| 1 | /* Copyright (c) University of Cambridge 1995 - 2018 */ |
| 2 | /* See the file NOTICE for conditions of use and distribution. */ |
| 3 | |
| 4 | #include "exim.h" |
| 5 | |
| 6 | #ifdef SUPPORT_I18N |
| 7 | |
| 8 | uschar * |
| 9 | imap_utf7_encode(uschar *string, const uschar *charset, uschar sep, |
| 10 | uschar *specials, uschar **error) |
| 11 | { |
| 12 | static uschar encode_base64[64] = |
| 13 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"; |
| 14 | size_t slen; |
| 15 | uschar *sptr; |
| 16 | gstring * yield = NULL; |
| 17 | int i = 0; /* compiler quietening */ |
| 18 | uschar c = 0; /* compiler quietening */ |
| 19 | BOOL base64mode = FALSE; |
| 20 | BOOL lastsep = FALSE; |
| 21 | uschar utf16buf[256]; |
| 22 | uschar *utf16ptr; |
| 23 | uschar *s; |
| 24 | uschar outbuf[256]; |
| 25 | uschar *outptr = outbuf; |
| 26 | #if HAVE_ICONV |
| 27 | iconv_t icd; |
| 28 | #endif |
| 29 | |
| 30 | if (!specials) specials = US""; |
| 31 | |
| 32 | /* Pass over the string. If it consists entirely of "normal" characters |
| 33 | (possibly with leading seps), return it as is. */ |
| 34 | for (s = string; *s; s++) |
| 35 | { |
| 36 | if (s == string && *s == sep) |
| 37 | string++; |
| 38 | if ( *s >= 0x7f |
| 39 | || *s < 0x20 |
| 40 | || strchr("./&", *s) |
| 41 | || *s == sep |
| 42 | || Ustrchr(specials, *s) |
| 43 | ) |
| 44 | break; |
| 45 | } |
| 46 | |
| 47 | if (!*s) |
| 48 | return string; |
| 49 | |
| 50 | sptr = string; |
| 51 | slen = Ustrlen(string); |
| 52 | |
| 53 | #if HAVE_ICONV |
| 54 | if ((icd = iconv_open("UTF-16BE", CCS charset)) == (iconv_t)-1) |
| 55 | { |
| 56 | *error = string_sprintf( |
| 57 | "imapfolder: iconv_open(\"UTF-16BE\", \"%s\") failed: %s%s", |
| 58 | charset, strerror(errno), |
| 59 | errno == EINVAL ? " (maybe unsupported conversion)" : ""); |
| 60 | return NULL; |
| 61 | } |
| 62 | #endif |
| 63 | |
| 64 | while (slen > 0) |
| 65 | { |
| 66 | #if HAVE_ICONV |
| 67 | size_t left = sizeof(utf16buf); |
| 68 | utf16ptr = utf16buf; |
| 69 | |
| 70 | if ( iconv(icd, (ICONV_ARG2_TYPE)&sptr, &slen, CSS &utf16ptr, &left) |
| 71 | == (size_t)-1 |
| 72 | && errno != E2BIG |
| 73 | ) |
| 74 | { |
| 75 | *error = string_sprintf("imapfolder: iconv() failed to convert from %s: %s", |
| 76 | charset, strerror(errno)); |
| 77 | iconv_close(icd); |
| 78 | return NULL; |
| 79 | } |
| 80 | #else |
| 81 | for (utf16ptr = utf16buf; |
| 82 | slen > 0 && (utf16ptr - utf16buf) < sizeof(utf16buf); |
| 83 | utf16ptr += 2, slen--, sptr++) |
| 84 | { |
| 85 | *utf16ptr = *sptr; |
| 86 | *(utf16ptr+1) = '\0'; |
| 87 | } |
| 88 | #endif |
| 89 | |
| 90 | s = utf16buf; |
| 91 | while (s < utf16ptr) |
| 92 | { |
| 93 | /* Now encode utf16buf as modified UTF-7 */ |
| 94 | if ( s[0] != 0 |
| 95 | || s[1] >= 0x7f |
| 96 | || s[1] < 0x20 |
| 97 | || (Ustrchr(specials, s[1]) && s[1] != sep) |
| 98 | ) |
| 99 | { |
| 100 | lastsep = FALSE; |
| 101 | /* Encode as modified BASE64 */ |
