156 lines
2.4 KiB
C
156 lines
2.4 KiB
C
/*
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* For decoding the files that get passed to validateattachment.
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* NOT a general mime decoder.
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*/
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#include <u.h>
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#include <libc.h>
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#include <bio.h>
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enum { None, Base64, Quoted };
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static int decquoted(char *out, char *in, char *e);
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void
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main(void)
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{
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Biobuf b, b1;
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char *p, *encoding;
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int e, len;
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Binit(&b, 0, OREAD);
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Binit(&b1, 1, OWRITE);
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/* header */
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encoding = nil;
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while((p = Brdstr(&b, '\n', 1)) != nil){
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if(p[0] == 0)
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break;
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if(strncmp(p, "Content-Transfer-Encoding: ", 27) == 0)
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encoding = strdup(p+27);
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free(p);
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}
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e = None;
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if(encoding == nil)
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e = None;
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else if(strcmp(encoding, "base64") == 0)
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e = Base64;
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else if(strcmp(encoding, "quoted-printable") == 0)
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e = Quoted;
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while((p = Brdstr(&b, '\n', 0)) != nil){
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if(strncmp(p, "--", 2) == 0 && e != None)
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break;
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len = strlen(p);
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switch(e){
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case None:
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break;
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case Base64:
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len = dec64((uchar*)p, len, p, len);
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break;
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case Quoted:
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len = decquoted(p, p, p+len);
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break;
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}
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Bwrite(&b1, p, len);
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free(p);
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}
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exits(0);
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}
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/*
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* decode quoted
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*/
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enum
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{
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Self= 1,
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Hex= 2
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};
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uchar tableqp[256];
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static void
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initquoted(void)
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{
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int c;
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memset(tableqp, 0, 256);
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for(c = ' '; c <= '<'; c++)
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tableqp[c] = Self;
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for(c = '>'; c <= '~'; c++)
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tableqp[c] = Self;
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tableqp['\t'] = Self;
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tableqp['='] = Hex;
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}
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static int
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hex2int(int x)
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{
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if(x >= '0' && x <= '9')
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return x - '0';
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if(x >= 'A' && x <= 'F')
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return (x - 'A') + 10;
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if(x >= 'a' && x <= 'f')
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return (x - 'a') + 10;
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return 0;
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}
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static char*
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decquotedline(char *out, char *in, char *e)
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{
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int c, soft;
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/* dump trailing white space */
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while(e >= in && (*e == ' ' || *e == '\t' || *e == '\r' || *e == '\n'))
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e--;
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/* trailing '=' means no newline */
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if(*e == '='){
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soft = 1;
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e--;
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} else
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soft = 0;
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while(in <= e){
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c = (*in++) & 0xff;
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switch(tableqp[c]){
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case Self:
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*out++ = c;
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break;
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case Hex:
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c = hex2int(*in++)<<4;
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c |= hex2int(*in++);
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*out++ = c;
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break;
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}
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}
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if(!soft)
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*out++ = '\n';
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*out = 0;
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return out;
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}
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static int
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decquoted(char *out, char *in, char *e)
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{
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char *p, *nl;
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if(tableqp[' '] == 0)
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initquoted();
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p = out;
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while((nl = strchr(in, '\n')) != nil && nl < e){
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p = decquotedline(p, in, nl);
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in = nl + 1;
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}
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if(in < e)
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p = decquotedline(p, in, e-1);
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/* make sure we end with a new line */
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if(*(p-1) != '\n'){
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*p++ = '\n';
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*p = 0;
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}
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return p - out;
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}
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