From 510290269278239490e3850613f568728e84fdcb Mon Sep 17 00:00:00 2001
From: Xavier Del Campo <xavi.dcr@tutanota.com>
Date: Tue, 28 Sep 2021 22:51:08 +0200
Subject: [PATCH 1/3] at_send_command: call write(2) in a loop

write(2) might return less than expected due to various reasons.
Therefore, unless we are dealing with a critical error, it must be
called in a loop until all bytes are written.
---
 src/at.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/at.c b/src/at.c
index 2527bca..4d3b3f3 100644
--- a/src/at.c
+++ b/src/at.c
@@ -9,6 +9,7 @@
 #include "gpio.h"
 #include "gnss.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -50,7 +51,7 @@ gboolean at_send_command(struct EG25Manager *manager)
 {
     char command[256];
     struct AtCommand *at_cmd = manager->at_cmds ? g_list_nth_data(manager->at_cmds, 0) : NULL;
-    int ret, len = 0;
+    int ret, len = 0, pos = 0;
 
     if (at_cmd) {
     	/* Wake up the modem from soft sleep before sending an AT command */
@@ -82,9 +83,27 @@ gboolean at_send_command(struct EG25Manager *manager)
 
         manager->at_callback = at_cmd->callback;
 
-        ret = write(manager->at_fd, command, len);
-        if (ret < len)
-            g_warning("Couldn't write full AT command: wrote %d/%d bytes", ret, len);
+        do {
+            ret = write(manager->at_fd, &command[pos], len);
+
+            if (ret < 0) {
+                switch (errno) {
+                case EAGAIN:
+                case EINTR:
+                    /* Try again. */
+                    break;
+
+                default:
+                    g_warning("write(2): %s", strerror(errno));
+                    at_next_command(manager);
+                    return FALSE;
+                }
+            }
+            else {
+                len -= ret;
+                pos += ret;
+            }
+        } while (len > 0);
 
         g_message("Sending command: %s", g_strstrip(command));
     } else {

From 082cf996d132028e7ca08f033119de1c77b6039e Mon Sep 17 00:00:00 2001
From: Arnaud Ferraris <arnaud.ferraris@gmail.com>
Date: Thu, 30 Sep 2021 19:59:24 +0000
Subject: [PATCH 2/3] Use a more meaningful message on AT send failure

---
 src/at.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/at.c b/src/at.c
index 4d3b3f3..64ad466 100644
--- a/src/at.c
+++ b/src/at.c
@@ -94,7 +94,7 @@ gboolean at_send_command(struct EG25Manager *manager)
                     break;
 
                 default:
-                    g_warning("write(2): %s", strerror(errno));
+                    g_warning("error sending AT command: %s", strerror(errno));
                     at_next_command(manager);
                     return FALSE;
                 }

From 6b2f0e8fbd54a68499881437a3af8535cdbf773a Mon Sep 17 00:00:00 2001
From: Xavier Del Campo <xavi.dcr@tutanota.com>
Date: Sat, 2 Oct 2021 11:17:47 +0200
Subject: [PATCH 3/3] at.c: fix misleading g_message

---
 src/at.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/at.c b/src/at.c
index 64ad466..b50ceea 100644
--- a/src/at.c
+++ b/src/at.c
@@ -83,6 +83,8 @@ gboolean at_send_command(struct EG25Manager *manager)
 
         manager->at_callback = at_cmd->callback;
 
+        g_message("Sending command: %s", g_strstrip(command));
+
         do {
             ret = write(manager->at_fd, &command[pos], len);
 
@@ -105,7 +107,7 @@ gboolean at_send_command(struct EG25Manager *manager)
             }
         } while (len > 0);
 
-        g_message("Sending command: %s", g_strstrip(command));
+        g_message("Successfully sent command: %s", g_strstrip(command));
     } else {
     	/* Allow the modem to enter soft sleep again when we sent the AT command*/
     	gpio_sequence_sleep(manager);