我的问题是系统调用写入。arc 文件包含多个文件包含。我知道每个文件的大小。我想创建不同的输出文件，我想将这些包含写入这些输出文件中。我可以创建文件，但我不能写入这些文件。我在代码下面标记了“这里的问题”。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#define BUFSIZE 4096
struct stat st;
struct inputfiles{
unsigned char numchar;
char *filename;
unsigned int filesize;
} file[255];
struct outputfiles{
unsigned char num_char;
char *file_name;
unsigned int file_size;
} outfile[255];
int main(int argc,char *argv[])
{
int i,j,k,m,h;
int input_file,output_file;
unsigned char chinput_file;
int fd;
int infile,outfile,arcfile;
int extfile[255];
char buffer[BUFSIZE];
char outbuffer[BUFSIZE];
char n;
char flength;
int file_len;
char *f_name;
char *tempsize;
int sizeoffile[255];
ssize_t nread,xread;
input_file=argc-3;
chinput_file=(unsigned char)input_file;
if(argc<=2)
{
fprintf(stderr,"Error: you must enter least 3 argument\n");
exit(1);
}
else if(strcmp(argv[1],"-c")==0)
{
if((outfile=open(argv[2],O_WRONLY | O_CREAT,0644))==-1)
{
fprintf(stderr,"Error: Archive file can't open %s\n",argv[2]);
remove(argv[2]);
exit(1);
}
/*** write number of files into the archive file ***/
write(outfile,(char*)&chinput_file,sizeof(char));
j=0;
for(i=3;i<argc;i++)
{
file[j].numchar=(unsigned char)strlen(argv[i]);
/**** write filename size into archive file ****/
write(outfile,(char*)&file[j].numchar,sizeof(char));
file[j].filename=malloc(file[j].numchar);
strcpy(file[j].filename,argv[i]);
/**** write filename into the archive file ****/
write(outfile,file[j].filename,file[j].numchar);
stat(argv[i],&st);
file[j].filesize=st.st_size;
/**** write size of file into the archive file ****/
write(outfile,&file[j].filesize,sizeof(int));
j++;
}
for(m=3;m<argc;m++)
{
if((infile=open(argv[m],O_RDONLY))==-1)
{
fprintf(stderr,"Error: File can't open %s\n",argv[m]);
exit(1);
}
while((nread=read(infile,buffer,BUFSIZE))>0)
{
if(write(outfile,buffer,nread)<nread)
{
fprintf(stderr,"Error : input file size too much\n");
exit(1);
}
if(nread==-1)
{
fprintf(stderr,"Error occurred while reading.\n");
exit(1);
}
}
}
}
else if((strcmp(argv[1],"-x")==0))
{
if(argc!=3)
{
fprintf(stderr,"Error : you must enter 3 argument for extract \n");
exit(1);
}
else
{
if((arcfile=open(argv[2],O_RDONLY))==-1)
{
fprintf(stderr,"Error:File can't open %s\n",argv[2]);
remove(argv[2]);
exit(1);
}
read(arcfile,(char*)&n,sizeof(char));
output_file =(int)n;
for(m=0;m<n;m++)
{
read(arcfile,&flength,sizeof(char));
file_len=((int)flength);
f_name=malloc(file_len+1);
read(arcfile,f_name,file_len);
if((extfile[m]=open(f_name,O_WRONLY | O_CREAT ,0644))==-1)
{
fprintf(stderr,"Error :extract file is %s can't open\n",f_name);
remove(f_name);
exit(1);
}
tempsize=malloc(sizeof(int));
read(arcfile,&tempsize,sizeof(int));
sizeoffile[m]=(int)tempsize;
//outfile[m].file_size=sizeoffile;
//printf("file name length: %d\n",file_len);
printf("file name: %s\n",f_name);
printf("file size: %d\n",sizeoffile[m]);
//printf("file size : %d\n",outfile[m].file_size);
}
for(m=0;m<n;m++)
{
while((xread=read(arcfile,outbuffer,sizeoffile[m]))!=0)
{
//printf("xread is : %d\n",xread);
//if(write(extfile[m],outbuffer,xread)!=xread)
//{
// fprintf(stderr,"Error : input file size too much\n");
// exit(1);
//}
if(xread==-1)
{
fprintf(stderr,"Error occurred while reading.\n");
exit(1);
}
write(extfile[m],outbuffer,xread); <-------- PROBLEM IS HERE
}//end of while
} //end of second for loop
}//end of else
}//end of else if
else {
fprintf(stderr,"invalid command line\n");
exit(1);
}
}