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Fix stream life-time race condition by reversing ownership
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This commit is contained in:
Kamil Kowalczyk
2026-04-30 17:25:21 +02:00
parent 77fa271cca
commit 6a0aeea88a
10 changed files with 52 additions and 36 deletions
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4
ce/edit.c
View File

@@ -233,11 +233,11 @@ void edit_start(const char* volume, const char* file_path, const char* text, siz
(int)(editor.cursor.line - editor.row_offset) + 1,
(int)(editor.cursor.col - editor.col_offset) + 1 + (int)gutter_width);
stream_write(process_get_pgid(), STREAM_OUT, backbuffer, bbptr - backbuffer);
stream_write(process_get_exec_pgid(), STREAM_OUT, backbuffer, bbptr - backbuffer);
uint8_t ch = 0;
for (;;) {
if (stream_read(process_get_pgid(), STREAM_IN, &ch, 1) > 0)
if (stream_read(STREAM_IN, &ch, 1) > 0)
break;
else
sched();

39
ce/interp.c
View File

@@ -188,7 +188,7 @@ static void cat(struct context* context, char** file_paths, size_t files_count)
return;
}
stream_write(process_get_pgid(), STREAM_OUT, buffer, chunk_size);
stream_write(process_get_exec_pgid(), STREAM_OUT, buffer, chunk_size);
}
if (rem > 0) {
@@ -198,7 +198,7 @@ static void cat(struct context* context, char** file_paths, size_t files_count)
return;
}
stream_write(process_get_pgid(), STREAM_OUT, buffer, rem);
stream_write(process_get_exec_pgid(), STREAM_OUT, buffer, rem);
}
filereader_fini(&fr);
@@ -463,25 +463,17 @@ struct cmd_write_proc_ctx {
int cancel_pid;
};
static void cmd_collect_proc(void* arg) {
int pgid = (int)(uintptr_t)arg;
char recv[1024];
int n;
for (;;) {
if ((n = stream_read(pgid, STREAM_OUT, (void*)recv, sizeof(recv) - 1)) > 0)
stream_write(process_get_pgid(), STREAM_OUT, (void*)recv, n);
else
sched();
}
}
struct cmd_collect_proc_ctx {
int pgid;
int collect_pid;
};
static void cmd_write_proc(void* arg) {
struct cmd_write_proc_ctx* ctx = arg;
uint8_t ch = 0;
for (;;) {
if (stream_read(process_get_pgid(), STREAM_IN, &ch, 1) > 0) {
if (stream_read(STREAM_IN, &ch, 1) > 0) {
if (ch == KB_CTRL('C')) {
kill(ctx->cancel_pid);
return;
@@ -494,6 +486,20 @@ static void cmd_write_proc(void* arg) {
}
}
static void cmd_collect_proc(void* arg) {
struct cmd_collect_proc_ctx* ctx = arg;
int n;
char recv[1024];
for (;;) {
if ((n = stream_read(STREAM_OUT, recv, sizeof(recv))) > 0) {
stream_write(process_get_exec_pgid(), STREAM_OUT, recv, n);
} else {
sched();
}
}
}
static void execute_cmd(struct ast_cmd* cmd, struct context* context, bool run_bg) {
if (strcmp(cmd->name, "echo") == 0) {
echo(context, cmd->args, cmd->arg_count);
@@ -576,9 +582,10 @@ static void execute_cmd(struct ast_cmd* cmd, struct context* context, bool run_b
cprintf(context, "started background process: PID %d\n", pid);
} else {
struct cmd_write_proc_ctx wpctx = {.pgid = pgid, .cancel_pid = pid};
struct cmd_collect_proc_ctx cpctx = {.pgid = pgid, .collect_pid = pid};
struct process_data* write_pdata = process_spawn(&cmd_write_proc, (void*)&wpctx);
struct process_data* collect_pdata = process_spawn(&cmd_collect_proc, (void*)(uintptr_t)pgid);
struct process_data* collect_pdata = process_spawn(&cmd_collect_proc, (void*)&cpctx);
exec_partial_fini(pid);
wait_for_pid(pid);

1
include/syscall_defs.h
View File

@@ -41,5 +41,6 @@
#define SYS_VOLUME_DELETE 40
#define SYS_DATE_TIME 41
#define SYS_GET_CMDLINE 42
#define SYS_PROC_IS_ALIVE 43
#endif // _M_SYSCALL_DEFS_H

2
init/init.c
View File

@@ -18,7 +18,7 @@ static void receiver(void* arg) {
char recv[RECV_MAX];
int n;
for (;;) {
n = stream_read(ce_pgid, STREAM_OUT, (void*)recv, RECV_MAX - 1);
n = stream_read(STREAM_OUT, (void*)recv, RECV_MAX - 1);
if (n > 0)
terminal_print(recv, n);

2
kernel/amd64/proc.c
View File

@@ -60,7 +60,7 @@ struct proc* proc_from_elf(uint8_t* elf_contents) {
proc->pdata.regs.rip = aux.entry;
fx_init(proc->pdata.fx_env);
proc->exec_pid = -1;
proc->exec_pid = proc->pid;
return proc;
}

