System [Linux]: Support clonefile() on Linux.

pikelang · Dec 6, 2024 · 9ac9e4f · 9ac9e4f
1 parent 86f3758
commit 9ac9e4f
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Showing 2 changed files with 54 additions and 6 deletions.
diff --git a/src/modules/system/configure.in b/src/modules/system/configure.in
@@ -22,7 +22,7 @@ AC_CHECK_HEADERS(syslog.h sys/syslog.h sys/types.h errno.h unistd.h pwd.h \
         sys/systeminfo.h windows.h sys/param.h utime.h sys/utime.h sys/id.h \
 	sys/time.h sys/shm.h sys/mman.h fcntl.h sys/fcntl.h netinfo/ni.h \
 	sys/prctl.h cygwin/ipc.h cygwin/sem.h cygwin/shm.h ws2tcpip.h \
-	NewAPIs.h sys/loadavg.h sys/clonefile.h)
+	NewAPIs.h sys/loadavg.h sys/clonefile.h linux/fs.h sys/ioctl.h)
 
 # some Linux systems have a broken resource.h that compiles anyway /Mirar
 AC_MSG_CHECKING([for working sys/resource.h])
@@ -98,7 +98,7 @@ AC_HAVE_FUNCS(syslog link symlink readlink resolvepath realpath chown lchown \
         getrlimit setrlimit setproctitle \
         setitimer getitimer mmap munmap \
 	gettimeofday settimeofday prctl inet_ntoa inet_ntop getaddrinfo \
-	getloadavg daemon clonefile)
+	getloadavg daemon clonefile copy_file_range)
 
 if test "x$ac_cv_func_setpgrp" = "xyes"; then
   AC_MSG_CHECKING([if setpgrp takes two arguments (BSD)])

diff --git a/src/modules/system/system.c b/src/modules/system/system.c
@@ -43,6 +43,7 @@
 #include "pike_rusage.h"
 #include "pike_netlib.h"
 #include "pike_cpulib.h"
+#include "fdlib.h"
 
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
@@ -119,8 +120,15 @@
 #include <sys/clonefile.h>
 #endif
 
-#include "dmalloc.h"
+#ifdef HAVE_LINUX_FS_H
+#include <linux/fs.h>
+#endif
 
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+
+#include "dmalloc.h"
 
 #define sp Pike_sp
 
@@ -437,16 +445,56 @@ void f_resolvepath(INT32 args)
 }
 #endif /* HAVE_RESOLVEPATH || HAVE_REALPATH */
 
+#if !defined(HAVE_CLONEFILE) && defined(HAVE_COPY_FILE_RANGE)
+int clonefile(const char *from, const char *to, int flags)
+{
+  int ret = -1;
+  int fromfd = -1;
+  int tofd = -1;
+  struct stat stat;
+
+  if (flags) {
+    /* No flags are supported currently. */
+    errno = EINVAL;
+    return -1;
+  }
+
+  fromfd = fd_open(from, fd_RDONLY, 0);
+  if (fromfd < 0) return -1;
+
+  if (fd_fstat(fromfd, &stat) < 0) goto cleanup;
+
+  if ((stat.st_mode & S_IFMT) != S_IFREG) {
+    errno = EINVAL;
+    goto cleanup;
+  }
+
+  tofd = fd_open(to, fd_CREAT|fd_TRUNC|fd_RDWR, stat.st_mode);
+  if (tofd < 0) goto cleanup;
+
+  ret = copy_file_range(fromfd, NULL, tofd, NULL, stat.st_size, 0);
+
+ cleanup:
+  if (tofd >= 0) close(tofd);
+
+  if (fromfd >= 0) close(fromfd);
+
+  return ret;
+}
+
+#define HAVE_CLONEFILE
+#endif
+
 #ifdef HAVE_CLONEFILE
 /*! @decl void clonefile(string from, string to)
  *!
  *! Copy a file @[from] with copy-on-write semantics to the destination named
  *! @[to].
  *!
  *! @note
- *!   This function is currently only available on macOS, and then only when
- *!   @[from] and @[to] reference a common file system with copy-on-write
- *!   support (e.g. an APFS volume).
+ *!   This function is currently only available on macOS and Linux, and then
+ *!   only when @[from] and @[to] reference a common file system with
+ *!   copy-on-write support (e.g. an APFS volume).
  *!
  *! @seealso
  *!   @[hardlink()], @[symlink()]