add: added projectsHEADmain

2 files changed, 49 insertions, 0 deletions

diff --git a/21sh/mypipe/mypipe.c b/21sh/mypipe/mypipe.c
new file mode 100644
index 0000000..c019e42
--- /dev/null
+++ b/21sh/mypipe/mypipe.c
@@ -0,0 +1,43 @@
+#include "mypipe.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+int exec_pipe(char **argv_left, char **argv_right)
+{
+    int fds[2];
+    if (pipe(fds))
+        return 1;
+    pid_t pid = fork();
+    if (pid == 0)
+    {
+        // close read end
+        close(fds[0]);
+        // redirect stdout to write end
+        dup2(fds[1], STDOUT_FILENO);
+        // tell OS to close write end after exec
+        fcntl(fds[1], F_SETFD, FD_CLOEXEC);
+        // exec left
+        execvp(argv_left[0], argv_left);
+        return 0;
+    }
+    else if (pid > 0)
+    {
+        // close write end
+        close(fds[1]);
+        // redirect stdin to read end
+        dup2(fds[0], STDIN_FILENO);
+        // tell OS to close read end after exec
+        fcntl(fds[0], F_SETFD, FD_CLOEXEC);
+        // exec right
+        execvp(argv_right[0], argv_right);
+        // return 1
+        return 1;
+    }
+    else
+    {
+        close(fds[0]);
+        close(fds[1]);
+        return 1;
+    }
+}
diff --git a/21sh/mypipe/mypipe.h b/21sh/mypipe/mypipe.h
new file mode 100644
index 0000000..d8c14e4
--- /dev/null
+++ b/21sh/mypipe/mypipe.h
@@ -0,0 +1,6 @@
+#ifndef MYPIPE_H
+#define MYPIPE_H
+
+int exec_pipe(char **argv_left, char **argv_right);
+
+#endif /* ! MYPIPE_H */