Re: Apache + mod_php performance

On 10/7/2024 11:52 AM, Dan Cross wrote:

// Demonstration of a listener process that accepts
// incoming TCP connections and passes them to a
// worker process over Unix domain sockets.
//
// Dan Cross <cross@gajendra.net>
 #include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
 #include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
 // Sends a file descripter, `fd`, over a Unix domain socket `sd`
// via the 4.4BSD access rights passing mechanism.
//
// Returns 1 on success, -1 on failure.
int
sendfd(int sd, int fd)
{
struct msghdr mh;
struct iovec iv;
struct cmsghdr *ptr;
size_t len;
int ret;
char dummy;
  // Construct the control message header.  Note this is
// malloc'ed to ensure proper alignment.
len = CMSG_SPACE(sizeof(int));
ptr = malloc(len);
if (ptr == NULL)
return -1;
memset(ptr, 0, len);
ptr->cmsg_len = len;
ptr->cmsg_level = SOL_SOCKET;
ptr->cmsg_type = SCM_RIGHTS;
memcpy(CMSG_DATA(ptr), &fd, sizeof(int));
  // We send a single byte of dummy data in case the
// implementation does not pass control data with an
// otherwise empty data transfer.
dummy = 0;
memset(&iv, 0, sizeof(iv));
iv.iov_base = &dummy;
iv.iov_len = 1;
  // Construct the message header.  Points to the dummy
// data and the control message header.
memset(&mh, 0, sizeof(mh));
mh.msg_name = NULL;
mh.msg_namelen = 0;
mh.msg_iov = &iv;
mh.msg_iovlen = 1;
mh.msg_control = (caddr_t)ptr;
mh.msg_controllen = len;
mh.msg_flags = 0;
  // Loop in case there's no room in the kernel buffer
// to send.  Cf.Stevens et al.
do {
ret = sendmsg(sd, &mh, 0);
} while (ret == 0);
free(ptr);
  return ret;
}
 // Receives a file descriptor over the Unix domain socket `sd`
// and store it into `*fdp` on success.
//
// Returns 1 on success, 0 on EOF, -1 on error.
int
recvfd(int sd, int *fdp)
{
struct msghdr mh;
struct iovec iv;
struct cmsghdr *ptr;
size_t len;
int ret;
char dummy;
  if (fdp == NULL)
return -1;
  // Allocate space for the control message.
len = CMSG_SPACE(sizeof(int));
ptr = malloc(len);
if (ptr == NULL)
return -1;
  // Fill in an iovec to receive one byte of dummy data.
// Required on some systems that do not pass control
// messages on empty data transfers.
memset(&iv, 0, sizeof(iv));
iv.iov_base = &dummy;
iv.iov_len = 1;
  // Fill in the msghdr structure.  `recvmsg(2)` will
// update it.
memset(&mh, 0, sizeof(mh));
mh.msg_name = NULL;
mh.msg_namelen = 0;
mh.msg_iov = &iv;
mh.msg_iovlen = 1;
mh.msg_control = ptr;
mh.msg_controllen = len;
mh.msg_flags = 0;
  ret = recvmsg(sd, &mh, 0);
if (ret <= 0) {
free(ptr);
return ret;
}
if (mh.msg_flags != 0) {
free(ptr);
return -1;
}
memcpy(fdp, CMSG_DATA(ptr), sizeof(int));
free(ptr);
  return 1;
}
 void
dispatcher(int sdworker, int port)
{
int sd, nsd;
struct sockaddr_in sa;
struct sockaddr_in client;
socklen_t clientlen;
  sd = socket(AF_INET, SOCK_STREAM, 0);
if (sd < 0) {
perror("socket");
close(sdworker);
exit(EXIT_FAILURE);
}
memset(&sa, 0, sizeof sa);
sa.sin_family = AF_INET;
sa.sin_port = htons((unsigned short)port);
sa.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(sd, (struct sockaddr *)&sa, sizeof sa) < 0) {
perror("bind");
close(sdworker);
close(sd);
exit(EXIT_FAILURE);
}
if (listen(sd, 255) < 0) {
perror("listen");
close(sdworker);
close(sd);
exit(EXIT_FAILURE);
}
  memset(&client, 0, sizeof client);
clientlen = sizeof client;
while ((nsd = accept(sd, (struct sockaddr *)&client, &clientlen)) >= 0) {
if (sendfd(sdworker, nsd) < 0) {
perror("sendfd");
close(sdworker);
close(nsd);
close(sd);
exit(EXIT_FAILURE);
}
close(nsd);
}
}
 static void
echo(int sd)
{
char *p;
char buf[1024];
ssize_t nb, wb;
  for (;;) {
nb = read(sd, buf, sizeof buf);
if (nb < 0)
perror("read");
if (nb <= 0)
return;
p = buf;
while (nb > 0) {
wb = write(sd, p, nb);
if (wb < 0)
perror("write");
if (wb <= 0)
return;
nb -= wb;
p += wb;
}
}
}
 void
worker(int sddispatcher)
{
int sd;
  while (recvfd(sddispatcher, &sd) > 0) {
echo(sd);
close(sd);
}
}
 int
main(void)
{
int sds[2];
pid_t pid;
  if (socketpair(AF_UNIX, SOCK_STREAM, 0, sds) > 0) {
perror("socketpair");
exit(EXIT_FAILURE);
}
  for (int k = 0; k < 3; k++) {
pid = fork();
if (pid < 0) {
perror("fork");
exit(EXIT_FAILURE);
}
if (pid == 0) { // Child
close(sds[0]);
worker(sds[1]);
exit(EXIT_SUCCESS);
}
}
close(sds[1]);
dispatcher(sds[0], 8200);
  return EXIT_SUCCESS;
}

$ cc zz
    len = CMSG_SPACE(sizeof(int));
.........^
%CC-I-IMPLICITFUNC, In this statement, the identifier "CMSG_SPACE" is implicitly declared as a function.
at line number 33 in file DKA0:[arne]zz.c;1
    mh.msg_control = (caddr_t)ptr;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_control" is not a member of "mh".
at line number 56 in file DKA0:[arne]zz.c;1
    mh.msg_controllen = len;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_controllen" is not a member of "mh".
at line number 57 in file DKA0:[arne]zz.c;1
    mh.msg_flags = 0;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_flags" is not a member of "mh".
at line number 58 in file DKA0:[arne]zz.c;1
    mh.msg_control = ptr;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_control" is not a member of "mh".
at line number 100 in file DKA0:[arne]zz.c;1
    mh.msg_controllen = len;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_controllen" is not a member of "mh".
at line number 101 in file DKA0:[arne]zz.c;1
    mh.msg_flags = 0;
...^
%CC-E-NEEDMEMBER, In this statement, "msg_flags" is not a member of "mh".
at line number 102 in file DKA0:[arne]zz.c;1
    if (mh.msg_flags != 0) {
.......^
%CC-E-NEEDMEMBER, In this statement, "msg_flags" is not a member of "mh".
at line number 108 in file DKA0:[arne]zz.c;1
       pid = fork();
............^
%CC-I-IMPLICITFUNC, In this statement, the identifier "fork" is implicitly declared as a function.
at line number 201 in file DKA0:[arne]zz.c;1
Arne