util.c

   1 #include <ctype.h>
   2 #include <stddef.h>
   3 #include <stdbool.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7
   8 #include <stdio.h>
   9
  10 #include "util.h"
  11
  12 char **
  13 parse_command(const char *cmdline)
  14 {
  15         const char *p = cmdline, *s;
  16         char **argv = NULL, *out;
  17         size_t arglen = 0;
  18         int argnum = 0;
  19         bool esc;
  20
  21         while (isspace(*cmdline))
  22                 cmdline++;
  23
  24         for (p = cmdline, s = p, esc = false; p; p++) {
  25                 if (esc) {
  26                         esc = false;
  27                 }
  28                 else if (*p == '\\' && p[1] != 0) {
  29                         esc = true;
  30                 }
  31                 else if (isspace(*p) || *p == 0) {
  32                         if (p > s) {
  33                                 argnum += 1;
  34                                 arglen += sizeof(char *) + (p - s) + 1;
  35                         }
  36
  37                         s = p + 1;
  38                 }
  39
  40                 if (*p == 0)
  41                         break;
  42         }
  43
  44         if (arglen == 0)
  45                 return NULL;
  46
  47         argv = calloc(1, arglen + sizeof(char *));
  48
  49         if (!argv)
  50                 return NULL;
  51
  52         out = (char *)argv + sizeof(char *) * (argnum + 1);
  53         argv[0] = out;
  54
  55         for (p = cmdline, s = p, esc = false, argnum = 0; p; p++) {
  56                 if (esc) {
  57                         esc = false;
  58                         *out++ = *p;
  59                 }
  60                 else if (*p == '\\' && p[1] != 0) {
  61                         esc = true;
  62                 }
  63                 else if (isspace(*p) || *p == 0) {
  64                         if (p > s) {
  65                                 *out++ = ' ';
  66                                 argv[++argnum] = out;
  67                         }
  68
  69                         s = p + 1;
  70                 }
  71                 else {
  72                         *out++ = *p;
  73                 }
  74
  75                 if (*p == 0)
  76                         break;
  77         }
  78
  79         argv[argnum] = NULL;
  80         out[-1] = 0;
  81
  82         return argv;
  83 }
  84
  85 char *
  86 postdecode_fields(char *postbuf, ssize_t len, char **fields, int n_fields)
  87 {
  88         char *p;
  89         int i, field, found = 0;
  90
  91         for (p = postbuf, i = 0; i < len; i++)
  92         {
  93                 if (postbuf[i] == '=')
  94                 {
  95                         postbuf[i] = 0;
  96
  97                         for (field = 0; field < (n_fields * 2); field += 2)
  98                         {
  99                                 if (!strcmp(p, fields[field]))
 100                                 {
 101                                         fields[field + 1] = postbuf + i + 1;
 102                                         found++;
 103                                 }
 104                         }
 105                 }
 106                 else if (postbuf[i] == '&' || postbuf[i] == '\0')
 107                 {
 108                         postbuf[i] = 0;
 109
 110                         if (found >= n_fields)
 111                                 break;
 112
 113                         p = postbuf + i + 1;
 114                 }
 115         }
 116
 117         for (field = 0; field < (n_fields * 2); field += 2)
 118         {
 119                 if (!urldecode(fields[field + 1]))
 120                 {
 121                         free(postbuf);
 122                         return NULL;
 123                 }
 124         }
 125
 126         return postbuf;
 127 }
 128
 129 char *
 130 postdecode(char **fields, int n_fields)
 131 {
 132         const char *var;
 133         char *p, *postbuf;
 134         ssize_t len = 0, rlen = 0, content_length = 0;
 135
 136         var = getenv("CONTENT_TYPE");
 137
 138         if (!var || strncmp(var, "application/x-www-form-urlencoded", 33))
