syscall: log when unimplemented syscall is invoked

mosmeh · Sep 4, 2024 · 96d67d0 · 96d67d0
1 parent 8c97847
commit 96d67d0
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Showing 4 changed files with 383 additions and 3 deletions.
diff --git a/docs/cmdline.md b/docs/cmdline.md
@@ -15,3 +15,4 @@ The kernel command-line parameters are in the form of `key=value`, where the `=v
 - `console=<device>`: The device to use as the system console `/dev/console`. The default is `tty1`.
 - `nosmp`: Disables symmetric multiprocessing.
 - `font=<path>`: The path to the PSF font file to use for the framebuffer console. The default is `/usr/share/fonts/default.psf`.
+- `ni_syscall_log`: Log a message when an unimplemented system call is invoked.
diff --git a/kernel/api/sys/syscall.h b/kernel/api/sys/syscall.h
@@ -2,8 +2,8 @@
 
 #define SYSCALL_VECTOR 0x80
 
-// The syscall numbers are defined in the Linux kernel source code:
-// arch/x86/entry/syscalls/syscall_32.tbl
+// The syscall numbers are in sync with Linux:
+// arch/x86/entry/syscalls/syscall_32.tbl in the Linux kernel source.
 #define SYS_exit 1
 #define SYS_fork 2
 #define SYS_read 3

diff --git a/kernel/syscall/syscall.c b/kernel/syscall/syscall.c
@@ -1,4 +1,5 @@
 #include "syscall.h"
+#include "unimplemented.h"
 #include <kernel/api/sys/reboot.h>
 #include <kernel/api/sys/syscall.h>
 #include <kernel/api/unistd.h>
@@ -62,18 +63,32 @@ int sys_dbgprint(const char* user_str) {
     return kprint(user_str);
 }
 
+#define F(num, name)                                                           \
+    static int sys_ni_##name(void) {                                           \
+        if (cmdline_contains("ni_syscall_log"))                                \
+            kprint("syscall: " #name                                           \
+                   " (" STRINGIFY(num) ") is unimplemented\n");                \
+        return -ENOSYS;                                                        \
+    }
+ENUMERATE_UNIMPLEMENTED_SYSCALLS(F)
+#undef F
+
 struct syscall {
     uintptr_t handler;
     unsigned flags;
 };
 
 static struct syscall syscalls[] = {
+#define F(num, name) [num] = {(uintptr_t)sys_ni_##name, 0},
+    ENUMERATE_UNIMPLEMENTED_SYSCALLS(F)
+#undef F
+
 #define F(name, handler, flags)                                                \
     [SYS_##name] = {                                                           \
         (uintptr_t)(handler),                                                  \
         (flags),                                                               \
     },
-    ENUMERATE_SYSCALLS(F)
+        ENUMERATE_SYSCALLS(F)
 #undef F
 };