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/*
* This was copied from atheme/libathemecore/email.c
*
* Copyright (c) 2021 Aaron Jones <me@aaronmdjones.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <string.h>
#include <ctype.h>
#include <stdio.h>
int validemail(const char *email)
{
int i, valid = 1, chars = 0, atcnt = 0, dotcnt1 = 0;
char c;
const char *lastdot = NULL;
/* sane length */
if (strlen(email) > 50)
return 0;
/* RFC2822 */
#define EXTRA_ATEXTCHARS "!#$%&'*+-/=?^_`{|}~"
/* note that we do not allow domain literals or quoted strings */
for (i = 0; email[i] != '\0'; i++) {
c = email[i];
if (c == '.') {
dotcnt1++;
lastdot = &email[i];
/* dot may not be first or last, no consecutive dots */
if (i == 0 || email[i - 1] == '.' ||
email[i - 1] == '@' ||
email[i + 1] == '\0' || email[i + 1] == '@')
return 0;
} else if (c == '@') {
atcnt++;
dotcnt1 = 0;
} else if ((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
strchr(EXTRA_ATEXTCHARS, c))
chars++;
else
return 0;
}
/* must have exactly one @, and at least one . after the @ */
if (atcnt != 1 || dotcnt1 == 0)
return 0;
/* no mail to IP addresses, this should be done using [10.2.3.4]
* like syntax but we do not allow that either
*/
if (isdigit((unsigned char)lastdot[1]))
return 0;
/* make sure there are at least 4 characters besides the above
* mentioned @ and .
*/
if (chars < 4)
return 0;
return valid;
}
int main(int argc, char **argv)
{
if (argc < 2) {
printf("no\n");
return 1;
}
printf("%d\n", validemail(argv[1]));
}
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