24
kernel/syscall/syscall.c
View File

@@ -770,17 +770,11 @@ DEFINE_SYSCALL(sys_stream_write) {
return SYSRESULT(ST_OK);
}
/* int stream_read (int pgid, int rid, void* buffer, size_t size) */
/* int stream_read (int rid, void* buffer, size_t size) */
DEFINE_SYSCALL(sys_stream_read) {
int pgid = (int)a1;
int rid = (int)a2;
uintptr_t uvaddr_buffer = a3;
size_t buffer_size = (size_t)a4;
struct procgroup* target_procgroup = procgroup_find(pgid);
if (target_procgroup == NULL)
return SYSRESULT(-ST_NOT_FOUND);
int rid = (int)a1;
uintptr_t uvaddr_buffer = a2;
size_t buffer_size = (size_t)a3;
struct procgroup* procgroup = proc->procgroup;
@@ -789,7 +783,7 @@ DEFINE_SYSCALL(sys_stream_read) {
if (buffer == NULL)
return SYSRESULT(-ST_BAD_ADDRESS_SPACE);
struct proc_resource* stream_resource = proc_find_resource(target_procgroup, rid);
struct proc_resource* stream_resource = proc_find_resource(procgroup, rid);
if (stream_resource == NULL)
return SYSRESULT(-ST_NOT_FOUND);
@@ -893,6 +887,13 @@ DEFINE_SYSCALL(sys_get_cmdline) {
return SYSRESULT(procgroup->uvaddr_cmdline);
}
/* int proc_is_alive(int pid) */
DEFINE_SYSCALL(sys_proc_is_alive) {
int pid = (int)a1;
return SYSRESULT(proc_find_pid(pid) != NULL ? 1 : 0);
}
static syscall_handler_func_t handler_table[] = {
[SYS_QUIT] = &sys_quit,
[SYS_TEST] = &sys_test,
@@ -934,6 +935,7 @@ static syscall_handler_func_t handler_table[] = {
[SYS_VOLUME_DELETE] = &sys_volume_delete,
[SYS_DATE_TIME] = &sys_date_time,
[SYS_GET_CMDLINE] = &sys_get_cmdline,
[SYS_PROC_IS_ALIVE] = &sys_proc_is_alive,
};
syscall_handler_func_t syscall_find_handler(int syscall_num) {

2
libu/in_input.c
View File

@@ -46,7 +46,7 @@ void in_stream_read_line(const char* prompt, char* buffer, size_t max) {
for (;;) {
uint8_t ch;
if (stream_read(process_get_pgid(), STREAM_IN, &ch, 1) <= 0) {
if (stream_read(STREAM_IN, &ch, 1) <= 0) {
sched();
continue;
}

3
libu/mprintf.c
View File

@@ -1,3 +1,4 @@
#include <debugconsole.h>
#include <mprintf.h>
#include <printf.h>
#include <process.h>
@@ -32,7 +33,7 @@ void mprintf(const char* fmt, ...) {
va_end(args);
stream_write(process_get_pgid(), STREAM_OUT, mprintf_buffer, len);
stream_write(process_get_exec_pgid(), STREAM_OUT, mprintf_buffer, len);
mprintf_buffer_unlock();
}

6
libu/system.c
View File

@@ -101,8 +101,8 @@ int stream_write(int pgid, int rid, void* buffer, size_t size) {
return (int)do_syscall(SYS_STREAM_WRITE, pgid, rid, buffer, size);
}
int stream_read(int pgid, int rid, void* buffer, size_t size) {
return (int)do_syscall(SYS_STREAM_READ, pgid, rid, buffer, size);
int stream_read(int rid, void* buffer, size_t size) {
return (int)do_syscall(SYS_STREAM_READ, rid, buffer, size);
}
int get_proc_info(struct proc_info* infos, size_t count) {
@@ -122,3 +122,5 @@ int volume_delete(const char* key) { return (int)do_syscall(SYS_VOLUME_DELETE, k
int date_time(struct date_time* dt) { return (int)do_syscall(SYS_DATE_TIME, dt); }
const char* get_cmdline(void) { return (const char*)do_syscall(SYS_GET_CMDLINE, 0); }
int proc_is_alive(int pid) { return (int)do_syscall(SYS_PROC_IS_ALIVE, pid); }

5
libu/system.h
View File

@@ -110,7 +110,7 @@ int get_self_pid(void);
int stream_write(int pgid, int rid, void* buffer, size_t size);
/* Read from a stream */
int stream_read(int pgid, int rid, void* buffer, size_t size);
int stream_read(int rid, void* buffer, size_t size);
/* get process information */
int get_proc_info(struct proc_info* infos, size_t count);
@@ -130,4 +130,7 @@ int date_time(struct date_time* dt);
/* Get commandline string */
const char* get_cmdline(void);
/* check if PID is alive */
int proc_is_alive(int pid);
#endif // _LIBMSL_M_SYSTEM_H