6b6b6635cf
Smatch[1][2] is a pluggable static analysis for C. It may help us find
out the potential problem of the example code.
Doing with smatch, if set the --file-output flag, it will generate the
{}.c.smatch report for each c file. This will make a little bit
complicated to collect all the report messages. So, here we stay at the
default setting, stdout for the smatch messages.
For more information, see:
- https://lwn.net/Articles/696624/
- https://elinux.org/images/d/d3/Bargmann.pdf
Also, fix the warning from Smatch:
Smatch failed: 1 warning(s), 1 error(s)
lkmpg/examples/procfs2.c:57 procfile_write() error: buffer overflow 'procfs_buffer' 1024 <= 1024
lkmpg/examples/kbleds.c:58 kbleds_init() warn: argument 5 to %lx specifier is cast from pointer
Furthermore, the effect of the write operation in procfs2.c is too
implied. So after writing, print the buffer every time.
Close #122
[1] https://github.com/error27/smatch
[2] https://repo.or.cz/w/smatch.git
86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
/*
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* kbleds.c - Blink keyboard leds until the module is unloaded.
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*/
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#include <linux/init.h>
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#include <linux/kd.h> /* For KDSETLED */
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#include <linux/module.h>
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#include <linux/tty.h> /* For tty_struct */
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#include <linux/vt.h> /* For MAX_NR_CONSOLES */
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#include <linux/vt_kern.h> /* for fg_console */
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#include <linux/console_struct.h> /* For vc_cons */
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MODULE_DESCRIPTION("Example module illustrating the use of Keyboard LEDs.");
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static struct timer_list my_timer;
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static struct tty_driver *my_driver;
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static unsigned long kbledstatus = 0;
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#define BLINK_DELAY HZ / 5
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#define ALL_LEDS_ON 0x07
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#define RESTORE_LEDS 0xFF
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/* Function my_timer_func blinks the keyboard LEDs periodically by invoking
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* command KDSETLED of ioctl() on the keyboard driver. To learn more on virtual
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* terminal ioctl operations, please see file:
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* drivers/tty/vt/vt_ioctl.c, function vt_ioctl().
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*
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* The argument to KDSETLED is alternatively set to 7 (thus causing the led
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* mode to be set to LED_SHOW_IOCTL, and all the leds are lit) and to 0xFF
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* (any value above 7 switches back the led mode to LED_SHOW_FLAGS, thus
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* the LEDs reflect the actual keyboard status). To learn more on this,
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* please see file: drivers/tty/vt/keyboard.c, function setledstate().
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*/
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static void my_timer_func(struct timer_list *unused)
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{
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struct tty_struct *t = vc_cons[fg_console].d->port.tty;
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if (kbledstatus == ALL_LEDS_ON)
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kbledstatus = RESTORE_LEDS;
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else
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kbledstatus = ALL_LEDS_ON;
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(my_driver->ops->ioctl)(t, KDSETLED, kbledstatus);
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my_timer.expires = jiffies + BLINK_DELAY;
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add_timer(&my_timer);
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}
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static int __init kbleds_init(void)
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{
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int i;
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pr_info("kbleds: loading\n");
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pr_info("kbleds: fgconsole is %x\n", fg_console);
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for (i = 0; i < MAX_NR_CONSOLES; i++) {
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if (!vc_cons[i].d)
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break;
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pr_info("poet_atkm: console[%i/%i] #%i, tty %p\n", i, MAX_NR_CONSOLES,
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vc_cons[i].d->vc_num, (void *)vc_cons[i].d->port.tty);
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}
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pr_info("kbleds: finished scanning consoles\n");
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my_driver = vc_cons[fg_console].d->port.tty->driver;
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pr_info("kbleds: tty driver magic %x\n", my_driver->magic);
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/* Set up the LED blink timer the first time. */
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timer_setup(&my_timer, my_timer_func, 0);
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my_timer.expires = jiffies + BLINK_DELAY;
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add_timer(&my_timer);
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return 0;
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}
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static void __exit kbleds_cleanup(void)
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{
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pr_info("kbleds: unloading...\n");
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del_timer(&my_timer);
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(my_driver->ops->ioctl)(vc_cons[fg_console].d->port.tty, KDSETLED,
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RESTORE_LEDS);
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}
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module_init(kbleds_init);
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module_exit(kbleds_cleanup);
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MODULE_LICENSE("GPL");
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