From ac74cec51fa9c31e4c8cea2dd9f01b7b895d61b4 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 22 Aug 2021 13:40:22 +0200
Subject: fs_open() stub
---
src/init/main.c | 24 +++---------------------
src/init/syscalls.c | 4 ++++
src/kernel/syscalls.c | 25 +++++++++++++++++++++++++
src/kernel/syscalls.h | 6 ++++++
src/kernel/vfs/path.h | 2 ++
5 files changed, 40 insertions(+), 21 deletions(-)
diff --git a/src/init/main.c b/src/init/main.c
index fb379d2..51764ce 100644
--- a/src/init/main.c
+++ b/src/init/main.c
@@ -14,27 +14,9 @@ const char *multipageify(const char *str) {
}
int main() {
- char buf[64];
- int len = 64;
-
- // try to print a string crossing page boundaries
- _syscall_debuglog(
- multipageify("I cross pages. "),
- sizeof("I cross pages. ") - 1);
-
- if (_syscall_fork() > 0) {
- _syscall_debuglog("parent ",
- sizeof("parent ") - 1);
-
- len = _syscall_await(buf, 64);
- _syscall_debuglog(buf, len);
- } else {
- _syscall_debuglog("child ",
- sizeof("child ") - 1);
- _syscall_exit(
- multipageify("this is the child's exit message!"),
- sizeof("this is the child's exit message!") - 1);
- }
+ _syscall_fs_open(
+ multipageify("/some/../path"),
+ sizeof("/some/../path") - 1);
_syscall_exit("bye from init! ",
sizeof("bye from init! ") - 1);
diff --git a/src/init/syscalls.c b/src/init/syscalls.c
index 1e11705..b0e1587 100644
--- a/src/init/syscalls.c
+++ b/src/init/syscalls.c
@@ -16,6 +16,10 @@ int _syscall_await(char *buf, int len) {
return _syscall(_SYSCALL_AWAIT, (int)buf, (int)len, 0);
}
+fd_t _syscall_fs_open(const char *path, size_t len) {
+ return _syscall(_SYSCALL_FS_OPEN, (int)path, len, 0);
+}
+
int _syscall_debuglog(const char *msg, size_t len) {
return _syscall(_SYSCALL_DEBUGLOG, (int)msg, len, 0);
}
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 2b3dafc..13e0535 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -3,6 +3,7 @@
#include <kernel/panic.h>
#include <kernel/proc.h>
#include <kernel/syscalls.h>
+#include <kernel/vfs/path.h>
#include <stdint.h>
_Noreturn static void await_finish(struct process *dead, struct process *listener) {
@@ -64,6 +65,28 @@ int _syscall_fork() {
return 1;
}
+fd_t _syscall_fs_open(const char *path, size_t len) {
+ struct virt_iter iter;
+ static char buffer[PATH_MAX]; // holds the simplified path
+ size_t pos = 0;
+
+ if (len > PATH_MAX) return -1;
+
+ // copy the path to buffer
+ virt_iter_new(&iter, (void*)path, len, process_current->pages, true, false);
+ while (virt_iter_next(&iter)) {
+ memcpy(buffer + pos, iter.frag, iter.frag_len);
+ pos += iter.frag_len;
+ }
+ if (iter.error) return -1;
+
+ len = path_simplify(buffer, buffer, len);
+ if (len < 0) return -1;
+
+ tty_write(buffer, len);
+ return -1;
+}
+
int _syscall_debuglog(const char *msg, size_t len) {
struct virt_iter iter;
size_t written = 0;
@@ -84,6 +107,8 @@ int syscall_handler(int num, int a, int b, int c) {
return _syscall_await((void*)a, b);
case _SYSCALL_FORK:
return _syscall_fork();
+ case _SYSCALL_FS_OPEN:
+ return _syscall_fs_open((void*)a, b);
case _SYSCALL_DEBUGLOG:
return _syscall_debuglog((void*)a, b);
default:
diff --git a/src/kernel/syscalls.h b/src/kernel/syscalls.h
index 83a68b2..5f55454 100644
--- a/src/kernel/syscalls.h
+++ b/src/kernel/syscalls.h
@@ -2,12 +2,16 @@
#pragma once
#include <stddef.h>
+typedef int fd_t;
+
enum {
// idc about stable syscall numbers just yet
_SYSCALL_EXIT,
_SYSCALL_AWAIT,
_SYSCALL_FORK,
+ _SYSCALL_FS_OPEN,
+
_SYSCALL_DEBUGLOG
};
@@ -27,6 +31,8 @@ int _syscall_await(char *buf, int len);
*/
int _syscall_fork();
+fd_t _syscall_fs_open(const char *path, size_t len);
+
/** Prints a message to the debug console.
* @return the amount of bytes written (can be less than len)
*/
diff --git a/src/kernel/vfs/path.h b/src/kernel/vfs/path.h
index 769aa27..8efa0d4 100644
--- a/src/kernel/vfs/path.h
+++ b/src/kernel/vfs/path.h
@@ -1,6 +1,8 @@
#pragma once
#include <stddef.h>
+#define PATH_MAX 512
+
/** Reduce a path to its simplest form.
*
* @return length of the string in *out, always less than len. Negative if the path was invalid.
--
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