Updates

Author: EnArvy

Assignment-2/a

@@ -0,0 +1 @@
+This repo contains various Operating System Modules such as a shell, process scheduler, memory management module, reader writer problem and filesearch. These are all made for Unix systems.

Readme.md

@@ -1,123 +1,123 @@
-#include <unistd.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/mman.h>
-
-
-
-//Initialize freelist
-struct header{
-    size_t size;
-    struct header* next;
-};
-static struct header* freelist=NULL;
-void init(){
-    if(freelist==NULL){
-        freelist=mmap(NULL,4096,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,-1,0);
-        freelist->size=4096-sizeof(struct header);
-        freelist->next=NULL;
-    }
-}
-//Function to show state of freelist
-void info(){
-    struct header* current = freelist;
-    int blocknumber = 1;
-
-    fprintf(stderr,"------------------------------------\n");
-    fprintf(stderr,"Free List Contents:\n");
-    while (current) {
-        fprintf(stderr,"Block %d: Address=%p, Size=%zu\n", blocknumber, current, current->size);
-        current = current->next;
-        blocknumber++;
-    }
-    fprintf(stderr,"------------------------------------\n");
-}
-
-
-
-//Function to check int overflow on multiplication
-int checkoverflow(int m, int n){
-    if(m==0)return 0;
-    int p=m*n;
-    if(p/n==m)return 0;
-    else return 1;
-}
-
-
-
-// Own implemetnation of malloc
-void* my_malloc(size_t size) {
-
-    if(size==0)return NULL;
-    init();
-    
-    struct header* prev = NULL;
-    struct header* current = freelist;
-
-// First Fit
-    while (current) {
-        if (current->size >= size + sizeof(struct header)) {
-            if (current->size > size + sizeof(struct header)) {
-
-                struct header* new_block = (struct header*)((char*)current + size + sizeof(struct header));
-                new_block->size = current->size - size - sizeof(struct header);
-                new_block->next = current->next;
-                current->size = size;
-                current->next = (struct header*)123456; //magic
-                if (prev)
-                    prev->next = new_block;
-                else
-                    freelist = new_block;
-                return (void*)(current + 1);
-            }
-            else{
-                if (prev)
-                    prev->next = current->next;
-                else
-                    freelist = current->next;
-                current->next = (struct header*)123456; //magic
-                current->size = size;
-                return (void*)(current + 1);
-            }
-        }
-        prev = current;
-        current = current->next;
-    }
-
-    // If no suitable block is found, request more memory.
-    struct header* new_block = sbrk(size+sizeof(struct header));
-    if (new_block == (void*)-1) {
-        errno = ENOMEM;
-        return NULL; // Out of memory
-    }
-    new_block->size = size;
-    new_block->next = (struct header*)123456; //magic
-    return (void*)(new_block + 1);
-}
-
-// Own implementation of calloc
-void* my_calloc(size_t nelem, size_t size) {
-
-    if(checkoverflow(nelem,size)==1){
-        errno=EOVERFLOW;
-        return NULL;
-    }
-    size_t finalsize = nelem * size;
-    void* ptr = my_malloc(finalsize);
-    if(ptr==NULL)return NULL;
-    memset(ptr, 0, finalsize);
-    return ptr;
-
-}
-
-// Own implementation of free
-void my_free(void* ptr) {
-
-    if(ptr==NULL)return;
-    struct header* block = (struct header*)ptr - 1;
-    if(block->next!=(struct header*)123456) return;
-    block->next = freelist;
-    freelist = block;
-
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+
+
+
+//Initialize freelist
+struct header{
+    size_t size;
+    struct header* next;
+};
+static struct header* freelist=NULL;
+void init(){
+    if(freelist==NULL){
+        freelist=mmap(NULL,4096,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,-1,0);
+        freelist->size=4096-sizeof(struct header);
+        freelist->next=NULL;
+    }
+}
+//Function to show state of freelist
+void info(){
+    struct header* current = freelist;
+    int blocknumber = 1;
+
+    fprintf(stderr,"------------------------------------\n");
+    fprintf(stderr,"Free List Contents:\n");
+    while (current) {
+        fprintf(stderr,"Block %d: Address=%p, Size=%zu\n", blocknumber, current, current->size);
+        current = current->next;
+        blocknumber++;
+    }
+    fprintf(stderr,"------------------------------------\n");
+}
+
+
+
+//Function to check int overflow on multiplication
+int checkoverflow(int m, int n){
+    if(m==0)return 0;
+    int p=m*n;
+    if(p/n==m)return 0;
+    else return 1;
+}
+
+
+
+// Own implemetnation of malloc
+void* my_malloc(size_t size) {
+
+    if(size==0)return NULL;
+    init();
+    
+    struct header* prev = NULL;
+    struct header* current = freelist;
+
+// First Fit
+    while (current) {
+        if (current->size >= size + sizeof(struct header)) {
+            if (current->size > size + sizeof(struct header)) {
+
+                struct header* new_block = (struct header*)((char*)current + size + sizeof(struct header));
+                new_block->size = current->size - size - sizeof(struct header);
+                new_block->next = current->next;
+                current->size = size;
+                current->next = (struct header*)123456; //magic
+                if (prev)
+                    prev->next = new_block;
+                else
+                    freelist = new_block;
+                return (void*)(current + 1);
+            }
+            else{
+                if (prev)
+                    prev->next = current->next;
+                else
+                    freelist = current->next;
+                current->next = (struct header*)123456; //magic
+                current->size = size;
+                return (void*)(current + 1);
+            }
+        }
+        prev = current;
+        current = current->next;
+    }
+
+    // If no suitable block is found, request more memory.
+    struct header* new_block = sbrk(size+sizeof(struct header));
+    if (new_block == (void*)-1) {
+        errno = ENOMEM;
+        return NULL; // Out of memory
+    }
+    new_block->size = size;
+    new_block->next = (struct header*)123456; //magic
+    return (void*)(new_block + 1);
+}
+
+// Own implementation of calloc
+void* my_calloc(size_t nelem, size_t size) {
+
+    if(checkoverflow(nelem,size)==1){
+        errno=EOVERFLOW;
+        return NULL;
+    }
+    size_t finalsize = nelem * size;
+    void* ptr = my_malloc(finalsize);
+    if(ptr==NULL)return NULL;
+    memset(ptr, 0, finalsize);
+    return ptr;
+
+}
+
+// Own implementation of free
+void my_free(void* ptr) {
+
+    if(ptr==NULL)return;
+    struct header* block = (struct header*)ptr - 1;
+    if(block->next!=(struct header*)123456) return;
+    block->next = freelist;
+    freelist = block;
+
 }

