Add prototypes for process management...

9 files changed, 99 insertions, 40 deletions

diff --git a/README.md b/README.md
index 0b460bc..4ae6939 100644
--- a/README.md
+++ b/README.md
@@ -104,8 +104,13 @@ running the tests):
 
 ### Plans for soon
 
+* Complete process management (implement process exiting, process deletion, waiting, ...)
 * Implement missing syscalls
-* Write device drivers : VGA, keyboard, ATA, FAT, VESA
+* Write device drivers : VGA, keyboard, FAT (or EXT2 ?), VESA
+* Work on userland
+* Define a format for "packages", ie readonly filesystem images used for adding system
+  components or apps to the OS ; make sure to implement it in a way that does not waste
+  memory
 
 ### Things to design
 
@@ -121,7 +126,6 @@ running the tests):
     we can always reload them from the disk.
   - An on-disk file with a page cache must be aware of all the places where the page is mapped,
     so that it can unmap it when reclaiming pages.
-  - Simpler model : cached pages cannot be freed while the file is open with `FM_MMAP`
 * Reclaiming physical memory :
   - Freeing some cached stuff, ie swapping pages from mmap regions
   - Swapping pages from processes non-mmap regions (ie real data regions)
@@ -132,6 +136,8 @@ running the tests):
   have the possibility of crashing the system
 * How does a process transmit information (such as environment, arguments, file
   descriptors) to its children ?
+* How do we do stream-like IO on files ? (ie how do we implement the append acces mode
+  and non-position-dependant read/write calls & seek call)
 
 ### Things not sure
 
@@ -147,5 +153,6 @@ running the tests):
 
 None of the source files have a licence header because it's cumbersome. All the
 code and associated documentation found in this repository is released under
-the ISC licence as detailed in the `COPYING` file.
+the ISC licence as detailed in the `COPYING` file. Some parts of the code are very
+directly inspired from examples found on the OSDev wiki, thank you all!
 
diff --git a/src/common/include/proc.h b/src/common/include/proc.h
new file mode 100644
index 0000000..01a6722
--- /dev/null
+++ b/src/common/include/proc.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define PS_LOADING	1
+#define PS_RUNNING  2
+#define PS_DONE		3
+#define PS_FAILURE	4	// exception or segfault or stuff
+#define PS_KILLED	5
+
+typedef struct {
+	int pid;
+	int state;				// one of PS_*
+	int return_code;		// an error code if state == PS_FAILURE
+} proc_status_t;
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/common/include/syscallproto.h b/src/common/include/syscallproto.h
index 7b85a49..518cdb4 100644
--- a/src/common/include/syscallproto.h
+++ b/src/common/include/syscallproto.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <proc.h>
 
 #define SC_MAX		128		// maximum number of syscalls
 
@@ -40,8 +41,9 @@
 #define SC_PROC_EXEC	55		// args: pid, exec_name, exec_name_strlen -- execute binary in process
 #define SC_PROC_STATUS	56		// args: pid, proc_status_t*
 #define SC_PROC_KILL	57		// args: pid, proc_status_t* -- inconditionnally kill child process
-#define SC_PROC_WAIT	58		// args: pid, proc_status_t*
-#define SC_PROC_WAIT_ANY 59		// args: proc_status_t*
+#define SC_PROC_WAIT	58		// args: pid?, block?, proc_status_t*
+
+#define INVALID_PID 0		// do a wait with this PID to wayt for any child
 
 typedef struct {
 	const char* driver;
@@ -71,16 +73,4 @@ typedef struct {
 	int bind_to_pid;		// used only for SC_BIND_SUBFS
 } sc_subfs_args_t;
 
-#define PS_LOADING	1
-#define PS_RUNNING  2
-#define PS_DONE		3
-#define PS_FAILURE	4	// exception or segfault or stuff
-#define PS_KILLED	5
-typedef struct {
-	int pid;
-	int state;				// one of PS_*
-	int return_code;		// an error code if state == PS_FAILURE
-} proc_status_t;
-
-
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/include/process.h b/src/kernel/include/process.h
index 6e287e1..82f1b4d 100644
--- a/src/kernel/include/process.h
+++ b/src/kernel/include/process.h
@@ -18,8 +18,10 @@
 
 #include <mmap.h>
 
+#include <proc.h> 	// common header defining process statuses
+
 #define USERSTACK_ADDR	0xB8000000
-#define USERSTACK_SIZE	0x00020000		// 32 KB
+#define USERSTACK_SIZE	0x00020000		// 32 KB - it is allocated on demand so no worries
 
 typedef struct process process_t;
 
