Make mga-bg-res a systemd service that uses monitor-probe

Now runs as a systemd service with root privileges, therefore the mga-bg-res C binary is no longer needed.
Uses monitor-probe to find the optimal resolution when X is not yet started, and handles cases where monitor-probe fails by defaulting to 4:3 aspect ratio.

5 files changed, 60 insertions, 123 deletions

diff --git a/mga-bg-res/NEWS b/mga-bg-res/NEWS
index 0211c74..ead83b4 100644
--- a/mga-bg-res/NEWS
+++ b/mga-bg-res/NEWS
@@ -1,3 +1,7 @@
+- Make mga-bg-res a systemd service
+- Uses monitor-probe to find the optimal resolution when X is not yet started
+- Handle cases where monitor-probe fails by defaulting to 4:3 aspect ratio
+
 Version 0.6 (2015-04-22):
 - xinit script: Work also when default.jpg symlink is missing
 
diff --git a/mga-bg-res/mga-bg-res.c b/mga-bg-res/mga-bg-res.c
deleted file mode 100644
index 6061587..0000000
--- a/mga-bg-res/mga-bg-res.c
+++ /dev/null
@@ -1,82 +0,0 @@
-#include <stdio.h>
-#include <string.h>
-#include <errno.h>
-#include <unistd.h>
-
-#define PATH "/usr/share/mga/backgrounds/"
-#define DSTLINK PATH"default.jpg"
-#define SRCLINK_PREFIX PATH"Mageia-Default-"
-#define SRCLINK_SUFFIX ".jpg"
-#define SRCLINK SRCLINK_PREFIX"%s"SRCLINK_SUFFIX
-#define RESSIZE 20
-#define SRCSIZE (RESSIZE+strlen(SRCLINK_PREFIX)+strlen(SRCLINK_SUFFIX) + 1)
-#define ALLOWCHARS "0123456789x"
-
-int main(int argc, char* argv[]) {
-	char src[SRCSIZE];
-	char res[RESSIZE];
-	int l;
-
-	// check argument
-	if (argc != 2) {
-		fprintf(stderr, "Need a resolution argument, eg: '1920x1080'.\n");
-		return 1;
-	}
-
-	// get the res (max RESSIZE)
-	l = snprintf(res, RESSIZE, argv[1]);
-	if (l < 5) {
-		fprintf(stderr, "Malformed resolution argument, eg: '1920x1080'.\n");
-		return 2;
-	}
-
-	// to be sure, set the last char as 0
-	if (l < RESSIZE)
-		res[l] = 0;
-	else
-		res[RESSIZE-1] = 0;
-
-	// check if the resolution contains acceptable chars
-	l = strspn(res, ALLOWCHARS);
-	if (l < 5) {
-		fprintf(stderr, "Malformed resolution argument, eg: '1920x1080'.\n");
-		return 2;
-	}
-
-	// to be sure, set the last char as 0
-	if (l < RESSIZE)
-		res[l] = 0;
-	else
-		res[RESSIZE-1] = 0;
-
-	// create target string
-	if (snprintf(src, SRCSIZE, SRCLINK, res) < 0) {
-		fprintf(stderr, "Unknown error determining symlink target.\n");
-		return 3;
-	}
-
-	// check if symlink target exists
-	if (access(src, F_OK) < 0) {
-		fprintf(stderr, "No image for this resolution.\n");
-		return 0;
-	}
-
-	// set symlink
-	if (symlink(src, DSTLINK) < 0) {
-		if (errno != EEXIST) {
-			fprintf(stderr, "Symlink could not be set: %s.\n", strerror(errno));
-			return 4;
-		}
-
-		// since the destination exists, remove and try again
-		if (unlink(DSTLINK) < 0) {
-			fprintf(stderr, "Symlink could not be forced: %s.\n", strerror(errno));
-			return 5;
-		}
-		if (symlink(src, DSTLINK) < 0) {
-			fprintf(stderr, "Unknown error during forced symlink: %s.\n", strerror(errno));
-			return 6;
-		}
-	}
-	return 0;
-}
diff --git a/mga-bg-res/mga-bg-res.service b/mga-bg-res/mga-bg-res.service
new file mode 100644
index 0000000..821fb9f
--- /dev/null
+++ b/mga-bg-res/mga-bg-res.service
@@ -0,0 +1,9 @@
+[Unit]
+Description=Adapt Mageia theme to the monitor resolution
+
+[Service]
+Type=oneshot
+ExecStart=/usr/libexec/mga-bg-res
+
+[Install]
+WantedBy=multi-user.target
diff --git a/mga-bg-res/mga-bg-res.sh b/mga-bg-res/mga-bg-res.sh
new file mode 100755
index 0000000..db937cb
--- /dev/null
+++ b/mga-bg-res/mga-bg-res.sh
@@ -0,0 +1,47 @@
+#!/bin/bash
+
+bgpath="/usr/share/mga/backgrounds"
+theme="Mageia-Default"
+curlink=$(readlink $bgpath/default.jpg)
+
+# If the following tests bail out, default to 4:3 aspect ratio (e.g. 1024x768)
+res="1600x1200"
+
+# Search for the optimal background resolution according to the driver
