AutoLogin - Revision history

Searchworks: remove spam

2010-11-23T23:48:13Z

remove spam

Aqisecoxefi at 22:43, 23 November 2010

2010-11-23T22:43:00Z

Ashcharles at 17:12, 11 May 2010

2010-05-11T17:12:22Z

Ashcharles: Created page with 'For some applications, it is useful to login to an account directly from boot without having to enter login credentials. The GPE login manager provided with the palmtop image pr…'

2010-05-11T17:06:05Z

Created page with 'For some applications, it is useful to login to an account directly from boot without having to enter login credentials. The GPE login manager provided with the palmtop image pr…'

New page

For some applications, it is useful to login to an account directly from boot without having to enter login credentials. The GPE login manager provided with the palmtop image provides a mechanism to do it. However, for simple console images, we can simply set a blank password for our particular account and modify our login program to achieve this. With autologin enabled, it is easy to start tasks automatically after the system is booted in cases where adding sysvinit scripts (/etc/init.d) isn't appropriate.

== Autologin.c ==
This autologin program replaces the normal 'login' program and should be compiled and placed in /sbin. The login program is typically provided by tinylogin, busybox or as a standalone tool.
<pre>
#include <unistd.h>
#include <stdio.h>

int main()
{
int nrv = 0;
FILE* fptr = 0;
char user[64];

// clear buffer
memset(user,'\0',64);

// open autologin profile file
fptr = fopen("/usr/autologin.profile\0","r\0");

// make sure the file exists and was opened
if (fptr != 0)
{
// the return value from fscanf will be 1 if the autologin profile name is read correctly
nrv = fscanf(fptr,"%s\0",user);
}

// only autologin if the profile name was read successfully,
// otherwise show the regular login prompt
if (nrv > 0)
nrv = execlp("login\0","login\0","-f\0",user,0);
else
nrv = execlp("login\0","login\0","\0",0,0);

return 0;
}
</pre>

== The /etc/inittab ==
It is necessary to modify your /etc/inittab file to use your autologin program rather than the default login program.
Specifically, you'll want to change a line that looks like this:
<pre>S:2345:respawn:/sbin/getty 115200 ttyS2</pre>
with one that looks like this:
<pre>S:2345:respawn:/sbin/getty -n -l /usr/sbin/autologin 115200 ttyS2</pre>

== A Bitbake Recipe ==
To do the cross-compilation and to set up the inittab file, we might use a bitbake recipe like this:
<pre>
DESCRIPTION = "a simple tool to login to root with no prompt"
PACKAGES ="${PN}"
PR="r0"
RDEPENDS="tinylogin sed"

SRC_URI = "file://autologin.c \
"

S = "${WORKDIR}"

do_compile () {
${CC} ${CFLAGS} ${LDFLAGS} -o autologin autologin.c
}

do_install () {
install -d ${D}${bindir}/
install -m 0755 ${WORKDIR}/autologin ${D}${bindir}/
}

pkg_postinst_${PN} () {
sed 's_S:2345:respawn:/sbin/getty_S:2345:respawn:/sbin/getty -n -l /usr/bin/autologin_' /etc/inittab > inittab.tmp
mv inittab.tmp /etc/inittab
passwd -d root
echo 'NOTE: remove the password from the root account'
rm inittab.tmp
}

pkg_prerm_${PN} () {
sed 's_ -n -l /usr/bin/autologin__' /etc/inittab > inittab.tmp
mv inittab.tmp /etc/inittab
echo 'NOTE: there is still no password on the root account'
rm inittab.tmp
}

PACKAGES = "${PN}"
FILES_${PN} = "${bindir}/autologin"
</pre>

← Older revision		Revision as of 17:12, 11 May 2010
Line 85:		Line 85:
	FILES_${PN} = "${bindir}/autologin"		FILES_${PN} = "${bindir}/autologin"
	</pre>		</pre>
		+
		+	== Starting Task on Login ===
		+	Once the autologin is working, you can add tasks to be executed on startup to your .profile file or the system /etc/profile file. This is a compliment to the methods already offered by sysvinit scripts and cron (@reboot).
		+
		+	=== More Info ===
		+	The text for this this wiki page was pieced together from this thread:
		+	http://old.nabble.com/A-very-unique-auto-login-on-verdex-td28224459.html#a28517599

