diff options
Diffstat (limited to 'Documentation/early-userspace')
| -rw-r--r-- | Documentation/early-userspace/buffer-format.rst (renamed from Documentation/early-userspace/buffer-format.txt) | 19 | ||||
| -rw-r--r-- | Documentation/early-userspace/early_userspace_support.rst (renamed from Documentation/early-userspace/README) | 3 | ||||
| -rw-r--r-- | Documentation/early-userspace/index.rst | 18 |
3 files changed, 34 insertions, 6 deletions
diff --git a/Documentation/early-userspace/buffer-format.txt b/Documentation/early-userspace/buffer-format.rst index e1fd7f9dad16..7f74e301fdf3 100644 --- a/Documentation/early-userspace/buffer-format.txt +++ b/Documentation/early-userspace/buffer-format.rst @@ -1,8 +1,10 @@ - initramfs buffer format - ----------------------- +======================= +initramfs buffer format +======================= - Al Viro, H. Peter Anvin - Last revision: 2002-01-13 +Al Viro, H. Peter Anvin + +Last revision: 2002-01-13 Starting with kernel 2.5.x, the old "initial ramdisk" protocol is getting {replaced/complemented} with the new "initial ramfs" @@ -18,7 +20,8 @@ archive can be compressed using gzip(1). One valid version of an initramfs buffer is thus a single .cpio.gz file. The full format of the initramfs buffer is defined by the following -grammar, where: +grammar, where:: + * is used to indicate "0 or more occurrences of" (|) indicates alternatives + indicates concatenation @@ -49,7 +52,9 @@ hexadecimal ASCII numbers fully padded with '0' on the left to the full width of the field, for example, the integer 4780 is represented by the ASCII string "000012ac"): +============= ================== ============================================== Field name Field size Meaning +============= ================== ============================================== c_magic 6 bytes The string "070701" or "070702" c_ino 8 bytes File inode number c_mode 8 bytes File mode and permissions @@ -65,6 +70,7 @@ c_rmin 8 bytes Minor part of device node reference c_namesize 8 bytes Length of filename, including final \0 c_chksum 8 bytes Checksum of data field if c_magic is 070702; otherwise zero +============= ================== ============================================== The c_mode field matches the contents of st_mode returned by stat(2) on Linux, and encodes the file type and file permissions. @@ -82,7 +88,8 @@ If the filename is "TRAILER!!!" this is actually an end-of-archive marker; the c_filesize for an end-of-archive marker must be zero. -*** Handling of hard links +Handling of hard links +====================== When a nondirectory with c_nlink > 1 is seen, the (c_maj,c_min,c_ino) tuple is looked up in a tuple buffer. If not found, it is entered in diff --git a/Documentation/early-userspace/README b/Documentation/early-userspace/early_userspace_support.rst index 955d667dc87e..3deefb34046b 100644 --- a/Documentation/early-userspace/README +++ b/Documentation/early-userspace/early_userspace_support.rst @@ -1,3 +1,4 @@ +======================= Early userspace support ======================= @@ -26,6 +27,7 @@ archive to be used as the image or have the kernel build process build the image from specifications. CPIO ARCHIVE method +------------------- You can create a cpio archive that contains the early userspace image. Your cpio archive should be specified in CONFIG_INITRAMFS_SOURCE and it @@ -34,6 +36,7 @@ CONFIG_INITRAMFS_SOURCE and directory and file names are not allowed in combination with a cpio archive. IMAGE BUILDING method +--------------------- The kernel build process can also build an early userspace image from source parts rather than supplying a cpio archive. This method provides diff --git a/Documentation/early-userspace/index.rst b/Documentation/early-userspace/index.rst new file mode 100644 index 000000000000..2b8eb6132058 --- /dev/null +++ b/Documentation/early-userspace/index.rst @@ -0,0 +1,18 @@ +:orphan: + +=============== +Early Userspace +=============== + +.. toctree:: + :maxdepth: 1 + + early_userspace_support + buffer-format + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` |