add support for authentication using SCM_CREDENTIALS

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@596 fefdeb5f-60dc-0310-8127-8f9354f1896f

src/polypcore/iochannel.c

@@ -27,12 +27,14 @@
 #include <assert.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include "winsock.h"
 
 #include <polypcore/util.h>
 #include <polypcore/socket-util.h>
 #include <polypcore/xmalloc.h>
+#include <polypcore/log.h>
 
 #include "iochannel.h"
 
@@ -242,6 +244,134 @@ ssize_t pa_iochannel_read(pa_iochannel*io, void*data, size_t l) {
     return r;
 }
 
+#ifdef SCM_CREDENTIALS
+
+int pa_iochannel_creds_supported(pa_iochannel *io) {
+    struct sockaddr_un sa;
+    socklen_t l;
+    
+    assert(io);
+    assert(io->ifd >= 0);
+    assert(io->ofd == io->ifd);
+
+    l = sizeof(sa);
+    
+    if (getsockname(io->ifd, (struct sockaddr*) &sa, &l) < 0)
+        return 0;
+
+    return sa.sun_family == AF_UNIX;
+}
+
+int pa_iochannel_creds_enable(pa_iochannel *io) {
+    int t = 1;
+
+    assert(io);
+    assert(io->ifd >= 0);
+    
+    if (setsockopt(io->ifd, SOL_SOCKET, SO_PASSCRED, &t, sizeof(t)) < 0) {
+        pa_log_error("setsockopt(SOL_SOCKET, SO_PASSCRED): %s", strerror(errno));
+        return -1;
+    }
+
+    return 0;
+}
+
+ssize_t pa_iochannel_write_with_creds(pa_iochannel*io, const void*data, size_t l) {
+    ssize_t r;
+    struct msghdr mh;
+    struct iovec iov;
+    uint8_t cmsg_data[CMSG_SPACE(sizeof(struct ucred))];
+    struct ucred *ucred;
+    struct cmsghdr *cmsg;
+    
+    assert(io);
+    assert(data);
+    assert(l);
+    assert(io->ofd >= 0);
+
+    memset(&iov, 0, sizeof(iov));
+    iov.iov_base = (void*) data;
+    iov.iov_len = l;
+
+    memset(cmsg_data, 0, sizeof(cmsg_data));
+    cmsg = (struct cmsghdr*)  cmsg_data;
+    cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type = SCM_CREDENTIALS;
+
+    ucred = (struct ucred*) CMSG_DATA(cmsg);
+    ucred->pid = getpid();
+    ucred->uid = getuid();
+    ucred->gid = getgid();
+    
+    memset(&mh, 0, sizeof(mh));
+    mh.msg_name = NULL;
+    mh.msg_namelen = 0;
+    mh.msg_iov = &iov;
+    mh.msg_iovlen = 1;
+    mh.msg_control = cmsg_data;
+    mh.msg_controllen = sizeof(cmsg_data);
+    mh.msg_flags = 0;
+
+    if ((r = sendmsg(io->ofd, &mh, MSG_NOSIGNAL)) >= 0) {
+        io->writable = 0;
+        enable_mainloop_sources(io);
+    }
+
+    return r;
+}
+
+ssize_t pa_iochannel_read_with_creds(pa_iochannel*io, void*data, size_t l, struct ucred *ucred, int *creds_valid) {
+    ssize_t r;
+    struct msghdr mh;
+    struct iovec iov;
+    uint8_t cmsg_data[CMSG_SPACE(sizeof(struct ucred))];
+    
+    assert(io);
+    assert(data);
+    assert(l);
+    assert(io->ifd >= 0);
+    assert(ucred);
+    assert(creds_valid);
+
+    memset(&iov, 0, sizeof(iov));
+    iov.iov_base = data;
+    iov.iov_len = l;
+
+    memset(cmsg_data, 0, sizeof(cmsg_data));
+
+    memset(&mh, 0, sizeof(mh));
+    mh.msg_name = NULL;
+    mh.msg_namelen = 0;
+    mh.msg_iov = &iov;
+    mh.msg_iovlen = 1;
+    mh.msg_control = cmsg_data;
+    mh.msg_controllen = sizeof(cmsg_data);
+    mh.msg_flags = 0;
+
+    if ((r = recvmsg(io->ifd, &mh, MSG_NOSIGNAL)) >= 0) {
+        struct cmsghdr *cmsg;
+
+        *creds_valid = 0;
+    
+        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+            
+            if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDENTIALS) {
+                assert(cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)));
+                memcpy(ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
+                *creds_valid = 1;
+                break;
+            }
+        }
+
+        io->readable = 0;
+        enable_mainloop_sources(io);
+    }
+    
+    return r;
+}
+#endif
+
 void pa_iochannel_set_callback(pa_iochannel*io, pa_iochannel_cb_t _callback, void *userdata) {
     assert(io);