Add scram(2).

kernel/include/sortix/kernel/syscall.h

@@ -134,6 +134,7 @@ ssize_t sys_readv(int, const struct iovec*, int);
 ssize_t sys_recv(int, void*, size_t, int);
 ssize_t sys_recvmsg(int, struct msghdr*, int);
 int sys_renameat(int, const char*, int, const char*);
+void sys_scram(int, const void*);
 int sys_sched_yield(void);
 ssize_t sys_send(int, const void*, size_t, int);
 ssize_t sys_sendmsg(int, const struct msghdr*, int);

kernel/include/sortix/syscall.h

@@ -180,6 +180,14 @@
 #define SYSCALL_CLOSEFROM 152
 #define SYSCALL_RESERVED1 153
 #define SYSCALL_PSCTL 154
-#define SYSCALL_MAX_NUM 155 /* index of highest constant + 1 */
+#define SYSCALL_RESERVED2 155
+#define SYSCALL_RESERVED3 156
+#define SYSCALL_RESERVED4 157
+#define SYSCALL_RESERVED5 158
+#define SYSCALL_RESERVED6 159
+#define SYSCALL_RESERVED7 160
+#define SYSCALL_RESERVED8 161
+#define SYSCALL_SCRAM 162
+#define SYSCALL_MAX_NUM 163 /* index of highest constant + 1 */
 
 #endif

kernel/process.cpp

@@ -29,6 +29,7 @@
 #include <errno.h>
 #include <limits.h>
 #include <msr.h>
+#include <scram.h>
 #include <signal.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -1643,4 +1644,93 @@ mode_t sys_getumask(void)
 	return process->umask;
 }
 
+static void GetAssertInfo(struct scram_assert* info,
+                          const void* user_info_ptr)
+{
+	memset(info, 0, sizeof(*info));
+	struct scram_assert user_info;
+	if ( !CopyFromUser(&user_info, user_info_ptr, sizeof(user_info)) )
+		return;
+	info->filename = GetStringFromUser(user_info.filename);
+	info->line = user_info.line;
+	info->function = GetStringFromUser(user_info.function);
+	info->expression = GetStringFromUser(user_info.expression);
+}
+
+static void FreeAssertInfo(struct scram_assert* info)
+{
+	delete[] (char*) info->filename;
+	delete[] (char*) info->function;
+	delete[] (char*) info->expression;
+}
+
+static
+void GetUndefinedBehaviorInfo(struct scram_undefined_behavior* info,
+                              const void* user_info_ptr)
+{
+	memset(info, 0, sizeof(*info));
+	struct scram_undefined_behavior user_info;
+	if ( !CopyFromUser(&user_info, user_info_ptr, sizeof(user_info)) )
+		return;
+	info->filename = GetStringFromUser(user_info.filename);
+	info->line = user_info.line;
+	info->column = user_info.column;
+	info->violation = GetStringFromUser(user_info.violation);
+}
+
+static void FreeUndefinedBehaviorInfo(struct scram_undefined_behavior* info)
+{
+	delete[] info->filename;
+	delete[] info->violation;
+}
+
+__attribute__((noreturn))
+void sys_scram(int event, const void* user_info)
+{
+	Process* process = CurrentProcess();
+	// TODO: Prohibit execve such that program_image_path is protected.
+	process->ExitThroughSignal(SIGABRT);
+	if ( event == SCRAM_ASSERT )
+	{
+		struct scram_assert info;
+		GetAssertInfo(&info, user_info);
+		Log::PrintF("%s[%ji]: Assertion failure: %s:%lu: %s: %s\n",
+			process->program_image_path,
+			(intmax_t) process->pid,
+			info.filename ? info.filename : "<unknown>",
+			info.line,
+			info.function ? info.function : "<unknown>",
+			info.expression ? info.expression : "<unknown>");
+		FreeAssertInfo(&info);
+	}
+	else if ( event == SCRAM_STACK_SMASH )
+	{
+		Log::PrintF("%s[%ji]: Stack smashing detected\n",
+			process->program_image_path,
+			(intmax_t) process->pid);
+	}
+	else if ( event == SCRAM_UNDEFINED_BEHAVIOR )
+	{
+		struct scram_undefined_behavior info;
+		GetUndefinedBehaviorInfo(&info, user_info);
+		Log::PrintF("%s[%ji]: Undefined behavior: %s at %s:%lu:%lu\n",
+			process->program_image_path,
+			(intmax_t) process->pid,
+			info.violation ? info.violation : "<unknown>",
+			info.filename ? info.filename : "<unknown>",
+			info.line,
+			info.column);
+		FreeUndefinedBehaviorInfo(&info);
+	}
+	else
+	{
+		Log::PrintF("%s[%ji]: Unknown scram event %i\n",
+			process->program_image_path,
+			(intmax_t) process->pid,
+			event);
+	}
+	// TODO: Allow debugging this event.
+	kthread_exit();
+}
+
 } // namespace Sortix

