if.c

完整的Bell实验室的嵌入式文件系统TFS

/* if.c:
 *  This file started off as the file for the "if" command in the monitor,
 *  and has since grown into the file that contains the commands that only
 *  make sense if they are used in scripts; hence, a prerequisite to these
 *  commands is that TFS is included in the build.
 *  It also contains the script runner portion of TFS.  The name of this
 *  file should have been changed to tfsscript.c!
 *  
 *  if:
 *  Supports the monitor's ability to do conditional branching within
 *  scripts executed through TFS.
 *
 *  goto:
 *  Tag based jumping in a script.
 *
 *  item:
 *  A simple way to process a list (similar to KSH's 'for' construct).
 *
 *  General notice:
 *  This code is part of a boot-monitor package developed as a generic base
 *  platform for embedded system designs.  As such, it is likely to be
 *  distributed to various projects beyond the control of the original
 *  author.  Please notify the author of any enhancements made or bugs found
 *  so that all may benefit from the changes.  In addition, notification back
 *  to the author will allow the new user to pick up changes that may have
 *  been made by other users after this version of the code was distributed.
 *
 *  Note1: the majority of this code was edited with 4-space tabs.
 *  Note2: as more and more contributions are accepted, the term "author"
 *         is becoming a mis-representation of credit.
 *
 *  Original author:    Ed Sutter
 *  Email:              [e-mail]
 *  Phone:              908-582-2351
 */
#include "config.h"
#include "genlib.h"
#include "stddefs.h"
#include "tfs.h"
#include "tfsprivate.h"
#include "ether.h"
#include "cli.h"

#if INCLUDE_TFSSCRIPT

#define MAXGOSUBDEPTH   15
static long ReturnToTbl[MAXGOSUBDEPTH+1];
static int  ReturnToDepth, ReturnToTfd, ScriptIsRunning;
static char *ScriptGotoTag;
int ScriptExitFlag;

/* If:
 *  A simple test/action statement.
 *  Currently, the only action supported is "goto tag". 
 *  Syntax:
 *      if ARG1 compar ARG2 {action} [else action]
 *      if -t TEST {action} [else action]
 */
char *IfHelp[] = {
    "Conditional branching",
    "-[t:v] [{arg1} {compar} {arg2}] {action} [else action]",
    " Numeric/logic compare:",
    "  gt lt le ge eq ne and or xor",
    " String compare:",
    "  seq sne",
    " Other tests (-t args):",
    "  gc, ngc, iscmp {filename}",
    " Action:",
    " goto tag | gosub tag | exit | return",
    0,
};

int
If(int argc, char *argv[])
{
    int     opt, arg, true, if_else, offset, verbose;
    void    (*iffunc)(), (*elsefunc)();
    long    var1, var2;
    char    *testtype, *arg1, *arg2, *iftag, *elsetag;

    verbose = 0;
    testtype = 0;
    while((opt=getopt(argc,argv,"vt:")) != -1) {
        switch(opt) {
        case 'v':
            verbose = 1;
            break;
        case 't':
            testtype = optarg;
            break;
        default:
            return(CMD_PARAM_ERROR);
        }
    }

    elsetag = 0;
    elsefunc = 0;
    offset = true = if_else = 0;

    /* First see if there is an 'else' present... */
    for (arg=optind;arg<argc;arg++) {
        if (!strcmp(argv[arg],"else")) {
            if_else = 1;
            break;
        }
    }

    if (if_else) {
        elsetag = argv[argc-1];
        if (!strcmp(argv[argc-1],"exit")) {
            offset = 2;
            elsefunc = exitscript;
        }
        else if (!strcmp(argv[argc-1],"return")) {
            offset = 2;
            elsefunc = gosubret;
        }
        else if (!strcmp(argv[argc-2],"goto")) {
            offset = 3;
            elsefunc = gototag;
        }
        else if (!strcmp(argv[argc-2],"gosub")) {
            offset = 3;
            elsefunc = gosubtag;
        }
        else
            return(CMD_PARAM_ERROR);
    }
    
    iftag = argv[argc-offset-1];
    if (!strcmp(argv[argc-offset-1],"exit"))
        iffunc = exitscript;
    else if (!strcmp(argv[argc-offset-1],"return"))
        iffunc = gosubret;
    else if (!strcmp(argv[argc-offset-2],"goto"))
        iffunc = gototag;
    else if (!strcmp(argv[argc-offset-2],"gosub"))
        iffunc = gosubtag;
    else
        return(CMD_PARAM_ERROR);

