Cat read error invalid argument

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Mordillo98
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n00b

Joined: 28 Mar 2012
Posts: 17

Posted: Tue Jun 28, 2016 4:44 pm Post subject: cat: read error: Invalid argument

Hi, Installed Gentoo with systemd. Everything works great except at boot I get this…. :: Loading from net: :: Loading from iscsi: ::Loading from crypto: cat: read error: Invalid argument cat: read error: Invalid argument cat: read error: Invalid argument cat: read error: Invalid argument cat: read error: Invalid argument >> Determining root device … How can I resolve this cat read error thing? https://s31.postimg.org/7ppx7mf97/Gentoo4_LFS_x86_2016_06_28_12_31_44.png Thx…

Roman_Gruber
Advocate

Joined: 03 Oct 2006
Posts: 3836
Location: Austro Bavaria

Posted: Wed Jun 29, 2016 10:13 pm Post subject:

May I ask! Does your box boot? Usually, determining the root device, implies that the kernel is looking for the way to mount your root file system. The kernel needs access to / needs a way to mount and read your root partition. Means => hardware support / file system support build in the kernel and proper kernel parameters in your bootloader. I assume your box does not goes on after this message. If so you need to specify your root drive and enalbe the support in your kernel. The gentoo handbook is a good starting point for that. Arch wiki has very often a decent guide for stuff too

Mordillo98
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Joined: 28 Mar 2012
Posts: 17

Posted: Thu Jun 30, 2016 1:12 pm Post subject:

Yup. After all those messages, I boot successfully up to the end. I am new @ systemd so I tried to figure out if I could get some logs about what it’s trying to load, or if this is related to the encryption module. A good test would be to NOT have the encryption module to load at boot and see as a test, but can’t figure out how.

pilla
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Joined: 07 Aug 2002
Posts: 7729
Location: Underworld

Posted: Fri Jul 01, 2016 12:54 am Post subject:

I would check configuration files for the crypto service… looks like it uses a cat inside itself but some parameter is breaking it. _________________ «I’m just very selective about the reality I choose to accept.» — Calvin

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Cat read error invalid argument

Installed Gentoo with systemd. Everything works great except at boot I get this.

:: Loading from net:
:: Loading from iscsi:
::Loading from crypto:
cat: read error: Invalid argument
cat: read error: Invalid argument
cat: read error: Invalid argument
cat: read error: Invalid argument
cat: read error: Invalid argument
>> Determining root device .

How can I resolve this cat read error thing?

Thx. Вернуться к началу

Roman_Gruber
Advocate

Зарегистрирован: 03 окт 2006
Сообщений: 3834
Откуда: Austro Bavaria

Добавлено: ср июн 29, 2016 10:13 pm Заголовок сообщения:

May I ask!

Does your box boot?

Usually, determining the root device, implies that the kernel is looking for the way to mount your root file system. The kernel needs access to / needs a way to mount and read your root partition. Means => hardware support / file system support build in the kernel and proper kernel parameters in your bootloader.

I assume your box does not goes on after this message. If so you need to specify your root drive and enalbe the support in your kernel. The gentoo handbook is a good starting point for that. Arch wiki has very often a decent guide for stuff too

Вернуться к началу

Mordillo98
n00b

Зарегистрирован: 28 мар 2012
Сообщений: 17

Добавлено: чт июн 30, 2016 1:12 pm Заголовок сообщения:

Yup. After all those messages, I boot successfully up to the end.

I am new @ systemd so I tried to figure out if I could get some logs about what it’s trying to load, or if this is related to the encryption module. A good test would be to NOT have the encryption module to load at boot and see as a test, but can’t figure out how.

Вернуться к началу

pilla
Bodhisattva

Зарегистрирован: 07 авг 2002
Сообщений: 7728
Откуда: Underworld

Добавлено: пт июл 01, 2016 12:54 am Заголовок сообщения:
I would check configuration files for the crypto service. looks like it uses a cat inside itself but some parameter is breaking it. _________________ «I’m just very selective about the reality I choose to accept.» — Calvin

Вернуться к началу

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Cat read error invalid argument

Installed Gentoo with systemd. Everything works great except at boot I get this.

