posix file: Add an `Offset` parameter and make `Len` optional
Give Map() an `Offset` parameter that will be passed to mmap(). Make the
`Len` parameter of Map() optional. If it's left at the default, `0`, map
until the end of the file (up to SIZE_MAX bytes).
Change-Id: I7b062ce1e9cddab87a66a2aedc8b64e4e8524d9f
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/20553
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/ada/posix/hw-file.adb b/ada/posix/hw-file.adb
index d9b15ba..e2384be 100644
--- a/ada/posix/hw-file.adb
+++ b/ada/posix/hw-file.adb
@@ -29,6 +29,7 @@
(addr : out Word64;
path : chars_ptr;
len : Word32;
+ off : Word32;
mode : Word32;
copy : int)
return int;
@@ -37,7 +38,8 @@
procedure Map
(Addr : out Word64;
Path : in String;
- Len : in Natural;
+ Len : in Natural := 0;
+ Offset : in Natural := 0;
Readable : in Boolean := False;
Writable : in Boolean := False;
Map_Copy : in Boolean := False;
@@ -50,6 +52,7 @@
(addr => Addr,
path => cpath,
len => Word32 (Len),
+ off => Word32 (Offset),
mode => (if Readable then READ else 0) or
(if Writable then WRITE else 0),
copy => (if Map_Copy then 1 else 0));
diff --git a/c/hw-file.c b/c/hw-file.c
index 7a9478d..afa62a0 100644
--- a/c/hw-file.c
+++ b/c/hw-file.c
@@ -14,6 +14,8 @@
#include <stdint.h>
#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
@@ -21,9 +23,26 @@
#define HW_FILE_READ 0x01
#define HW_FILE_WRITE 0x02
+static size_t stat_length(size_t *const len, const size_t off, const int fd)
+{
+ struct stat statbuf;
+
+ if (*len == 0 && !fstat(fd, &statbuf)) {
+ if (statbuf.st_size == 0)
+ errno = EINVAL;
+ else if (statbuf.st_size - (off_t)off <= SIZE_MAX)
+ *len = (size_t)(statbuf.st_size - (off_t)off);
+ else
+ *len = SIZE_MAX;
+ }
+
+ return *len;
+}
+
static int map_file(uint64_t *const addr,
const char *const path,
- const uint32_t len,
+ size_t len,
+ const size_t off,
const uint32_t mode)
{
const int prot = (mode & HW_FILE_READ ? PROT_READ : 0) |
@@ -37,7 +56,12 @@
if (fd < 0)
return errno;
- void *const mapped = mmap(NULL, len, prot, MAP_SHARED, fd, (off_t)0);
+ if (!stat_length(&len, off, fd)) {
+ close(fd);
+ return errno;
+ }
+
+ void *const mapped = mmap(NULL, len, prot, MAP_SHARED, fd, (off_t)off);
close(fd);
if (mapped == MAP_FAILED)
return errno;
@@ -48,23 +72,27 @@
static int map_fill_from_file(uint64_t *const addr,
const char *const path,
- const uint32_t len,
+ size_t len,
+ const size_t off,
const uint32_t mode)
{
- uint32_t xferred;
+ size_t xferred;
ssize_t read_ret;
if (mode != HW_FILE_READ)
return EINVAL;
- void *const mapped = mmap(NULL, len, PROT_READ | PROT_WRITE,
- MAP_ANONYMOUS | MAP_PRIVATE, -1, (off_t)0);
- if (mapped == MAP_FAILED)
- return errno;
-
const int fd = open(path, O_RDONLY);
if (fd < 0)
- goto _munmap;
+ return errno;
+
+ if (!stat_length(&len, off, fd))
+ goto _close;
+
+ void *const mapped = mmap(NULL, len, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, -1, (off_t)off);
+ if (mapped == MAP_FAILED)
+ goto _close;
xferred = 0;
do {
@@ -73,7 +101,6 @@
xferred += read_ret;
} while ((read_ret > 0 || (read_ret == -1 && errno == EINTR))
&& xferred < len);
- close(fd);
if (xferred < len)
goto _munmap;
@@ -81,22 +108,28 @@
if (mprotect(mapped, len, PROT_READ))
goto _munmap;
+ close(fd);
+
*addr = (uint64_t)(uintptr_t)mapped;
return 0;
_munmap:
munmap(mapped, len);
+_close:
+ close(fd);
return errno;
}
int hw_file_map(uint64_t *const addr,
const char *const path,
const uint32_t len,
+ const uint32_t off,
const uint32_t mode,
const int copy)
{
if (copy)
- return map_fill_from_file(addr, path, len, mode);
+ return map_fill_from_file(
+ addr, path, (size_t)len, (size_t)off, mode);
else
- return map_file(addr, path, len, mode);
+ return map_file(addr, path, (size_t)len, (size_t)off, mode);
}
diff --git a/common/hw-file.ads b/common/hw-file.ads
index 57cf429..9dbfcf7 100644
--- a/common/hw-file.ads
+++ b/common/hw-file.ads
@@ -17,17 +17,20 @@
--
-- Map a file's content into our address space
--
- -- If `Map_Copy` is `False`, `Len` bytes from the start of the file
- -- given by `Path` shall be mapped into the application's address
- -- space using mmap().
+ -- If `Map_Copy` is `False`, `Len` bytes at `Offset` from the start
+ -- of the file given by `Path` should be mapped into the application's
+ -- address space using mmap().
--
-- If `Map_Copy` is `True`, anonymous memory should be mapped instead
-- and be filled with a copy of the file's content using read().
--
+ -- If `Len` is zero, the whole file should be mapped.
+ --
procedure Map
(Addr : out Word64;
Path : in String;
- Len : in Natural;
+ Len : in Natural := 0;
+ Offset : in Natural := 0;
Readable : in Boolean := False;
Writable : in Boolean := False;
Map_Copy : in Boolean := False;