netutils/rexec/rexecd: Supports remote execution and interaction

and support popen in "r+ w+" mode

Signed-off-by: dongjiuzhu1 <[email protected]>

netutils/rexec/rexec.c

@@ -22,6 +22,7 @@
  * Included Files
  ****************************************************************************/
 
+#include <sys/poll.h>
 #include <sys/types.h>
 #include <getopt.h>
 #include <netdb.h>
@@ -82,6 +83,7 @@ static void usage(FAR const char *progname)
 static int do_rexec(FAR struct rexec_arg_s *arg)
 {
   char buffer[REXEC_BUFSIZE];
+  struct pollfd fds[2];
   int sock;
   int ret;
 
@@ -93,16 +95,52 @@ static int do_rexec(FAR struct rexec_arg_s *arg)
       return sock;
     }
 
+  memset(fds, 0, sizeof(fds));
+  fds[0].fd = sock;
+  fds[0].events = POLLIN;
+  fds[1].fd = STDIN_FILENO;
+  fds[1].events = POLLIN;
+
   while (1)
     {
-      ret = read(sock, buffer, REXEC_BUFSIZE);
+      ret = poll(fds, 2, -1);
       if (ret <= 0)
         {
-          break;
+          continue;
+        }
+
+      if (fds[0].revents & POLLIN)
+        {
+          ret = read(sock, buffer, REXEC_BUFSIZE);
+          if (ret <= 0)
+            {
+              break;
+            }
+
+          ret = write(STDOUT_FILENO, buffer, ret);
+          if (ret < 0)
+            {
+              break;
+            }
+        }
+
+      if (fds[1].revents & POLLIN)
+        {
+          ret = read(STDIN_FILENO, buffer, REXEC_BUFSIZE);
+          if (ret <= 0)
+            {
+              break;
+            }
+
+          ret = write(sock, buffer, ret);
+          if (ret < 0)
+            {
+              break;
+            }
         }
 
-      ret = write(STDOUT_FILENO, buffer, ret);
-      if (ret < 0)
+      if (((fds[0].revents | fds[1].revents) & POLLHUP) &&
+          ((fds[0].revents | fds[1].revents) & POLLIN) == 0)
         {
           break;
         }

netutils/rexecd/rexecd.c

@@ -80,10 +80,10 @@ static int getstr(int fd, FAR char *buf)
 static FAR void *doit(pthread_addr_t pvarg)
 {
   char buf[REXECD_BUFSIZE];
+  struct pollfd fds[2];
   FAR FILE *fp;
   int sock = (int)pvarg;
   int ret;
-  int len;
 
   /* we need to read err_sock, user and passwd, but ignore them */
 
@@ -94,31 +94,61 @@ static FAR void *doit(pthread_addr_t pvarg)
   /* we need to read command */
 
   getstr(sock, buf);
-  fp = popen(buf, "r");
+  fp = popen(buf, "r+");
   if (!fp)
     {
       goto errout;
     }
 
+  memset(fds, 0, sizeof(fds));
+  fds[0].fd = fileno(fp);
+  fds[0].events = POLLIN;
+  fds[1].fd = sock;
+  fds[1].events = POLLIN;
+
   while (1)
     {
-      ret = fread(buf, 1, REXECD_BUFSIZE, fp);
+      ret = poll(fds, 2, -1);
       if (ret <= 0)
         {
-          break;
+          continue;
         }
 
-      do
+      if (fds[0].revents & POLLIN)
         {
-          len = write(sock, buf, ret);
-          if (len <= 0)
+          ret = read(fileno(fp), buf, REXECD_BUFSIZE);
+          if (ret <= 0)
+            {
+              break;
+            }
+
+          ret = write(sock, buf, ret);
+          if (ret < 0)
             {
               break;
             }
+        }
 
-          ret -= len;
+      if (fds[1].revents & POLLIN)
+        {
+          ret = read(sock, buf, REXECD_BUFSIZE);
+          if (ret <= 0)
+            {
+              break;
+            }
+
+          ret = write(fileno(fp), buf, ret);
+          if (ret < 0)
+            {
+              break;
+            }
+        }
+
+      if (((fds[0].revents | fds[1].revents) & POLLHUP) &&
+          ((fds[0].revents | fds[1].revents) & POLLIN) == 0)
+        {
+          break;
         }
-      while (ret > 0);
     }
 
   pclose(fp);

system/popen/popen.c

@@ -115,11 +115,12 @@ FILE *popen(FAR const char *command, FAR const char *mode)
   posix_spawn_file_actions_t file_actions;
   FAR char *argv[4];
   int fd[2];
-  int oldfd;
-  int newfd;
+  int oldfd[2];
+  int newfd[2];
   int retfd;
   int errcode;
-  int result;
+  int result = 0;
+  bool rw = false;
 
