sandbox: Add a way to map a file into memory

It is useful to map a file into memory so that it can be accessed using
simple pointers. Add a function to support this.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index a426288..b72dafc 100644 (file)
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -182,6 +182,35 @@ err:
        return ret;
 }
 
+int os_map_file(const char *pathname, int os_flags, void **bufp, int *sizep)
+{
+       void *ptr;
+       int size;
+       int ifd;
+
+       ifd = os_open(pathname, os_flags);
+       if (ifd < 0) {
+               printf("Cannot open file '%s'\n", pathname);
+               return -EIO;
+       }
+       size = os_filesize(ifd);
+       if (size < 0) {
+               printf("Cannot get file size of '%s'\n", pathname);
+               return -EIO;
+       }
+
+       ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, ifd, 0);
+       if (ptr == MAP_FAILED) {
+               printf("Can't map file '%s': %s\n", pathname, strerror(errno));
+               return -EPERM;
+       }
+
+       *bufp = ptr;
+       *sizep = size;
+
+       return 0;
+}
+
 /* Restore tty state when we exit */
 static struct termios orig_term;
 static bool term_setup;

diff --git a/include/os.h b/include/os.h
index 7661078..770d76e 100644 (file)
--- a/include/os.h
+++ b/include/os.h
@@ -406,6 +406,19 @@ int os_write_file(const char *name, const void *buf, int size);
  */
 int os_read_file(const char *name, void **bufp, int *sizep);
 
+/**
+ * os_map_file() - Map a file from the host filesystem into memory
+ *
+ * This can be useful when to provide a backing store for an emulated device
+ *
+ * @pathname:  File pathname to map
+ * @os_flags:  Flags, like OS_O_RDONLY, OS_O_RDWR
+ * @bufp:      Returns buffer containing the file
+ * @sizep:     Returns size of data
+ * Return:     0 if OK, -ve on error
+ */
+int os_map_file(const char *pathname, int os_flags, void **bufp, int *sizep);
+
 /*
  * os_find_text_base() - Find the text section in this running process
  *