From Lucho: enable interactive re-execution of the SHELL.

git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@795 6ac86273-5f31-0410-b378-82cca8765d1b

kernel/init-mod.h

@@ -152,6 +152,9 @@ VOID ASMCFUNC FAR int2a_handler(void);
 VOID ASMCFUNC FAR int2f_handler(void);
 VOID ASMCFUNC FAR cpm_entry(void);
 
+/* kernel.asm */
+VOID ASMCFUNC FAR init_call_p_0(struct config FAR *Config); /* P_0, actually */
+
 /* main.c */
 VOID ASMCFUNC FreeDOSmain(void);
 BOOL init_device(struct dhdr FAR * dhp, char * cmdLine,

kernel/intr.asm

@@ -89,6 +89,36 @@ segment	HMA_TEXT
 _intr:
 		INTR
 
+;; COUNT ASMCFUNC res_DosExec(COUNT mode, exec_blk * ep, BYTE * lp)
+    global _res_DosExec
+_res_DosExec:        
+        mov ah, 4bh
+        mov bx, sp
+        mov al, [bx+2]
+        push ds
+        pop es
+        mov dx, [bx+6]          ; filename
+        mov bx, [bx+4]          ; exec block
+        int 21h
+        jc short no_exec_error
+        xor ax, ax
+no_exec_error:
+        ret
+
+;; UCOUNT ASMCFUNC res_read(int fd, void *buf, UCOUNT count); 
+    global _res_read
+_res_read: 
+        mov bx, sp
+        mov cx, [bx+6]
+        mov dx, [bx+4]
+        mov bx, [bx+2]
+        mov ah, 3fh
+        int 21h
+        jnc no_read_error
+        mov ax, -1
+no_read_error:
+        ret
+
 segment	INIT_TEXT
 ;
 ;       void init_call_intr(nr, rp)

kernel/kernel.asm

@@ -673,6 +673,10 @@ _swap_indos:
 ; _swap_indos but only if int2a ah=80/81 (critical section start/end)
 ; are called upon entry and exit of the device drivers
 
+                times 96 dw 0x9090 ; Process 0 Stack
+                global  _p_0_tos
+_p_0_tos:
+
 segment DYN_DATA
 
         global _Dyn
@@ -830,6 +834,11 @@ _reloc_call_clk_driver:
 _CharMapSrvc:   jmp 0:_reloc_call_CharMapSrvc
                 call near forceEnableA20
 
+                global _init_call_p_0
+                extern reloc_call_p_0
+_init_call_p_0: jmp  0:reloc_call_p_0
+                call near forceEnableA20
+
 
    global __HMARelocationTableEnd
 __HMARelocationTableEnd:    

kernel/main.c

@@ -336,17 +336,14 @@ STATIC VOID signon()
 
 STATIC void kernel()
 {
-  exec_blk exb;
   CommandTail Cmd;
-  int rc;
 
-  exb.exec.env_seg = DOS_PSP + 8;
   if (master_env[0] == '\0')   /* some shells panic on empty master env. */
     strcpy(master_env, "PATH=.");
-  fmemcpy(MK_FP(exb.exec.env_seg, 0), master_env, sizeof(master_env));
+  fmemcpy(MK_FP(DOS_PSP + 8, 0), master_env, sizeof(master_env));
 
   /* process 0       */
-  /* Execute command.com /P from the drive we just booted from    */
+  /* Execute command.com from the drive we just booted from    */
   memset(Cmd.ctBuffer, 0, sizeof(Cmd.ctBuffer));
   memcpy(Cmd.ctBuffer, Config.cfgInitTail, sizeof(Config.cfgInitTail));
 
@@ -356,7 +353,8 @@ STATIC void kernel()
 
   /* if stepping CONFIG.SYS (F5/F8), tell COMMAND.COM about it */
 
-  if (Cmd.ctCount < sizeof(Cmd.ctBuffer) - 3)
+  /* 3 for string + 2 for "\r\n" */
+  if (Cmd.ctCount < sizeof(Cmd.ctBuffer) - 5)
   {
     char *insertString = NULL;
 
@@ -376,55 +374,16 @@ STATIC void kernel()
       {
         if (*p == ' ' || *p == '\t' || *p == '\r')
         {
-          for (q = &Cmd.ctBuffer[Cmd.ctCount - 1]; q >= p; q--)
+          for (q = &Cmd.ctBuffer[Cmd.ctCount + 1]; q >= p; q--)
             q[3] = q[0];
-
           memcpy(p, insertString, 3);
-
-          Cmd.ctCount += 3;
           break;
         }
       }
+      strcpy(Config.cfgInitTail, Cmd.ctBuffer); /* save buffer */
     }
   }
-
+  init_call_p_0(&Config); /* go execute process 0 (the shell) */
-  exb.exec.cmd_line = (CommandTail FAR *) & Cmd;
-  exb.exec.fcb_1 = exb.exec.fcb_2 = (fcb FAR *) 0xfffffffful;
-  
-#ifdef DEBUG
-  printf("Process 0 starting: %s\n\n", Config.cfgInit);
-#endif
-
-  while ((rc =
-          init_DosExec(Config.cfgP_0_startmode, &exb,
-                       Config.cfgInit)) != SUCCESS)
-  {
-    BYTE *pLine;
-    printf("\nBad or missing Command Interpreter: %d - %s\n", rc,
-           Cmd.ctBuffer);
-    printf
-        ("\nPlease enter the correct location (for example C:\\COMMAND.COM):\n");
-    rc = read(STDIN, Cmd.ctBuffer, sizeof(Cmd.ctBuffer) - 1);
-    Cmd.ctBuffer[rc] = '\0';
-
-    /* Get the string argument that represents the new init pgm     */
-    pLine = GetStringArg(Cmd.ctBuffer, Config.cfgInit);
-
-    /* Now take whatever tail is left and add it on as a single     */
-    /* string.                                                      */
-    strcpy(Cmd.ctBuffer, pLine);
-
-    /* and add a DOS new line just to be safe                       */
-    strcat(Cmd.ctBuffer, "\r\n");
-
-    Cmd.ctCount = rc - (pLine - Cmd.ctBuffer);
-
-#ifdef DEBUG
-    printf("Process 0 starting: %s\n\n", Config.cfgInit);
-#endif
-  }
-  printf("\nSystem shutdown complete\nReboot now.\n");
-  for (;;) ;
 }
 
