.

wcfs/internal/wcfs_misc.cpp

@@ -27,6 +27,9 @@
 
 #include <memory>
 
+static error _pathError(const char *op, const string &path, int syserr);
+
+
 // os::
 namespace os {
 
@@ -63,13 +66,39 @@ error File::stat(struct stat *st) {
 // _errno returns error corresponding to file->op and errno.
 error File::_errno(const char *op) {
     File *f = this;
-    char ebuf[128];
-    char *estr = strerror_r(errno, ebuf, sizeof(ebuf));
-    return fmt::errorf("%s %s: %s", op, f->_path, estr);
+    return _pathError(op, f->_path, errno);
 }
 
 }   // os::
 
+// _pathError returns os.PathError-like for op/path and system error
+// indicated by syserr.
+static error _pathError(const char *op, const string &path, int syserr) {
+    char ebuf[128];
+    char *estr = strerror_r(syserr, ebuf, sizeof(ebuf));
+    return fmt::errorf("%s %s: %s", op, path.c_str(), estr);
+}
+
+// mm::
+namespace mm {
+    // map_into memory-maps f.fd[offset +size) as into [addr +size).
+    // prot  is PROT_* from mmap(2).
+    // flags is MAP_*  from mmap(2); MAP_FIXED is added to flags.
+    //
+    // XXX split from File?
+    error map_into(void *addr, size_t size, int prot, int flags, const File &f, off_t offset) {
+        void *addr2;
+
+        addr2 = mmap(addr, size, PROT_READ, MAP_FIXED | MAP_SHARED, f->fd(), offset);
+        if (addr2 == MAP_FAILED)
+            return _pathError("mmap", f.name(), errno);
+        if (addr2 != addr)
+            panic("mmap(addr, MAP_FIXED): returned !addr");
+        return nil;
+    }
+
+}   // mm::
+
 
 // fmt::
 namespace fmt {

wcfs/internal/wcfs_misc.h

@@ -80,6 +80,13 @@ tuple<File, error> open(const string &path, int flags = O_RDONLY,
 
 }   // os::
 
+// mm::
+namespace mm {
+    error map_into(void *addr, size_t, int prot, int flags, const os::File &f, off_t offset);
+    // XXX unmap
+
+}   // mm::
+
 
 // fmt::
 namespace fmt {

wcfs/internal/wcfs_virtmem.cpp

@@ -38,6 +38,7 @@ using namespace golang;
 #include <vector>
 
 #include <sys/types.h>
+#include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <stdint.h>
@@ -278,14 +279,8 @@ error _Mapping::_remmapblk(int64_t blk, Tid at) {
     }
     // block is inside file - mmap file data
     else {
-        mm.map_into_ro(blkmem, fsfile.fd(), blk*f->blksize);  // XXX err
-
-        err = mmap_into_ro(blkmem, f->blksize, fsfile, blk*f->blksize);
-
-        err = fsfile.mmapfix(blkmem, f->blksize, PROT_READ, MAP_SHARED, blk*f->blksize);
-
-        mmap(blkmem, f->blksize, PROT_READ, MAP_FIXED | MAP_SHARED,
-                fsfile.fd(), blk*f->blksize);
+        err = mm::map_into(blkmem, f->blksize, PROT_READ, MAP_SHARED, fsfile, blk*f->blksize);
+        // XXX err handle
     }
 
     return nil;
@@ -314,14 +309,3 @@ tuple<os::File, error> WCFS::_open(const string &path, int flags) {
 string h(uint64_t v) {
     return fmt::sprintf("%016x", v);
 }
-
-// map_into_ro memory-maps f.fd[offset +size) as read-only into [addr +size).
-// The mapping is created with MAP_SHARED.
-error mmap_into_ro(void *addr, size_t size, const File &f. off_t offset) {
-    void *addr2;
-
-    addr2 = mmap(blkmem, size, PROT_READ, MAP_FIXED | MAP_SHARED, f.fd(), offset);
-    // XXX -> err
-
-    // XXX assert addr2 == addr
-}