+DRIVER=$(grep -A 6 'Device' /etc/X11/xorg.conf | grep 'Driver')  # => Driver    "DriverName"
+DRIVER=$(expr "$DRIVER" : '.*"\(.*\)"')  # isolate driver's name
+if [ ! -z "$DRIVER" -a -e /usr/sbin/monitor-probe ]; then
+    res=$(exec /usr/sbin/monitor-probe $DRIVER | grep -m 1 ModeLine)  # => ModeLine "1920x1080" ...
+    res=$(expr "$res" : '.*"\(.*\)".*')  # isolate the resolution
+fi
+
+# Check if the symlink is already good
+if [ "$curlink" = "$bgpath/$theme-$res.jpg" ]; then
+    exit 1
+fi
+
+# Check if this is a supported resolution, if not, find the background with a similar aspect ratio
+if [ ! -e "$bgpath/$theme-$res.jpg" ]; then
+    width=$(echo $res | cut -f1 -d"x")
+    height=$(echo $res | cut -f2 -d"x")
+    # Bash only does integer arithmetic, we multiply everything by 1000 to workaround this
+    ratio=$((1000*$width/$height))
+    declare -A refRatios=( ["1250"]="1280x1024" ["1333"]="1600x1200" ["1600"]="1920x1200"
+                           ["1667"]="1280x768" ["1707"]="1024x600" ["1778"]="1920x1080" )
+    for key in "${!refRatios[@]}"; do
+        if [ $(($ratio % $key)) -lt 25 -o $(($key % $ratio)) -lt 25 ]; then
+            res=${refRatios[$key]}
+            break
+        fi
+    done
+fi
+
+# Check again if the symlink does not already point to this new resolution
+# If not, create a new symlink
+if [ "$curlink" != "$bgpath/$theme-$res.jpg" ]; then
+    if [ -e "$bgpath/$theme-$res.jpg" ]; then
+        ln -sf $bgpath/$theme-$res.jpg $bgpath/default.jpg 
+    else
+        echo -e "Could not find this file: $bgpath/$theme-$res.jpg.\nPlease check that the mageia-theme-Default package is properly installed, or disable the mga-bg-res systemd service if you do not want to force using the Mageia theme."
+    fi
+fi
diff --git a/mga-bg-res/mga-bg-res.xinit b/mga-bg-res/mga-bg-res.xinit
deleted file mode 100755
index 42d79da..0000000
--- a/mga-bg-res/mga-bg-res.xinit
+++ /dev/null
@@ -1,41 +0,0 @@
-#!/bin/bash
-
-# Find currently used resolution
-res=$( xrandr | awk '/\sconnected/{i=split(substr($0,0,index($0,"+")-1),a);if($0~/\sprimary\s/){if(p==""){p=a[i]}}else{if(d==""){d=a[i]}}}END{if(p==""){print d}else{print p}}' )
-
-bgpath="/usr/share/mga/backgrounds"
-if [ "$(readlink $bgpath/default.jpg)" != "$bgpath/Mageia-Default-$res.jpg" ]; then
-   # Check if this is a supported resolution, if not, find the background with the same aspect ratio
-    if [ ! -e "$bgpath/Mageia-Default-$res.jpg" ]; then
-        width=$(echo $res | cut -f1 -d"x")
-        height=$(echo $res | cut -f2 -d"x")
-        # Bash only does integer arithmetic, we multiply everything by 1000 to workaround this
-        ratio=$((1000*$width/$height))
-
-        found=false
-        declare -A refRatios=( ["1250"]="1280x1024" ["1333"]="1600x1200" ["1600"]="1920x1200"
-                               ["1667"]="1280x768" ["1707"]="1024x600" ["1778"]="1920x1080" )
-        for key in "${!refRatios[@]}"; do
-            if [ $(($ratio % $key)) -lt 25 -o $(($key % $ratio)) -lt 25 ]; then
-                res=${refRatios[$key]}
-                ratio=$key
-                found=true
-                break
-            fi
-        done
-
-        if ! $found; then
-            echo "mga-bg-res: Your aspect ratio does not seem to be supported, keeping default background resolution."
-            exit 1
-        fi
-    fi
-
-    if [ "$(readlink $bgpath/default.jpg)" != "$bgpath/Mageia-Default-$res.jpg" ]; then
-        echo "mga-bg-res: Changing the background symlink to point to Mageia-Default-$res.jpg (aspect ratio ${ratio:0:1}.${ratio:1:3})"
-        /usr/bin/mga-bg-res $res
-    else
-        echo "mga-bg-res: Nothing to do, the background symlink is already correct."
-    fi
-else
-    echo "mga-bg-res: Nothing to do, the background symlink is already correct."
-fi