 /* check for a block device and update  device control block    */

kernel/procsupt.asm

@@ -275,3 +275,22 @@ _spawn_int23:
 ;                cli
 ;                ret
 ;_disable        endp
+
+        extern _p_0_tos,_P_0
+
+; prepare to call process 0 (the shell) from P_0() in C
+
+    global reloc_call_p_0
+reloc_call_p_0:
+        pop ax          ; return address (32-bit, unused)
+        pop ax
+        pop ax          ; fetch parameter 0 (32-bit) from the old stack
+        pop dx
+        mov ds,[cs:_DGROUP_]
+        cli
+        mov ss,[cs:_DGROUP_]
+        mov sp,_p_0_tos ; load the dedicated process 0 stack
+        sti
+        push dx         ; pass parameter 0 onto the new stack
+        push ax
+        call _P_0       ; no return, allow parameter fetch from C

kernel/proto.h

@@ -220,6 +220,10 @@ UBYTE FcbClose(xfcb FAR * lpXfcb);
 void FcbCloseAll(void);
 UBYTE FcbFindFirstNext(xfcb FAR * lpXfcb, BOOL First);
 
+/* intr.asm */
+COUNT ASMCFUNC res_DosExec(COUNT mode, exec_blk * ep, BYTE * lp);
+UCOUNT ASMCFUNC res_read(int fd, void *buf, UCOUNT count);
+
 /* ioctl.c */
 COUNT DosDevIOctl(lregs * r);
 

kernel/task.c

@@ -48,6 +48,13 @@ static BYTE *RcsId =
 
 #define ExeHeader (*(exe_header *)(SecPathName + 0))
 #define TempExeBlock (*(exec_blk *)(SecPathName + sizeof(exe_header)))
+#define Shell (SecPathName + sizeof(exe_header) + sizeof(exec_blk))
+
+#ifdef __TURBOC__ /* this is a Borlandism and doesn't work elsewhere */
+ #if sizeof(SecPathName) < sizeof(exe_header) + sizeof(exec_blk) + NAMEMAX
+  #error No room in SecPathName to be recycled!
+ #endif
+#endif
 
 #define CHUNK 32256
 #define MAXENV 32768u
@@ -792,3 +799,46 @@ COUNT DosExec(COUNT mode, exec_blk FAR * ep, BYTE FAR * lp)
   return rc;
 }
 
+#include "config.h" /* config structure definition */
+
+/* start process 0 (the shell) */
+VOID ASMCFUNC P_0(struct config FAR *Config)
+{
+  BYTE *tailp, *endp;
+  exec_blk exb;
+  UBYTE mode = Config->cfgP_0_startmode;
+
+  /* build exec block and save all parameters here as init part will vanish! */
+  exb.exec.fcb_1 = exb.exec.fcb_2 = (fcb FAR *)-1L;
+  exb.exec.env_seg = DOS_PSP + 8;
+  fstrcpy(Shell, Config->cfgInit);
+  fstrcpy(Shell + strlen(Shell), Config->cfgInitTail); /* join name and tail */
+  endp =  Shell + strlen(Shell);
+
+  for ( ; ; )   /* endless shell load loop - reboot or shut down to exit it! */
+  {
+    BYTE *p;
+    /* if there are no parameters, point to end without "\r\n" */
+    if((tailp = strchr(Shell,'\t')) == NULL &&
+       (tailp = strchr(Shell, ' ')) == NULL)
+        tailp = endp - 2;
+    /* shift tail to right by 2 to make room for '\0', ctCount */
+    for (p = endp - 1; p >= tailp; p--)
+      *(p + 2) = *p;
+    /* terminate name and tail */
+    *tailp =  *(endp + 2) = '\0';
+    /* ctCount: just past '\0' do not count the "\r\n" */
+    exb.exec.cmd_line = (CommandTail *)(tailp + 1);
+    exb.exec.cmd_line->ctCount = endp - tailp - 2;
+#ifdef DEBUG
+    printf("Process 0 starting: %s%s\n\n", Shell, tailp + 2);
+#endif
+    res_DosExec(mode, &exb, Shell);
+    put_string("Bad or missing Command Interpreter: "); /* failure _or_ exit */
+    put_string(Shell);
+    put_string(tailp + 2);
+    put_string(" Enter the full shell command line: ");
+    endp = Shell + res_read(STDIN, Shell, NAMEMAX);
+    *endp = '\0';                             /* terminate string for strchr */
+  }
+}