Fix duplication syscalls so that they handle pipes correctly

Author: Hood

Diff for: src/library_syscall.js

@@ -137,10 +137,13 @@ var SyscallsLibrary = {
       }
       return 0;
     },
-    doDup: function(path, flags, suggestFD) {
-      var suggest = FS.getStream(suggestFD);
-      if (suggest) FS.close(suggest);
-      return FS.open(path, flags, 0, suggestFD, suggestFD).fd;
+    doDup: function(stream, minFD, maxFD) {
+      if(stream.path.startsWith("pipe[")){
+        // A pipe
+        stream.node.pipe.refcnt++;
+        return FS.createStream(stream, minFD, maxFD).fd;
+      }
+      return FS.open(stream.path, stream.flags, 0, minFD, maxFD).fd;
     },
     doReadv: function(stream, iov, iovcnt, offset) {
       var ret = 0;
@@ -374,7 +377,7 @@ var SyscallsLibrary = {
   },
   __sys_dup: function(fd) {
     var old = SYSCALLS.getStreamFromFD(fd);
-    return FS.open(old.path, old.flags, 0).fd;
+    return SYSCALLS.doDup(old);
   },
   __sys_pipe__deps: ['$PIPEFS'],
   __sys_pipe: function(fdPtr) {
@@ -461,7 +464,8 @@ var SyscallsLibrary = {
   __sys_dup2: function(oldfd, suggestFD) {
     var old = SYSCALLS.getStreamFromFD(oldfd);
     if (old.fd === suggestFD) return suggestFD;
-    return SYSCALLS.doDup(old.path, old.flags, suggestFD);
+    FS.closeStream(suggestFD);
+    return SYSCALLS.doDup(old, suggestFD, suggestFD);
   },
   __sys_getppid__nothrow: true,
   __sys_getppid__proxy: false,
@@ -1107,9 +1111,7 @@ var SyscallsLibrary = {
         if (arg < 0) {
           return -{{{ cDefine('EINVAL') }}};
         }
-        var newStream;
-        newStream = FS.open(stream.path, stream.flags, 0, arg);
-        return newStream.fd;
+        return SYSCALLS.doDup(stream, arg);
       }
       case {{{ cDefine('F_GETFD') }}}:
       case {{{ cDefine('F_SETFD') }}}:
@@ -1329,7 +1331,8 @@ var SyscallsLibrary = {
     assert(!flags);
 #endif
     if (old.fd === suggestFD) return -{{{ cDefine('EINVAL') }}};
-    return SYSCALLS.doDup(old.path, old.flags, suggestFD);
+    FS.closeStream(suggestFD);
+    return SYSCALLS.doDup(old, suggestFD, suggestFD);
   },
 
   __sys_prlimit64: function(pid, resource, new_limit, old_limit) {

Diff for: tests/unistd/pipe.c

@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <string.h>
 #include <stdio.h>
+#include "emscripten.h"
 
 unsigned char buf[1 << 16];
 
@@ -136,9 +137,10 @@ int main()
     test_read (fd[0], &rchar, 10);
     test_poll(fd, FALSE);
 
+    // Test closing pipes.
+
     // Clear buffer
     memset(buf, 0, sizeof(buf));
-    // Test closing pipes.
     // Write to pipe
     assert(write(fd[1], "XXXX", 4) == 4);
     // Close write end
@@ -160,6 +162,36 @@ int main()
     // The error number is EBADF
     assert(errno == EBADF);
 
+
+    // Test copying pipes.
+    // Clear buffer
+    memset(buf, 0, sizeof(buf));
+    // We closed last pipe so make new one
+    assert(pipe(fd) == 0);
+    int fdr = dup(fd[0]);
+    int fdw = fcntl(fd[1], F_DUPFD, 7);
+    // Write to pipe
+    assert(write(fd[1], "XXXX", 4) == 4);
+    // close write end
+    assert(close(fd[1]) == 0);
+    // This write should fail
+    assert(write(fd[1], "YYYY", 4) == -1);
+    // The error number is EBADF
+    assert(errno == EBADF);
+    // Read from duped read end
+    assert(read(fdr, buf, 5) == 4);
+    assert(memcmp(buf, "XXXX", 4) == 0);
+    assert(close(fdr) == 0);
+    assert(write(fdw, "YYYY", 4) == 4);
+    assert(close(fdw) == 0);
+    // This write should fail
+    assert(write(fdw, "YYYY", 4) == -1);
+    // The error number is EBADF
+    assert(errno == EBADF);
+    assert(read(fd[0], buf, 5) == 4);
+    assert(memcmp(buf, "YYYY", 5) == 0);
+    assert(close(fd[0]) == 0);
+
     puts("success");
 
     return 0;