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Vastly improve logging

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This commit is contained in:
Christopher Wellons 2019-02-03 08:09:21 -05:00
parent 81046bcdec
commit 112e5b303f
2 changed files with 77 additions and 29 deletions
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6
README.md
View File

@ -24,6 +24,12 @@ Usage: endlessh [-vh] [-d MSECS] [-m LIMIT] [-p PORT]
-v Print diagnostics to standard output (repeatable)
```
By default no log messages are produced. The first `-v` enables basic
logging and a second `-v` enables debug logging (noisy). All log
messages are sent to standard output.
endlessh -v >endlessh.log 2>endlessh.err
The purpose of limiting the number of clients (`-m`) is to avoid tying
up too many system resources with the tarpit. Clients beyond this limit
are left in the accept queue, not rejected instantly.

90
endlessh.c
View File

@ -12,6 +12,7 @@
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#define DEFAULT_MAX_CLIENTS 4096
@ -30,8 +31,12 @@ uepoch(void)
}
struct client {
long long send_next; // epoch milliseconds for next line
char ipaddr[INET6_ADDRSTRLEN];
long long connect_time;
long long send_next;
long long bytes_sent;
struct client *next;
int port;
int fd;
};
@ -40,9 +45,30 @@ client_new(int fd, long long send_next)
{
struct client *c = malloc(sizeof(*c));
if (c) {
c->connect_time = uepoch();
c->send_next = send_next;
c->bytes_sent = 0;
c->next = 0;
c->fd = fd;
/* Get IP address */
struct sockaddr_storage addr;
socklen_t len = sizeof(addr);
if (getpeername(fd, (struct sockaddr*)&addr, &len) == -1) {
c->ipaddr[0] = 0;
} else {
if (addr.ss_family == AF_INET) {
struct sockaddr_in *s = (struct sockaddr_in *)&addr;
c->port = ntohs(s->sin_port);
inet_ntop(AF_INET, &s->sin_addr,
c->ipaddr, sizeof(c->ipaddr));
} else {
struct sockaddr_in6 *s = (struct sockaddr_in6 *)&addr;
c->port = ntohs(s->sin6_port);
inet_ntop(AF_INET6, &s->sin6_addr,
c->ipaddr, sizeof(c->ipaddr));
}
}
}
return c;
}
@ -151,16 +177,26 @@ randline(char *line)
return len;
}
enum loglevel {
LOG_NONE,
LOG_INFO,
LOG_DEBUG
};
static enum loglevel loglevel = LOG_NONE;
static void
logmsg(const char *format, ...)
logmsg(enum loglevel level, const char *format, ...)
{
if (loglevel >= level) {
long long now = uepoch();
fprintf(stderr, "%lld.%03lld: ", now / 1000, now % 1000);
printf("%lld.%03lld: ", now / 1000, now % 1000);
va_list ap;
va_start(ap, format);
vfprintf(stderr, format, ap);
vprintf(format, ap);
va_end(ap);
fputc('\n', stderr);
fputc('\n', stdout);
}
}
static void
@ -180,7 +216,6 @@ usage(FILE *f)
int
main(int argc, char **argv)
{
int verbose = 0;
int port = DEFAULT_PORT;
long delay = DEFAULT_DELAY;
long max_clients = DEFAULT_MAX_CLIENTS;
@ -218,7 +253,7 @@ main(int argc, char **argv)
port = tmp;
break;
case 'v':
verbose++;
loglevel++;
break;
default:
usage(stderr);
@ -244,8 +279,7 @@ main(int argc, char **argv)
check(bind(server, (void *)&addr, sizeof(addr)));
check(listen(server, INT_MAX));
if (verbose >= 1)
logmsg("listen(port=%d)", port);
logmsg(LOG_DEBUG, "listen(port=%d)", port);
srand(time(0));
for (;;) {
@ -265,17 +299,14 @@ main(int argc, char **argv)
}
/* Wait for next event */
if (verbose >= 2)
logmsg("poll(%zu, %d)%s", pollvec->fill, timeout,
logmsg(LOG_DEBUG, "poll(%zu, %d)%s", pollvec->fill, timeout,
nclients >= max_clients ? " (no accept)" : "");
int r = poll(pollvec->fds, pollvec->fill, timeout);
if (verbose >= 2)
logmsg("= %d", r);
logmsg(LOG_DEBUG, "= %d", r);
if (r == -1) {
switch (errno) {
case EINTR:
if (verbose >= 1)
logmsg("EINTR");
logmsg(LOG_DEBUG, "EINTR");
continue;
default:
fprintf(stderr, "endlessh: fatal: %s\n", strerror(errno));
@ -286,16 +317,16 @@ main(int argc, char **argv)
/* Check for new incoming connections */
if (pollvec->fds[0].revents & POLLIN) {
int fd = accept(server, 0, 0);
if (verbose >= 1)
logmsg("accept() = %d", fd);
logmsg(LOG_DEBUG, "accept() = %d", fd);
if (fd == -1) {
const char *msg = strerror(errno);
switch (errno) {
case EMFILE:
case ENFILE:
max_clients = nclients;
if (verbose >= 1)
logmsg("max clients reduced to %ld", nclients);
logmsg(LOG_INFO,
"maximum number of clients reduced to %ld",
nclients);
break;
case ECONNABORTED:
case EINTR:
@ -314,8 +345,11 @@ main(int argc, char **argv)
fprintf(stderr, "endlessh: warning: out of memory\n");
close(fd);
}
queue_append(queue, client);
nclients++;
logmsg(LOG_INFO, "ACCEPT host=%s:%d fd=%d n=%ld/%ld",
client->ipaddr, client->port, client->fd,
nclients, max_clients);
queue_append(queue, client);
}
}
@ -326,17 +360,25 @@ main(int argc, char **argv)
struct client *client = queue_remove(queue, fd);
if (revents & POLLHUP) {
if (verbose >= 1)
logmsg("close(%d)", fd);
logmsg(LOG_DEBUG, "close(%d)", fd);
long long dt = uepoch() - client->connect_time;
logmsg(LOG_INFO,
"CLOSE host=%s:%d fd=%d "
"time=%lld.%03lld bytes=%lld",
client->ipaddr, client->port, fd,
dt / 1000, dt % 1000,
client->bytes_sent);
close(fd);
free(client);
nclients--;
} else if (revents & POLLOUT) {
char line[255];
char line[256];
int len = randline(line);
/* Don't really care if this send fails */
send(fd, line, len, MSG_DONTWAIT);
ssize_t out = send(fd, line, len, MSG_DONTWAIT);
logmsg(LOG_DEBUG, "send(%d) = %d", fd, (int)out);
client->bytes_sent += out > 0 ? out : out;
client->send_next = uepoch() + delay;
queue_append(queue, client);
}