/*

  *  Copyright (C) 2013-2019 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
  *  Copyright (C) 2007-2013 Sourcefire, Inc.

  *
  *  Authors: Tomasz Kojm, Trog, Török Edvin

  *
  *  This program is free software; you can redistribute it and/or modify

  *  it under the terms of the GNU General Public License version 2 as
  *  published by the Free Software Foundation.

  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software

  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  *  MA 02110-1301, USA.

  */
 

 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif
 

 /* must be first because it may define _XOPEN_SOURCE */
 #include "shared/fdpassing.h"

 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>

 #ifdef HAVE_UNISTD_H

 #include <unistd.h>

 #endif

 #include <fcntl.h>
 #include <time.h>
 #include <sys/stat.h>

 #include <errno.h>

 #ifndef _WIN32

 #include <sys/time.h>

 #include <sys/wait.h>

 #include <sys/socket.h>
 #include <sys/ioctl.h>

 #endif

 #if HAVE_SYS_PARAM_H
 #include <sys/param.h>
 #endif
 

 #ifdef HAVE_SYS_TYPES_H

 #include <sys/types.h>
 #endif

 #ifdef HAVE_SYS_FILIO_H

 #include <sys/filio.h>
 #endif

 #include <pthread.h>

 #if HAVE_POLL
 #if HAVE_POLL_H
 #include <poll.h>
 #else /* HAVE_POLL_H */
 #if HAVE_SYS_SELECT_H
 #include <sys/select.h>
 #endif /* HAVE_SYS_SELECT_H */
 #endif /* HAVE_POLL_H */
 #endif /* HAVE_POLL */

 #include <limits.h>

 #include "libclamav/clamav.h"

 #include "libclamav/scanners.h"

 #include "shared/optparser.h"

 #include "shared/output.h"

 #include "shared/misc.h"

 #include "libclamav/others.h"

 #include "others.h"

 static pthread_mutex_t virusaction_lock = PTHREAD_MUTEX_INITIALIZER;
 

 static void xfree(void *p)
 {
     if (p)
         free(p);
 }
 

 #ifdef _WIN32
 void virusaction(const char *filename, const char *virname,
                  const struct optstruct *opts)

 {

     if (optget(opts, "VirusEvent")->enabled)
         logg("^VirusEvent is not supported on this platform"); /* Yet */

 }
 
 #else

 #define VE_FILENAME "CLAM_VIRUSEVENT_FILENAME"

 #define VE_VIRUSNAME "CLAM_VIRUSEVENT_VIRUSNAME"
 

 void virusaction(const char *filename, const char *virname,
                  const struct optstruct *opts)

 {

     pid_t pid;
     const struct optstruct *opt;

     char *buffer_file, *buffer_vir, *buffer_cmd, *path;

     const char *pt;
     size_t i, j, v = 0, len;
     char *env[4];
 

     if (!(opt = optget(opts, "VirusEvent"))->enabled)

         return;
 

     path   = getenv("PATH");

     env[0] = path ? strdup(path) : NULL;

     j      = env[0] ? 1 : 0;

     /* Allocate env vars.. to be portable env vars should not be freed */
     buffer_file =

         (char *)malloc(strlen(VE_FILENAME) + strlen(filename) + 2);
     if (buffer_file) {
         sprintf(buffer_file, "%s=%s", VE_FILENAME, filename);

         env[j++] = buffer_file;
     }
 
     buffer_vir =

         (char *)malloc(strlen(VE_VIRUSNAME) + strlen(virname) + 2);
     if (buffer_vir) {
         sprintf(buffer_vir, "%s=%s", VE_VIRUSNAME, virname);

         env[j++] = buffer_vir;
     }
     env[j++] = NULL;
 
     pt = opt->strarg;

     while ((pt = strstr(pt, "%v"))) {

         pt += 2;
         v++;
     }

     len = strlen(opt->strarg);

     buffer_cmd =

         (char *)calloc(len + v * strlen(virname) + 1, sizeof(char));
     if (!buffer_cmd) {

         if (path)
             xfree(env[0]);

         xfree(buffer_file);
         xfree(buffer_vir);

         return;
     }

     for (i = 0, j = 0; i < len; i++) {
         if (i + 1 < len && opt->strarg[i] == '%' && opt->strarg[i + 1] == 'v') {
             strcat(buffer_cmd, virname);
             j += strlen(virname);

             i++;

