdr { background-color:#eee5de; }"                  "\n"\
  78 "tr.o { background-color:#ffffff; }"                    "\n"\
  79 /* tr.e { ... } - for even rows (currently none) */         \
  80 "tr.foot { background-color:#eee5de; }"                 "\n"\
  81 "th.cnt { text-align:left; }"                           "\n"\
  82 "th.sz { text-align:right; }"                           "\n"\
  83 "th.dt { text-align:right; }"                           "\n"\
  84 "td.sz { text-align:right; }"                           "\n"\
  85 "td.dt { text-align:right; }"                           "\n"\
  86 "col.nm { width:98%; }"                                 "\n"\
  87 "col.sz { width:1%; }"                                  "\n"\
  88 "col.dt { width:1%; }"                                  "\n"\
  89 "</style>"                                              "\n"\
  90
  91 typedef struct dir_list_t {
  92         char  *dl_name;
  93         mode_t dl_mode;
  94         off_t  dl_size;
  95         time_t dl_mtime;
  96 } dir_list_t;
  97
  98 static int compare_dl(dir_list_t *a, dir_list_t *b)
  99 {
 100         /* ".." is 'less than' any other dir entry */
 101         if (strcmp(a->dl_name, "..") == 0) {
 102                 return -1;
 103         }
 104         if (strcmp(b->dl_name, "..") == 0) {
 105                 return 1;
 106         }
 107         if (S_ISDIR(a->dl_mode) != S_ISDIR(b->dl_mode)) {
 108                 /* 1 if b is a dir (and thus a is 'after' b, a > b),
 109                  * else -1 (a < b) */
 110                 return (S_ISDIR(b->dl_mode) != 0) ? 1 : -1;
 111         }
 112         return strcmp(a->dl_name, b->dl_name);
 113 }
 114
 115 static char buffer[2*1024 > sizeof(STYLE_STR) ? 2*1024 : sizeof(STYLE_STR)];
 116 static char *dst = buffer;
 117 enum {
 118         BUFFER_SIZE = sizeof(buffer),
 119         HEADROOM = 64,
 120 };
 121
 122 /* After this call, you have at least size + HEADROOM bytes available
 123  * ahead of dst */
 124 static void guarantee(int size)
 125 {
 126         if (buffer + (BUFFER_SIZE-HEADROOM) - dst >= size)
 127                 return;
 128         write(STDOUT_FILENO, buffer, dst - buffer);
 129         dst = buffer;
 130 }
 131
 132 /* NB: formatters do not store terminating NUL! */
 133
 134 /* HEADROOM bytes are available after dst after this call */
 135 static void fmt_str(/*char *dst,*/ const char *src)
 136 {
 137         unsigned len = strlen(src);
 138         guarantee(len);
 139         memcpy(dst, src, len);
 140         dst += len;
 141 }
 142
 143 /* HEADROOM bytes after dst are available after this call */
 144 static void fmt_url(/*char *dst,*/ const char *name)
 145 {
 146         while (*name) {
 147                 unsigned c = *name++;
 148                 guarantee(3);
 149                 *dst = c;
 150                 if ((c - '0') > 9 /* not a digit */
 151                  && ((c|0x20) - 'a') > 26 /* not A-Z or a-z */
 152                  && !strchr("._-+@", c)
 153                 ) {
 154                         *dst++ = '%';
 155                         *dst++ = "0123456789ABCDEF"[c >> 4];
 156                         *dst = "0123456789ABCDEF"[c & 0xf];
 157                 }
 158                 dst++;
 159         }
 160 }
 161
 162 /* HEADROOM bytes are available after dst after this call */
 163 static void fmt_html(/*char *dst,*/ const char *name)
 164 {
 165         while (*name) {
 166                 char c = *name++;
 167                 if (c == '<')
 168                         fmt_str("&lt;");
 169                 else if (c == '>')
 170                         fmt_str("&gt;");
 171                 else if (c == '&') {
 172                         fmt_str("&amp;");
 173                 } else {
 174                         guarantee(1);
 175                         *dst++ = c;
 176                         continue;
 177                 }
 178         }
 179 }
 180
 181 /* HEADROOM bytes are available after dst after this call */
 182 static void fmt_ull(/*char *dst,*/ unsigned long long n)
 183 {
 184         char buf[sizeof(n)*3 + 2];
 185         char *p;
 186
 187         p = buf + sizeof(buf) - 1;
 188         *p = '\0';
 189         do {
 190                 *--p = (n % 10) + '0';
 191                 n /= 10;
 192         } while (n);
 193         fmt_str(/*dst,*/ p);
 194 }
 195
 196 /* Does not call guarantee - eats into headroom instead */
 197 static void fmt_02u(/*char *dst,*/ unsigned n)
 198 {
 199         /* n %= 100; - not needed, callers don't pass big n */
 200         dst[0] = (n / 10) + '0';
 201         dst[1] = (n % 10) + '0';
 202         dst += 2;
 203 }
 204
 205 /* Does not call guarantee - eats into headroom instead */
 206 static void fmt_04u(/*char *dst,*/ unsigned n)
 207 {
 208         /* n %= 10000; - not needed, callers don't pass big n */
 209         fmt_02u(n / 100);
 210         fmt_02u(n % 100);
 211 }
 212
 213 int main(void)
 214 {
 215         dir_list_t *dir_list;
 216         dir_list_t *cdir;
 217         unsigned dir_list_count;
 218         unsigned count_dirs;
 219         unsigned count_files;
 220         unsigned long long size_total;
 221         int odd;
 222         DIR *dirp;
 223         char *QUERY_STRING;
 224
 225         QUERY_STRING = getenv("QUERY_STRING");
 226         if (!QUERY_STRING
 227          || QUERY_STRING[0] != '/'
 228          || strstr(QUERY_STRING, "/../")
 229          || strcmp(strrchr(QUERY_STRING, '/'), "/..") == 0
 230         ) {
 231                 return 1;
 232         }
 233
 234         if (chdir("..")