How can I resolve this cat read error thing?

Thx.

Вернуться к началу

Roman_Gruber
Advocate

Зарегистрирован: 03 окт 2006
Сообщений: 3834
Откуда: Austro Bavaria

Добавлено: ср июн 29, 2016 10:13 pm Заголовок сообщения:

May I ask!

Does your box boot?

Вернуться к началу

Mordillo98
n00b

Зарегистрирован: 28 мар 2012
Сообщений: 17

Добавлено: чт июн 30, 2016 1:12 pm Заголовок сообщения:

Yup. After all those messages, I boot successfully up to the end.

Вернуться к началу

pilla
Bodhisattva

Зарегистрирован: 07 авг 2002
Сообщений: 7728
Откуда: Underworld

Добавлено: пт июл 01, 2016 12:54 am Заголовок сообщения:
I would check configuration files for the crypto service. looks like it uses a cat inside itself but some parameter is breaking it. _________________ «I’m just very selective about the reality I choose to accept.» — Calvin

Вернуться к началу

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Cat read error invalid argument

Installed Gentoo with systemd. Everything works great except at boot I get this.

How can I resolve this cat read error thing?

Thx.

Вернуться к началу

Roman_Gruber
Advocate

Зарегистрирован: 03 окт 2006
Сообщений: 3834
Откуда: Austro Bavaria

Добавлено: ср июн 29, 2016 10:13 pm Заголовок сообщения:

May I ask!

Does your box boot?

Вернуться к началу

Mordillo98
n00b

Зарегистрирован: 28 мар 2012
Сообщений: 17

Добавлено: чт июн 30, 2016 1:12 pm Заголовок сообщения:

Yup. After all those messages, I boot successfully up to the end.

Вернуться к началу

pilla
Bodhisattva

Зарегистрирован: 07 авг 2002
Сообщений: 7728
Откуда: Underworld

Добавлено: пт июл 01, 2016 12:54 am Заголовок сообщения:
I would check configuration files for the crypto service. looks like it uses a cat inside itself but some parameter is breaking it. _________________ «I’m just very selective about the reality I choose to accept.» — Calvin

Вернуться к началу

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Writing to a custom character device using

cat 123 > /dev/chardev

gives

cat: write error: Invalid argument

I have changed the permissions to 666 and even tried it with sudo. Still the same results.
Also tried echo in similar way

I use Arch linux 4.8.

Edit: The code for the driver

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <asm/uaccess.h>


//Prototypes
static int __init init(void);
static void __exit cleanup(void);
static int device_open(struct inode *,struct file *);
static int device_release(struct inode *, struct file *);
static ssize_t device_read(struct file *, char *, size_t, loff_t *);
static ssize_t device_write(struct file *, const char *, size_t, loff_t *);

#define SUCCESS 0
#define DEVICE_NAME "chardev" /* Dev name as it appears in /proc/devices*/
#define BUF_LEN 80 /* Max length of the message from the device */

static int Major; //Major number of the devices
static int Device_Open = 0;

static char msg[BUF_LEN]; //Message given when asked
static char *msg_Ptr;

static struct file_operations fops = {
    .read = device_read,
    .write = device_write,
    .open = device_open,
    .release = device_release
};

static int __init init(){
    Major = register_chrdev(0,DEVICE_NAME,&fops);
    if(Major < 0){
        printk(KERN_ALERT "Failure in registering the device. %dn", Major);
        return Major;
  }
    printk(KERN_INFO "%s registered with major %d n",DEVICE_NAME,Major);
    printk(KERN_INFO "create a device with 'mknod /dev/%s c %d 0'n",DEVICE_NAME,Major);
    printk(KERN_INFO "Try to cat and echo the file and shit man.n");
    return SUCCESS;
}

static void __exit cleanup(){
    unregister_chrdev(Major, DEVICE_NAME);
    printk(KERN_ALERT "Unregistered the device %s i guess? n"DEVICE_NAME);
}   

static int device_open(struct inode *inode,struct file *file){
    static int counter = 0;
    if(Device_Open)
        return -EBUSY;

