factor out kver detection to functions file

This leaves bash completion with a duplication, but this is intentional
to avoid pulling in the entire functions file and worrying about
pollution.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

4 files changed, 24 insertions, 23 deletions

diff --git a/bash-completion b/bash-completion
index 597eab2..0108863 100644
--- a/bash-completion
+++ b/bash-completion
@@ -1,5 +1,4 @@
 #!/bin/bash
-# mkinitcpio bash completion by Seblu <seblu@seblu.net>
 
 detect_kver() {
     local kver_validator='^[[:digit:]]+(\.[[:digit:]]+)+'
diff --git a/functions b/functions
index 5a44ac9..8be43ed 100644
--- a/functions
+++ b/functions
@@ -133,6 +133,28 @@ parseopts() {
     return 0
 }
 
+kver() {
+    # this is intentionally very loose. only ensure that we're
+    # dealing with some sort of string that starts with something
+    # resembling dotted decimal notation. remember that there's no
+    # requirement for CONFIG_LOCALVERSION to be set.
+    local kver re='^[[:digit:]]+(\.[[:digit:]]+)+'
+
+    # scrape the version out of the kernel image. locate the offset
+    # to the version string by reading 2 bytes out of image at at
+    # address 0x20E. this leads us to a string of, at most, 128 bytes.
+    # read the first word from this string as the kernel version.
+    local offset=$(hexdump -s 526 -n 2 -e '"%0d"' "$1")
+    [[ $offset = +([0-9]) ]] || return 1
+
+    read kver _ < \
+        <(dd if="$1" bs=1 count=127 skip=$(( offset + 0x200 )) 2>/dev/null)
+
+    [[ $kver =~ $re ]] || return 1
+
+    printf '%s' "$kver"
+}
+
 plain() {
     local mesg=$1; shift
     printf "    $_color_bold$mesg$_color_none\n" "$@" >&1
diff --git a/lsinitcpio b/lsinitcpio
index 5984cf8..c4129d5 100755
--- a/lsinitcpio
+++ b/lsinitcpio
@@ -108,10 +108,7 @@ detect_filetype() {
     fi
 
     # still nothing? hrmm, maybe the user goofed and it's a kernel
-    offt=$(hexdump -s 526 -n 2 -e '"%0d"' "$1")
-    read kver _ < \
-        <(dd if="$1" bs=1 count=127 skip=$(( offt + 0x200 )) 2>/dev/null)
-    if [[ $kver =~ $kver_validator ]]; then
+    if kver "$1" >/dev/null; then
         die '%s is a kernel image, not an initramfs image!' "$1"
     fi
 
diff --git a/mkinitcpio b/mkinitcpio
index 30e9236..d5cf895 100755
--- a/mkinitcpio
+++ b/mkinitcpio
@@ -84,12 +84,6 @@ cleanup() {
 resolve_kernver() {
     local kernel=$1 offset kver
 
-    # this is intentionally very loose. only ensure that we're
-    # dealing with some sort of string that starts with something
-    # resembling dotted decimal notation. remember that there's no
-    # requirement for CONFIG_LOCALVERSION to be set.
-    local kver_validator='^[[:digit:]]+(\.[[:digit:]]+)+'
-
     if [[ -z $kernel ]]; then
         uname -r
         return 0
@@ -105,18 +99,7 @@ resolve_kernver() {
         return 1
     fi
 
-    # scrape the version out of the kernel image. locate the offset
-    # to the version string by reading 2 bytes out of image at at
-    # address 0x20E. this leads us to a string of, at most, 128 bytes.
-    # read the first word from this string as the kernel version.
-    offset=$(hexdump -s 526 -n 2 -e '"%0d"' "$kernel")
-    read kver _ < \
-        <(dd if="$kernel" bs=1 count=127 skip=$(( offset + 0x200 )) 2>/dev/null)
-
-    if [[ $kver =~ $kver_validator ]]; then
-        printf '%s' "$kver"
-        return 0
-    fi
+    kver "$kernel" && return
 
     error "invalid kernel specified: \`%s'" "$_optkver"