Assignment-5/Assignment-5.pdf renamed to filesearch/Assignment-5.pdf

@@ -1,42 +1,42 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <sys/mman.h>
-// Include your Headers below
-#include <unistd.h>
-
-
-// You are not allowed to use the function malloc and calloc directly .
-
-struct header{
-    size_t size;
-};
-
-// Function to allocate memory using mmap
-void* my_malloc(size_t size) {
-    // Your implementation of my_malloc goes here
-    if(size==0)return NULL;
-    struct header* ptr=mmap(NULL,size+sizeof(struct header),PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,-1,0);
-    if(ptr==NULL)return NULL;
-    ptr->size=size;
-    return (void*)(ptr+1);
-}
-
-// Function to allocate and initialize memory to zero using mmap
-void* my_calloc(size_t nelem, size_t size) {
-    // Your implementation of my_calloc goes here
-    void* ptr = my_malloc(nelem*size);
-    if(ptr==NULL)return NULL;
-    memset(ptr,0,nelem*size);
-    return (void*)(ptr);
-}
-
-// Function to release memory allocated using my_malloc and my_calloc
-void my_free(void* ptr) {
-    // Your implementation of my_free goes here
-    if(ptr==NULL)return;
-    munmap((struct header*)ptr-1,((struct header*)ptr-1)->size+sizeof(struct header));
-}
-
-void info(){
-    printf("This is a custom memory allocator\n");
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+// Include your Headers below
+#include <unistd.h>
+
+
+// You are not allowed to use the function malloc and calloc directly .
+
+struct header{
+    size_t size;
+};
+
+// Function to allocate memory using mmap
+void* my_malloc(size_t size) {
+    // Your implementation of my_malloc goes here
+    if(size==0)return NULL;
+    struct header* ptr=mmap(NULL,size+sizeof(struct header),PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,-1,0);
+    if(ptr==NULL)return NULL;
+    ptr->size=size;
+    return (void*)(ptr+1);
+}
+
+// Function to allocate and initialize memory to zero using mmap
+void* my_calloc(size_t nelem, size_t size) {
+    // Your implementation of my_calloc goes here
+    void* ptr = my_malloc(nelem*size);
+    if(ptr==NULL)return NULL;
+    memset(ptr,0,nelem*size);
+    return (void*)(ptr);
+}
+
+// Function to release memory allocated using my_malloc and my_calloc
+void my_free(void* ptr) {
+    // Your implementation of my_free goes here
+    if(ptr==NULL)return;
+    munmap((struct header*)ptr-1,((struct header*)ptr-1)->size+sizeof(struct header));
+}
+
+void info(){
+    printf("This is a custom memory allocator\n");
 }