         } else {

             buffer_cmd[j++] = opt->strarg[i];
         }
     }
 

     pthread_mutex_lock(&virusaction_lock);

     /* We can only call async-signal-safe functions after fork(). */

     pid = fork();
     if (pid == 0) { /* child */
         exit(execle("/bin/sh", "sh", "-c", buffer_cmd, NULL, env));
     } else if (pid > 0) { /* parent */

         pthread_mutex_unlock(&virusaction_lock);

         while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) continue;
     } else {
         pthread_mutex_unlock(&virusaction_lock);
         logg("!VirusEvent: fork failed.\n");

     }

     if (path)
         xfree(env[0]);

     xfree(buffer_cmd);
     xfree(buffer_file);
     xfree(buffer_vir);

 }

 #endif /* _WIN32 */

 /* Function: writen
 	Try hard to write the specified number of bytes
 */

 int writen(int fd, void *buff, unsigned int count)

 {

     int retval;
     unsigned int todo;
     unsigned char *current;
 

     todo    = count;
     current = (unsigned char *)buff;

     do {
         retval = write(fd, current, todo);
         if (retval < 0) {
             if (errno == EINTR) {

                 continue;
             }
             return -1;
         }
         todo -= retval;
         current += retval;

     } while (todo > 0);

     return count;
 }

 static int

 realloc_polldata(struct fd_data *data)

 {
 #ifdef HAVE_POLL
     if (data->poll_data_nfds == data->nfds)

         return 0;

     if (data->poll_data)

         free(data->poll_data);
     data->poll_data = malloc(data->nfds * sizeof(*data->poll_data));
     if (!data->poll_data) {
         logg("!realloc_polldata: Memory allocation failed for poll_data\n");

         return -1;

     }

     data->poll_data_nfds = data->nfds;

 #endif

     return 0;

 }

 int poll_fd(int fd, int timeout_sec, int check_signals)

 {

     int ret;

     struct fd_data fds = FDS_INIT(NULL);

     if (fds_add(&fds, fd, 1, timeout_sec) == -1)

         return -1;

     do {
         ret = fds_poll_recv(&fds, timeout_sec, check_signals, NULL);
     } while (ret == -1 && errno == EINTR);
     fds_free(&fds);

     return ret;
 }
 

 void fds_cleanup(struct fd_data *data)

 {
     struct fd_buf *newbuf;

     unsigned i, j;
 

     for (i = 0, j = 0; i < data->nfds; i++) {
         if (data->buf[i].fd < 0) {

             if (data->buf[i].buffer)

                 free(data->buf[i].buffer);

             continue;
         }
         if (i != j)
             data->buf[j] = data->buf[i];
         j++;

     }

     if (j == data->nfds)

         return;
     for (i = j; i < data->nfds; i++)
         data->buf[i].fd = -1;

     data->nfds = j;

     logg("$Number of file descriptors polled: %u fds\n",
          (unsigned)data->nfds);

     /* Shrink buffer */

     newbuf = realloc(data->buf, j * sizeof(*newbuf));

     if (!j)
         data->buf = NULL;

     else if (newbuf)

         data->buf = newbuf; /* non-fatal if shrink fails */

 }
 

 static int

 read_fd_data(struct fd_buf *buf)

 {

     ssize_t n;

     buf->got_newdata = 1;

     if (!buf->buffer) /* listen-only socket */

         return 1;

     if (buf->off >= buf->bufsize)

         return -1;

         /* Read the pending packet, it may contain more than one command, but

      * that is to the cmdparser to handle. 
      * It will handle 1st command, and then move leftover to beginning of buffer
      */

 #ifdef HAVE_FD_PASSING

     {
         struct msghdr msg;
         struct cmsghdr *cmsg;

         union {
             unsigned char buff[CMSG_SPACE(sizeof(int))];

             struct cmsghdr hdr;
         } b;
         struct iovec iov[1];
 

         if (buf->recvfd != -1) {
             logg("$Closing unclaimed FD: %d\n", buf->recvfd);
             close(buf->recvfd);

             buf->recvfd = -1;
         }

         memset(&msg, 0, sizeof(msg));
         iov[0].iov_base    = buf->buffer + buf->off;
         iov[0].iov_len     = buf->bufsize - buf->off;
         msg.msg_iov        = iov;
         msg.msg_iovlen     = 1;
         msg.msg_control    = b.buff;
         msg.msg_controllen = sizeof(b.buff);
 
