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-rw-r--r--arch/um/os-Linux/skas/process.c122
1 files changed, 74 insertions, 48 deletions
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 1f39f2bf7ce9..5c088a55396c 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -34,6 +34,7 @@
#include "process.h"
#include "longjmp.h"
#include "kern_constants.h"
+#include "as-layout.h"
int is_skas_winch(int pid, int fd, void *data)
{
@@ -60,37 +61,42 @@ static int ptrace_dump_regs(int pid)
return 0;
}
-void wait_stub_done(int pid, int sig, char * fname)
+/*
+ * Signals that are OK to receive in the stub - we'll just continue it.
+ * SIGWINCH will happen when UML is inside a detached screen.
+ */
+#define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
+
+/* Signals that the stub will finish with - anything else is an error */
+#define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
+
+void wait_stub_done(int pid)
{
int n, status, err;
- do {
- if ( sig != -1 ) {
- err = ptrace(PTRACE_CONT, pid, 0, sig);
- if(err)
- panic("%s : continue failed, errno = %d\n",
- fname, errno);
- }
- sig = 0;
-
+ while(1){
CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
- } while((n >= 0) && WIFSTOPPED(status) &&
- ((WSTOPSIG(status) == SIGVTALRM) ||
- /* running UML inside a detached screen can cause
- * SIGWINCHes
- */
- (WSTOPSIG(status) == SIGWINCH)));
-
- if((n < 0) || !WIFSTOPPED(status) ||
- (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
- err = ptrace_dump_regs(pid);
+ if((n < 0) || !WIFSTOPPED(status))
+ goto bad_wait;
+
+ if(((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
+ break;
+
+ err = ptrace(PTRACE_CONT, pid, 0, 0);
if(err)
- printk("Failed to get registers from stub, "
- "errno = %d\n", -err);
- panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
- "pid = %d, n = %d, errno = %d, status = 0x%x\n",
- fname, pid, n, errno, status);
+ panic("wait_stub_done : continue failed, errno = %d\n",
+ errno);
}
+
+ if(((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
+ return;
+
+bad_wait:
+ err = ptrace_dump_regs(pid);
+ if(err)
+ printk("Failed to get registers from stub, errno = %d\n", -err);
+ panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
+ "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
}
extern unsigned long current_stub_stack(void);
@@ -112,7 +118,11 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi)
sizeof(struct ptrace_faultinfo));
}
else {
- wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
+ err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
+ if(err)
+ panic("Failed to continue stub, pid = %d, errno = %d\n",
+ pid, errno);
+ wait_stub_done(pid);
/* faultinfo is prepared by the stub-segv-handler at start of
* the stub stack page. We just have to copy it.
@@ -304,10 +314,13 @@ void userspace(union uml_pt_regs *regs)
UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
if(WIFSTOPPED(status)){
- switch(WSTOPSIG(status)){
+ int sig = WSTOPSIG(status);
+ switch(sig){
case SIGSEGV:
- if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
- user_signal(SIGSEGV, regs, pid);
+ if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo){
+ get_skas_faultinfo(pid, &regs->skas.faultinfo);
+ (*sig_info[SIGSEGV])(SIGSEGV, regs);
+ }
else handle_segv(pid, regs);
break;
case SIGTRAP + 0x80:
@@ -322,11 +335,13 @@ void userspace(union uml_pt_regs *regs)
case SIGBUS:
case SIGFPE:
case SIGWINCH:
- user_signal(WSTOPSIG(status), regs, pid);
+ block_signals();
+ (*sig_info[sig])(sig, regs);
+ unblock_signals();
break;
default:
printk("userspace - child stopped with signal "
- "%d\n", WSTOPSIG(status));
+ "%d\n", sig);
}
pid = userspace_pid[0];
interrupt_end();
@@ -338,11 +353,29 @@ void userspace(union uml_pt_regs *regs)
}
}
+static unsigned long thread_regs[MAX_REG_NR];
+static unsigned long thread_fp_regs[HOST_FP_SIZE];
+
+static int __init init_thread_regs(void)
+{
+ get_safe_registers(thread_regs, thread_fp_regs);
+ /* Set parent's instruction pointer to start of clone-stub */
+ thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+ (unsigned long) stub_clone_handler -
+ (unsigned long) &__syscall_stub_start;
+ thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
+ sizeof(void *);
+#ifdef __SIGNAL_FRAMESIZE
+ thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
+#endif
+ return 0;
+}
+
+__initcall(init_thread_regs);
+
int copy_context_skas0(unsigned long new_stack, int pid)
{
int err;
- unsigned long regs[MAX_REG_NR];
- unsigned long fp_regs[HOST_FP_SIZE];
unsigned long current_stack = current_stub_stack();
struct stub_data *data = (struct stub_data *) current_stack;
struct stub_data *child_data = (struct stub_data *) new_stack;
@@ -357,23 +390,12 @@ int copy_context_skas0(unsigned long new_stack, int pid)
.timer = ((struct itimerval)
{ { 0, 1000000 / hz() },
{ 0, 1000000 / hz() }})});
- get_safe_registers(regs, fp_regs);
-
- /* Set parent's instruction pointer to start of clone-stub */
- regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
- (unsigned long) stub_clone_handler -
- (unsigned long) &__syscall_stub_start;
- regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
- sizeof(void *);
-#ifdef __SIGNAL_FRAMESIZE
- regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
-#endif
- err = ptrace_setregs(pid, regs);
+ err = ptrace_setregs(pid, thread_regs);
if(err < 0)
panic("copy_context_skas0 : PTRACE_SETREGS failed, "
"pid = %d, errno = %d\n", pid, -err);
- err = ptrace_setfpregs(pid, fp_regs);
+ err = ptrace_setfpregs(pid, thread_fp_regs);
if(err < 0)
panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
"pid = %d, errno = %d\n", pid, -err);
@@ -384,7 +406,11 @@ int copy_context_skas0(unsigned long new_stack, int pid)
/* Wait, until parent has finished its work: read child's pid from
* parent's stack, and check, if bad result.
*/
- wait_stub_done(pid, 0, "copy_context_skas0");
+ err = ptrace(PTRACE_CONT, pid, 0, 0);
+ if(err)
+ panic("Failed to continue new process, pid = %d, "
+ "errno = %d\n", pid, errno);
+ wait_stub_done(pid);
pid = data->err;
if(pid < 0)
@@ -394,7 +420,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
/* Wait, until child has finished too: read child's result from
* child's stack and check it.
*/
- wait_stub_done(pid, -1, "copy_context_skas0");
+ wait_stub_done(pid);
if (child_data->err != UML_CONFIG_STUB_DATA)
panic("copy_context_skas0 - stub-child reports error %ld\n",
child_data->err);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.