Thread: execl()/fork() output

Code:

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{

     char small[32], big[128];
     int i = 16;

if(strstr(argv[1], "t8")) { i = 8; }
if(strstr(argv[1], "t16")) { i = 16; }
if(strstr(argv[1], "t32")) { i = 32; }
if(strstr(argv[1], "t64")) { i = 64; }
if(strstr(argv[1], "t128")) { i = 128; }

     memset(big, 'Z', sizeof(big));

     snprintf(small, i, "%s", big);
     printf("%s\n", small);

     return 0;

}

That is the program I am running through the parent. As you can see, if the values are t64 or t128, the program crashes. I simply want to run that program 5 times with the 5 different values and be able to see the segmentation faults when they occur.

Code:

bash$ ./bvss t8
ZZZZZZZ
bash$ ./bvss t16
ZZZZZZZZZZZZZZZ
bash$ ./bvss t32
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
bash$ ./bvss t64
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
Segmentation fault
bash$ ./bvss t128
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
Segmentation fault
bash$

bash$ ./test
ZZZZZZZ
ZZZZZZZZZZZZZZZ
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
bash$

Code:

void run(char *bin, char *data)
{

if(fork() == 0)
{

if(execl(bin, bin, data, 0) == -1)
{

     perror("execl");
     _exit(1);

}
}

else
{

int pid, status;

     pid = wait(&status);

}
}

.....

for(i = 0; i < 5; i++)
{

     run(PATH, data);

}

See as I've explained my complete situation, I still can't get my code to work. I ask kindly for a solution.

Thanks both of you, I finally got it to work using the signal catching solution.

Couple short questions:

1) snprintf() null terminates for us, so I don't need to do a snprintf(blah, sizeof(blah)-1 just sizeof(blah), correct?

2) With memset(blah, 'Z', sizeof(blah)), could I and would I need to null terminate blah like blah[SIZE] = '\0' or blah[SIZE-1] = '\0' or ?

Thanks again for you help