linux多进程拷贝程序

  1 #include <stdio.h>
  2 #include <unistd.h>
  3 #include <stdlib.h>
  4 #include <sys/mman.h>
  5 #include <fcntl.h>
  6 #include <string.h>
  7 #include <sys/stat.h>
  8 #include <sys/types.h>
  9 
 10 int fCopy(char *fName[],int num)
 11 {
 12         int   fd1    =   0;
 13         int   fd2    =   0;
 14         char* p1     =   NULL;
 15         char* p2     =   NULL;
 16         int   fSize  =   0;
 17         int   offset =   0;
 18         int   move   =   0;
 19         int   add    =   0;
 20         pid_t pid    =   0;
 21         struct stat st;
 22 
 23         stat(fName[1],&st);
 24 
 25         fSize=st.st_size;
 26 
 27         fd1=open(fName[1],O_RDWR);
 28         if(fd1==-1)
 29         {
 30                 perror("open file1");
 31                 exit(-1);
 32         }
 33 
 34         fd2=open(fName[2],O_RDWR|O_CREAT,0777);
 35         if(fd2==-1)
 36         {
 37                 perror("open file2");
 38                 exit(-2);
 39         }
 40 
 41         ftruncate(fd2,fSize);
 42 
 43         p1=mmap(NULL,fSize,PROT_READ,MAP_SHARED,fd1,0);
 44         if(p1==MAP_FAILED)
 45         {
 46                  perror("mmap file1");
 47                  exit(-3);
 48         }
 49 
 50         p2=mmap(NULL,fSize,PROT_WRITE,MAP_SHARED,fd2,0);
 51         if(p2==MAP_FAILED)
 52         {
 53                 perror("mmap file2");
 54                 exit(-4);
 55         }
 56 
 57         if(num==0)
 58         {
 59                 memcpy(p2,p1,fSize);
 60 
 61                 munmap(p1,fSize);
 62                 munmap(p2,fSize);
 63 
 64                 close(fd1);
 65                 close(fd2);
 66 
 67                 printf("finished\n");
 68         }
 69         else
 70         {
 71                 offset=fSize/num;
 72                 add=fSize%num;
 73         }
 74 
 75         for(int i=0;i<num;i++)
 76         {
 77                 int move=offset*i;
 78                 pid=fork();
 79                 if(pid==-1)
 80                 {
 81                         perror("fork");
 82                         exit(1);
 83                 }
 84                 else if(pid==0)
 85                 {
 86                         memcpy(p2+move,p1+move,offset);
 87                         break;
 88                 }
 89         }
 90 
 91         if(pid>0)
 92         {
 93                 for(int i=0;i<num;i++)
 94                 {
 95                         wait(NULL);
 96                 }
 97 
 98                 memcpy(p2+fSize-add,p1+fSize-add,add);
 99                 munmap(p1,fSize);
100                 munmap(p2,fSize);
101 
102                 close(fd1);
103                 close(fd2);
104 
105                 printf("finished\n");
106         }
107 
108         return 0;
109 }
110 int main(int argc,char *argv[])
111 {
112         if(argc<3)
113         {
114                 printf("error:Too few argumemts\n");
115                 exit(0);
116         }
117         else if(argc>4)
118         {
119                 printf("error:Too more arguments\n");
120                 exit(0);
121         }
122 
123         int  num=0;
124 
125         if(argc==3||strcmp(argv[3],"-f"))
126         {
127                 printf("please input the number of processes:");
128                 scanf("%d",&num);
129         }
130 
131         printf("waiting.......\n");
132         fCopy(argv,num);
133 
134         return 0;
135 }