 235          || (QUERY_STRING[1] && chdir(QUERY_STRING + 1))
 236         ) {
 237                 return 1;
 238         }
 239
 240         dirp = opendir(".");
 241         if (!dirp)
 242                 return 1;
 243         dir_list = NULL;
 244         dir_list_count = 0;
 245         while (1) {
 246                 struct dirent *dp;
 247                 struct stat sb;
 248
 249                 dp = readdir(dirp);
 250                 if (!dp)
 251                         break;
 252                 if (dp->d_name[0] == '.' && !dp->d_name[1])
 253                         continue;
 254                 if (stat(dp->d_name, &sb) != 0)
 255                         continue;
 256                 dir_list = realloc(dir_list, (dir_list_count + 1) * sizeof(dir_list[0]));
 257                 dir_list[dir_list_count].dl_name = strdup(dp->d_name);
 258                 dir_list[dir_list_count].dl_mode = sb.st_mode;
 259                 dir_list[dir_list_count].dl_size = sb.st_size;
 260                 dir_list[dir_list_count].dl_mtime = sb.st_mtime;
 261                 dir_list_count++;
 262         }
 263         closedir(dirp);
 264
 265         qsort(dir_list, dir_list_count, sizeof(dir_list[0]), (void*)compare_dl);
 266
 267         fmt_str(
 268                 "" /* Additional headers (currently none) */
 269                 "\r\n" /* Mandatory empty line after headers */
 270                 "<html><head><title>Index of ");
 271         /* Guard against directories with &, > etc */
 272         fmt_html(QUERY_STRING);
 273         fmt_str(
 274                 "</title>\n"
 275                 STYLE_STR
 276                 "</head>" "\n"
 277                 "<body>" "\n"
 278                 "<h1>Index of ");
 279         fmt_html(QUERY_STRING);
 280         fmt_str(
 281                 "</h1>" "\n"
 282                 "<table>" "\n"
 283                 "<col class=nm><col class=sz><col class=dt>" "\n"
 284                 "<tr class=hdr><th class=cnt>Name<th class=sz>Size<th class=dt>Last modified" "\n");
 285
 286         odd = 0;
 287         count_dirs = 0;
 288         count_files = 0;
 289         size_total = 0;
 290         cdir = dir_list;
 291         while (dir_list_count--) {
 292                 struct tm *tm;
 293
 294                 if (S_ISDIR(cdir->dl_mode)) {
 295                         count_dirs++;
 296                 } else if (S_ISREG(cdir->dl_mode)) {
 297                         count_files++;
 298                         size_total += cdir->dl_size;
 299                 } else
 300                         goto next;
 301
 302                 fmt_str("<tr class=");
 303                 *dst++ = (odd ? 'o' : 'e');
 304                 fmt_str("><td class=nm><a href='");
 305                 fmt_url(cdir->dl_name); /* %20 etc */
 306                 if (S_ISDIR(cdir->dl_mode))
 307                         *dst++ = '/';
 308                 fmt_str("'>");
 309                 fmt_html(cdir->dl_name); /* &lt; etc */
 310                 if (S_ISDIR(cdir->dl_mode))
 311                         *dst++ = '/';
 312                 fmt_str("</a><td class=sz>");
 313                 if (S_ISREG(cdir->dl_mode))
 314                         fmt_ull(cdir->dl_size);
 315                 fmt_str("<td class=dt>");
 316                 tm = gmtime(&cdir->dl_mtime);
 317                 fmt_04u(1900 + tm->tm_year); *dst++ = '-';
 318                 fmt_02u(tm->tm_mon + 1); *dst++ = '-';
 319                 fmt_02u(tm->tm_mday); *dst++ = ' ';
 320                 fmt_02u(tm->tm_hour); *dst++ = ':';
 321                 fmt_02u(tm->tm_min); *dst++ = ':';
 322                 fmt_02u(tm->tm_sec);
 323                 *dst++ = '\n';
 324
 325                 odd = 1 - odd;
 326  next:
 327                 cdir++;
 328         }
 329
 330         fmt_str("<tr class=foot><th class=cnt>Files: ");
 331         fmt_ull(count_files);
 332         /* count_dirs - 1: we don't want to count ".." */
 333         fmt_str(", directories: ");
 334         fmt_ull(count_dirs - 1);
 335         fmt_str("<th class=sz>");
 336         fmt_ull(size_total);
 337         fmt_str("<th class=dt>\n");
 338         /* "</table></body></html>" - why bother? */
 339         guarantee(BUFFER_SIZE * 2); /* flush */
 340
 341         return 0;
 342 }