    Device_Open++;
    sprintf(msg, "I already told you %d times Hello world!n", counter++);
    msg_Ptr = msg;
    try_module_get(THIS_MODULE);
    return SUCCESS;
}

static int device_release(struct inode *inode,struct file *file){
    Device_Open--;
    module_put(THIS_MODULE);
    return 0;
}

static ssize_t device_read(struct file *filp, char *buffer, size_t length, loff_t * offset){
    int bytes_read = 0;
    if(*msg_Ptr == 0)
        return 0;
    while(length && *msg_Ptr){
        put_user(*(msg_Ptr++),buffer++);
        length--;   
        bytes_read++;
    }
    return bytes_read;
}

static ssize_t device_write(struct file *filp,const char *buff, size_t len, loff_t *off){
    printk(KERN_ALERT "You cannot write to this device.n");
    return -EINVAL;
}

module_init(init);
module_exit(cleanup);

So here we can see that i have even used a device_write function and assigned it in the fops struct to .write. So isn’t it supposed to accept write command and print that statement in the log?

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[ubuntu] cat write error invalid argument

cat write error invalid argument

hi, i am trying to:
abc@abc-linux:~/Desktop$ cat «sample.au» > /dev/snd/seq

but it says:cat write error invalid argument

do you see what the problem is?
Re: cat write error invalid argument

Do you have write permissions for that file? Try running the command with sudo.
Re: cat write error invalid argument

Originally Posted by drmrgd

Do you have write permissions for that file? Try running the command with sudo.

yes i tried it with sudo but same error occured.
Re: cat write error invalid argument
I don’t think «cat» is the command you need here. Try using «echo» instead. And use double redirector if you want to add to existing file instead of replacing all information.
Code:

abc@abc-linux:~/Desktop$ sudo echo "sample.au" >> /dev/snd/seq
Break it, fix it, learn something.
People who never make mistakes seldom make anything!
Re: cat write error invalid argument
Originally Posted by Miljet

I don’t think «cat» is the command you need here. Try using «echo» instead. And use double redirector if you want to add to existing file instead of replacing all information.

Code:

abc@abc-linux:~/Desktop$ sudo echo "sample.au" >> /dev/snd/seq
i tried echo but the error is same:echo: write error: Invalid argument
Re: cat write error invalid argument

/dev/snd/seq is a character special file — I think this is more likely why you’re getting the error (and why it’s ‘invalid argument’ not ‘permission denied’)

What exactly are you trying to do? I don’t really know anything about sound but afaik there are some alsa utilities for this kind of thing at a higher level (amidi? aplaymidi?)

[btw if it was a permissions issue then ‘sudo cat’ wouldn’t help because it’s the redirect of stdout that needs elevated write permissions — you could use a ‘sudo tee’ instead of the ‘>’ or wrap the whole command in a sudo sh ‘cat …’ however iirc the default is for /etc/snd/seq to be rw for members of the audio group so provided user is a member of ‘audio’ there should be no permission issue]
Re: cat write error invalid argument
Originally Posted by steeldriver

/dev/snd/seq is a character special file — I think this is more likely why you’re getting the error (and why it’s ‘invalid argument’ not ‘permission denied’)

What exactly are you trying to do? I don’t really know anything about sound but afaik there are some alsa utilities for this kind of thing at a higher level (amidi? aplaymidi?)

[btw if it was a permissions issue then ‘sudo cat’ wouldn’t help because it’s the redirect of stdout that needs elevated write permissions — you could use a ‘sudo tee’ instead of the ‘>’ or wrap the whole command in a sudo sh ‘cat …’ however iirc the default is for /etc/snd/seq to be rw for members of the audio group so provided user is a member of ‘audio’ there should be no permission issue]
this is an example of accessing devices in a pdf document.it should play the file but it didnt via this codes:
Code:

sudo cat sample.au > /dev/snd/seq