@@ Line 1: / Line 1: @@
 For some applications, it is useful to login to an account directly from boot without having to enter login credentials.  The GPE login manager provided with the palmtop image provides a mechanism to do it.  However, for simple console images, we can simply set a blank password for our particular account and modify our login program to achieve this.  With autologin enabled, it is easy to start tasks automatically after the system is booted in cases where adding sysvinit scripts (/etc/init.d) isn't appropriate.
 == Autologin.c ==
 This autologin program replaces the normal 'login' program and should be compiled and placed in /sbin.  The login program is typically provided by tinylogin, busybox or as a standalone tool.
-&lt;pre&gt;
+<pre>
-#include &lt;unistd.h&gt;
+#include <unistd.h>
-#include &lt;stdio.h&gt;
+#include <stdio.h>
 int main()
@@ Line 25: / Line 17: @@
         // open autologin profile file
-        fptr = fopen(&quot;/usr/autologin.profile\0&quot;,&quot;r\0&quot;);
+        fptr = fopen("/usr/autologin.profile\0","r\0");
         // make sure the file exists and was opened
@@ Line 31: / Line 23: @@
+        {
                 // the return value from fscanf will be 1 if the autologin profile name is read correctly
-                nrv = fscanf(fptr,&quot;%s\0&quot;,user);
+                nrv = fscanf(fptr,"%s\0",user);
+        }
         // only autologin if the profile name was read successfully,
         // otherwise show the regular login prompt
-        if (nrv &gt; 0)
+        if (nrv > 0)
-                nrv = execlp(&quot;login\0&quot;,&quot;login\0&quot;,&quot;-f\0&quot;,user,0);
+                nrv = execlp("login\0","login\0","-f\0",user,0);
         else
-                nrv = execlp(&quot;login\0&quot;,&quot;login\0&quot;,&quot;\0&quot;,0,0);
+                nrv = execlp("login\0","login\0","\0",0,0);
         return 0;
+}
-&lt;/pre&gt;
+</pre>
 == The /etc/inittab ==
 It is necessary to modify your /etc/inittab file to use your autologin program rather than the default login program.
 Specifically, you'll want to change a line that looks like this:
-&lt;pre&gt;S:2345:respawn:/sbin/getty 115200 ttyS2&lt;/pre&gt;
+<pre>S:2345:respawn:/sbin/getty 115200 ttyS2</pre>
 with one that looks like this:
-&lt;pre&gt;S:2345:respawn:/sbin/getty -n -l /usr/sbin/autologin 115200 ttyS2&lt;/pre&gt;
+<pre>S:2345:respawn:/sbin/getty -n -l /usr/sbin/autologin 115200 ttyS2</pre>
 == A Bitbake Recipe ==
 To do the cross-compilation and to set up the inittab file, we might use a bitbake recipe like this:
-&lt;pre&gt;
+<pre>
-DESCRIPTION = &quot;a simple tool to login to root with no prompt&quot;
+DESCRIPTION = "a simple tool to login to root with no prompt"
-PACKAGES =&quot;${PN}&quot;
+PACKAGES ="${PN}"
-PR=&quot;r0&quot;
+PR="r0"
-RDEPENDS=&quot;tinylogin sed&quot;
+RDEPENDS="tinylogin sed"
-SRC_URI = &quot;file://autologin.c \
+SRC_URI = "file://autologin.c \
-            &quot;
-S = &quot;${WORKDIR}&quot;
+S = "${WORKDIR}"
 do_compile () {
@@ Line 75: / Line 67: @@
 pkg_postinst_${PN} () {
-   sed 's_S:2345:respawn:/sbin/getty_S:2345:respawn:/sbin/getty -n -l /usr/bin/autologin_' /etc/inittab &gt; inittab.tmp
+   sed 's_S:2345:respawn:/sbin/getty_S:2345:respawn:/sbin/getty -n -l /usr/bin/autologin_' /etc/inittab > inittab.tmp
    mv inittab.tmp /etc/inittab
    passwd -d root
@@ Line 83: / Line 75: @@
 pkg_prerm_${PN} () {
-   sed 's_ -n -l /usr/bin/autologin__' /etc/inittab &gt; inittab.tmp
+   sed 's_ -n -l /usr/bin/autologin__' /etc/inittab > inittab.tmp
    mv inittab.tmp /etc/inittab
    echo 'NOTE: there is still no password on the root account'
@@ Line 90: / Line 82: @@
-PACKAGES = &quot;${PN}&quot;
+PACKAGES = "${PN}"
-FILES_${PN} = &quot;${bindir}/autologin&quot;
+FILES_${PN} = "${bindir}/autologin"
-&lt;/pre&gt;
+</pre>
 == Starting Task on Login ===