rewrite popen to use posix_spawn instead of fragile vfork hacks

[musl] / src / stdio / __stdio_write.c

diff --git a/src/stdio/__stdio_write.c b/src/stdio/__stdio_write.c
index d4264ef..e52e91a 100644 (file)
--- a/src/stdio/__stdio_write.c
+++ b/src/stdio/__stdio_write.c
@@ -1,9 +1,50 @@
 #include "stdio_impl.h"
+#include <sys/uio.h>
+#include <pthread.h>
+
+static void cleanup(void *p)
+{
+       FILE *f = p;
+       if (!f->lockcount) __unlockfile(f);
+}
 
 size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
 {
-       const unsigned char *stop = buf+len;
-       ssize_t cnt = 1;
-       for (; buf<stop && (cnt=syscall(SYS_write, f->fd, buf, len))>0; buf+=cnt);
-       return len-(stop-buf);
+       struct iovec iovs[2] = {
+               { .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
+               { .iov_base = (void *)buf, .iov_len = len }
+       };
+       struct iovec *iov = iovs;
+       size_t rem = iov[0].iov_len + iov[1].iov_len;
+       int iovcnt = 2;
+       ssize_t cnt;
+       for (;;) {
+               if (libc.main_thread) {
+                       pthread_cleanup_push(cleanup, f);
+                       cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
+                       pthread_cleanup_pop(0);
+               } else {
+                       cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
+               }
+               if (cnt == rem) {
+                       f->wend = f->buf + f->buf_size;
+                       f->wpos = f->wbase = f->buf;
+                       return len;
+               }
+               if (cnt < 0) {
+                       f->wpos = f->wbase = f->wend = 0;
+                       f->flags |= F_ERR;
+                       return iovcnt == 2 ? 0 : len-iov[0].iov_len;
+               }
+               rem -= cnt;
+               if (cnt > iov[0].iov_len) {
+                       f->wpos = f->wbase = f->buf;
+                       cnt -= iov[0].iov_len;
+                       iov++; iovcnt--;
+               } else if (iovcnt == 2) {
+                       f->wbase += cnt;
+               }
+               iov[0].iov_base = (char *)iov[0].iov_base + cnt;
+               iov[0].iov_len -= cnt;
+       }
 }