read.c

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#include "hal/cpu/core.h"
#include "libk/serial.h"
#include "sys/err_no.h"
#include "vfs/vnode.h"
#include <sys/syscall.h>
#include <dev/event.h>
#include <sys/fd.h>
 
int syscall_read(int fd, void* buf, long count) {
    auto curr_procc = get_current_core_data()->active_thread->process;
    auto fdt = (struct fdtable*)curr_procc->fdtable;
    auto curr_fd = fdt->fds[fd];
 
    if (fd < 0 || fd > (int)fdt->max_fds) {
        LOG2_ERROR("writev", "fd %d is invalid, max fd %d", fd,
                   fdt->max_fds);
        return -EBADF;
    }
 
    auto ops = (vops_file_t*)curr_fd->ops;
    if (!ops) {
        LOG2_ERROR("writev", "fd %d ops is missing", fd);
        return -EBADF;
    }
 
    if (!curr_fd->vnode) {
        LOG2_ERROR("writev", "fd %d vnode is missing", fd);
        return -EBADF;
    }
 
    if (!ops->read) {
        LOG2_ERROR("writev", "fd %d `write` ops is missing", fd);
        return -ENOTTY;
    }
 
    return ops->read(curr_fd->vnode, buf, (size_t)count, 0);
}