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 source tree.
   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
  32 /* Size (i386, static uclibc, approximate):
  33  *   text    data     bss     dec     hex filename
  34  *  13036      44    3052   16132    3f04 index.cgi
  35  *   2576       4    2048    4628    1214 index.cgi.o
  36  */
  37
  38 #define _GNU_SOURCE 1  /* for strchrnul */
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #include <errno.h>
  42 #include <stdint.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46 #include <stdio.h>
  47 #include <dirent.h>
  48 #include <time.h>
  49
  50 /* Appearance of the table is controlled by style sheet *ONLY*,
  51  * formatting code uses <TAG class=CLASS> to apply style
  52  * to elements. Edit stylesheet to your liking and recompile. */
  53
  54 #define STYLE_STR \
  55 "<style>"                                               "\n"\
  56 "table {"                                               "\n"\
  57   "width:100%;"                                         "\n"\
  58   "background-color:#fff5ee;"                           "\n"\
  59   "border-width:1px;" /* 1px 1px 1px 1px; */            "\n"\
  60   "border-spacing:2px;"                                 "\n"\
  61   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  62   "border-color:black;" /* black black black black; */  "\n"\
  63   "border-collapse:collapse;"                           "\n"\
  64 "}"                                                     "\n"\
  65 "th {"                                                  "\n"\
  66   "border-width:1px;" /* 1px 1px 1px 1px; */            "\n"\
  67   "padding:1px;" /* 1px 1px 1px 1px; */                 "\n"\
  68   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  69   "border-color:black;" /* black black black black; */  "\n"\
  70 "}"                                                     "\n"\
  71 "td {"                                                  "\n"\
  72              /* top right bottom left */                    \
  73   "border-width:0px 1px 0px 1px;"                       "\n"\
  74   "padding:1px;" /* 1px 1px 1px 1px; */                 "\n"\
  75   "border-style:solid;" /* solid solid solid solid; */  "\n"\
  76   "border-color:black;" /* black black black black; */  "\n"\
  77   "white-space:nowrap;"                                 "\n"\
  78 "}"                                                     "\n"\
  79 "tr.hdr { background-color:#eee5de; }"                  "\n"\
  80 "tr.o { background-color:#ffffff; }"                    "\n"\
  81 /* tr.e { ... } - for even rows (currently none) */         \
  82 "tr.foot { background-color:#eee5de; }"                 "\n"\
  83 "th.cnt { text-align:left; }"                           "\n"\
  84 "th.sz { text-align:right; }"                           "\n"\
  85 "th.dt { text-align:right; }"                           "\n"\
  86 "td.sz { text-align:right; }"                           "\n"\
  87 "td.dt { text-align:right; }"                           "\n"\
  88 "col.nm { width:98%; }"                                 "\n"\
  89 "col.sz { width:1%; }"                                  "\n"\
  90 "col.dt { width:1%; }"                                  "\n"\
  91 "</style>"                                              "\n"\
  92
  93 typedef struct dir_list_t {
  94         char  *dl_name;
  95         mode_t dl_mode;
  96         off_t  dl_size;
  97         time_t dl_mtime;
  98 } dir_list_t;
  99
 100 static int compare_dl(dir_list_t *a, dir_list_t *b)
 101 {
 102         /* ".." is 'less than' any other dir entry */
 103         if (strcmp(a->dl_name, "..") == 0) {
 104                 return -1;
 105         }
 106         if (strcmp(b->dl_name, "..") == 0) {
 107                 return 1;
 108         }
 109         if (S_ISDIR(a->dl_mode) != S_ISDIR(b->dl_mode)) {
 110                 /* 1 if b is a dir (and thus a is 'after' b, a > b),
 111                  * else -1 (a < b) */
 112                 return (S_ISDIR(b->dl_mode) != 0) ? 1 : -1;
 113         }
 114         return strcmp(a->dl_name, b->dl_name);