@@ -46,21 +48,40 @@ typedef struct process {
 	hashtbl_t *files;
 	int next_fd;
 
-	thread_t *thread;
+	thread_t *threads;
 	uint64_t last_ran;
 
 	int pid;
 	struct process *parent;
+	struct process *next_child;
+	struct process *children;
 } process_t;
 
 typedef void* proc_entry_t;
 
+//  ---- Process creation, deletion, waiting, etc.
+// Simple semantics : when a process exits, all its ressources are freed immediately
+// except for the process_t that remains attached to the parent process until it does
+// a wait() and acknowleges the process' ending
+// When a process exits, all the children are orphaned and nobody can wait on them anymore,
+// which is a bad thing : a user process must always wait for all its children !
+
 process_t *current_process();
 
 process_t *new_process(process_t *parent);
-// void delete_process(process_t *p);	// TODO define semantics for freeing stuff
 
 bool start_process(process_t *p, proc_entry_t entry);	// maps a region for user stack
+void process_exit(process_t *p, int status, int exit_code);		// exit current process
+
+bool process_new_thread(process_t *p, proc_entry_t entry, void* sp);
+void process_thread_exited(thread_t *t);		// called by threading code when a thread exits
+
+process_t *process_find_child(process_t *p, int pid);
+void process_get_status(process_t *p, proc_status_t *st);
+void process_wait(process_t *p, proc_status_t *st, bool block);	// waits for exit and frees process_t structure 
+void process_wait_any_child(process_t *p, bool block);
+
+//  ---- Process FS namespace & FD set
 
 bool proc_add_fs(process_t *p, fs_t *fs, const char* name);
 fs_t *proc_find_fs(process_t *p, const char* name);
@@ -69,12 +90,14 @@ int proc_add_fd(process_t *p, fs_handle_t *f);		// on error returns 0, nonzero o
 fs_handle_t *proc_read_fd(process_t *p, int fd);
 void proc_close_fd(process_t *p, int fd);
 
+//  ---- Process virtual memory space
+
 bool mmap(process_t *proc, void* addr, size_t size, int mode);		// create empty zone
 bool mmap_file(process_t *proc, fs_handle_t *h, size_t offset, void* addr, size_t size, int mode);
 bool mchmap(process_t *proc, void* addr, int mode);
 bool munmap(process_t *proc, void* addr);
 
-// for syscalls : check that process is authorized to do that
+// for syscalls : check that process is authorized to read/write given addresses
 // (if not, process exits with a segfault)
 void probe_for_read(const void* addr, size_t len);
 void probe_for_write(const void* addr, size_t len);
diff --git a/src/kernel/include/thread.h b/src/kernel/include/thread.h
index 127b0d7..163045d 100644
--- a/src/kernel/include/thread.h
+++ b/src/kernel/include/thread.h
@@ -30,9 +30,10 @@ typedef struct thread {
 	region_info_t *stack_region;
 
 	process_t *proc;
-	isr_handler_t user_ex_handler;	// page fault in kernel memory accessed by user code (violation)
+	isr_handler_t user_ex_handler;	// exception in user code
 
 	struct thread *next_in_queue;
+	struct thread *next_in_proc;
 } thread_t;
 
 typedef void (*entry_t)(void*);
@@ -48,7 +49,7 @@ void exit();
 void usleep(int usecs);
 
 bool resume_thread(thread_t *thread);
-void kill_thread(thread_t *thread);
+void kill_thread(thread_t *thread);		// cannot be called for current thread
 
 // Kernel critical sections
 #define CL_EXCL			3	// No interruptions accepted, context switching not allowed
diff --git a/src/kernel/user/process.c b/src/kernel/user/process.c
index 3f8da08..649c801 100644
--- a/src/kernel/user/process.c
+++ b/src/kernel/user/process.c
@@ -17,6 +17,11 @@ process_t *current_process() {
 	return 0;
 }
 
+typedef struct {
+	proc_entry_t entry;
+	void *sp;
+} setup_data_t;
+
 // ============================== //
 // CREATING AND RUNNING PROCESSES //
 // ============================== //
@@ -39,7 +44,7 @@ process_t *new_process(process_t *parent) {
 
 	proc->last_ran = 0;
 	proc->regions = 0;
-	proc->thread = 0;
+	proc->threads = 0;
 	proc->pid = (next_pid++);
 	proc->parent = parent;
 	proc->next_fd = 1;
@@ -54,13 +59,17 @@ error:
 	return 0;
 }
 