         n = recvmsg(buf->fd, &msg, 0);

         if (n < 0)
             return -1;

         if (msg.msg_flags & MSG_TRUNC) {
             logg("^Message truncated at %d bytes\n", (int)n);

             return -1;
         }

         if (msg.msg_flags & MSG_CTRUNC) {

             if (msg.msg_controllen > 0)

                 logg("^Control message truncated at %d bytes, %d data read\n", (int)msg.msg_controllen, (int)n);

             else

                 logg("^Control message truncated, no control data received, %d bytes read"

 #ifdef C_LINUX

                      "(Is SELinux/AppArmor enabled, and blocking file descriptor passing?)"

 #endif

                      "\n",
                      (int)n);

             return -1;
         }

         if (msg.msg_controllen) {
             for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
                  cmsg = CMSG_NXTHDR(&msg, cmsg)) {
                 if (cmsg->cmsg_len == CMSG_LEN(sizeof(int)) &&

                     cmsg->cmsg_level == SOL_SOCKET &&

                     cmsg->cmsg_type == SCM_RIGHTS) {
                     if (buf->recvfd != -1) {
                         logg("$Unclaimed file descriptor received. closing: %d\n", buf->recvfd);
                         close(buf->recvfd);

                     }

                     buf->recvfd = *(int *)CMSG_DATA(cmsg);
                     logg("$Receveived a file descriptor: %d\n", buf->recvfd);

                 }
             }
         }
     }

 #else

     n = recv(buf->fd, buf->buffer + buf->off, buf->bufsize - buf->off, 0);

     if (n < 0)
         return -1;

 #endif

     buf->off += n;
     return n;

 }

 static int

 buf_init(struct fd_buf *buf, int listen_only, int timeout)

 {

     buf->off         = 0;

     buf->got_newdata = 0;

     buf->recvfd      = -1;
     buf->mode        = MODE_COMMAND;
     buf->id          = 0;
     buf->dumpfd      = -1;
     buf->chunksize   = 0;
     buf->quota       = 0;
     buf->dumpname    = NULL;
     buf->group       = NULL;
     buf->term        = '\0';
     if (!listen_only) {
         if (!buf->buffer) {

             buf->bufsize = PATH_MAX + 8;
             /* plus extra space for a \0 so we can make sure every command is \0
              * terminated */

             if (!(buf->buffer = malloc(buf->bufsize + 1))) {
                 logg("!add_fd: Memory allocation failed for command buffer\n");

                 return -1;
             }
         }

     } else {

         if (buf->buffer)

             free(buf->buffer);

         buf->bufsize = 0;

         buf->buffer  = NULL;

     }

     if (timeout) {
         time(&buf->timeout_at);

         buf->timeout_at += timeout;

     } else {

         buf->timeout_at = 0;

     }

     return 0;
 }

 int fds_add(struct fd_data *data, int fd, int listen_only, int timeout)

 {
     struct fd_buf *buf;
     unsigned n;

     if (fd < 0) {
         logg("!add_fd: invalid fd passed to add_fd\n");

         return -1;

     }

     /* we may already have this fd, if
      * the old FD got closed, and the kernel reused the FD */
     for (n = 0; n < data->nfds; n++)

         if (data->buf[n].fd == fd) {

             /* clear stale data in buffer */

             if (buf_init(&data->buf[n], listen_only, timeout) < 0)

                 return -1;
             return 0;
         }

 
     n++;

     buf = realloc(data->buf, n * sizeof(*buf));
     if (!buf) {
         logg("!add_fd: Memory allocation failed for fd_buf\n");

         return -1;

     }

     data->buf               = buf;
     data->nfds              = n;

     data->buf[n - 1].buffer = NULL;

     if (buf_init(&data->buf[n - 1], listen_only, timeout) < 0)

         return -1;
     data->buf[n - 1].fd = fd;

     return 0;

 }

 static inline void

 fds_lock(struct fd_data *data)

 {
     if (data->buf_mutex)

         pthread_mutex_lock(data->buf_mutex);

 }
 

 static inline void

 fds_unlock(struct fd_data *data)

 {
     if (data->buf_mutex)

         pthread_mutex_unlock(data->buf_mutex);

