Fixing Linux AIO syscalls return value handling:

syscall(2) uses usual libc convention, it returns -1 on error and
sets errno. Obsolete _syscall(2) returns negative value of error.

Thanks to Hagai Avrahami.

2 files changed, 18 insertions, 19 deletions

diff --git a/src/event/modules/ngx_epoll_module.c b/src/event/modules/ngx_epoll_module.c
index e30501b00..114a27226 100644
--- a/src/event/modules/ngx_epoll_module.c
+++ b/src/event/modules/ngx_epoll_module.c
@@ -184,7 +184,7 @@ ngx_module_t  ngx_epoll_module = {
  * into single eventfd() function with different number of parameters.
  */
 
-static long
+static int
 io_setup(u_int nr_reqs, aio_context_t *ctx)
 {
     return syscall(SYS_io_setup, nr_reqs, ctx);
@@ -198,7 +198,7 @@ io_destroy(aio_context_t ctx)
 }
 
 
-static long
+static int
 io_getevents(aio_context_t ctx, long min_nr, long nr, struct io_event *events,
     struct timespec *tmo)
 {
@@ -247,10 +247,10 @@ ngx_epoll_init(ngx_cycle_t *cycle, ngx_msec_t timer)
         ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                        "eventfd: %d", ngx_eventfd);
 
-        n = io_setup(1024, &ngx_aio_ctx);
+        if (io_setup(1024, &ngx_aio_ctx) == -1) {
 
-        if (n != 0) {
-            ngx_log_error(NGX_LOG_EMERG, cycle->log, -n, "io_setup() failed");
+            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
+                          "io_setup() failed");
             return NGX_ERROR;
         }
 
@@ -316,7 +316,7 @@ ngx_epoll_done(ngx_cycle_t *cycle)
 
 #if (NGX_HAVE_FILE_AIO)
 
-    if (io_destroy(ngx_aio_ctx) != 0) {
+    if (io_destroy(ngx_aio_ctx) == -1) {
         ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                       "io_destroy() failed");
     }
@@ -667,8 +667,8 @@ ngx_epoll_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags)
 static void
 ngx_epoll_eventfd_handler(ngx_event_t *ev)
 {
-    int               n;
-    long              i, events;
+    int               n, events;
+    long              i;
     uint64_t          ready;
     ngx_err_t         err;
     ngx_event_t      *e;
@@ -738,8 +738,9 @@ ngx_epoll_eventfd_handler(ngx_event_t *ev)
             return;
         }
 
-        /* events < 0 */
-        ngx_log_error(NGX_LOG_ALERT, ev->log, -events, "io_getevents() failed");
+        /* events == -1 */
+        ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_errno,
+                      "io_getevents() failed");
         return;
     }
 }
diff --git a/src/os/unix/ngx_linux_aio_read.c b/src/os/unix/ngx_linux_aio_read.c
index b9d1d01cd..d31c4a064 100644
--- a/src/os/unix/ngx_linux_aio_read.c
+++ b/src/os/unix/ngx_linux_aio_read.c
@@ -16,7 +16,7 @@ extern aio_context_t  ngx_aio_ctx;
 static void ngx_file_aio_event_handler(ngx_event_t *ev);
 
 
-static long
+static int
 io_submit(aio_context_t ctx, long n, struct iocb **paiocb)
 {
     return syscall(SYS_io_submit, ctx, n, paiocb);
@@ -27,7 +27,7 @@ ssize_t
 ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
     ngx_pool_t *pool)
 {
-    long              n;
+    ngx_err_t         err;
     struct iocb      *piocb[1];
     ngx_event_t      *ev;
     ngx_event_aio_t  *aio;
@@ -96,9 +96,7 @@ ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
 
     piocb[0] = &aio->aiocb;
 
-    n = io_submit(ngx_aio_ctx, 1, piocb);
-
-    if (n == 1) {
+    if (io_submit(ngx_aio_ctx, 1, piocb) == 1) {
         ev->active = 1;
         ev->ready = 0;
         ev->complete = 0;
@@ -106,16 +104,16 @@ ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset,
         return NGX_AGAIN;
     }
 
-    n = -n;
+    err = ngx_errno;
 
-    if (n == NGX_EAGAIN) {
+    if (err == NGX_EAGAIN) {
         return ngx_read_file(file, buf, size, offset);
     }
 
-    ngx_log_error(NGX_LOG_CRIT, file->log, n,
+    ngx_log_error(NGX_LOG_CRIT, file->log, err,
                   "io_submit(\"%V\") failed", &file->name);
 
-    if (n == NGX_ENOSYS) {
+    if (err == NGX_ENOSYS) {
         ngx_file_aio = 0;
         return ngx_read_file(file, buf, size, offset);
     }