writev.c

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#include "hal/cpu/core.h"
#include "libk/serial.h"
#include "str.h"
#include "vfs/vnode.h"
#include <sys/err_no.h>
#include <sys/fd.h>
#include <sys/syscall.h>
 
long syscall_writev(int fd, const struct iovec* iov, int iovcnt) {
    // TODO: handle is fd is not found
 
    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 (!iov) {
        LOG2_ERROR("writev", "empty iovec");
        return -EINVAL;
    }
 
    if (!ops->write) {
        LOG2_ERROR("writev", "fd %d `write` ops is missing", fd);
        return -ENOTTY;
    }
 
    auto iovec_ =
        (struct iovec*)kalloc(sizeof(struct iovec) * (size_t)iovcnt);
    memcopy(iovec_, (void*)iov, sizeof(struct iovec) * (size_t)iovcnt);
 
    long total_read = 0;
    for (int i = 0; i < iovcnt; i++) {
        auto iov_ = &iovec_[i];
        if (!iov->iov_len || !iov->iov_base)
            continue;
 
        serial2_printf("write: from 0x%x\n", iov_->iov_base);
        auto write_count =
            ops->write(curr_fd->vnode, iov_->iov_base,
                       (size_t)iov_->iov_len, (size_t)total_read);
 
        if (write_count < 0)
            return -1;
        
        total_read += write_count;
    }
    return total_read;
}