webcit/mime_parser.c

   1 /*
   2  * mime_parser.c
   3  *
   4  * This is a really bad attempt at writing a parser to handle multipart
   5  * messages -- in the case of WebCit, a form containing uploaded files.
   6  */
   7
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <stdio.h>
  11 #include <signal.h>
  12 #include <sys/types.h>
  13 #include <ctype.h>
  14 #include <string.h>
  15 #include "webcit.h"
  16 #include "child.h"
  17
  18 /*
  19  * Take a part, figure out its length, and do something with it
  20  */
  21 void process_part(char *content, int part_length) {
  22         FILE *fp;
  23         char filename[256];
  24         static char partno = 0;
  25         char *start;
  26         char buf[512];
  27         int crlf = 0;   /* set to 1 for crlf-style newlines */
  28         int actual_length;
  29
  30         fprintf(stderr, "MIME: process_part() called with a length o' %d\n",
  31                 part_length);
  32
  33         /* Strip off any leading blank lines. */
  34         start = content;
  35         while ((!strncmp(start, "\r", 1)) || (!strncmp(start, "\n", 1))) {
  36                 ++start;
  37                 --part_length;
  38                 }
  39
  40         /* At this point all we have left is the headers and the content. */
  41         do {
  42                 strcpy(buf, "");
  43                 do {
  44                         buf[strlen(buf)+1] = 0;
  45                         strncpy(&buf[strlen(buf)], start, 1);
  46                         ++start;
  47                         --part_length;
  48                         } while((buf[strlen(buf)-1] != 10) && (part_length>0));
  49                 if (part_length <= 0) return;
  50                 buf[strlen(buf)-1] = 0;
  51                 if (buf[strlen(buf)-1]==13) {
  52                         buf[strlen(buf)-1] = 0;
  53                         crlf = 1;
  54                         }
  55                 fprintf(stderr, "MIME: <%s>\n", buf);
  56                 } while (strlen(buf)>0);
  57         fprintf(stderr, "MIME: done processing headers\n");
  58
  59         if (crlf) actual_length = part_length - 2;
  60         else actual_length = part_length - 1;
  61
  62         sprintf(filename, "content.%04x.%04x", getpid(), ++partno);
  63         fp = fopen(filename, "wb");
  64         fwrite(start, actual_length, 1, fp);
  65         fclose(fp);
  66         }
  67
  68
  69 /*
  70  * Main function of parser
  71  */
  72 void mime_parser(char *content, int ContentLength, char *ContentType) {
  73         char boundary[256];
  74         char endary[256];
  75         int have_boundary = 0;
  76         int a;
  77         char *ptr;
  78         char *beginning;
  79         int bytes_processed = 0;
  80         int part_length;
  81
  82         fprintf(stderr, "MIME: ContentLength: %d, ContentType: %s\n",
  83                 ContentLength, ContentType);
  84
  85         /* Figure out what the boundary is */
  86         strcpy(boundary, ContentType);
  87         for (a=0; a<strlen(boundary); ++a) {
  88                 if (!strncasecmp(&boundary[a], "boundary=", 9)) {
  89                         boundary[0]='-';
  90                         boundary[1]='-';
  91                         strcpy(&boundary[2], &boundary[a+9]);
  92                         have_boundary = 1;
  93                         a = 0;
  94                         }
  95                 if ((boundary[a]==13) || (boundary[a]==10)) {
  96                         boundary[a] = 0;
  97                         }
  98                 }
  99
 100         /* We can't process multipart messages without a boundary. */
 101         if (have_boundary == 0) return;
 102         strcpy(endary, boundary);
 103         strcat(endary, "--");
 104         fprintf(stderr, "MIME: boundary is %s\n", boundary);
 105         fprintf(stderr, "MIME:   endary is %s\n", endary);
 106
 107         ptr = content;
 108
 109         /* Seek to the beginning of the next boundary */
 110         while (bytes_processed < ContentLength) {
 111               /* && (strncasecmp(ptr, boundary, strlen(boundary))) ) { */
 112
 113                 if (strncasecmp(ptr, boundary, strlen(boundary))) {
 114                         ++ptr;
 115                         ++bytes_processed;
 116                         }
 117
 118                 /* See if we're at the end */
 119                 if (!strncasecmp(ptr, endary, strlen(endary))) {
 120                         fprintf(stderr, "MIME: the end.\n");
 121                         return;
 122                         }
 123
 124                 /* Seek to the end of the boundary string */
 125                 if (!strncasecmp(ptr, boundary, strlen(boundary))) {
 126                         fprintf(stderr, "MIME: founda bounda\n");
 127                         while ( (bytes_processed < ContentLength)
 128                               && (strncasecmp(ptr, "\n", 1)) ) {
 129                                 ++ptr;
 130                                 ++bytes_processed;
 131                                 }
 132                         beginning = ptr;
 133                         part_length = 0;
 134                         while ( (bytes_processed < ContentLength)
 135                           && (strncasecmp(ptr, boundary, strlen(boundary))) ) {
 136                                 ++ptr;
 137                                 ++bytes_processed;
 138                                 ++part_length;
 139                                 }
 140                         process_part(beginning, part_length);
 141                         /* Back off so we can see the next boundary */
 142                         --ptr;
 143                         --bytes_processed;
 144                         }
 145                 }
 146         }