Import Mesa 19.2.8

1 files changed, 142 insertions, 0 deletions

diff --git a/lib/mesa/src/util/os_file.c b/lib/mesa/src/util/os_file.c
new file mode 100644
index 000000000..c670e127c
--- /dev/null
+++ b/lib/mesa/src/util/os_file.c
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2019 Intel Corporation
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "os_file.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+
+#if defined(WIN32)
+#include <io.h>
+#define open _open
+#define fdopen _fdopen
+#define O_CREAT _O_CREAT
+#define O_EXCL _O_EXCL
+#define O_WRONLY _O_WRONLY
+#endif
+
+
+FILE *
+os_file_create_unique(const char *filename, int filemode)
+{
+   int fd = open(filename, O_CREAT | O_EXCL | O_WRONLY, filemode);
+   if (fd == -1)
+      return NULL;
+   return fdopen(fd, "w");
+}
+
+
+#if defined(__linux__)
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+
+static ssize_t
+readN(int fd, char *buf, size_t len)
+{
+   int err = -ENODATA;
+   size_t total = 0;
+   do {
+      ssize_t ret = read(fd, buf + total, len - total);
+
+      if (ret < 0)
+         ret = -errno;
+
+      if (ret == -EINTR || ret == -EAGAIN)
+         continue;
+
+      if (ret <= 0) {
+         err = ret;
+         break;
+      }
+
+      total += ret;
+   } while (total != len);
+
+   return total ? (ssize_t)total : err;
+}
+
+char *
+os_read_file(const char *filename)
+{
+   /* Note that this also serves as a slight margin to avoid a 2x grow when
+    * the file is just a few bytes larger when we read it than when we
+    * fstat'ed it.
+    * The string's NULL terminator is also included in here.
+    */
+   size_t len = 64;
+
+   int fd = open(filename, O_RDONLY);
+   if (fd == -1) {
+      /* errno set by open() */
+      return NULL;
+   }
+
+   /* Pre-allocate a buffer at least the size of the file if we can read
+    * that information.
+    */
+   struct stat stat;
+   if (fstat(fd, &stat) == 0)
+      len += stat.st_size;
+
+   char *buf = malloc(len);
+   if (!buf) {
+      close(fd);
+      errno = -ENOMEM;
+      return NULL;
+   }
+
+   ssize_t actually_read;
+   size_t offset = 0, remaining = len - 1;
+   while ((actually_read = readN(fd, buf + offset, remaining)) == (ssize_t)remaining) {
+      char *newbuf = realloc(buf, 2 * len);
+      if (!newbuf) {
+         free(buf);
+         close(fd);
+         errno = -ENOMEM;
+         return NULL;
+      }
+
+      buf = newbuf;
+      len *= 2;
+      offset += actually_read;
+      remaining = len - offset - 1;
+   }
+
+   close(fd);
+
+   if (actually_read > 0)
+      offset += actually_read;
+
+   /* Final resize to actual size */
+   len = offset + 1;
+   char *newbuf = realloc(buf, len);
+   if (!newbuf) {
+      free(buf);
+      errno = -ENOMEM;
+      return NULL;
+   }
+   buf = newbuf;
+
+   buf[offset] = '\0';
+
+   return buf;
+}
+
+#else
+
+char *
+os_read_file(const char *filename)
+{
+   errno = -ENOSYS;
+   return NULL;
+}
+
+#endif