 }
 

 void fds_remove(struct fd_data *data, int fd)

 {

     size_t i;

     fds_lock(data);
     if (data->buf) {
         for (i = 0; i < data->nfds; i++) {
             if (data->buf[i].fd == fd) {

                 data->buf[i].fd = -1;
                 break;
             }
         }

     }

     fds_unlock(data);

 }

 #define BUFFSIZE 1024
 /* Wait till data is available to be read on any of the fds,
  * read available data on all fds, and mark them as appropriate.
  * One of the fds should be a pipe, used by the accept thread to wake us.
  * timeout is specified in seconds, if check_signals is non-zero, then
  * poll_recv_fds() will return upon receipt of a signal, even if no data
  * is received on any of the sockets.

  * Must be called with buf_mutex lock held.

  */
 /* TODO: handle ReadTimeout */

 int fds_poll_recv(struct fd_data *data, int timeout, int check_signals,
                   void *event)

 {

     unsigned fdsok = data->nfds;
     size_t i;
     int retval;

     time_t now, closest_timeout;

     UNUSEDPARAM(event);
 

     /* we must have at least one fd, the control fd! */

     fds_cleanup(data);

 #ifndef _WIN32

     if (!data->nfds)

         return 0;

 #endif

     for (i = 0; i < data->nfds; i++) {

         data->buf[i].got_newdata = 0;

     }
 

     time(&now);

     if (timeout > 0)

         closest_timeout = now + timeout;

     else

         closest_timeout = 0;

     for (i = 0; i < data->nfds; i++) {

         time_t timeout_at = data->buf[i].timeout_at;

         if (timeout_at && timeout_at < now) {

             /* timed out */
             data->buf[i].got_newdata = -2;
             /* we must return immediately from poll/select, we have a timeout! */
             closest_timeout = now;

         } else {

             if (!closest_timeout)
                 closest_timeout = timeout_at;
             else if (timeout_at && timeout_at < closest_timeout)
                 closest_timeout = timeout_at;
         }

     }
     if (closest_timeout)

         timeout = closest_timeout - now;

     else

         timeout = -1;

     if (timeout > 0)

         logg("$fds_poll_recv: timeout after %d seconds\n", timeout);

 #ifdef HAVE_POLL
     /* Use poll() if available, preferred because:
      *  - can poll any number of FDs
      *  - can notify of both data available / socket disconnected events
      *  - when it says POLLIN it is guaranteed that a following recv() won't
      *  block (select may say that data is available to read, but a following 
      *  recv() may still block according to the manpage
      */
 

     if (realloc_polldata(data) == -1)

         return -1;

     if (timeout > 0) {

         /* seconds to ms */
         timeout *= 1000;

     }

     for (i = 0; i < data->nfds; i++) {
         data->poll_data[i].fd      = data->buf[i].fd;
         data->poll_data[i].events  = POLLIN;

         data->poll_data[i].revents = 0;

     }

     do {

         int n = data->nfds;

         fds_unlock(data);

 #ifdef _WIN32

         retval = poll_with_event(data->poll_data, n, timeout, event);

 #else

         retval = poll(data->poll_data, n, timeout);

 #endif

         fds_lock(data);

         if (retval > 0) {

             fdsok = 0;
             /* nfds may change during poll, but not
              * poll_data_nfds */

             for (i = 0; i < data->poll_data_nfds; i++) {

                 short revents;
                 if (data->buf[i].fd < 0)
                     continue;

                 if (data->buf[i].fd != data->poll_data[i].fd) {

                     /* should never happen */

                     logg("!poll_recv_fds FD mismatch\n");

                     continue;
                 }
                 revents = data->poll_data[i].revents;

                 if (revents & (POLLIN | POLLHUP)) {
                     logg("$Received POLLIN|POLLHUP on fd %d\n",
                          data->poll_data[i].fd);

                 }

 #ifndef _WIN32

                 if (revents & POLLHUP) {

                     /* avoid SHUT_WR problem on Mac OS X */

                     int ret = send(data->poll_data[i].fd, &n, 0, 0);

                     if (!ret || (ret == -1 && errno == EINTR))
                         revents &= ~POLLHUP;
                 }

 #endif

                 if (revents & POLLIN) {
                     int ret = read_fd_data(&data->buf[i]);

