Attempt to work around lseek SEEK_HOLE bug

Closes: https://trac.macports.org/ticket/67336
macports · Oct 7, 2024 · af49e24 · af49e24
1 parent 7354c0d
commit af49e24
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diff --git a/src/pextlib1.0/Pextlib.c b/src/pextlib1.0/Pextlib.c
@@ -1150,6 +1150,54 @@ int ClonefileCmd(ClientData clientData UNUSED, Tcl_Interp *interp, int objc, Tcl
     return TCL_ERROR;
 }
 
+static int fileIsSparseCmd(ClientData clientData UNUSED, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
+#ifdef SEEK_HOLE
+    const char *path;
+    struct stat st;
+    int fd;
+    off_t end_offset;
+    off_t hole_offset;
+
+    if (objc != 2) {
+        Tcl_WrongNumArgs(interp, 1, objv, "filename");
+        return TCL_ERROR;
+    }
+
+    path = Tcl_GetString(objv[1]);
+    if (-1 == lstat(path, &st)) {
+        /* an error occurred */
+        Tcl_SetErrno(errno);
+        Tcl_ResetResult(interp);
+        Tcl_AppendResult(interp, "lstat(", path, "):", (char *)Tcl_PosixError(interp), NULL);
+        return TCL_ERROR;
+    }
+    if (!S_ISREG(st.st_mode)) {
+        /* not a regular file, haven't seen directories which are sparse yet */
+        Tcl_SetObjResult(interp, Tcl_NewBooleanObj(false));
+        return TCL_OK;
+    }
+    if ((fd = open(path, O_RDONLY)) < 0) {
+        Tcl_SetErrno(errno);
+        Tcl_ResetResult(interp);
+        Tcl_AppendResult(interp, "open(", path, "): ", (char *)Tcl_PosixError(interp), NULL);
+        return TCL_ERROR;
+    }
+
+    lseek(fd, 0, SEEK_SET);
+    hole_offset = lseek(fd, 0, SEEK_HOLE);
+    end_offset = lseek(fd, 0, SEEK_END);
+    close(fd);
+    if (hole_offset >= 0 && end_offset >= 0
+        && hole_offset < end_offset) {
+        Tcl_SetObjResult(interp, Tcl_NewBooleanObj(true));
+        return TCL_OK;
+    }
+#endif /* SEEK_HOLE */
+
+    Tcl_SetObjResult(interp, Tcl_NewBooleanObj(false));
+    return TCL_OK;
+}
+
 int Pextlib_Init(Tcl_Interp *interp)
 {
     if (Tcl_InitStubs(interp, "8.4", 0) == NULL)
@@ -1184,6 +1232,7 @@ int Pextlib_Init(Tcl_Interp *interp)
 #ifdef __MACH__
     Tcl_CreateObjCommand(interp, "fileIsBinary", fileIsBinaryCmd, NULL, NULL);
 #endif
+    Tcl_CreateObjCommand(interp, "fileIsSparse", fileIsSparseCmd, NULL, NULL);
 
     Tcl_CreateObjCommand(interp, "readline", ReadlineCmd, NULL, NULL);
     Tcl_CreateObjCommand(interp, "rl_history", RLHistoryCmd, NULL, NULL);

diff --git a/src/port1.0/portdestroot.tcl b/src/port1.0/portdestroot.tcl
@@ -383,6 +383,23 @@ proc portdestroot::destroot_finish {args} {
         ui_warn "[format [msgcat::mc "%s installs files outside the common directory structure."] $subport]"
     }
 
+    # Work around apparent filesystem bug.
+    # https://trac.macports.org/ticket/67336
+    if {[fs_clone_capable $destroot]} {
+        global workpath
+        ui_debug "Applying sparse file lseek bug workaround"
+        fs-traverse -depth fullpath [list $destroot] {
+            if {[file type $fullpath] eq "file" && [fileIsSparse $fullpath]} {
+                ui_debug "Cloning $fullpath for workaround"
+                clonefile $fullpath ${workpath}/.macports-sparse-workaround
+                file delete ${workpath}/.macports-sparse-workaround
+                if {![fileIsSparse $fullpath]} {
+                    ui_debug "$fullpath is no longer sparse"
+                }
+            }
+        }
+    }
+
     # Restore umask
     umask $oldmask