058547e707
Follow-up fix on commit df4c061136
"
While it is true reversing the condition solves a single-byte read at
one before s, there is a second instance of UB.
Having a pointer to one before an object is in of itself UB in C, it's
on the side of language lawyering, but it's UB.
I add here a quote from a C standard draft:
> When an expression that has integer type is added to or subtracted
> from a pointer, the result has the type of the pointer operand.
> If both the pointer operand and the result point to elements of the
> same array object, or one past the last element of the array object,
> the evaluation shall not produce an overflow; otherwise, the
> behavior is undefined.
Taken from: http://www.iso-9899.info/n1570.html#6.5.6p8
"
Thanks Guilherme Janczak <guilherme.janczak@yandex.com>
67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
/* See LICENSE file for license details. */
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#include <netdb.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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static void
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eprint(const char *fmt, ...) {
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va_list ap;
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va_start(ap, fmt);
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vsnprintf(bufout, sizeof bufout, fmt, ap);
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va_end(ap);
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fprintf(stderr, "%s", bufout);
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if(fmt[0] && fmt[strlen(fmt) - 1] == ':')
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fprintf(stderr, " %s\n", strerror(errno));
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exit(1);
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}
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static int
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dial(char *host, char *port) {
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struct addrinfo hints;
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struct addrinfo *res, *r;
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int fd;
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memset(&hints, 0, sizeof hints);
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hints.ai_family = AF_UNSPEC;
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hints.ai_socktype = SOCK_STREAM;
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if(getaddrinfo(host, port, &hints, &res) != 0)
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eprint("error: cannot resolve hostname '%s':", host);
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for(r = res; r; r = r->ai_next) {
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if((fd = socket(r->ai_family, r->ai_socktype, r->ai_protocol)) == -1)
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continue;
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if(connect(fd, r->ai_addr, r->ai_addrlen) == 0)
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break;
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close(fd);
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}
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freeaddrinfo(res);
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if(!r)
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eprint("error: cannot connect to host '%s'\n", host);
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return fd;
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}
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static char *
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eat(char *s, int (*p)(int), int r) {
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while(*s != '\0' && p((unsigned char)*s) == r)
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s++;
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return s;
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}
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static char*
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skip(char *s, char c) {
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while(*s != c && *s != '\0')
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s++;
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if(*s != '\0')
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*s++ = '\0';
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return s;
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}
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static void
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trim(char *s) {
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char *e;
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for (e = s + strlen(s); e > s && isspace((unsigned char)*(e - 1)); e--)
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;
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*e = '\0';
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}
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