Merge branch 'lukas/erts/non-blocking-shell'

* lukas/erts/non-blocking-shell:
  erts: Make sure IOV_MAX is enforced for writev
  erts: Make erts_printf work with non-blocking

2 files changed, 54 insertions, 17 deletions

diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 5de0c281c4..47acd132ca 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -86,6 +86,14 @@ static erts_smp_rwmtx_t environ_rwmtx;
 #define DISABLE_VFORK 0
 #endif
 
+#if defined IOV_MAX
+#define MAXIOV IOV_MAX
+#elif defined UIO_MAXIOV
+#define MAXIOV UIO_MAXIOV
+#else
+#define MAXIOV 16
+#endif
+
 #ifdef USE_THREADS
 #  ifdef ENABLE_CHILD_WAITER_THREAD
 #    define CHLDWTHR ENABLE_CHILD_WAITER_THREAD
@@ -2524,32 +2532,28 @@ fd_async(void *async_data)
     SysIOVec      *iov0;
     SysIOVec      *iov;
     int            iovlen;
-    int            iovcnt;
-    int            p;
+    int            err;
     /* much of this code is stolen from efile_drv:invoke_writev */
     driver_pdl_lock(dd->blocking->pdl);
     iov0 = driver_peekq(dd->port_num, &iovlen);
-    /* Calculate iovcnt */
-    for (p = 0, iovcnt = 0; iovcnt < iovlen;
-         p += iov0[iovcnt++].iov_len)
-        ;
+    iovlen = iovlen < MAXIOV ? iovlen : MAXIOV;
     iov = erts_alloc_fnf(ERTS_ALC_T_SYS_WRITE_BUF,
-                         sizeof(SysIOVec)*iovcnt);
+                         sizeof(SysIOVec)*iovlen);
     if (!iov) {
         res = -1;
-        errno = ENOMEM;
-        erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov);
+        err = ENOMEM;
         driver_pdl_unlock(dd->blocking->pdl);
     } else {
-        memcpy(iov,iov0,iovcnt*sizeof(SysIOVec));
+        memcpy(iov,iov0,iovlen*sizeof(SysIOVec));
         driver_pdl_unlock(dd->blocking->pdl);
 
         res = writev(dd->ofd, iov, iovlen);
+        err = errno;
 
         erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov);
     }
     dd->blocking->res = res;
-    dd->blocking->err = errno;
+    dd->blocking->err = err;
 }
 
 void fd_ready_async(ErlDrvData drv_data,
diff --git a/erts/lib_src/common/erl_printf.c b/erts/lib_src/common/erl_printf.c
index 2c177ee5ac..0a0346ac2d 100644
--- a/erts/lib_src/common/erl_printf.c
+++ b/erts/lib_src/common/erl_printf.c
@@ -87,6 +87,39 @@ void (*erts_printf_unblock_fpe)(int) = NULL;
 #	define FWRITE fwrite
 #endif
 
+/* We use write for stdout and stderr as they could be
+   set to non-blocking by shell drivers, and non-blocking
+   FILE * functions work unpredictably as best */
+static int
+printf_putc(int c, FILE *stream) {
+    if ((FILE*)stream == stdout || (FILE*)stream == stderr) {
+        int fd = stream == stdout ? fileno(stdout) : fileno(stdin);
+        int res;
+        do {
+            res = write(fd,&c,1);
+        } while (res == -1 && (errno == EAGAIN || errno == EINTR));
+        if (res == -1) return EOF;
+        return res;
+    }
+
+    return PUTC(c, stream);
+}
+
+static size_t
+printf_fwrite(const void *ptr, size_t size, size_t nitems,
+          FILE *stream) {
+    if ((FILE*)stream == stdout || (FILE*)stream == stderr) {
+        int fd = stream == stdout ? fileno(stdout) : fileno(stdin);
+        int res;
+        do {
+            res = write(fd, ptr, size*nitems);
+        } while (res == -1 && (errno == EAGAIN || errno == EINTR));
+        if (res == -1) return 0;
+        return res;
+    }
+    return FWRITE(ptr, size, nitems, stream);
+}
+
 static int
 get_error_result(void)
 {
@@ -103,10 +136,10 @@ write_f_add_cr(void *vfp, char* buf, size_t len)
     size_t i;
     ASSERT(vfp);
     for (i = 0; i < len; i++) {
-	if (buf[i] == '\n' && PUTC('\r', (FILE *) vfp) == EOF)
-	    return get_error_result();
-	if (PUTC(buf[i], (FILE *) vfp) == EOF)
-	    return get_error_result();
+        if (buf[i] == '\n' && printf_putc('\r', (FILE *) vfp) == EOF)
+            return get_error_result();
+        if (printf_putc(buf[i], (FILE *) vfp) == EOF)
+            return get_error_result();
     }
     return len;
 }
@@ -119,12 +152,12 @@ write_f(void *vfp, char* buf, size_t len)
     if (len <= 64) { /* Try to optimize writes of small bufs. */
 	int i;
 	for (i = 0; i < len; i++)
-	    if (PUTC(buf[i], (FILE *) vfp) == EOF)
+	    if (printf_putc(buf[i], (FILE *) vfp) == EOF)
 		return get_error_result();
     }
     else
 #endif
-    if (FWRITE((void *) buf, sizeof(char), len, (FILE *) vfp) != len)
+    if (printf_fwrite((void *) buf, sizeof(char), len, (FILE *) vfp) != len)
 	return get_error_result();
     return len;
 }