Battery life in picoarch

[Xpndable]

Need to reconfigure the battery level for picoarch, not accurate and warning prematurely.

[Xpndable]

Still unable to replicate, adding logging mechanism for affected devices

[birby0]

Saw this post on Reddit regarding the battery prematurely warning for reference. I saw you're adding a logging mechanism, let me know if there's any way I can help!

https://reddit.com/r/MiyooMini/comments/12nrldl/we_need_to_talk_about_the_myioo_mini_battery/

[anzz1]

I think this will fix it, as there is a fun combination of buffer overflow (when batt is full) and underflow (always) when r/w the batt level to /tmp/battery. As there is a chance of the strlen to be anything random when batt==100 it can write whatever, also as the null byte was missing the read side could also read any garbage to fscanf as the string isnt terminated.

keymon.c

void checkAXP() {
	// Code adapted from OnionOS
    char *cmd = "cd /customer/app/ ; ./axp_test";  
    int batJsonSize = 100;
    char buf[batJsonSize];
    int battery_number;

    FILE *fp;      
    fp = popen(cmd, "r");
        if (fgets(buf, batJsonSize, fp) != NULL) {
           sscanf(buf,  "{\"battery\":%d, \"voltage\":%*d, \"charging\":%*d}", &battery_number);
        }
    pclose(fp);

    int bat_fd = open("/tmp/battery", O_CREAT | O_WRONLY | O_TRUNC);
	if (bat_fd>0) {
-		char value[3];
+		char value[4];
		sprintf(value, "%d", battery_number);
-		write(bat_fd, value, strlen(value));
+		write(bat_fd, value, strlen(value)+1);
		close(bat_fd);
	}
}