1 files changed, 338 insertions, 0 deletions

diff --git a/pintos-progos/utils/squish-unix.c b/pintos-progos/utils/squish-unix.c
new file mode 100644
index 0000000..805205b
--- /dev/null
+++ b/pintos-progos/utils/squish-unix.c
@@ -0,0 +1,338 @@
+#define _GNU_SOURCE 1
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stropts.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <termios.h>
+#include <unistd.h>
+
+static void
+fail_io (const char *msg, ...)
+     __attribute__ ((noreturn))
+     __attribute__ ((format (printf, 1, 2)));
+
+/* Prints MSG, formatting as with printf(),
+   plus an error message based on errno,
+   and exits. */
+static void
+fail_io (const char *msg, ...)
+{
+  va_list args;
+
+  va_start (args, msg);
+  vfprintf (stderr, msg, args);
+  va_end (args);
+
+  if (errno != 0)
+    fprintf (stderr, ": %s", strerror (errno));
+  putc ('\n', stderr);
+  exit (EXIT_FAILURE);
+}
+
+/* If FD is a terminal, configures it for noncanonical input mode
+   with VMIN and VTIME set as indicated.
+   If FD is not a terminal, has no effect. */
+static void
+make_noncanon (int fd, int vmin, int vtime)
+{
+  if (isatty (fd)) 
+    {
+      struct termios termios;
+      if (tcgetattr (fd, &termios) < 0)
+        fail_io ("tcgetattr");
+      termios.c_lflag &= ~(ICANON | ECHO);
+      termios.c_cc[VMIN] = vmin;
+      termios.c_cc[VTIME] = vtime;
+      if (tcsetattr (fd, TCSANOW, &termios) < 0)
+        fail_io ("tcsetattr");
+    }
+}
+
+/* Make FD non-blocking if NONBLOCKING is true,
+   or blocking if NONBLOCKING is false. */
+static void
+make_nonblocking (int fd, bool nonblocking) 
+{
+  int flags = fcntl (fd, F_GETFL);
+  if (flags < 0)
+    fail_io ("fcntl");
+  if (nonblocking)
+    flags |= O_NONBLOCK;
+  else
+    flags &= ~O_NONBLOCK;
+  if (fcntl (fd, F_SETFL, flags) < 0)
+    fail_io ("fcntl");
+}
+
+/* Handle a read or write on *FD, which is the socket if
+   FD_IS_SOCK is true, that returned end-of-file or error
+   indication RETVAL.  The system call is named CALL, for use in
+   error messages.  Returns true if processing may continue,
+   false if we're all done. */
+static bool
+handle_error (ssize_t retval, int *fd, bool fd_is_sock, const char *call)
+{
+  if (retval == 0)
+    {
+      if (fd_is_sock)
+        return false;
+      else
+        {
+          *fd = -1;
+          return true;
+        }
+    }
+  else
+    fail_io (call); 
+}
+
+/* Copies data from stdin to SOCK and from SOCK to stdout until no
+   more data can be read or written. */
+static void
+relay (int sock) 
+{
+  struct pipe 
+    {
+      int in, out;
+      char buf[BUFSIZ];
+      size_t size, ofs;
+      bool active;
+    };
+  struct pipe pipes[2];
+
+  /* In case stdin is a file, go back to the beginning.
+     This allows replaying the input on reset. */
+  lseek (STDIN_FILENO, 0, SEEK_SET);
+
+  /* Make SOCK, stdin, and stdout non-blocking. */
+  make_nonblocking (sock, true);
+  make_nonblocking (STDIN_FILENO, true);
+  make_nonblocking (STDOUT_FILENO, true);
+
+  /* Configure noncanonical mode on stdin to avoid waiting for
+     end-of-line. */
+  make_noncanon (STDIN_FILENO, 1, 0);
+
+  memset (pipes, 0, sizeof pipes);
+  pipes[0].in = STDIN_FILENO;
+  pipes[0].out = sock;
+  pipes[1].in = sock;
+  pipes[1].out = STDOUT_FILENO;
+  
+  while (pipes[0].in != -1 || pipes[1].in != -1
+         || (pipes[1].size && pipes[1].out != -1))
+    {
+      fd_set read_fds, write_fds;
+      sigset_t empty_set;
+      int retval;
+      int i;
+
+      FD_ZERO (&read_fds);
+      FD_ZERO (&write_fds);
+      for (i = 0; i < 2; i++)
+        {
+          struct pipe *p = &pipes[i];
+
+          /* Don't do anything with the stdin->sock pipe until we
+             have some data for the sock->stdout pipe.  If we get
+             too eager, vmplayer will throw away our input. */
+          if (i == 0 && !pipes[1].active)
+            continue;
+          
+          if (p->in != -1 && p->size + p->ofs < sizeof p->buf)
+            FD_SET (p->in, &read_fds);
+          if (p->out != -1 && p->size > 0)
+            FD_SET (p->out, &write_fds); 
+        }
+      sigemptyset (&empty_set);
+      retval = pselect (FD_SETSIZE, &read_fds, &write_fds, NULL, NULL,
+                        &empty_set);
+      if (retval < 0) 
+        {
+          if (errno == EINTR)
+            {
+              /* Child died.  Do final relaying. */
+              struct pipe *p = &pipes[1];
+              if (p->out == -1)
+                exit (0);
+              make_nonblocking (STDOUT_FILENO, false);
+              for (;;) 
+                {
+                  ssize_t n;
+                  
+                  /* Write buffer. */
+                  while (p->size > 0) 