                     /* Data available to be read */
                     if (ret == -1)
                         revents |= POLLERR;
                     else if (!ret)
                         revents = POLLHUP;
                 }
 

                 if (revents & (POLLHUP | POLLERR | POLLNVAL)) {
                     if (revents & (POLLHUP | POLLNVAL)) {

                         /* remote disconnected */

                         logg("*Client disconnected (FD %d)\n",
                              data->poll_data[i].fd);
                     } else {

                         /* error on file descriptor */

                         logg("^Error condition on fd %d\n",
                              data->poll_data[i].fd);

                     }
                     data->buf[i].got_newdata = -1;

                 } else {

                     fdsok++;
                 }
             }
         }

     } while (retval == -1 && !check_signals && errno == EINTR);

 #else

     {

         fd_set rfds;
         struct timeval tv;
         int maxfd = -1;
 

         for (i = 0; i < data->nfds; i++) {

             int fd = data->buf[i].fd;

             if (fd >= FD_SETSIZE) {
                 logg("!File descriptor is too high for FD_SET\n");

                 return -1;
             }
 

             maxfd = MAX(maxfd, fd);

         }
 

         do {
             FD_ZERO(&rfds);
             for (i = 0; i < data->nfds; i++) {

                 int fd = data->buf[i].fd;
                 if (fd >= 0)

                     FD_SET(fd, &rfds);

             }

             tv.tv_sec  = timeout;

             tv.tv_usec = 0;
 

             fds_unlock(data);

             retval =

                 select(maxfd + 1, &rfds, NULL, NULL,
                        timeout >= 0 ? &tv : NULL);
             fds_lock(data);
             if (retval > 0) {

                 fdsok = data->nfds;

                 for (i = 0; i < data->nfds; i++) {
                     if (data->buf[i].fd < 0) {

                         fdsok--;
                         continue;
                     }

                     if (FD_ISSET(data->buf[i].fd, &rfds)) {
                         int ret = read_fd_data(&data->buf[i]);
                         if (ret == -1 || !ret) {

                             if (ret == -1)

                                 logg("!Error condition on fd %d\n",
                                      data->buf[i].fd);
                             else {

                                 /* avoid SHUT_WR problem on Mac OS X */

                                 int ret = send(data->buf[i].fd, &i, 0, 0);

                                 if (!ret || (ret == -1 && errno == EINTR))
                                     continue;

                                 logg("*Client disconnected\n");

                             }
                             data->buf[i].got_newdata = -1;
                         }
                     }
                 }
             }

             if (retval < 0 && errno == EBADF) {

                 /* unlike poll(),  select() won't tell us which FD is bad, so
                  * we have to check them one by one. */

                 tv.tv_sec  = 0;

                 tv.tv_usec = 0;
                 /* with tv == 0 it doesn't check for EBADF */

                 FD_ZERO(&rfds);
                 for (i = 0; i < data->nfds; i++) {

                     if (data->buf[i].fd == -1)
                         continue;

                     FD_SET(data->buf[i].fd, &rfds);
                     do {

                         retval =

                             select(data->buf[i].fd + 1, &rfds, NULL, NULL,
                                    &tv);
                     } while (retval == -1 && errno == EINTR);
                     if (retval == -1) {

                         data->buf[i].fd = -1;

                     } else {
                         FD_CLR(data->buf[i].fd, &rfds);

                     }
                 }
                 retval = -1;

                 errno  = EINTR;

                 continue;
             }

         } while (retval == -1 && !check_signals && errno == EINTR);

     }

 #endif
 

     if (retval == -1 && errno != EINTR) {

         char err[128];

 #ifdef HAVE_POLL

         logg("!poll_recv_fds: poll failed: %s\n",
              cli_strerror(errno, err, sizeof(err)));

 #else

         logg("!poll_recv_fds: select failed: %s\n",
              cli_strerror(errno, err, sizeof(err)));

 #endif

     }

 
     return retval;
 }
 

 void fds_free(struct fd_data *data)

 {
     unsigned i;

     fds_lock(data);
     for (i = 0; i < data->nfds; i++) {
         if (data->buf[i].buffer) {
             free(data->buf[i].buffer);

         }

     }

     if (data->buf)

         free(data->buf);

 #ifdef HAVE_POLL
     if (data->poll_data)

         free(data->poll_data);

 #endif

     data->buf  = NULL;

     data->nfds = 0;

     fds_unlock(data);

 }