| 102 | if (!base64mode) |
| 103 | { |
| 104 | *outptr++ = '&'; |
| 105 | base64mode = TRUE; |
| 106 | i = 0; |
| 107 | } |
| 108 | |
| 109 | for (int j = 0; j < 2; j++, s++) switch (i++) |
| 110 | { |
| 111 | case 0: |
| 112 | /* Top 6 bits of the first octet */ |
| 113 | *outptr++ = encode_base64[(*s >> 2) & 0x3F]; |
| 114 | c = (*s & 0x03); break; |
| 115 | case 1: |
| 116 | /* Bottom 2 bits of the first octet, and top 4 bits of the second */ |
| 117 | *outptr++ = encode_base64[(c << 4) | ((*s >> 4) & 0x0F)]; |
| 118 | c = (*s & 0x0F); break; |
| 119 | case 2: |
| 120 | /* Bottom 4 bits of the second octet and top 2 bits of the third */ |
| 121 | *outptr++ = encode_base64[(c << 2) | ((*s >> 6) & 0x03)]; |
| 122 | /* Bottom 6 bits of the third octet */ |
| 123 | *outptr++ = encode_base64[*s & 0x3F]; |
| 124 | i = 0; |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | else if ( (s[1] != '.' && s[1] != '/') |
| 129 | || s[1] == sep |
| 130 | ) |
| 131 | { |
| 132 | /* Encode as self (almost) */ |
| 133 | if (base64mode) |
| 134 | { |
| 135 | switch (i) |
| 136 | { |
| 137 | case 1: |
| 138 | /* Remaining bottom 2 bits of the last octet */ |
| 139 | *outptr++ = encode_base64[c << 4]; |
| 140 | break; |
| 141 | case 2: |
| 142 | /* Remaining bottom 4 bits of the last octet */ |
| 143 | *outptr++ = encode_base64[c << 2]; |
| 144 | } |
| 145 | *outptr++ = '-'; |
| 146 | base64mode = FALSE; |
| 147 | } |
| 148 | |
| 149 | if (*++s == sep) |
| 150 | { |
| 151 | if (!lastsep) |
| 152 | { |
| 153 | *outptr++ = '.'; |
| 154 | lastsep = TRUE; |
| 155 | } |
| 156 | } |
| 157 | else |
| 158 | { |
| 159 | *outptr++ = *s; |
| 160 | if (*s == '&') |
| 161 | *outptr++ = '-'; |
| 162 | lastsep = FALSE; |
| 163 | } |
| 164 | |
| 165 | s++; |
| 166 | } |
| 167 | else |
| 168 | { |
| 169 | *error = string_sprintf("imapfolder: illegal character '%c'", s[1]); |
| 170 | return NULL; |
| 171 | } |
| 172 | |
| 173 | if (outptr > outbuf + sizeof(outbuf) - 3) |
| 174 | { |
| 175 | yield = string_catn(yield, outbuf, outptr - outbuf); |
| 176 | outptr = outbuf; |
| 177 | } |
| 178 | |
| 179 | } |
| 180 | } /* End of input string */ |
| 181 | |
| 182 | if (base64mode) |
| 183 | { |
| 184 | switch (i) |
| 185 | { |
| 186 | case 1: |
| 187 | /* Remaining bottom 2 bits of the last octet */ |
| 188 | *outptr++ = encode_base64[c << 4]; |
| 189 | break; |
| 190 | case 2: |
| 191 | /* Remaining bottom 4 bits of the last octet */ |
| 192 | *outptr++ = encode_base64[c << 2]; |
| 193 | } |
| 194 | *outptr++ = '-'; |
| 195 | } |
| 196 | |
| 197 | #if HAVE_ICONV |
| 198 | iconv_close(icd); |
| 199 | #endif |
| 200 | |
| 201 | yield = string_catn(yield, outbuf, outptr - outbuf); |
| 202 | |
| 203 | if (yield->s[yield->ptr-1] == '.') |
| 204 | yield->ptr--; |
| 205 | |
| 206 | return string_from_gstring(yield); |
| 207 | } |
| 208 | |
| 209 | #endif /* whole file */ |
| 210 | /* vi: aw ai sw=2 |
| 211 | */ |