utils.c

#include <elf.h>
#include <stdlib.h>
#include <zconf.h>
#include <stdio.h>
#include <fcntl.h>

#include "utils.h"


int open_file(const char* filename) {
    int f = open(filename, O_RDONLY);
    if (!f) {
        perror("Error opening file");
        exit(1);
    }
    return f;
}


int create_file(const char* filename) {
    int f = open(filename, O_CREAT | O_RDWR | O_TRUNC, S_IRWXU);
    if (!f) {
        perror("Error creating file");
        exit(1);
    }
    return f;
}


void write_eheader(int fd, const Elf_Data* elf) {
    ssize_t ret = pwrite(fd, elf->ehdr, sizeof(*(elf->ehdr)), 0);
    if (ret < 0) {
        perror("Error writing elf header");
        exit(1);
    }
}


void write_pheader(int fd, const Elf_Data* elf) {
    Elf64_Ehdr* ehdr = elf->ehdr;
    ssize_t ret = pwrite(fd, elf->phdr, ehdr->e_phnum * ehdr->e_phentsize,
                         HEADER_SIZE);
    if (ret < 0) {
        perror("Error writing program header");
        exit(1);
    }
}


void write_sheader(int fd, const Elf_Data* elf) {
    Elf64_Ehdr* ehdr = elf->ehdr;
    ssize_t ret = pwrite(fd, elf->shdr, ehdr->e_shnum * ehdr->e_shentsize,
                         ehdr->e_shoff);
    if (ret < 0) {
        perror("Error writing program header");
        exit(1);
    }
}


void copy_file(int fd_from, int fd_to, off_t start) {
    off_t off = start;
    ssize_t rret = 0, wret = 0;
    char* buffer[PAGE_SIZE];

    do {
        rret = pread(fd_from, buffer, PAGE_SIZE, off);
        if (rret < 0) {
            perror("Error copy file");
            exit(1);
        }

        if (rret != 0) {
            wret = pwrite(fd_to, buffer, (size_t)rret, off + PAGE_SIZE);
            if (wret < 0) {
                perror("Error copy file");
                exit(1);
            }
        }

        off += PAGE_SIZE;
    } while (rret != 0);
}


void write_addr(int fd, const void* addr, size_t addr_sz, off_t off) {
    ssize_t ret = pwrite(fd, addr, addr_sz, off);
    if (ret < 0) {
        perror("Error writing instr address");
        exit(1);
    }
}