Question

Using Unix processes

Submit a README file that lists the files you have submitted along with a one sentence explanation. Call it Prj1README.

MakeCopy.c : Write a C program that makes a new copy of an existing file using system calls for file manipulation. The names of the two files and copy block sizes are to be specified as command line arguments. Open the source file in read only mode and destination file in read/write mode.

ForkCopy.c : Write a C program that creates a new process to copy the files using the MyCopy. This program should spawn a new process using fork system call. Then use execl to execute MyCopy program. The source and destination file names presented as command-line arguments should be passed to execl as system call arguments. The main process waits for completion of copy operation using wait system call.

PipeCopy.c : Write a C program that forks two processes one for reading from a file (source file) and the other for writing (destination file) into. These two programs communicate using pipe system call. Once again the program accomplishes copying files, the names of which are specified as command-line arguments.

Use CompareTime.c for time to compare the three versions of the file copy programs as specified above and write an explanation about the results in Prj1README. You can either get the results through PreTest program or linux terminal with the command below.
./ComapareTime <ProgramToTest> <src> <dst> <bufferSize>

MyShell.c : Write a shell-like program that illustrates how UNIX spawns processes. This simple program will provide its own prompt to the user, read the command from the input and execute the command. It is sufficient to handle just ``argument- less'' commands, such as ls and date.

MoreShell.c :Make the mini-shell (from the previous part) a little more powerful by allowing arguments to the commands. For example, it should be able to execute commands such as more filename and ls –l ./tmp etc. (MoreShell.c MoreShell)

DupShell.c : Add to the mini-shell ability to execute command lines with commands connected by pipes. Use dup system call to redirect IO. Example: ls -l | wc . (DupShell.c DupShell).

Answer 1

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Code to copy:

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

   /* Size of the data blocks copied in bytes */
   #define DATA_BLOCKS_SIZE 1024

   int main(int argc, char const *argv[]) {
       /* Check number of arguments and print manual */
       if(argc < 3) {
           printf("ERROR: Too few arguments. Usage: ./MakeCopy source destinationination\n");
           return 3;
       }

       /* Open file pointer for source and handle error */
       FILE *source = fopen(argv[1], "r");
       if(source == NULL) {
           printf("ERROR: Unable to open source file \"%s\" (%s)\n", argv[1], strerror(errno));
           return 1;
       }

       /* Open file pointer for destinationination and handle error */
       FILE *destination = fopen(argv[2], "w+");
       if(destination == NULL) {
           printf("ERROR: Unable to create destinationination file \"%s\" (%s)\n", argv[2], strerror(errno));
           fclose(source);
           return 2;
       }

       /* Create buffer for efficent copying and counters */
       uint8_t buffer[DATA_BLOCKS_SIZE];
       uint16_t read_Data_Count = 0;
       uint64_t copied_Data_Count = 0;

       /* Copy blocks */
       while((read_Data_Count = fread(buffer, 1, DATA_BLOCKS_SIZE, source)) > 0) {
           fwrite(buffer, 1, read_Data_Count, destination);
           copied_Data_Count += read_Data_Count;
           printf("%" PRIu64 " bytes copied...\n", copied_Data_Count);
       }

       /* Check if a error occured while reading the source file */
       if(ferror(source)) {
           printf("ERROR: failure while reading the source file!\n");
           return 3;
       }

       /* Check if a error occured while writing the destinationination file */
       if(ferror(destination)) {
           printf("ERROR: failure while writing the destinationination file!\n");
           return 4;
       }

       /* Print success and exit */
       printf("SUCCESS.\n");
       return 0;
   }

srcfile.txt:

srcfile.txt saved 1 Hi, Chegg expert

Output Screenshots:

Execution: ./MakeCopy srcfile destfile

My filename is main.c, So i used ./main

} ./main srcfile.txt destfile.txt 16 bytes copied... SUCCESS.

destfile.txt:

destfile.txt saved 1 Hi, Chegg expert