1 files changed, 61 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/stdio/popen.c b/libc-top-half/musl/src/stdio/popen.c
new file mode 100644
index 0000000..3ec8339
--- /dev/null
+++ b/libc-top-half/musl/src/stdio/popen.c
@@ -0,0 +1,61 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <spawn.h>
+#include "stdio_impl.h"
+#include "syscall.h"
+
+extern char **__environ;
+
+FILE *popen(const char *cmd, const char *mode)
+{
+	int p[2], op, e;
+	pid_t pid;
+	FILE *f;
+	posix_spawn_file_actions_t fa;
+
+	if (*mode == 'r') {
+		op = 0;
+	} else if (*mode == 'w') {
+		op = 1;
+	} else {
+		errno = EINVAL;
+		return 0;
+	}
+	
+	if (pipe2(p, O_CLOEXEC)) return NULL;
+	f = fdopen(p[op], mode);
+	if (!f) {
+		__syscall(SYS_close, p[0]);
+		__syscall(SYS_close, p[1]);
+		return NULL;
+	}
+
+	e = ENOMEM;
+	if (!posix_spawn_file_actions_init(&fa)) {
+		for (FILE *l = *__ofl_lock(); l; l=l->next)
+			if (l->pipe_pid && posix_spawn_file_actions_addclose(&fa, l->fd))
+				goto fail;
+		if (!posix_spawn_file_actions_adddup2(&fa, p[1-op], 1-op)) {
+			if (!(e = posix_spawn(&pid, "/bin/sh", &fa, 0,
+			    (char *[]){ "sh", "-c", (char *)cmd, 0 }, __environ))) {
+				posix_spawn_file_actions_destroy(&fa);
+				f->pipe_pid = pid;
+				if (!strchr(mode, 'e'))
+					fcntl(p[op], F_SETFD, 0);
+				__syscall(SYS_close, p[1-op]);
+				__ofl_unlock();
+				return f;
+			}
+		}
+fail:
+		__ofl_unlock();
+		posix_spawn_file_actions_destroy(&fa);
+	}
+	fclose(f);
+	__syscall(SYS_close, p[1-op]);
+
+	errno = e;
+	return 0;
+}