Please finish the server of a client-server application. The client asks the use
ID: 3842259 • Letter: P
Question
Please finish the server of a client-server application. The client asks the user for a letter (a character in {A-Z,a-z}), and then sends that letter to the server. The server malloc()s memory to store both the loop variable i and the file descriptor from accept() for talking to the client. It then pthread_create()s a child to handle the client and gives it the malloc()ed memory. All of the threads except the last (i == (NUM_CLIENTS_TO_SERVE-1)) should be detached threads. The last thread should be an ordinary, joinable thread, which the parent thread should join with outside the loop.
The child thread should:
Get the thread id (coming in as the loop variable) and file descriptor. It then free()s that malloc()ed memory.
Gets the letter from the client
Attempts to open the current directory ("."). If it cannot open that directory then it:
sends CANT_READ_DIR_CODE back to the client (in network endian),
prints its id and "id num: Cannot read directory ",
returns NULL.
Iterates thru the directory to looking for a file (not a directory or anything else) whose name starts with the letter obtained from the client.
If the server finds no matching file then it
sends NO_MATCH_CODE back to the client (in network endian),
prints its id and "id num: No matching file ",
returns NULL.
Attempts to open the file for reading. If it cannot open the file then it:
sends CANT_READ_FILE_CODE back to the client (in network endian),
prints its id and "id num: Cannot read file <filename> ",
returns NULL.
Prints its id and "id num: Sending <filename>, <numBytes> bytes "
Sends the size of the file as a uint32_t integer to the client (in network endian)
Sends the bytes of the file to the client. It should send the file in buffers of bytes of size BUFFER_LEN.
close()s what it should close.
returns NULL.
Code:
Sample output:
To properly test this program I made a directory called Dir:
I also made a file that I did have permission to read called holdYourHeadUp.txt, and one that I did not called youCantOpenMe.txt. The contents of the second file can be whatever you want, but to make it so you cannot open it say:
My directory now has:
Client output: Server output:$ ./server Please enter port number to monopolize [1025-65535]: 2000
$ ./client Machine name [localhost]? (I just pressed enter) Port number? 2000 Please enter a letter to look for: A No matching file found for ANo file begins with A:
0: No matching file
$ ./client Machine name [localhost]? (I just pressed enter) Port number? 2000 Please enter a letter to look for: D No matching file found for DDir begins with D, but it is not a file.
1: No matching file
$ ./client Machine name [localhost]? (I just pressed enter) Port number? 2000 Please enter a letter to look for: y Matching file found for y, but could not openThe server cannot open youCantOpenMe.txt.
2: Cannot read file youCantOpenMe.txt
$ ./client Machine name [localhost]? (I just pressed enter) Port number? 2000 Please enter a letter to look for: h The file that matches h has size 437 And if it's bad Don't let it get you down, you can take it And if it hurts Don't let them see you cry, you can make it Hold your head up, woman Hold your head up, woman Hold your head up, woman Hold your head high Hold your head up, woman Hold your head up, woman Hold your head up, woman Hold your head high And if they stare Just let them burn their eyes on you moving And if they shout Don't let it change a thing that you're doingThe server can open holdYourHeadUp.txt, so it sends it to the client.
3: Sending holdYourHeadUp.txt, 437 bytes And if it's bad Don't let it get you down, you can take it And if it hurts Don't let them see you cry, you can make it Hold your head up, woman Hold your head up, woman Hold your head up, woman Hold your head high Hold your head up, woman Hold your head up, woman Hold your head up, woman Hold your head high And if they stare Just let them burn their eyes on you moving And if they shout Don't let it change a thing that you're doing
Explanation / Answer
server_getFileByFirstLetter.c
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client_getFileByFirstLetter.c
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getFileByFirstLetter.h
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