 115 }
 116
 117 static char buffer[2*1024 > sizeof(STYLE_STR) ? 2*1024 : sizeof(STYLE_STR)];
 118 static char *dst = buffer;
 119 enum {
 120         BUFFER_SIZE = sizeof(buffer),
 121         HEADROOM = 64,
 122 };
 123
 124 /* After this call, you have at least size + HEADROOM bytes available
 125  * ahead of dst */
 126 static void guarantee(int size)
 127 {
 128         if (buffer + (BUFFER_SIZE-HEADROOM) - dst >= size)
 129                 return;
 130         write(STDOUT_FILENO, buffer, dst - buffer);
 131         dst = buffer;
 132 }
 133
 134 /* NB: formatters do not store terminating NUL! */
 135
 136 /* HEADROOM bytes are available after dst after this call */
 137 static void fmt_str(/*char *dst,*/ const char *src)
 138 {
 139         unsigned len = strlen(src);
 140         guarantee(len);
 141         memcpy(dst, src, len);
 142         dst += len;
 143 }
 144
 145 /* HEADROOM bytes after dst are available after this call */
 146 static void fmt_url(/*char *dst,*/ const char *name)
 147 {
 148         while (*name) {
 149                 unsigned c = *name++;
 150                 guarantee(3);
 151                 *dst = c;
 152                 if ((c - '0') > 9 /* not a digit */
 153                  && ((c|0x20) - 'a') > ('z' - 'a') /* not A-Z or a-z */
 154                  && !strchr("._-+@", c)
 155                 ) {
 156                         *dst++ = '%';
 157                         *dst++ = "0123456789ABCDEF"[c >> 4];
 158                         *dst = "0123456789ABCDEF"[c & 0xf];
 159                 }
 160                 dst++;
 161         }
 162 }
 163
 164 /* HEADROOM bytes are available after dst after this call */
 165 static void fmt_html(/*char *dst,*/ const char *name)
 166 {
 167         while (*name) {
 168                 char c = *name++;
 169                 if (c == '<')
 170                         fmt_str("&lt;");
 171                 else if (c == '>')
 172                         fmt_str("&gt;");
 173                 else if (c == '&') {
 174                         fmt_str("&amp;");
 175                 } else {
 176                         guarantee(1);
 177                         *dst++ = c;
 178                         continue;
 179                 }
 180         }
 181 }
 182
 183 /* HEADROOM bytes are available after dst after this call */
 184 static void fmt_ull(/*char *dst,*/ unsigned long long n)
 185 {
 186         char buf[sizeof(n)*3 + 2];
 187         char *p;
 188
 189         p = buf + sizeof(buf) - 1;
 190         *p = '\0';
 191         do {
 192                 *--p = (n % 10) + '0';
 193                 n /= 10;
 194         } while (n);
 195         fmt_str(/*dst,*/ p);
 196 }
 197
 198 /* Does not call guarantee - eats into headroom instead */
 199 static void fmt_02u(/*char *dst,*/ unsigned n)
 200 {
 201         /* n %= 100; - not needed, callers don't pass big n */
 202         dst[0] = (n / 10) + '0';
 203         dst[1] = (n % 10) + '0';
 204         dst += 2;
 205 }
 206
 207 /* Does not call guarantee - eats into headroom instead */
 208 static void fmt_04u(/*char *dst,*/ unsigned n)
 209 {
 210         /* n %= 10000; - not needed, callers don't pass big n */
 211         fmt_02u(n / 100);
 212         fmt_02u(n % 100);
 213 }
 214
 215 int main(int argc, char *argv[])
 216 {
 217         dir_list_t *dir_list;
 218         dir_list_t *cdir;
 219         unsigned dir_list_count;
 220         unsigned count_dirs;
 221         unsigned count_files;
 222         unsigned long long size_total;
 223         int odd;
 224         DIR *dirp;
 225         char *location;
 226
 227         location = getenv("REQUEST_URI");
 228         if (!location)
 229                 return 1;
 230
 231         /* drop URL arguments if any */
 232         strchrnul(location, '?')[0] = '\0';
 233
 234         if (location[0] != '/'
 235          || strstr(location, "//")
 236          || strstr(location, "/../")
 237          || strcmp(strrchr(location, '/'), "/..") == 0
 238         ) {
 239                 return 1;
 240         }
 241
 242         if (chdir("..")