kernel/syscall.cpp

@@ -190,6 +190,14 @@ void* syscall_list[SYSCALL_MAX_NUM + 1] =
 	[SYSCALL_CLOSEFROM] = (void*) sys_closefrom,
 	[SYSCALL_RESERVED1] = (void*) sys_bad_syscall,
 	[SYSCALL_PSCTL] = (void*) sys_psctl,
+	[SYSCALL_RESERVED2] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED3] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED4] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED5] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED6] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED7] = (void*) sys_bad_syscall,
+	[SYSCALL_RESERVED8] = (void*) sys_bad_syscall,
+	[SYSCALL_SCRAM] = (void*) sys_scram,
 	[SYSCALL_MAX_NUM] = (void*) sys_bad_syscall,
 };
 } /* extern "C" */

libc/Makefile

@@ -401,6 +401,7 @@ pwd/getpwuid_r.o \
 pwd/openpw.o \
 pwd/setpwent.o \
 sched/sched_yield.o \
+scram/scram.o \
 signal/kill.o \
 signal/killpg.o \
 signal/psiginfo.o \

libc/assert/__assert.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
+    Copyright(C) Jonas 'Sortie' Termansen 2012, 2013, 2015.
 
     This file is part of the Sortix C Library.
 
@@ -23,12 +23,9 @@
 *******************************************************************************/
 
 #include <assert.h>
-#include <stdint.h>
+#include <scram.h>
-#include <stdio.h>
-#include <stdlib.h>
 
 #if defined(__is_sortix_kernel)
-#include <sortix/kernel/decl.h>
 #include <sortix/kernel/panic.h>
 #endif
 
@@ -42,8 +39,11 @@ void __assert(const char* filename,
 	Sortix::PanicF("Assertion failure: %s:%lu: %s: %s", filename, line,
 	               function_name, expression);
 #else
-	fprintf(stderr, "Assertion failure: %s:%lu: %s: %s\n", filename, line,
+	struct scram_assert info;
-	        function_name, expression);
+	info.filename = filename;
-	abort();
+	info.line = line;
+	info.function = function_name;
+	info.expression = expression;
+	scram(SCRAM_ASSERT, &info);
 #endif
 }

libc/include/scram.h

@@ -0,0 +1,61 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    scram.h
+    Emergency process shutdown.
+
+*******************************************************************************/
+
+#ifndef _SCRAM_H
+#define _SCRAM_H
+
+#include <sys/cdefs.h>
+
+#define SCRAM_ASSERT 1
+#define SCRAM_STACK_SMASH 2
+#define SCRAM_UNDEFINED_BEHAVIOR 3
+
+struct scram_assert
+{
+	const char* filename;
+	unsigned long line;
+	const char* function;
+	const char* expression;
+};
+
+struct scram_undefined_behavior
+{
+	const char* filename;
+	unsigned long line;
+	unsigned long column;
+	const char* violation;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+__attribute__((noreturn))
+void scram(int, const void*);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif

libc/scram/scram.cpp

@@ -0,0 +1,35 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    scram/scram.cpp
+    Emergency process shutdown.
+
+*******************************************************************************/
+
+#include <sys/syscall.h>
+
+#include <scram.h>
+
+DEFN_SYSCALL2(void, sys_scram, SYSCALL_SCRAM, int, const void*);
+
+extern "C" void scram(int event, const void* info)
+{
+	sys_scram(event, info);
+	__builtin_unreachable();
+}

libc/stdlib/realpath.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2013.
+    Copyright(C) Jonas 'Sortie' Termansen 2013, 2015.
 
     This file is part of the Sortix C Library.
 
@@ -25,34 +25,30 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
+#include <scram.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
+#ifdef PATH_MAX
+#error "This realpath implementation assumes no PATH_MAX"
+#endif
+
 extern "C"
 char* realpath(const char* restrict path, char* restrict resolved_path)
 {
+	if ( resolved_path )
+	{
+		struct scram_undefined_behavior info;
+		info.filename = __FILE__;
+		info.line = __LINE__;
+		info.column = 0;
+		info.violation = "realpath call with non-null argument and PATH_MAX unset";
+		scram(SCRAM_UNDEFINED_BEHAVIOR, &info);
+	}
 	char* ret_path = canonicalize_file_name(path);
 	if ( !ret_path )
 		return NULL;
-	if ( !resolved_path )
+	return ret_path;
-		return ret_path;
-#ifdef PATH_MAX
-	if ( PATH_MAX < strlen(ret_path) + 1 )
-		return errno = ENAMETOOLONG, (char*) NULL;
-	strcpy(resolved_path, ret_path);
-	free(ret_path);
-	return resolved_path;
-#else
-	if ( !isatty(2) )
-		dup2(open("/dev/tty", O_WRONLY), 2);
-	fprintf(stderr, "%s:%u: %s(\"%s\", %p) = \"%s\": "
-	        "This platform doesn't have PATH_MAX and the second argument "
-	        "wasn't NULL - You cannot reliably allocate a sufficiently large "
-	        "buffer and the POSIX standard specifies this as undefined "
-	        "behavior, aborting.\n", __FILE__, __LINE__, __func__, path,
-	        resolved_path, ret_path);
-	abort();
-#endif
 }