Kernel/syscalls/native/readlink.cpp
2024-01-19 06:47:42 +02:00

82 lines
2.0 KiB
C++

/*
This file is part of Fennix Kernel.
Fennix Kernel is free software: you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.
Fennix Kernel is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/
#include <syscalls.hpp>
#include <memory.hpp>
#include <utsname.h>
#include <lock.hpp>
#include <exec.hpp>
#include <errno.h>
#include <debug.h>
#include "../../syscalls.h"
#include "../../kernel.h"
using Tasking::PCB;
using namespace Memory;
/* https://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html */
ssize_t sys_readlink(SysFrm *, const char *path, char *buf,
size_t bufsize)
{
if (!path || !buf)
return -EINVAL;
if (bufsize > PAGE_SIZE)
{
warn("bufsize is too large: %ld", bufsize);
return -EINVAL;
}
PCB *pcb = thisProcess;
Memory::Virtual vmm(pcb->PageTable);
if (!vmm.Check((void *)buf, Memory::US))
{
warn("Invalid address %#lx", buf);
return -EFAULT;
}
const char *pPath = pcb->PageTable->Get(path);
char *pBuf = pcb->PageTable->Get(buf);
function("%s %#lx %ld", pPath, buf, bufsize);
vfs::FileDescriptorTable *fdt = pcb->FileDescriptors;
int fd = fdt->_open(pPath, O_RDONLY, 0);
if (fd < 0)
return -ENOENT;
vfs::FileDescriptorTable::Fildes fildes = fdt->GetDescriptor(fd);
vfs::Node *node = fildes.Handle->node;
fdt->_close(fd);
if (node->Type != vfs::NodeType::SYMLINK)
return -EINVAL;
if (!node->Symlink)
{
warn("Symlink null for \"%s\"?", pPath);
return -EINVAL;
}
size_t len = strlen(node->Symlink);
if (len > bufsize)
len = bufsize;
strncpy(pBuf, node->Symlink, len);
return len;
}