Renamed rfork(2) to sfork(2) to avoid compatibility issues.

sfork is much like rfork except sharing is default for everything.

Eventually, I'll make a rfork(3) wrapper function around sfork(2) to
provide compatibility to BSD programs.

I don't like Linux clone(2): that's some messy function.

libmaxsi/include/unistd.h

@@ -32,14 +32,6 @@
 #include <sortix/seek.h>
 #include <sortix/unistd.h>
 
-/* BSD compatibility: The problem with RFMEM is that isn't default to share, but
-   default to make a copy. However, Sortix rforks wants to make sharing default
-   and forking only happens if you ask for it. The Sortix RFFMEM extension
-   reverses this logic. */
-#if defined(RFMEM) && !defined(_BSD_SOURCE) && !defined(_WANT_RFMEM)
-#undef RFMEM
-#endif
-
 #define _SORTIX_ALWAYS_SBRK
 
 __BEGIN_DECLS
@@ -190,7 +182,7 @@ size_t pwriteall(int fd, const void* buf, size_t count, off_t off);
 size_t pwriteleast(int fd, const void* buf, size_t least, size_t max, off_t off);
 size_t readall(int fd, void* buf, size_t count);
 size_t readleast(int fd, void* buf, size_t least, size_t max);
-pid_t rfork(int flags);
+pid_t sfork(int flags);
 int uptime(uintmax_t* usecssinceboot);
 size_t writeall(int fd, const void* buf, size_t count);
 size_t writeleast(int fd, const void* buf, size_t least, size_t max);

libmaxsi/process.cpp

@@ -35,7 +35,7 @@ namespace Maxsi
 		DEFN_SYSCALL1_VOID(SysExit, SYSCALL_EXIT, int);
 		DEFN_SYSCALL3(int, SysExecVE, SYSCALL_EXEC, const char*, char* const*, char* const*);
 		DEFN_SYSCALL0(pid_t, SysFork, SYSCALL_FORK);
-		DEFN_SYSCALL1(pid_t, SysRFork, SYSCALL_RFORK, int);
+		DEFN_SYSCALL1(pid_t, SysSFork, SYSCALL_SFORK, int);
 		DEFN_SYSCALL0(pid_t, SysGetPID, SYSCALL_GETPID);
 		DEFN_SYSCALL0(pid_t, SysGetParentPID, SYSCALL_GETPPID);
 		DEFN_SYSCALL3(pid_t, SysWait, SYSCALL_WAIT, pid_t, int*, int);
@@ -76,9 +76,9 @@ namespace Maxsi
 			return SysFork();
 		}
 
-		extern "C" int rfork(int flags)
+		extern "C" pid_t sfork(int flags)
 		{
-			return SysRFork(flags);
+			return SysSFork(flags);
 		}
 
 		DUAL_FUNCTION(pid_t, getpid, GetPID, ())

sortix/include/sortix/syscallnum.h

@@ -74,7 +74,7 @@
 #define SYSCALL_KERNELINFO 48
 #define SYSCALL_PREAD 49
 #define SYSCALL_PWRITE 50
-#define SYSCALL_RFORK 51
+#define SYSCALL_SFORK 51
 #define SYSCALL_MAX_NUM 52 /* index of highest constant + 1 */
 
 #endif

sortix/include/sortix/unistd.h

@@ -34,16 +34,37 @@ __BEGIN_DECLS
 #define X_OK 1 /* Test for execute permission. */
 #define F_OK 0 /* Test for existence. */
 
-#define RFCLONE (1<<0) /* Creates child, otherwise affect current process. */
-#define RFPID (1<<1) /* Allocates new PID. */
-#define RFFDG (1<<2) /* Fork file descriptor table. */
-#define RFMEM (1<<3) /* Shares address space. */
-#define RFFMEM (1<<4) /* Forks address space. */
-#define RFCWD (1<<5) /* Forks current directory pointer. */
-#define RFNS (1<<6) /* Forks namespace. */
+/* The sfork system call is much like the rfork system call found in Plan 9 and
+   BSD systems, however it works slightly differently and was renamed to avoid
+   conflicts with existing programs. In particular, it never forks an item
+   unless its bit is set, whereas rfork sometimes forks an item by default. If
+   you wish to fork certain items simply set the proper flags. Note that since
+   flags may be added from time to time, you should use various compound flags
+   defined below such as SFFORK and SFALL. It can be useful do combine these
+   compount flags with bitoperations, for instance "I want traditional fork,
+   except share the working dir pointer" is sfork(SFFORK & ~SFCWD). */
+#define SFPROC (1<<0) /* Creates child, otherwise affect current process. */
+#define SFPID (1<<1) /* Allocates new PID. */
+#define SFFD (1<<2) /* Fork file descriptor table. */
+#define SFMEM (1<<3) /* Forks address space. */
+#define SFCWD (1<<4) /* Forks current directory pointer. */
+#define SFROOT (1<<5) /* Forks root directory pointer. */
+#define SFNAME (1<<6) /* Forks namespace. */
+#define SFSIG (1<<7) /* Forks signal table. */
+#define SFCSIG (1<<8) /* Child will have no pending signals, like fork(2). */
 
-#define RFPROC (RFCLONE | RFPID | RFFMEM | RFCWD) /* Create new process. */
-#define RFFORK (RFPROC | RFFDG) /* Traditional fork(2) behavior. */
+/* Provides traditional fork(2) behavior; use this instead of the above values
+   if you want "as fork(2), but also fork foo", or "as fork(2), except bar". In
+   those cases it is better to sfork(SFFORK & ~SFFOO); or sfork(SFFORK | SFBAR);
+   as that would allow to add new flags to SFFORK if a new kernel feature is
+   added to the system that applications don't know about yet. */
+#define SFFORK (SFPROC | SFPID | SFFD | SFMEM | SFCWD | SFROOT | SFCSIG)
+
+/* This allows creating a process that is completely forked from the original
+   process, unlike SFFORK which does share a few things (such as the process
+   namespace). Note that there is a few unset high bits in this value, these
+   are reserved and must not be set. */
+#define SFALL ((1<<20)-1)
 
 __END_DECLS
 

sortix/process.cpp

@@ -432,10 +432,10 @@ namespace Sortix
 		return SysExevVEStage2(state);
 	}
 
-	pid_t SysRFork(int flags)
+	pid_t SysSFork(int flags)
 	{
-		// TODO: Properly support rfork(2).
-		if ( flags != RFFORK ) { Error::Set(ENOSYS); return -1; }
+		// TODO: Properly support sfork(2).
+		if ( flags != SFFORK ) { Error::Set(ENOSYS); return -1; }
 
 		// Prepare the state of the clone.
 		Syscall::SyscallRegs()->result = 0;
@@ -449,7 +449,7 @@ namespace Sortix
 
 	pid_t SysFork()
 	{
-		return SysRFork(RFFORK);
+		return SysSFork(SFFORK);
 	}
 
 	pid_t SysGetPID()
@@ -755,7 +755,7 @@ namespace Sortix
 	{
 		Syscall::Register(SYSCALL_EXEC, (void*) SysExecVE);
 		Syscall::Register(SYSCALL_FORK, (void*) SysFork);
-		Syscall::Register(SYSCALL_RFORK, (void*) SysRFork);
+		Syscall::Register(SYSCALL_SFORK, (void*) SysSFork);
 		Syscall::Register(SYSCALL_GETPID, (void*) SysGetPID);
 		Syscall::Register(SYSCALL_GETPPID, (void*) SysGetParentPID);
 		Syscall::Register(SYSCALL_EXIT, (void*) SysExit);