Implement wait and exec.

2 files changed, 190 insertions, 5 deletions

diff --git a/src/kernel/user/process.c b/src/kernel/user/process.c
index 973e9d8..2812fc6 100644
--- a/src/kernel/user/process.c
+++ b/src/kernel/user/process.c
@@ -239,7 +239,8 @@ void process_exit(process_t *p, int status, int exit_code) {
 	// notify parent
 	process_t *par = p->parent;
 	if (par->status == PS_RUNNING) {
-		// TODO: notify that child is exited
+		resume_on(par->children);
+		resume_on(p);
 	}
 
 	mutex_unlock(&p->lock);
@@ -286,7 +287,127 @@ process_t *process_find_child(process_t *p, int pid) {
 	mutex_unlock(&p->lock);
 
 	return ret;
+}
+
+void process_get_status(process_t *p, proc_status_t *st) {
+	st->pid = p->pid;
+	st->status = p->status;
+	st->exit_code = p->exit_code;
+}
+
+void process_wait(process_t *p, proc_status_t *st, bool wait) {
+	// This is such a mess...
+
+	process_t *par = p->parent;
+
+	st->pid = 0;
+	st->status = 0;
+
+	mutex_lock(&par->lock);
+
+	while (true) {
+		// problem : p may not be in parent's children list anymore,
+		// meaning the associated process_t* has been deleted
+		bool found = false;
+		for (process_t *it = par->children; it != 0; it = it->next_child) {
+			if (it == p) {
+				found = true;
+				break;
+			}
+		}
+
+		if (found) {
+			if (p->status != PS_LOADING && p->status != PS_RUNNING) {
+				process_get_status(p, st);
+
+				if (par->children == p) {
+					par->children = p->next_child;
+				} else {
+					for (process_t *it = par->children; it->next_child != 0; it = it->next_child) {
+						if (it->next_child == p) {
+							it->next_child = p->next_child;
+							break;
+						}
+					}
+				}
+
+				free(p);
+			} else if (wait) {
+				bool wait_ok;
+
+				{	int st = enter_critical(CL_NOSWITCH);
+		
+					mutex_unlock(&par->lock);
+					wait_ok = wait_on(p);
+
+					exit_critical(st);	}
+				
+				if (!wait_ok) return;
+
+				mutex_lock(&par->lock);
+				continue;	// loop around
+			}
+		}
+		break;
+	}
+
+	mutex_unlock(&par->lock);
+}
+
+void process_wait_any_child(process_t *par, proc_status_t *st, bool wait) {
+	st->pid = 0;
+	st->status = 0;
+
+	mutex_lock(&par->lock);
+
+	while (true) {
+		// problem : p may not be in parent's children list anymore,
+		// meaning the associated process_t* has been deleted
+		process_t *p = 0;
+
+		for (process_t *it = par->children; it != 0; it = it->next_child) {
+			if (it->status != PS_LOADING && it->status != PS_RUNNING) {
+				p = it;
+				break;
+			}
+		}
+
+		if (p) {
+			process_get_status(p, st);
+
+			if (par->children == p) {
+				par->children = p->next_child;
+			} else {
+				for (process_t *it = par->children; it->next_child != 0; it = it->next_child) {
+					if (it->next_child == p) {
+						it->next_child = p->next_child;
+						break;
+					}
+				}
+			}
+
+			free(p);
+		} else {
+			if (wait) {
+				bool wait_ok;
+				
+				{	int st = enter_critical(CL_NOSWITCH);
+
+					mutex_unlock(&par->lock);
+					wait_ok = wait_on(par);
+
+					exit_critical(st);	}
+				
+				if (!wait_ok) return;
+
+				mutex_lock(&par->lock);
+				continue;	// loop around
+			}
+		}
+		break;
+	}
 
+	mutex_unlock(&par->lock);
 }
 
 
diff --git a/src/kernel/user/syscall.c b/src/kernel/user/syscall.c
index fe9b4fe..04144d4 100644
--- a/src/kernel/user/syscall.c
+++ b/src/kernel/user/syscall.c
@@ -1,6 +1,7 @@
 #include <string.h>
 #include <process.h>
 #include <vfs.h>
+#include <elf.h>
 
 #include <sct.h>
 
@@ -456,19 +457,82 @@ end_bind_fd:
 }
 
 static uint32_t proc_exec_sc(sc_args_t args) {
-	return -1; //TODO
+	bool ok = false;
+
+	process_t *p = 0;
+	char* exec_name = 0;
+	fs_handle_t *h = 0;
+	
+	p = process_find_child(current_process(), args.a);
+	if (p == 0) goto end_exec;
+
+	exec_name = sc_copy_string_x(args.b, args.c);
+	if (exec_name == 0) goto end_exec;
+
+	char* sep = strchr(exec_name, ':');
+	if (sep == 0) goto end_exec;
+
+	*sep = 0;
+	char* file = sep + 1;
+
+	fs_t *fs = proc_find_fs(current_process(), exec_name);
+	if (fs == 0) goto end_exec;
+
+	h = fs_open(fs, file, FM_READ | FM_MMAP);
+	if (h == 0) h = fs_open(fs, file, FM_READ);
+	if (h == 0) goto end_exec;
+
+	proc_entry_t *entry = elf_load(h, p);
+	if (entry == 0) goto end_exec;
+
+	ok = start_process(p, entry);
+
+end_exec:
+	if (exec_name) free(exec_name);
+	if (h) unref_file(h);
+	return ok;
 }
 
 static uint32_t proc_status_sc(sc_args_t args) {
-	return -1; //TODO
+	proc_status_t *st = (proc_status_t*)args.b;
+	probe_for_write(st, sizeof(proc_status_t));
+
+	process_t *p = process_find_child(current_process(), args.a);
+	if (p == 0) return false;
+
+	process_get_status(p, st);
+	return true;
 }
 
 static uint32_t proc_kill_sc(sc_args_t args) {
-	return -1; //TODO
+	proc_status_t *st = (proc_status_t*)args.b;
+	probe_for_write(st, sizeof(proc_status_t));
+
+	process_t *p = process_find_child(current_process(), args.a);
+	if (p == 0) return false;
+
+	process_exit(p, PS_KILLED, 0);
+	process_wait(p, st, true);		// (should return immediately)
+
+	return true;
 }
 
 static uint32_t proc_wait_sc(sc_args_t args) {
-	return -1; //TODO
+	proc_status_t *st = (proc_status_t*)args.c;
+	probe_for_write(st, sizeof(proc_status_t));
+
+	bool wait = (args.b != 0);
+
+	if (args.a == 0) {
+		process_wait_any_child(current_process(), st, wait);
+		return true;
+	} else {
+		process_t *p = process_find_child(current_process(), args.a);
+		if (p == 0) return false;
+
+		process_wait(p, st, wait);
+		return true;
+	}
 }
 
 // ====================== //