 243          || (location[1] && chdir(location + 1))
 244         ) {
 245                 return 1;
 246         }
 247
 248         dirp = opendir(".");
 249         if (!dirp)
 250                 return 1;
 251         dir_list = NULL;
 252         dir_list_count = 0;
 253         while (1) {
 254                 struct dirent *dp;
 255                 struct stat sb;
 256
 257                 dp = readdir(dirp);
 258                 if (!dp)
 259                         break;
 260                 if (dp->d_name[0] == '.' && !dp->d_name[1])
 261                         continue;
 262                 if (stat(dp->d_name, &sb) != 0)
 263                         continue;
 264                 dir_list = realloc(dir_list, (dir_list_count + 1) * sizeof(dir_list[0]));
 265                 dir_list[dir_list_count].dl_name = strdup(dp->d_name);
 266                 dir_list[dir_list_count].dl_mode = sb.st_mode;
 267                 dir_list[dir_list_count].dl_size = sb.st_size;
 268                 dir_list[dir_list_count].dl_mtime = sb.st_mtime;
 269                 dir_list_count++;
 270         }
 271         closedir(dirp);
 272
 273         qsort(dir_list, dir_list_count, sizeof(dir_list[0]), (void*)compare_dl);
 274
 275         fmt_str(
 276                 "" /* Additional headers (currently none) */
 277                 "\r\n" /* Mandatory empty line after headers */
 278                 "<html><head><title>Index of ");
 279         /* Guard against directories with &, > etc */
 280         fmt_html(location);
 281         fmt_str(
 282                 "</title>\n"
 283                 STYLE_STR
 284                 "</head>" "\n"
 285                 "<body>" "\n"
 286                 "<h1>Index of ");
 287         fmt_html(location);
 288         fmt_str(
 289                 "</h1>" "\n"
 290                 "<table>" "\n"
 291                 "<col class=nm><col class=sz><col class=dt>" "\n"
 292                 "<tr class=hdr><th class=cnt>Name<th class=sz>Size<th class=dt>Last modified" "\n");
 293
 294         odd = 0;
 295         count_dirs = 0;
 296         count_files = 0;
 297         size_total = 0;
 298         cdir = dir_list;
 299         while (dir_list_count--) {
 300                 struct tm *ptm;
 301
 302                 if (S_ISDIR(cdir->dl_mode)) {
 303                         count_dirs++;
 304                 } else if (S_ISREG(cdir->dl_mode)) {
 305                         count_files++;
 306                         size_total += cdir->dl_size;
 307                 } else
 308                         goto next;
 309
 310                 fmt_str("<tr class=");
 311                 *dst++ = (odd ? 'o' : 'e');
 312                 fmt_str("><td class=nm><a href='");
 313                 fmt_url(cdir->dl_name); /* %20 etc */
 314                 if (S_ISDIR(cdir->dl_mode))
 315                         *dst++ = '/';
 316                 fmt_str("'>");
 317                 fmt_html(cdir->dl_name); /* &lt; etc */
 318                 if (S_ISDIR(cdir->dl_mode))
 319                         *dst++ = '/';
 320                 fmt_str("</a><td class=sz>");
 321                 if (S_ISREG(cdir->dl_mode))
 322                         fmt_ull(cdir->dl_size);
 323                 fmt_str("<td class=dt>");
 324                 ptm = gmtime(&cdir->dl_mtime);
 325                 fmt_04u(1900 + ptm->tm_year); *dst++ = '-';
 326                 fmt_02u(ptm->tm_mon + 1); *dst++ = '-';
 327                 fmt_02u(ptm->tm_mday); *dst++ = ' ';
 328                 fmt_02u(ptm->tm_hour); *dst++ = ':';
 329                 fmt_02u(ptm->tm_min); *dst++ = ':';
 330                 fmt_02u(ptm->tm_sec);
 331                 *dst++ = '\n';
 332
 333                 odd = 1 - odd;
 334  next:
 335                 cdir++;
 336         }
 337
 338         fmt_str("<tr class=foot><th class=cnt>Files: ");
 339         fmt_ull(count_files);
 340         /* count_dirs - 1: we don't want to count ".." */
 341         fmt_str(", directories: ");
 342         fmt_ull(count_dirs - 1);
 343         fmt_str("<th class=sz>");
 344         fmt_ull(size_total);
 345         fmt_str("<th class=dt>\n");
 346         /* "</table></body></html>" - why bother? */
 347         guarantee(BUFFER_SIZE * 2); /* flush */
 348
 349         return 0;
 350 }