Getting a No such file or directory on fopen() - c

Question

I have a program I'm writing with a globally defined File variable that I'm trying to access by the parent after it forks a child. However, the child is the one that is writing to the file so when I try to read it as the parent I get a Error: No such file or directory. Only it's not thrown as an error, it's stored in the tmpFP file. I'm not sure how to get around this.
I've omitted some code for legibility, the references to sockets are from a custom library, assume that works. The relevant comments should be in all caps, they point to where I believe the problem arises.
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <stdarg.h>
#include "Socket.h"
#include "ToUpper.h" /* definitions shared by client and server */
#define LINE_SIZE 50
#define MAX_WORDS 10
#define MAX_LINE 1024
#define MAX_TMP 100
#define MAX_ARGS 4 /* allows program name + 3 positional parameters */
#define MIN_ARGS 2 /* must have at least 1 positional parameter */
#define NUM_PARMS 4 /* allows program name + 2 parameters + NULL */
#define ERR_RETURN -1
/* variables to hold socket descriptors */
ServerSocket welcome_socket;
Socket connect_socket;
char new_line[MAX_LINE];
char tmp_name[MAX_TMP]; //DECLARING FILENAME
char id_str[MAX_TMP];
char arr[LINE_SIZE]={0};
int id;
FILE *fp; //FILE USED IN CHILD PROCESS
void toupper_service(void);
int main(int argc, char* argv[])
{
FILE *tmpFP; //FILE USED IN PARENT PROCESS
pid_t spid; /* pid_t is typedef for Linux process ID */
int c=0,index=0;
id = (int) getpid();
sprintf(id_str, "%d", id);
strcpy(tmp_name,"tmp");
strcat(tmp_name, id_str);
if (argc < 2)
{
printf("No port specified\n");
return (-1);
}
welcome_socket = ServerSocket_new(atoi(argv[1]));
connect_socket = ServerSocket_accept(welcome_socket);
Socket_close(welcome_socket);
while (c!=EOF)
{
while((c=Socket_getc(connect_socket))!='\n')
{
arr[index]=c;
index++;
}
arr[index]='\0';
/* accept an incoming client connection; blocks the
* process until a connection attempt by a client.
* creates a new data transfer socket.
*/
spid = fork(); /* create child == service process */
if (spid == -1)
{
perror("fork");
exit (-1);
}
if (spid == 0)
{/* code for the service process */
toupper_service();
Socket_close(connect_socket);
exit (0);
} /* end service process */
else /* daemon process closes its connect socket */
{
waitpid(spid,NULL,0);
//PASSES THIS TEST SOMEHOW
if((tmpFP = fopen (tmp_name, "r")) == NULL)
{
fprintf(stderr, "%s\n",tmp_name);
fprintf (stderr, "error opening tmp file\n");
exit (-1);
}
while((c=fgetc(tmpFP))!=EOF)
{
//PRINTS OUT ERROR HERE A LETTER AT A TIME
fprintf(stderr, "c: %d %c\n", c, (char)c);
Socket_putc(c, connect_socket);
}
remove(tmp_name);
Socket_putc('\0', connect_socket);
Socket_close(connect_socket);
/* reap a zombie every time through the loop, avoid blocking*/
}
}/* end of infinite loop for daemon process */
fprintf(stderr, "C: %d\n",c);
}
void toupper_service(void)
{
int i=0, c, pointer,num_words=0,index=0;
int too_many_words=0;
char *word[MAX_WORDS]={NULL};
//THIS IS THE OTHER PLACE TMP_NAME IS USED
fp = freopen(tmp_name, "w", stdout);
while ((c=arr[index])!='\0')
{
if(c==' '||c=='\t'||c=='\n') //word encountered
{
if(num_words>=MAX_WORDS-1)
{
printf("Too many commands passed\n");
too_many_words=1;
exit(0);
break;
}
arr[index]='\0';
word[num_words]=&arr[pointer];
pointer=i+1;
num_words++;
}
index++;
}
word[num_words]=NULL;
if(too_many_words==0)
{
c=0;
int error=execvp(word[0],word);
}
return;
}