 139                 return NULL;
 140
 141         var = getenv("CONTENT_LENGTH");
 142
 143         if (!var)
 144                 return NULL;
 145
 146         content_length = strtol(var, &p, 10);
 147
 148         if (p == var || content_length <= 0 || content_length >= POST_LIMIT)
 149                 return NULL;
 150
 151         postbuf = calloc(1, content_length + 1);
 152
 153         if (postbuf == NULL)
 154                 return NULL;
 155
 156         for (len = 0; len < content_length; )
 157         {
 158                 rlen = read(0, postbuf + len, content_length - len);
 159
 160                 if (rlen <= 0)
 161                         break;
 162
 163                 len += rlen;
 164         }
 165
 166         if (len < content_length)
 167         {
 168                 free(postbuf);
 169                 return NULL;
 170         }
 171
 172         return postdecode_fields(postbuf, len, fields, n_fields);
 173 }
 174
 175 char *
 176 datadup(const void *in, size_t len)
 177 {
 178         char *out = malloc(len + 1);
 179
 180         if (!out)
 181                 return NULL;
 182
 183         memcpy(out, in, len);
 184
 185         *(out + len) = 0;
 186
 187         return out;
 188 }
 189
 190 char *
 191 canonicalize_path(const char *path, size_t len)
 192 {
 193         char *canonpath, *cp;
 194         const char *p, *e;
 195
 196         if (path == NULL || *path == '\0')
 197                 return NULL;
 198
 199         canonpath = datadup(path, len);
 200
 201         if (canonpath == NULL)
 202                 return NULL;
 203
 204         /* normalize */
 205         for (cp = canonpath, p = path, e = path + len; p < e; ) {
 206                 if (*p != '/')
 207                         goto next;
 208
 209                 /* skip repeating / */
 210                 if ((p + 1 < e) && (p[1] == '/')) {
 211                         p++;
 212                         continue;
 213                 }
 214
 215                 /* /./ or /../ */
 216                 if ((p + 1 < e) && (p[1] == '.')) {
 217                         /* skip /./ */
 218                         if ((p + 2 >= e) || (p[2] == '/')) {
 219                                 p += 2;
 220                                 continue;
 221                         }
 222
 223                         /* collapse /x/../ */
 224                         if ((p + 2 < e) && (p[2] == '.') && ((p + 3 >= e) || (p[3] == '/'))) {
 225                                 while ((cp > canonpath) && (*--cp != '/'))
 226                                         ;
 227
 228                                 p += 3;
 229                                 continue;
 230                         }
 231                 }
 232
 233 next:
 234                 *cp++ = *p++;
 235         }
 236
 237         /* remove trailing slash if not root / */
 238         if ((cp > canonpath + 1) && (cp[-1] == '/'))
 239                 cp--;
 240         else if (cp == canonpath)
 241                 *cp++ = '/';
 242
 243         *cp = '\0';
 244
 245         return canonpath;
 246 }
 247
 248 bool
 249 urldecode(char *buf)
 250 {
 251         char *c, *p;
 252
 253         if (!buf || !*buf)
 254                 return true;
 255
 256 #define hex(x) \
 257         (((x) <= '9') ? ((x) - '0') : \
 258                 (((x) <= 'F') ? ((x) - 'A' + 10) : \
 259                         ((x) - 'a' + 10)))
 260
 261         for (c = p = buf; *p; c++)
 262         {
 263                 if (*p == '%')
 264                 {
 265                         if (!isxdigit(*(p + 1)) || !isxdigit(*(p + 2)))
 266                                 return false;
 267
 268                         *c = (char)(16 * hex(*(p + 1)) + hex(*(p + 2)));
 269
 270                         p += 3;
 271                 }
 272                 else if (*p == '+')
 273                 {
 274                         *c = ' ';
 275                         p++;
 276                 }
 277                 else
 278                 {
 279                         *c = *p++;
 280                 }
 281         }
 282
 283         *c = 0;
 284
 285         return true;
 286 }