Attachment 228584 Details for Bug 259071 – Simple file ops program

Simple file ops program

simple.c (text/plain), 1.58 KB, created by Agata on 2021-10-11 12:44:27 UTC

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Creator: Agata

Created: 2021-10-11 12:44:27 UTC

Size: 1.58 KB

patch

obsolete

>#include <stdio.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <fcntl.h>
>#include <sys/stat.h>
>#include <sys/types.h>
>#include <signal.h>
>
>// if you remove this define then program will work fine.
>#define DO_STAT_ON_CHILD 1
>
>void child(void) {
>	struct stat st;
>	while (1) {
>		usleep(100000);
>#ifdef DO_STAT_ON_CHILD
>		if (stat("test.bin",&st)<0) {
>			perror("stat");
>		}
>#endif
>		printf(".");
>		fflush(stdout);
>	}
>}
>
>int parent(void) {
>	char buff[0x40000];
>	long size,r,exp;
>	long csize;
>	int fd;
>	struct stat st;
>
>	fd = open("test.bin",O_RDWR|O_TRUNC|O_CREAT,0666);
>	if (fd<0) {
>		perror("open");
>		return 1;
>	}
>	csize = 0;
>	while (1) {
>		size = random()&0x3FFFF;
>		switch (random()%3) {
>			case 0:
>				if (ftruncate(fd,size)<0) {
>					perror("ftruncate");
>					return 1;
>				}
>				csize = size;
>				break;
>			case 1:
>				lseek(fd,0,SEEK_SET);
>				r = write(fd,buff,size);
>				if (r<0) {
>					perror("write");
>					return 1;
>				}
>				exp = size;
>				if (r!=exp) {
>					fprintf(stderr,"write returned wrong number of bytes (returned: %ld, expected: %ld)\n",r,exp);
>					return 2;
>				}
>				if (size>csize) {
>					csize = size;
>				}
>				break;
>			case 2:
>				lseek(fd,0,SEEK_SET);
>				r = read(fd,buff,size);
>				if (r<0) {
>					perror("read");
>					return 1;
>				}
>				exp = (size<csize)?size:csize;
>				if (r!=exp) {
>					fprintf(stderr,"read returned wrong number of bytes (returned: %ld, expected: %ld)\n",r,exp);
>					return 2;
>				}
>				break;
>		}
>	}
>	return 0;
>}
>
>int main(void) {
>	int chpid;
>	int res;
>
>	if ((chpid=fork())==0) {
>		child();
>		return 0;
>	}
>	res = parent();
>	kill(chpid,SIGTERM);
>	return res;
>}

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