-static void run_user_code(void* entry) {
+static void run_user_code(void* param) {
+	setup_data_t *d = (setup_data_t*)param;
+
 	process_t *proc = current_thread->proc;
 	ASSERT(proc != 0);
 
 	switch_pagedir(proc->pd);
 
-	void* esp = (void*)USERSTACK_ADDR + USERSTACK_SIZE;
+	void* esp = d->sp;
+	proc_entry_t entry = d->entry;
+	free(d);
 
 	asm volatile("				\
 			cli;				\
@@ -86,14 +95,34 @@ bool start_process(process_t *p, void* entry) {
 	bool stack_ok = mmap(p, (void*)USERSTACK_ADDR, USERSTACK_SIZE, MM_READ | MM_WRITE);
 	if (!stack_ok) return false;
 
-	thread_t *th = new_thread(run_user_code, entry);
-	if (th == 0) {
+	bool ok = process_new_thread(p, entry, (void*)USERSTACK_ADDR + USERSTACK_SIZE);
+	if (!ok) {
 		munmap(p, (void*)USERSTACK_ADDR);
 		return false;
 	}
 
+	return true;
+}
+
+bool process_new_thread(process_t *p, proc_entry_t entry, void* sp) {
+	setup_data_t *d = (setup_data_t*)malloc(sizeof(setup_data_t));
+	d->entry = entry;
+	d->sp = sp;
+
+	thread_t *th = new_thread(run_user_code, d);
+	if (th == 0) {
+		return false;
+	}
+
 	th->proc = p;
 	th->user_ex_handler = proc_user_exception;
+
+	{	int st = enter_critical(CL_NOINT);	// it's a bit complicated to use mutexes on process_t (TODO: think)
+
+		th->next_in_proc = p->threads;
+		p->threads = th;
+
+		exit_critical(st);	}
 	
 	resume_thread(th);
 
diff --git a/src/kernel/user/syscall.c b/src/kernel/user/syscall.c
index 3041c6d..009903c 100644
--- a/src/kernel/user/syscall.c
+++ b/src/kernel/user/syscall.c
@@ -319,10 +319,6 @@ static uint32_t proc_wait_sc(sc_args_t args) {
 	return -1; //TODO
 }
 
-static uint32_t proc_wait_any_sc(sc_args_t args) {
-	return -1; //TODO
-}
-
 // ====================== //
 // SYSCALLS SETUP ROUTINE //
 // ====================== //
@@ -365,7 +361,6 @@ void setup_syscall_table() {
 	sc_handlers[SC_PROC_STATUS] = proc_status_sc;
 	sc_handlers[SC_PROC_KILL] = proc_kill_sc;
 	sc_handlers[SC_PROC_WAIT] = proc_wait_sc;
-	sc_handlers[SC_PROC_WAIT_ANY] = proc_wait_any_sc;
 }
 
 void syscall_handler(registers_t *regs) {
diff --git a/src/lib/include/syscall.h b/src/lib/include/syscall.h
index c26a805..ddc0e18 100644
--- a/src/lib/include/syscall.h
+++ b/src/lib/include/syscall.h
@@ -49,7 +49,6 @@ bool bind_fd(pid_t pid, fd_t new_fd, fd_t fd);
 bool proc_exec(pid_t pid, const char* file);
 bool proc_status(pid_t pid, proc_status_t *s);
 bool proc_kill(pid_t pid, proc_status_t *s);
-void proc_wait(pid_t pid, proc_status_t *s);
-void proc_wait_any(proc_status_t *s);
+void proc_wait(pid_t pid, bool wait, proc_status_t *s);
 
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/lib/libkogata/syscall.c b/src/lib/libkogata/syscall.c
index 6f37c47..4b31ab3 100644
--- a/src/lib/libkogata/syscall.c
+++ b/src/lib/libkogata/syscall.c
@@ -153,11 +153,8 @@ bool proc_status(pid_t pid, proc_status_t *s) {
 bool proc_kill(pid_t pid, proc_status_t *s) {
 	return call(SC_PROC_KILL, pid, (uint32_t)s, 0, 0, 0);
 }
-void proc_wait(pid_t pid, proc_status_t *s) {
-	call(SC_PROC_WAIT, pid, (uint32_t)s, 0, 0, 0);
-}
-void proc_wait_any(proc_status_t *s) {
-	call(SC_PROC_WAIT_ANY, (uint32_t)s, 0, 0, 0, 0);
+void proc_wait(pid_t pid, bool block, proc_status_t *s) {
+	call(SC_PROC_WAIT, pid, block, (uint32_t)s, 0, 0);
 }