    if (testtype) {
        if (!strcmp(testtype,"gc")) {
            if (gotachar())
                true=1;
        }
        else if (!strcmp(testtype,"ngc")) {
            if (!gotachar())
                true=1;
        }
        else if (!strcmp(testtype,"iscmp")) {
            TFILE *tfp;

            tfp = tfsstat(argv[optind]);
            if (tfp) {
                if (TFS_ISCPRS(tfp))
                    true=1;
            }
            else
                printf("'%s' not found\n",argv[optind]);
        }
        else
            return(CMD_PARAM_ERROR);
    }
    else {
        arg1 = argv[optind];
        testtype = argv[optind+1];
        arg2 = argv[optind+2];

        var1 = strtoul(arg1,(char **)0,0);
        var2 = strtoul(arg2,(char **)0,0);

        if (!strcmp(testtype,"gt")) {
            if (var1 > var2)
                true = 1;
        }
        else if (!strcmp(testtype,"lt")) {
            if (var1 < var2)
                true = 1;
        }
        else if (!strcmp(testtype,"le")) {
            if (var1 <= var2)
                true = 1;
        }
        else if (!strcmp(testtype,"ge")) {
            if (var1 >= var2)
                true = 1;
        }
        else if (!strcmp(testtype,"eq")) {
            if (var1 == var2)
                true = 1;
        }
        else if (!strcmp(testtype,"ne")) {
            if (var1 != var2)
                true = 1;
        }
        else if (!strcmp(testtype,"and")) {
            if (var1 & var2)
                true = 1;
        }
        else if (!strcmp(testtype,"xor")) {
            if (var1 ^ var2)
                true = 1;
        }
        else if (!strcmp(testtype,"or")) {
            if (var1 | var2)
                true = 1;
        }
        else if (!strcmp(testtype,"seq")) {
            if (!strcmp(arg1,arg2))
                true = 1;
        }
        else if (!strcmp(testtype,"sne")) {
            if (strcmp(arg1,arg2))
                true = 1;
        }
        else
            return(CMD_PARAM_ERROR);
    }
    
    /* If the true flag is set, call the 'if' function.
     * If the true flag is clear, and "else" was found on the command
     * line, then call the 'else' function...
     */
    if (true) {
        if (verbose)
            printf("TRUE\n");
        iffunc(iftag);
    }
    else {
        if (verbose)
            printf("FALSE\n");
        if (if_else)
            elsefunc(elsetag);
    }

    return(CMD_SUCCESS);
}

int
InAScript(void)
{
    if (ScriptIsRunning)
        return(1);
    else {
        printf("Invalid from outside a script\n");
        return(0);
    }
}

void
exitscript(char *ignored)
{
    if (InAScript()) {
        ScriptExitFlag = EXIT_SCRIPT;
    }
}


char *ExitHelp[] = {
    "Exit a script",
    "-[r]",
    "Options:",
    " -r   remove script after exit",
    0,
};

int
Exit(int argc, char *argv[])
{
    ScriptExitFlag = EXIT_SCRIPT;
    if ((argc == 2) && (!strcmp(argv[1],"-r")))
        ScriptExitFlag |= REMOVE_SCRIPT;
    return(CMD_SUCCESS);
}

char *GotoHelp[] = {
    "Branch to file tag",
    "{tagname}",
    0,
};

int
Goto(int argc, char *argv[])
{
    if (argc != 2)
        return(CMD_PARAM_ERROR);
    gototag(argv[1]);
    return(CMD_SUCCESS);
}


char *GosubHelp[] = {
    "Call a subroutine",
    "{tagname}",
    0,
};

int
Gosub(int argc, char *argv[])
{
    if (argc != 2)
        return(CMD_PARAM_ERROR);
    gosubtag(argv[1]);
    return(CMD_SUCCESS);
}

char *ReturnHelp[] = {
    "Return from subroutine",
    "",
    0,
};

int
Return(int argc, char *argv[])
{
    if (argc != 1)
        return(CMD_PARAM_ERROR);
    gosubret(0);
    return(CMD_SUCCESS);
}

/* Item:
 *  This is a simple replacement for the KSH "for" construct...
 *  It allows the user to build a list of strings and retrieve one at a time.