A simple program to detect memory leak in our C program

// We assume max 1000 allocations will take place #define MAX_ALLOCATIONS 1000/* Data Structure to keep track of memory allocationsaddress -> Memory address allocatedsize -> Size allocatedline -> Line number where allocation is done*/typedef struct {    size_t address;    size_t size;    uint32_t line;} Mem;/*mem -> store all the allocation in arraytotal_allocated_size -> Keep track total memory allocatedtotal_free_size -> Keep track total memory freed*/struct {    Mem mem[MAX_ALLOCATIONS];    size_t total_allocated_size;    size_t total_free_size;} data;

/** * Find a memory by its address *  * @return: Pointer to memory*/Mem *find_by_address(size_t address) {    for (uint32_t i=0; i<MAX_ALLOCATIONS; i++) {        if (data.mem[i].address == address)            return &data.mem[i]; // as soon as find return    }    // otherwise return null    return NULL;}/** * insert memory allocated with size*/void insert(size_t address, size_t size, uint32_t line) {    // check for null    if (address == 0) {        WARN("Memory allocation failed", line);        return;    }    Mem *mem = find_by_address(0);    // if the return value is null we need to increase the MAX_ALLOCATIONS value    if (mem == NULL) {        WARN("Max allocations reached", line);        return;    }    // save all the allocation info    mem->address = address;    mem->size = size;    mem->line = line;    data.total_allocated_size += size;}/** * Remove the memory allocation *  * @return: -1 on failure else 0*/int erase(size_t address, uint32_t line) {    if (address == 0) {        WARN("Tried to free a null ptr", line);        return -1;    }    Mem *mem = find_by_address(address);    // if the address is not found we assume it is already deleted    if (mem == NULL) {        WARN("Double free detected", line);        return -1;    }    // set address to null and update info    mem->address = 0;    data.total_free_size += mem->size;    return 0;}

void print_report() {    printf("
Leak Summary
");    printf("Total Memory allocated %lu bytes
", data.total_allocated_size);    printf("Total Memory freed     %lu bytes
", data.total_free_size);    printf("Memory Leaked          %lu bytes

",         data.total_allocated_size - data.total_free_size);    if (data.total_free_size != data.total_allocated_size) {        printf("Detailed Report
");        for (int i=0; i<MAX_ALLOCATIONS; i++) {            if (data.mem[i].address != 0) {                printf("Memory leak at line %d: (%lu bytes)
",                     data.mem[i].line,                    data.mem[i].size);            }        }    }}

// Create allocator functionsvoid *_malloc(size_t size, uint32_t line) {    void *ptr = malloc(size);    // insert to memory data    insert((size_t)ptr, size, line);    return ptr;}void _free(void *ptr, uint32_t line) {    // erase memory data    if (erase((size_t)ptr, line) == 0)        free(ptr);}

// redefine allocator functions#define malloc(size) _malloc(size, __LINE__)#define free(ptr) _free(ptr, __LINE__)

#include <stdio.h>#include <stdlib.h>#include <stdint.h>#define MAX_ALLOCATIONS 100#define WARN(msg, line) (printf("Warning %d: %s
", line, msg))/* Data Structure to keep track of memory allocations*/typedef struct {    size_t address;    size_t size;    uint32_t line;} Mem;struct {    Mem mem[MAX_ALLOCATIONS];    size_t total_allocated_size;    size_t total_free_size;} data;/** * Find a memory by its address *  * @return: Pointer to memory*/Mem *find_by_address(size_t address) {    for (uint32_t i=0; i<MAX_ALLOCATIONS; i++) {        if (data.mem[i].address == address)            return &data.mem[i]; // as soon as find return    }    // otherwise return null    return NULL;}/** * insert memory allocated with size*/void insert(size_t address, size_t size, uint32_t line) {    // check for null    if (address == 0) {        WARN("Memory allocation failed", line);        return;    }    Mem *mem = find_by_address(0);    // if the return value is null we need to increase the MAX_ALLOCATIONS value    if (mem == NULL) {        WARN("Max allocations reached", line);        return;    }    // save all the allocation info    mem->address = address;    mem->size = size;    mem->line = line;    data.total_allocated_size += size;}/** * Remove the memory allocation *  * @return: -1 on failure else 0*/int erase(size_t address, uint32_t line) {    if (address == 0) {        WARN("Tried to free a null ptr", line);        return -1;    }    Mem *mem = find_by_address(address);    // if the address is not found we assume it is already deleted    if (mem == NULL) {        WARN("Double free detected", line);        return -1;    }    // set address to null and update info    mem->address = 0;    data.total_free_size += mem->size;    return 0;}void print_report() {    printf("
Leak Summary
");    printf("Total Memory allocated %lu bytes
", data.total_allocated_size);    printf("Total Memory freed     %lu bytes
", data.total_free_size);    printf("Memory Leaked          %lu bytes

",         data.total_allocated_size - data.total_free_size);    if (data.total_free_size != data.total_allocated_size) {        printf("Detailed Report
");        for (int i=0; i<MAX_ALLOCATIONS; i++) {            if (data.mem[i].address != 0) {                printf("Memory leak at line %d: (%lu bytes)
",                     data.mem[i].line,                    data.mem[i].size);            }        }    }}// Override allocation functionsvoid *_malloc(size_t size, uint32_t line) {    void *ptr = malloc(size);    // insert to memory data    insert((size_t)ptr, size, line);    return ptr;}void _free(void *ptr, uint32_t line) {    // erase memory data    if (erase((size_t)ptr, line) == 0)        free(ptr);}// redefine allocator functions#define malloc(size) _malloc(size, __LINE__)#define free(ptr) _free(ptr, __LINE__)int main() {    int *n1 = malloc(sizeof(int));    free(n1);    int *n2 = NULL;    free(n2);    int *n3 = malloc(sizeof(int));    free(n3);    free(n3);    int *n4 = malloc(sizeof(int));    print_report();    return 0;}

naman@namantam1:~/programs$ gcc main.c && ./a.outWarning 143: Tried to free a null ptrWarning 147: Double free detectedLeak SummaryTotal Memory allocated 12 bytesTotal Memory freed     8 bytesMemory Leaked          4 bytesDetailed ReportMemory leak at line 149: (4 bytes)