source/blender/blenlib/BLI_fileops.h

@@ -290,6 +290,14 @@ void *BLI_gzopen(const char *filepath, const char *mode) ATTR_WARN_UNUSED_RESULT
 int BLI_open(const char *filepath, int oflag, int pmode) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 int BLI_access(const char *filepath, int mode) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 
+/**
+ * A version of `read` with the following differences:
+ * - continues reading until failure or the requested size is met.
+ * - Reads `size_t` bytes instead of `int` on WIN32.
+ * \return the number of bytes read.
+ */
+ssize_t BLI_read(int fd, void *buf, size_t nbytes);
+
 /**
  * Returns true if the file with the specified name can be written.
  * This implementation uses access(2), which makes the check according

source/blender/blenlib/intern/fileops.c

@@ -92,6 +92,51 @@ static char *windows_operation_string(FileExternalOperation operation)
 }
 #endif
 
+ssize_t BLI_read(int fd, void *buf, size_t nbytes)
+{
+  /* Define our own read as `read` is not guaranteed to read the number of bytes requested.
+   * This happens rarely but was observed with larger than 2GB files on Linux, see: #113473.
+   *
+   * Even though this is a loop, the most common code-path will exit with "Success" case.
+   * In the case where read more data than the file contains, it will loop twice,
+   * exiting on EOF with the second iteration. */
+  ssize_t nbytes_read_total = 0;
+  while (true) {
+    ssize_t nbytes_read = read(fd,
+                               buf,
+#ifdef WIN32
+                               /* Read must not exceed INT_MAX on WIN32, clamp. */
+                               MIN2(nbytes, INT_MAX)
+#else
+                               nbytes
+#endif
+    );
+    if (nbytes_read == nbytes) {
+      /* Success (common case). */
+      return nbytes_read_total + nbytes_read;
+    }
+    if (nbytes_read == 0) {
+      /* EOF (common case for the second iteration when reading more data than `fd` contains). */
+      return nbytes_read_total;
+    }
+    if (nbytes_read < 0) {
+      /* Error. */
+      return nbytes_read;
+    }
+    if (UNLIKELY(nbytes_read > nbytes)) {
+      /* Badly behaving C-API - this should never happen.
+       * Possibly an invalid internal state/corruption, only check to prevent an eternal loop. */
+      BLI_assert_unreachable();
+      return -1;
+    }
+
+    /* If this is reached, fewer bytes were read than were requested. */
+    buf = (void *)(((char *)buf) + nbytes_read);
+    nbytes_read_total += nbytes_read;
+    nbytes -= nbytes_read;
+  }
+}
+
 bool BLI_file_external_operation_supported(const char *filepath, FileExternalOperation operation)
 {
 #ifdef WIN32

source/blender/windowmanager/intern/wm_playanim.cc

@@ -124,7 +124,7 @@ static bool buffer_from_filepath(const char *filepath, void **r_mem, size_t *r_s
   else if (r_mem && UNLIKELY(!(mem = static_cast<uchar *>(MEM_mallocN(size, __func__))))) {
     CLOG_WARN(&LOG, "error allocating buffer for '%s'", filepath);
   }
-  else if (r_mem && UNLIKELY((size_read = read(file, mem, size)) != size)) {
+  else if (r_mem && UNLIKELY((size_read = BLI_read(file, mem, size)) != size)) {
     CLOG_WARN(&LOG,
               "error '%s' while reading '%s' (expected %" PRIu64 ", was %" PRId64 ")",
               strerror(errno),