Last active
September 27, 2018 13:30
-
-
Save benaryorg/4897ce5fe7cdb27cb8d86a6fef318789 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// somewhat performant discard service I guess. | |
// listens on localhost:1337 (it's not port 9 since I prefer non-priv users) | |
// | |
// compile with something like that: | |
// clang -Wall -Wextra -Werror -pedantic -std=c11 -O2 -o discard discard.c | |
#include <err.h> | |
#include <fcntl.h> | |
#include <netdb.h> | |
#include <stdlib.h> | |
#include <string.h> | |
#include <sys/sendfile.h> | |
#include <sys/socket.h> | |
#include <sys/wait.h> | |
#include <unistd.h> | |
void sigchld(int sig) | |
{ | |
(void)sig; | |
int status; | |
if(waitpid(-1,&status,WNOHANG) == -1) | |
{ | |
err(EXIT_FAILURE,"waitpid"); | |
} | |
} | |
int main(int argc,char **argv) | |
{ | |
if(argc > 1) | |
{ | |
errx(EXIT_FAILURE,"Usage: %s",argv[0]); | |
} | |
struct addrinfo hints; | |
struct addrinfo *result,*rp; | |
int n; | |
pid_t pid; | |
memset(&hints,0,sizeof(struct addrinfo)); | |
hints.ai_family = AF_UNSPEC; | |
hints.ai_socktype = SOCK_STREAM; | |
hints.ai_flags = AI_PASSIVE; | |
n = getaddrinfo("localhost","1337",&hints,&result); | |
if(n != 0) | |
{ | |
errx(EXIT_FAILURE,"getaddrinfo: %s",gai_strerror(n)); | |
} | |
int server; | |
for(rp = result;rp != NULL;rp = rp->ai_next) | |
{ | |
server = socket(rp->ai_family,rp->ai_socktype,rp->ai_protocol); | |
if(server == -1) | |
{ | |
warn("socket"); | |
continue; | |
} | |
int optval = 1; | |
setsockopt(server,SOL_SOCKET,SO_REUSEADDR,&optval,sizeof optval); | |
if(bind(server,rp->ai_addr,rp->ai_addrlen) == 0) | |
{ | |
break; | |
} | |
warn("bind"); | |
close(server); | |
} | |
if(rp == NULL) | |
{ | |
errx(EXIT_FAILURE,"Could not bind"); | |
} | |
freeaddrinfo(result); | |
listen(server,4); | |
signal(SIGCHLD,sigchld); | |
for(;;) | |
{ | |
int them = accept(server,NULL,NULL); | |
if(them < 0) | |
{ | |
warn("accept"); | |
continue; | |
} | |
if((pid=fork())) | |
{ | |
if(pid < 0) | |
{ | |
err(EXIT_FAILURE,"fork"); | |
} | |
close(them); | |
continue; | |
} | |
int devnull = open("/dev/null",O_WRONLY); | |
while((n = sendfile(devnull,them,0,0x8000000)) > 0); | |
if(n < 0) | |
{ | |
warn("sendfile"); | |
} | |
close(them); | |
close(devnull); | |
err(EXIT_SUCCESS,"prnt"); | |
} | |
} | |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment