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Commit becc5a9d authored by Brandon Rodriguez's avatar Brandon Rodriguez
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Implement handling of multiple threads to read multiple files

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Examples/MyExamples/PassFirstLineInEachDirFile.c 0 → 100644
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View file @ becc5a9d
/**
* Brandon Rodriguez
* CS 3240
* 11-15-17
* a4 (Assignment 5)
*/
/**
* Description:
* Testing of thread implementation to solve a problem.
* Slightly more advanced example of joining with data passing.
*
* This reads in a provided directory and opens up threads equivalent to the number of
* files within. Each process handles a diffierent file, grabbing the first line,
* reading it, then returning the line to main which reads line again.
*/
/**
* Known Issues:
* No valgrind issues in small-data folder but valgrind finds four issues
* in large-data folder. Not sure where the errors are comming from, as valgrind
* (seemingly?) doesn't even point to any lines of code for this issue. Baffling.
*/
#define _BSD_SOURCE
// Import headers.
#include <ctype.h>
#include <dirent.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "apue.h"
#include "HelperHeader.h"
// Define Vars.
#define BUFFER_SIZE 4096
// Variables.
typedef struct{
char* user_name;
char* password;
char* blood_type;
char* domain_name;
int db_index;
} data_struct;
int dir_file_counter;
char* absolute_path;
pthread_t* thread_array;
// Method Declaration.
int change_directory();
void open_folder();
void* thread_read_file(); // Reads given file and reorganizes data.
/**
* Program's main.
* Initializes and runs program.
*/
int main(int argc, char* argv[]) {
int index;
int return_int;
char* return_string;
// Check for valid args.
if (argc < 2) {
err_msg("Must enter a directory path.");
return -1;
} else if (argc > 2) {
err_msg("Must enter exacly one directory path.");
return -1;
} else {
return_int = change_directory(argv[1]);
if (return_int == 0) {
// Get absolute path.
absolute_path = calloc(BUFFER_SIZE, sizeof(char*));
if (getcwd(absolute_path, BUFFER_SIZE) == NULL) {
err_sys("Failed to get absolute path.");
}
// Open folder and create appropriate number of threads.
open_folder();
// Iterate through all threads and grab returned value.
for (index = 0; index < dir_file_counter; index++) {
pthread_join(thread_array[index], (void**) &return_string);
printf("Thread returned: %s", return_string);
free(return_string);
}
free(absolute_path);
free(thread_array);
}
}
return 0;
}
/**
* Safely changes directory by first checking path value and permissions.
*
* Returns 0 on success or -1 on failure.
*/
int change_directory(char* folder_location) {
int return_int;
struct stat stat_buffer;
return_int =lstat(folder_location, &stat_buffer);
if (return_int <0) {
err_sys("Failed to stat file with err %d", return_int);
return -1;
}
// First, ensure that it is, infact, a directory.
if (S_ISDIR(stat_buffer.st_mode)) {
// Next, check permissions.
if (access(folder_location, X_OK) == 0) {
// Change into directory.
return_int = chdir(folder_location);
if (return_int < 0) {
err_sys("Failed to change directory with err %d", return_int);
return -1;
}
} else { // No execute permission.
err_msg("No execute permission. Cannot change into directory.\n");
return -1;
}
} else { // Not a dir.
err_msg("Provided path is not a directory.\n");
return -1;
}
return 0;
}
/**
* Opens indicated folder and hands files off to threads.
*/
void open_folder() {
int index;
int return_int;
char* temp_string;
struct dirent* dir_struct;
struct stat stat_buffer;
DIR* dir_pointer;
// Iterate through directory first time, to count number of files to open/threads to make.
dir_file_counter = 0;
dir_pointer = opendir(absolute_path);
// Check that directory has read permissions.
if (access(absolute_path, R_OK) == 0) {
// Loop until no more files in directory.
while (dir_pointer != NULL) {
if ((dir_struct = readdir(dir_pointer)) != NULL) {
// New file found. Check if standard file type.
return_int = lstat(dir_struct->d_name, &stat_buffer);
if (return_int < 0) {
err_sys("Failed to stat file with err %d", return_int);
}
if (S_ISREG(stat_buffer.st_mode)) {
dir_file_counter++;
}
} else {
// End of files in directory. Closing stream.
return_int = closedir(dir_pointer);
if (return_int < 0) {
err_msg("Failed to properly close directory.");
}
dir_pointer = NULL;
}
}
} else {
err_msg("Directory does not have read access. Cannot view files.");
}
printf("Directory File Counter: %d\n", dir_file_counter);
// Prepare to set up threads.
thread_array = calloc(dir_file_counter, sizeof(pthread_t));
index = 0;
pthread_attr_t attr;
size_t stacksize;
pthread_attr_init(&attr);
pthread_attr_getstacksize(&attr, &stacksize);
if (stacksize < 8388608) {
stacksize = 8388608;
}
pthread_attr_setstacksize(&attr, (stacksize * 2));
// Iterate through directory again. This time, actually create threads and hand off files.
dir_pointer = opendir(absolute_path);
// Check that directory has read permissions.
if (access(absolute_path, R_OK) == 0) {
// Loop until no more files in directory.
while (dir_pointer != NULL) {
if ((dir_struct = readdir(dir_pointer)) != NULL) {
// New file found. Check if standard file type.
return_int = lstat(dir_struct->d_name, &stat_buffer);
if (return_int < 0) {
err_sys("Failed to stat file with err %d", return_int);
}
if (S_ISREG(stat_buffer.st_mode)) {
// Get absolute file path.
temp_string = copy_string_with_buffer(absolute_path, BUFFER_SIZE);
strcat(temp_string, "/");
strcat(temp_string, dir_struct->d_name);
printf("Path: %s\n", temp_string);
// Actually create threads.
pthread_create(&thread_array[index], &attr, thread_read_file, (void*) copy_string(temp_string));
index++;
free(temp_string);
}
} else {
// End of files in directory. Closing stream.
return_int = closedir(dir_pointer);
if (return_int < 0) {
err_msg("Failed to properly close directory.");
}
dir_pointer = NULL;
}
}
} else {
err_msg("Directory does not have read access. Cannot view files.");
}
}
/**
* Uses thread to read file value.
*/
void* thread_read_file(void* file_location) {
FILE* read_file;
char* line_buffer = calloc(BUFFER_SIZE, sizeof(char*));
int result_int;
// printf("I'ma child and I was given dis: %s\n", file_location);
// pthread_exit(file_location);
read_file = fopen(file_location, "r");
fgets(line_buffer, BUFFER_SIZE, read_file);
free(file_location);
result_int = fclose(read_file);
if (result_int != 0) {
err_msg("Failed to close file properly.");
}
printf("I'ma child and I found dis: %s", line_buffer);
pthread_exit(line_buffer);
}
Main.c
+ 191
− 11
View file @ becc5a9d
...@@ -27,14 +27,19 @@ ...@@ -27,14 +27,19 @@
*/ */
#define _BSD_SOURCE
// Import headers. // Import headers.
#include <ctype.h> #include <ctype.h>
#include <dirent.h>
#include <fcntl.h> #include <fcntl.h>
#include <pthread.h> #include <pthread.h>
#include <stdio.h> #include <stdio.h>
#include <string.h> #include <string.h>
#include <stdlib.h> #include <stdlib.h>
#include <sys/stat.h>
#include "apue.h" #include "apue.h"
#include "HelperHeader.h"
// Define Vars. // Define Vars.
...@@ -49,10 +54,15 @@ typedef struct{ ...@@ -49,10 +54,15 @@ typedef struct{
char* domain_name; char* domain_name;
int db_index; int db_index;
} data_struct; } data_struct;
int dir_file_counter;
char* absolute_path;
pthread_t* thread_array;
// Method Declaration. // Method Declaration.
void* ThreadReadFile(); // Reads given file and reorganizes data. int change_directory();
void open_folder();
void* thread_read_file(); // Reads given file and reorganizes data.
/** /**
...@@ -60,34 +70,204 @@ void* ThreadReadFile(); // Reads given file and reorganizes data. ...@@ -60,34 +70,204 @@ void* ThreadReadFile(); // Reads given file and reorganizes data.
* Initializes and runs program. * Initializes and runs program.
*/ */
int main(int argc, char* argv[]) { int main(int argc, char* argv[]) {
pthread_t thread; int index;
int return_int;
char* file_location = "Data/small-data/0";
char* return_string; char* return_string;
pthread_create(&thread, NULL, ThreadReadFile, (void*) file_location); // Check for valid args.
pthread_join(thread, (void**) &return_string); if (argc < 2) {
printf("Thread returned:\n%s", return_string); err_msg("Must enter a directory path.");
free(return_string); return -1;
} else if (argc > 2) {
err_msg("Must enter exacly one directory path.");
return -1;
} else {
return_int = change_directory(argv[1]);
if (return_int == 0) {
// Get absolute path.
absolute_path = calloc(BUFFER_SIZE, sizeof(char*));
if (getcwd(absolute_path, BUFFER_SIZE) == NULL) {
err_sys("Failed to get absolute path.");
}
// Open folder and create appropriate number of threads.
open_folder();
// Iterate through all threads and grab returned value.
for (index = 0; index < dir_file_counter; index++) {
pthread_join(thread_array[index], (void**) &return_string);
printf("Thread returned: %s", return_string);
free(return_string);
}
free(absolute_path);
free(thread_array);
}
}
return 0;
}
/**
* Safely changes directory by first checking path value and permissions.
*
* Returns 0 on success or -1 on failure.
*/
int change_directory(char* folder_location) {
int return_int;
struct stat stat_buffer;
return_int =lstat(folder_location, &stat_buffer);
if (return_int <0) {
err_sys("Failed to stat file with err %d", return_int);
return -1;
}
// First, ensure that it is, infact, a directory.
if (S_ISDIR(stat_buffer.st_mode)) {
// Next, check permissions.
if (access(folder_location, X_OK) == 0) {
// Change into directory.
return_int = chdir(folder_location);
if (return_int < 0) {
err_sys("Failed to change directory with err %d", return_int);
return -1;
}
} else { // No execute permission.
err_msg("No execute permission. Cannot change into directory.\n");
return -1;
}
} else { // Not a dir.
err_msg("Provided path is not a directory.\n");
return -1;
}
return 0;
}
/**
* Opens indicated folder and hands files off to threads.
*/
void open_folder() {
int index;
int return_int;
char* temp_string;
struct dirent* dir_struct;
struct stat stat_buffer;
DIR* dir_pointer;
// Iterate through directory first time, to count number of files to open/threads to make.
dir_file_counter = 0;
dir_pointer = opendir(absolute_path);
// Check that directory has read permissions.
if (access(absolute_path, R_OK) == 0) {
// Loop until no more files in directory.
while (dir_pointer != NULL) {
if ((dir_struct = readdir(dir_pointer)) != NULL) {
// New file found. Check if standard file type.
return_int = lstat(dir_struct->d_name, &stat_buffer);
if (return_int < 0) {
err_sys("Failed to stat file with err %d", return_int);
}
if (S_ISREG(stat_buffer.st_mode)) {
dir_file_counter++;
}
} else {
// End of files in directory. Closing stream.
return_int = closedir(dir_pointer);
if (return_int < 0) {
err_msg("Failed to properly close directory.");
}
dir_pointer = NULL;
}
}
} else {
err_msg("Directory does not have read access. Cannot view files.");
}
printf("Directory File Counter: %d\n", dir_file_counter);
// Prepare to set up threads.
thread_array = calloc(dir_file_counter, sizeof(pthread_t));
index = 0;
pthread_attr_t attr;
size_t stacksize;
pthread_attr_init(&attr);
pthread_attr_getstacksize(&attr, &stacksize);
if (stacksize < 8388608) {
stacksize = 8388608;
}
pthread_attr_setstacksize(&attr, (stacksize * 2));
// Iterate through directory again. This time, actually create threads and hand off files.
dir_pointer = opendir(absolute_path);
// Check that directory has read permissions.
if (access(absolute_path, R_OK) == 0) {
// Loop until no more files in directory.
while (dir_pointer != NULL) {
if ((dir_struct = readdir(dir_pointer)) != NULL) {
// New file found. Check if standard file type.
return_int = lstat(dir_struct->d_name, &stat_buffer);
if (return_int < 0) {
err_sys("Failed to stat file with err %d", return_int);
}
if (S_ISREG(stat_buffer.st_mode)) {
// Get absolute file path.
temp_string = copy_string_with_buffer(absolute_path, BUFFER_SIZE);
strcat(temp_string, "/");
strcat(temp_string, dir_struct->d_name);
printf("Path: %s\n", temp_string);
// Actually create threads.
pthread_create(&thread_array[index], &attr, thread_read_file, (void*) copy_string(temp_string));
index++;
free(temp_string);
}
} else {
// End of files in directory. Closing stream.
return_int = closedir(dir_pointer);
if (return_int < 0) {
err_msg("Failed to properly close directory.");
}
dir_pointer = NULL;
}
}
} else {
err_msg("Directory does not have read access. Cannot view files.");
}
} }
/** /**
* Uses thread to read file value. * Uses thread to read file value.
*/ */
void* ThreadReadFile(void* file_location) { void* thread_read_file(void* file_location) {
FILE* read_file; FILE* read_file;
char* line_buffer = calloc(BUFFER_SIZE, sizeof(char*)); char* line_buffer = calloc(BUFFER_SIZE, sizeof(char*));
int result_int; int result_int;
read_file = fopen(file_location, "r"); read_file = fopen(file_location, "r");
fgets(line_buffer, BUFFER_SIZE, read_file); fgets(line_buffer, BUFFER_SIZE, read_file);
free(file_location);
result_int = fclose(read_file); result_int = fclose(read_file);
if (result_int != 0) { if (result_int != 0) {
err_sys("Failed to close file properly."); err_msg("Failed to close file properly.");
} }
printf("I'ma child and I found dis: \n%s\n", line_buffer); printf("I'ma child and I found dis: %s", line_buffer);
pthread_exit(line_buffer); pthread_exit(line_buffer);
} }
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