+                    {
+                      n = write (p->out, p->buf + p->ofs, p->size);
+                      if (n < 0)
+                        fail_io ("write");
+                      else if (n == 0)
+                        fail_io ("zero-length write");
+                      p->ofs += n;
+                      p->size -= n;
+                    }
+                  p->ofs = 0;
+
+                  p->size = n = read (p->in, p->buf, sizeof p->buf);
+                  if (n <= 0)
+                    exit (0);
+                }
+            }
+          fail_io ("select"); 
+        }
+
+      for (i = 0; i < 2; i++) 
+        {
+          struct pipe *p = &pipes[i];
+          if (p->in != -1 && FD_ISSET (p->in, &read_fds))
+            {
+              ssize_t n = read (p->in, p->buf + p->ofs + p->size,
+                                sizeof p->buf - p->ofs - p->size);
+              if (n > 0) 
+                {
+                  p->active = true;
+                  p->size += n;
+                  if (p->size == BUFSIZ && p->ofs != 0)
+                    {
+                      memmove (p->buf, p->buf + p->ofs, p->size);
+                      p->ofs = 0;
+                    }
+                }
+              else if (!handle_error (n, &p->in, p->in == sock, "read"))
+                return;
+            }
+          if (p->out != -1 && FD_ISSET (p->out, &write_fds)) 
+            {
+              ssize_t n = write (p->out, p->buf + p->ofs, p->size);
+              if (n > 0) 
+                {
+                  p->ofs += n;
+                  p->size -= n;
+                  if (p->size == 0)
+                    p->ofs = 0;
+                }
+              else if (!handle_error (n, &p->out, p->out == sock, "write"))
+                return;
+            }
+        }
+    }
+}
+
+static void
+sigchld_handler (int signo __attribute__ ((unused))) 
+{
+  /* Nothing to do. */
+}
+
+int
+main (int argc __attribute__ ((unused)), char *argv[])
+{
+  pid_t pid;
+  struct itimerval zero_itimerval;
+  struct sockaddr_un sun;
+  sigset_t sigchld_set;
+  int sock;
+  
+  if (argc < 3) 
+    {
+      fprintf (stderr,
+               "usage: squish-unix SOCKET COMMAND [ARG]...\n"
+               "Squishes both stdin and stdout into a single Unix domain\n"
+               "socket named SOCKET, and runs COMMAND as a subprocess.\n");
+      return EXIT_FAILURE;
+    }
+
+  /* Create socket. */
+  sock = socket (PF_LOCAL, SOCK_STREAM, 0);
+  if (sock < 0)
+    fail_io ("socket");
+
+  /* Configure socket. */
+  sun.sun_family = AF_LOCAL;
+  strncpy (sun.sun_path, argv[1], sizeof sun.sun_path);
+  sun.sun_path[sizeof sun.sun_path - 1] = '\0';
+  if (unlink (sun.sun_path) < 0 && errno != ENOENT)
+    fail_io ("unlink");
+  if (bind (sock, (struct sockaddr *) &sun,
+            (offsetof (struct sockaddr_un, sun_path)
+             + strlen (sun.sun_path) + 1)) < 0)
+    fail_io ("bind");
+
+  /* Listen on socket. */
+  if (listen (sock, 1) < 0)
+    fail_io ("listen");
+
+  /* Block SIGCHLD and set up a handler for it. */
+  sigemptyset (&sigchld_set);
+  sigaddset (&sigchld_set, SIGCHLD);
+  if (sigprocmask (SIG_BLOCK, &sigchld_set, NULL) < 0)
+    fail_io ("sigprocmask");
+  if (signal (SIGCHLD, sigchld_handler) == SIG_ERR)
+    fail_io ("signal");
+
+  /* Save the virtual interval timer, which might have been set
+     by the process that ran us.  It really should be applied to
+     our child process. */
+  memset (&zero_itimerval, 0, sizeof zero_itimerval);
+  if (setitimer (ITIMER_VIRTUAL, &zero_itimerval, NULL) < 0)
+    fail_io ("setitimer");
+  
+  pid = fork ();
+  if (pid < 0)
+    fail_io ("fork");
+  else if (pid != 0) 
+    {
+      /* Running in parent process. */
+      make_nonblocking (sock, true);
+      for (;;) 
+        {
+          fd_set read_fds;
+          sigset_t empty_set;
+          int retval;
+          int conn;
+
+          /* Wait for connection. */
+          FD_ZERO (&read_fds);
+          FD_SET (sock, &read_fds);
+          sigemptyset (&empty_set);
+          retval = pselect (sock + 1, &read_fds, NULL, NULL, NULL, &empty_set);
+          if (retval < 0) 
+            {
+              if (errno == EINTR)
+                break;
+              fail_io ("select"); 
+            }
+
+          /* Accept connection. */
+          conn = accept (sock, NULL, NULL);
+          if (conn < 0)
+            fail_io ("accept");
+
+          /* Relay connection. */
+          relay (conn);
+          close (conn);
+        }
+      return 0; 
+    }
+  else 
+    {
+      /* Running in child process. */
+      if (close (sock) < 0)
+        fail_io ("close");
+      execvp (argv[2], argv + 2);
+      fail_io ("exec");
+    }
+}