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add fd passing functions

master
Felix von Leitner 16 years ago
parent
commit
ec2f230bb4
5 changed files with 129 additions and 0 deletions
  1. +1
    -0
      CHANGES
  2. +12
    -0
      io.h
  3. +32
    -0
      io/io_passfd.c
  4. +45
    -0
      io/io_receivefd.c
  5. +39
    -0
      test/fdpassing.c

+ 1
- 0
CHANGES View File

@@ -1,5 +1,6 @@
0.19:
add io_socketpair
add io_passfd and io_receivefd (and test/fdpassing.c)

0.18:
make libowfat compile on BSD again (sorry, and thanks to everyone who


+ 12
- 0
io.h View File

@@ -7,12 +7,16 @@
#include "taia.h"

/* like open(s,O_RDONLY) */
/* return 1 if ok, 0 on error */
int io_readfile(int64* d,const char* s);
/* like open(s,O_WRONLY|O_CREAT|O_TRUNC,0600) */
/* return 1 if ok, 0 on error */
int io_createfile(int64* d,const char* s);
/* like pipe(d) */
/* return 1 if ok, 0 on error */
int io_pipe(int64* d);
/* like socketpair() */
/* return 1 if ok, 0 on error */
int io_socketpair(int64* d);

/* non-blocking read(), -1 for EAGAIN and -3+errno for other errors */
@@ -82,6 +86,14 @@ void io_finishandshutdown(void);
/* return number of bytes written */
int64 io_sendfile(int64 s,int64 fd,uint64 off,uint64 n);

/* Pass fd over sock (must be a unix domain socket) to other process.
* Return 0 if ok, -1 on error, setting errno. */
int io_passfd(int64 sock,int64 fd);

/* Receive fd over sock (must be a unix domain socket) from other
* process. Return sock if ok, -1 on error, setting errno. */
int64 io_receivefd(int64 sock);

#ifdef __MINGW32__
#include_next <io.h>
#endif


+ 32
- 0
io/io_passfd.c View File

@@ -0,0 +1,32 @@
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#include "io_internal.h"

union fdmsg {
struct cmsghdr h;
char buf[CMSG_SPACE(sizeof(int))];
};

int io_passfd(int64 sock,int64 fd) {
struct msghdr msg = {0};
struct cmsghdr *cmsg;
struct iovec iov;
char buf[CMSG_SPACE(sizeof(int))];
iov.iov_len=1;
iov.iov_base="x";
msg.msg_control = buf;
msg.msg_controllen = sizeof buf;
msg.msg_iov=&iov;
msg.msg_iovlen=1;
msg.msg_name=0;
msg.msg_namelen=0;
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
*((int*)CMSG_DATA(cmsg))=fd;
msg.msg_controllen = cmsg->cmsg_len;
return sendmsg(sock,&msg,0);
}

+ 45
- 0
io/io_receivefd.c View File

@@ -0,0 +1,45 @@
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <errno.h>
#include "io_internal.h"

union fdmsg {
struct cmsghdr h;
char buf[CMSG_SPACE(sizeof(int))];
};

int64 io_receivefd(int64 sock) {
struct iovec iov;
struct msghdr msg;
union fdmsg cmsg;
struct cmsghdr* h;
char x[100];
char name[100];
iov.iov_base=x;
iov.iov_len=100;
msg.msg_name=name;
msg.msg_namelen=100;
msg.msg_control=cmsg.buf;
msg.msg_controllen=sizeof(union fdmsg);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_flags=0;
h=CMSG_FIRSTHDR(&msg);
h->cmsg_len=CMSG_LEN(sizeof(int));
h->cmsg_level=SOL_SOCKET;
h->cmsg_type=SCM_RIGHTS;
*((int*)CMSG_DATA(h))=-1;
if (recvmsg(sock,&msg,0)==-1)
return -1;
h=CMSG_FIRSTHDR(&msg);
if (!h || h->cmsg_len!=CMSG_LEN(sizeof(int)) || h->cmsg_level!=SOL_SOCKET || h->cmsg_type!=SCM_RIGHTS) {
#ifdef EPROTO
errno=EPROTO;
#else
errno=EINVAL;
#endif
return -1;
}
return *((int*)CMSG_DATA(h));
}

+ 39
- 0
test/fdpassing.c View File

@@ -0,0 +1,39 @@
#include <unistd.h>
#include "io.h"
#include "buffer.h"

void child(int64 fd) {
int64 x=io_receivefd(fd);
char buf[8192];
int i;
if (x==-1) {
buffer_putsflush(buffer_2,"fd passing failed!\n");
exit(1);
}
i=read(x,buf,sizeof(buf));
write(1,buf,i);
io_close(x);
}

void father(int64 fd) {
int64 x;
if (io_readfile(&x,"/etc/resolv.conf"))
io_passfd(fd,x);
}

main() {
int64 sp[2];
if (io_socketpair(sp)==-1) return 1;
switch (fork()) {
case -1: return 1;
case 0: /* child */
io_close(sp[0]);
child(sp[1]);
break;
default:
io_close(sp[1]);
father(sp[0]);
break;
}
return 0;
}

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