C - segmentation fault on long running while loop - c

Question

I wrote small daemon for rotating screen on Thinkpad X41 convertible laptop using built-in motion sensor (used by harddisk active protection system) or manually by button. Program works very well, but after some amount of time (5 to 15 minutes) will crash with segfault.
I know there are lot of scripts on the internet to do this written in bash or python, but none of them suit my needs and vision how should program work.
I know that for example mentioned bash is probably better for this, but I have zero experiences with it compared to C In which I have at least minimal basic experiences from few high school lessons, so I choose this.
here is the code:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#define TRUE 1
#define FALSE 0
#define NIL -1
#define XRANDR_GREP_COMMAND "xrandr -q --verbose|grep LVDS1|cut -b37-37"
#define DAEMON_LOCK_FILE "/dev/shm/thinkrotate.lock"
#define DAEMON_STATE_FILE "/dev/shm/thinkrotate.st"
#define SWIVEL_STATE_FILE "/sys/devices/platform/thinkpad_acpi/hotkey_tablet_mode"
#define GYRO_STATE_FILE "/sys/devices/platform/hdaps/position"
#define BUBBLE_TERMINATED "notify-send 'Ukončenie programu' 'ThinkRotate démon dostal príkaz na ukončenie'"
#define BUBBLE_SWIVEL_DOWN "notify-send 'Notebook v tablet móde' 'Veko bolo sklopené, aktivovaná automatická rotácia'"
#define BUBBLE_SWIVEL_UP "notify-send 'Notebook v štandartnom režime' 'Rotácia je deaktivovaná'"
#define BUBBLE_RETURN_POSITION "notify-send 'Automatická rotácia zapnutá' 'Pre vypnutie automatickej rotácie obrazu stlačte tlačítko rotácie.'"
#define BUBBLE_START_MANUAL_ROTATION "notify-send 'Automatická rotácia vypnutá' 'Rotácia bude zapnutá znovu až pri návrate do tejto polohy, dovtedy na otáčanie obrazu používajte tlačidlo.'"
#define SWIVEL_DOWN_COMMANDS ""
#define SWIVEL_UP_COMMANDS ""
#define WIDTH_COMMANDS ""
#define HEIGHT_COMMANDS ""
int get_lock(void) {
int fdlock;
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 1;
if((fdlock = open(DAEMON_LOCK_FILE, O_WRONLY|O_CREAT, 0666)) == -1) { return 0; }
if(fcntl(fdlock, F_SETLK, &fl) == -1) { return 0; }
return 1;
}
int next_rotation(int direction) {
int next;
int pos;
pos = current_pos();
if (direction == 1) {
switch (pos) {
case 0:
next = 1;
break;
case 1:
next = 2;
break;
case 2:
next = 3;
break;
case 3:
next = 0;
break;
}
} else if (direction == 2) {
switch (pos) {
case 0:
next = 3;
break;
case 1:
next = 0;
break;
case 2:
next = 1;
break;
case 3:
next = 2;
break;
}
}
return next;
}
int current_pos(void) {
FILE *frotpos;
char rotpos;
int pos;
frotpos = popen(XRANDR_GREP_COMMAND, "r");
fscanf(frotpos, "%c", &rotpos);
fclose(frotpos);
switch (rotpos) {
case 110:
pos = 0;
break;
case 108:
pos = 1;
break;
case 105:
pos = 2;
break;
case 114:
pos = 3;
break;
}
return pos;
}
void rotate(int poz) {
char buff[32];
if ((poz == 2)||(poz == 0)) {
system(WIDTH_COMMANDS);
} else {
system(HEIGHT_COMMANDS);
}
sprintf(buff, "xrandr -o %i", poz);
system(buff);
}
int main(int argc, char *argv[]) {
if(!get_lock()) {
if (argc >= 2) {
int cmd;
FILE *fparams;
fparams = fopen(DAEMON_STATE_FILE, "w");
if (!strncmp(argv[1], "r", 1)) { cmd = 1; }
else if (!strncmp(argv[1], "l", 1)) { cmd = 2; }
else if (!strncmp(argv[1], "k", 1)) { cmd = 0; }
fprintf(fparams, "%i", cmd);
fclose(fparams);
}
return 1;
}
int autorotate = TRUE;
int prevmode = NIL;
FILE *fstate;
int tabletmode;
FILE *fgyrovals;
char gyroval_x[5];
char gyroval_y[5];
int x;
int y;
FILE *fargs;
int argum = NIL;
int next_p;
int prev_p = current_pos();
int last_auto_p = NIL;
while (TRUE) {
fstate = fopen(SWIVEL_STATE_FILE, "r");
fscanf(fstate, "%d", &tabletmode);
if (fargs = fopen(DAEMON_STATE_FILE, "r")) {
if (fscanf(fargs, "%d", &argum) == NIL) { argum = NIL; }
}
fargs = fopen(DAEMON_STATE_FILE, "w");
fclose(fargs);
fclose(fstate);
if (argum == 0) {
system(BUBBLE_TERMINATED);
return 1;
}
if (prevmode != tabletmode) {
if (tabletmode) {
system(BUBBLE_SWIVEL_DOWN);
system(SWIVEL_DOWN_COMMANDS);
} else {
system(BUBBLE_SWIVEL_UP);
system(SWIVEL_UP_COMMANDS);
rotate(0);
}
}
if (tabletmode) {
if (argum == 1 || argum == 2) {
next_p = next_rotation(argum);
if (next_p == last_auto_p) {
rotate(next_p);
autorotate = TRUE;
last_auto_p = NIL;
system(BUBBLE_RETURN_POSITION);
} else if ((autorotate)&&(current_pos() == last_auto_p)) {
autorotate = FALSE;
system(BUBBLE_START_MANUAL_ROTATION);
} else {
if (autorotate) {
system(BUBBLE_START_MANUAL_ROTATION);
last_auto_p = current_pos();
} else {
rotate(next_p);
}
autorotate = FALSE;
}
}
if (autorotate) {
fgyrovals = fopen(GYRO_STATE_FILE, "r");
fscanf(fgyrovals, "(%4[^,], %4[^)]", &gyroval_x, &gyroval_y);
fclose(fgyrovals);
x = atoi(gyroval_x);
y = atoi(gyroval_y) * (-1);
if (y < 465) {
if (x < 210) {
next_p = 1;
} else if (x > 425) {
next_p = 3;
} else {
next_p = 2;
}
} else if (y > 525) {
if (x < 210) {
next_p = 1;
} else if (x > 425) {
next_p = 3;
} else {
next_p = 0;
}
} else {
if (x < 305) {
next_p = 1;
} else if (x > 345) {
next_p = 3;
}
}
if (next_p != prev_p) {
rotate(next_p);
prev_p = next_p;
}
}
} else {
if (argum == 1 || argum == 2) {
system(BUBBLE_SWIVEL_UP);
}
}
prevmode = tabletmode;
sleep(1);
}
return 0;
}

Answer 1

Thanks to comment of user "inspired". Now the program is running more than a hour without segfault.
if (fargs = fopen(DAEMON_STATE_FILE, "r")) {
if (fscanf(fargs, "%d", &argum) == NIL) { argum = NIL; }
fclose(fargs);
}
fargs = fopen(DAEMON_STATE_FILE, "w");
fclose(fargs);
As said, file should be closed before opened next time for writing.