X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Futil%2Fos_file.c;h=c5970ddb2431b058334dd6b97b0b142e2bb724ff;hb=HEAD;hp=a700f3aada3088b6f1164fbc78a7e6f9dc886ac2;hpb=93349d71183d4a50ef5ad90b32cb96b9f84d3eec;p=mesa.git

diff --git a/src/util/os_file.c b/src/util/os_file.c
index a700f3aada3..c5970ddb243 100644
--- a/src/util/os_file.c
+++ b/src/util/os_file.c
@@ -4,16 +4,91 @@
  */
 
 #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
+#else
+#include <unistd.h>
+#ifndef F_DUPFD_CLOEXEC
+#define F_DUPFD_CLOEXEC 1030
+#endif
+#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 DETECT_OS_WINDOWS
+int
+os_dupfd_cloexec(int fd)
+{
+   /*
+    * On Windows child processes don't inherit handles by default:
+    * https://devblogs.microsoft.com/oldnewthing/20111216-00/?p=8873
+    */
+   return dup(fd);
+}
+#else
+int
+os_dupfd_cloexec(int fd)
+{
+   int minfd = 3;
+   int newfd = fcntl(fd, F_DUPFD_CLOEXEC, minfd);
+
+   if (newfd >= 0)
+      return newfd;
+
+   if (errno != EINVAL)
+      return -1;
+
+   newfd = fcntl(fd, F_DUPFD, minfd);
+
+   if (newfd < 0)
+      return -1;
 
-#if defined(__linux__)
+   long flags = fcntl(newfd, F_GETFD);
+   if (flags == -1) {
+      close(newfd);
+      return -1;
+   }
+
+   if (fcntl(newfd, F_SETFD, flags | FD_CLOEXEC) == -1) {
+      close(newfd);
+      return -1;
+   }
+
+   return newfd;
+}
+#endif
+
+
+#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)
@@ -41,7 +116,7 @@ readN(int fd, char *buf, size_t len)
 }
 
 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
@@ -92,18 +167,56 @@ os_read_file(const char *filename)
    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