util/os_file: replace broken windows-detection code with detect_os.h

[mesa.git] / src / util / os_file.c

diff --git a/src/util/os_file.c b/src/util/os_file.c
index da17d12b50e5d67e5ea89a59da3397fa131f7214..f02d74afd2ca1158e91cfd750defc783c7cbc2f2 100644 (file)
--- a/src/util/os_file.c
+++ b/src/util/os_file.c
@@ -4,16 +4,42 @@
  */
 
 #include "os_file.h"
+#include "detect_os.h"
 
 #include <errno.h>
+#include <fcntl.h>
 #include <stdlib.h>
+#include <sys/stat.h>
+
+#if DETECT_OS_WINDOWS
+#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
 
-#if defined(__linux__)
+
+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 DETECT_OS_LINUX
 
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <sys/syscall.h>
 #include <unistd.h>
 
+/* copied from <linux/kcmp.h> */
+#define KCMP_FILE 0
 
 static ssize_t
 readN(int fd, char *buf, size_t len)
@@ -37,11 +63,11 @@ readN(int fd, char *buf, size_t len)
       total += ret;
    } while (total != len);
 
-   return total ? total : err;
+   return total ? (ssize_t)total : err;
 }
 
 char *
-os_read_file(const char *filename)
+os_read_file(const char *filename, size_t *size)
 {
    /* 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
@@ -70,9 +96,9 @@ os_read_file(const char *filename)
       return NULL;
    }
 
-   ssize_t read;
+   ssize_t actually_read;
    size_t offset = 0, remaining = len - 1;
-   while ((read = readN(fd, buf + offset, remaining)) == remaining) {
+   while ((actually_read = readN(fd, buf + offset, remaining)) == (ssize_t)remaining) {
       char *newbuf = realloc(buf, 2 * len);
       if (!newbuf) {
          free(buf);
@@ -83,27 +109,65 @@ os_read_file(const char *filename)
 
       buf = newbuf;
       len *= 2;
-      offset += read;
+      offset += actually_read;
       remaining = len - offset - 1;
    }
 
    close(fd);
 
-   if (read > 0)
-      offset += read;
+   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';
 
+   if (size)
+      *size = offset;
+
    return buf;
 }
 
+int
+os_same_file_description(int fd1, int fd2)
+{
+   pid_t pid = getpid();
+
+   /* Same file descriptor trivially implies same file description */
+   if (fd1 == fd2)
+      return 0;
+
+   return syscall(SYS_kcmp, pid, pid, KCMP_FILE, fd1, fd2);
+}
+
 #else
 
+#include "u_debug.h"
+
 char *
-os_read_file(const char *filename)
+os_read_file(const char *filename, size_t *size)
 {
    errno = -ENOSYS;
    return NULL;
 }
 
+int
+os_same_file_description(int fd1, int fd2)
+{
+   /* Same file descriptor trivially implies same file description */
+   if (fd1 == fd2)
+      return 0;
+
+   /* Otherwise we can't tell */
+   return -1;
+}
+
 #endif