   /* Allocate a container for returned FILE stream */
 
@@ -130,34 +131,51 @@ FILE *popen(FAR const char *command, FAR const char *mode)
       goto errout;
     }
 
+  oldfd[1] = 0;
+  newfd[1] = 0;
+
   /* Create a pipe.  fd[0] refers to the read end of the pipe; fd[1] refers
    * to the write end of the pipe.
+   * Is the pipe the input to the shell?  Or the output?
    */
 
-  result = pipe(fd);
-  if (result < 0)
-    {
-      errcode = errno;
-      goto errout_with_container;
-    }
-
-  /* Is the pipe the input to the shell?  Or the output? */
-
-  if (strcmp(mode, "r") == 0)
+  if (strcmp(mode, "r") == 0 && (result = pipe(fd)) >= 0)
     {
       /* Pipe is the output from the shell */
 
-      oldfd = 1;     /* Replace stdout with the write side of the pipe */
-      newfd = fd[1];
-      retfd = fd[0]; /* Use read side of the pipe to create the return stream */
+      oldfd[0] = 1;     /* Replace stdout with the write side of the pipe */
+      newfd[0] = fd[1];
+      retfd    = fd[0]; /* Use read side of the pipe to create the return stream */
     }
-  else if (strcmp(mode, "w") == 0)
+  else if (strcmp(mode, "w") == 0 && (result = pipe(fd)) >= 0)
     {
       /* Pipe is the input to the shell */
 
-      oldfd = 0;     /* Replace stdin with the read side of the pipe */
-      newfd = fd[0];
-      retfd = fd[1]; /* Use write side of the pipe to create the return stream */
+      oldfd[0] = 0;     /* Replace stdin with the read side of the pipe */
+      newfd[0] = fd[0];
+      retfd    = fd[1]; /* Use write side of the pipe to create the return stream */
+    }
+
+  /* Create a socketpair. Using fd[0] as the input and output to the shell */
+
+#if defined(CONFIG_NET_LOCAL) && defined(CONFIG_NET_LOCAL_STREAM)
+  else if ((strcmp(mode, "r+") == 0 || strcmp(mode, "w+") == 0) &&
+           (result = socketpair(AF_UNIX, SOCK_STREAM, 0, fd)) >= 0)
+    {
+      /* Socketpair is the input/output to the shell */
+
+      rw = true;
+      oldfd[0] = 0;     /* Replace stdin with the one side of a socket pair */
+      newfd[0] = fd[0];
+      oldfd[1] = 1;     /* Replace stdout with the one side of a socket pair */
+      newfd[1] = fd[0];
+      retfd    = fd[1]; /* Use other side of the socket pair to create the return stream */
+    }
+#endif
+  else if (result < 0)
+    {
+      errcode = errno;
+      goto errout_with_container;
     }
   else
     {
@@ -236,12 +254,23 @@ FILE *popen(FAR const char *command, FAR const char *mode)
 
   /* Redirect input or output as determined by the mode parameter */
 
-  errcode = posix_spawn_file_actions_adddup2(&file_actions, newfd, oldfd);
+  errcode = posix_spawn_file_actions_adddup2(&file_actions,
+                                             newfd[0], oldfd[0]);
   if (errcode != 0)
     {
       goto errout_with_actions;
     }
 
+  if (rw)
+    {
+      errcode = posix_spawn_file_actions_adddup2(&file_actions,
+                                                 newfd[1], oldfd[1]);
+      if (errcode != 0)
+        {
+          goto errout_with_actions;
+        }
+    }
+
   /* Call task_spawn() (or posix_spawn), re-directing stdin or stdout
    * appropriately.
    */
@@ -273,7 +302,12 @@ FILE *popen(FAR const char *command, FAR const char *mode)
    * the interface.
    */
 
-  close(newfd);
+  close(newfd[0]);
+
+  if (rw)
+    {
+      close(newfd[1]);
+    }
 
   /* Free attributes and file actions.  Ignoring return values in the case
    * of an error.