vm: fix potential null deref

[minix.git] / commands / less / lesskey / lesskey.c

/*      $NetBSD: lesskey.c,v 1.9 2006/10/26 01:33:08 mrg Exp $  */

/*
 * Copyright (C) 1984-2004  Mark Nudelman
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information about less, or for information on how to 
 * contact the author, see the README file.
 */


/*
 *      lesskey [-o output] [input]
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 *
 *      Make a .less file.
 *      If no input file is specified, standard input is used.
 *      If no output file is specified, $HOME/.less is used.
 *
 *      The .less file is used to specify (to "less") user-defined
 *      key bindings.  Basically any sequence of 1 to MAX_CMDLEN
 *      keystrokes may be bound to an existing less function.
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 *
 *      The input file is an ascii file consisting of a 
 *      sequence of lines of the form:
 *              string <whitespace> action [chars] <newline>
 *
 *      "string" is a sequence of command characters which form
 *              the new user-defined command.  The command
 *              characters may be:
 *              1. The actual character itself.
 *              2. A character preceded by ^ to specify a
 *                 control character (e.g. ^X means control-X).
 *              3. A backslash followed by one to three octal digits
 *                 to specify a character by its octal value.
 *              4. A backslash followed by b, e, n, r or t
 *                 to specify \b, ESC, \n, \r or \t, respectively.
 *              5. Any character (other than those mentioned above) preceded 
 *                 by a \ to specify the character itself (characters which
 *                 must be preceded by \ include ^, \, and whitespace.
 *      "action" is the name of a "less" action, from the table below.
 *      "chars" is an optional sequence of characters which is treated
 *              as keyboard input after the command is executed.
 *
 *      Blank lines and lines which start with # are ignored, 
 *      except for the special control lines:
 *              #command        Signals the beginning of the command
 *                              keys section.
 *              #line-edit      Signals the beginning of the line-editing
 *                              keys section.
 *              #env            Signals the beginning of the environment
 *                              variable section.
 *              #stop           Stops command parsing in less;
 *                              causes all default keys to be disabled.
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 *
 *      The output file is a non-ascii file, consisting of a header,
 *      one or more sections, and a trailer.
 *      Each section begins with a section header, a section length word
 *      and the section data.  Normally there are three sections:
 *              CMD_SECTION     Definition of command keys.
 *              EDIT_SECTION    Definition of editing keys.
 *              END_SECTION     A special section header, with no 
 *                              length word or section data.
 *
 *      Section data consists of zero or more byte sequences of the form:
 *              string <0> <action>
 *      or
 *              string <0> <action|A_EXTRA> chars <0>
 *
 *      "string" is the command string.
 *      "<0>" is one null byte.
 *      "<action>" is one byte containing the action code (the A_xxx value).
 *      If action is ORed with A_EXTRA, the action byte is followed
 *              by the null-terminated "chars" string.
 *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 
 */

#include "less.h"
#include "lesskey.h"
#include "cmd.h"

struct cmdname
{
        char *cn_name;
        int cn_action;
};

struct cmdname cmdnames[] = 
{
        { "back-bracket",       A_B_BRACKET },
        { "back-line",          A_B_LINE },
        { "back-line-force",    A_BF_LINE },
        { "back-screen",        A_B_SCREEN },
        { "back-scroll",        A_B_SCROLL },
        { "back-search",        A_B_SEARCH },
        { "back-window",        A_B_WINDOW },
        { "debug",              A_DEBUG },
        { "digit",              A_DIGIT },
        { "display-flag",       A_DISP_OPTION },
        { "display-option",     A_DISP_OPTION },
        { "end",                A_GOEND },
        { "examine",            A_EXAMINE },
        { "first-cmd",          A_FIRSTCMD },
        { "firstcmd",           A_FIRSTCMD },
        { "flush-repaint",      A_FREPAINT },
        { "forw-bracket",       A_F_BRACKET },
        { "forw-forever",       A_F_FOREVER },
        { "forw-line",          A_F_LINE },
        { "forw-line-force",    A_FF_LINE },
        { "forw-screen",        A_F_SCREEN },
        { "forw-screen-force",  A_FF_SCREEN },
        { "forw-scroll",        A_F_SCROLL },
        { "forw-search",        A_F_SEARCH },
        { "forw-window",        A_F_WINDOW },
        { "goto-end",           A_GOEND },
        { "goto-line",          A_GOLINE },
        { "goto-mark",          A_GOMARK },
        { "help",               A_HELP },
        { "index-file",         A_INDEX_FILE },
        { "invalid",            A_UINVALID },
        { "left-scroll",        A_LSHIFT },
        { "next-file",          A_NEXT_FILE },
        { "next-tag",           A_NEXT_TAG },
        { "noaction",           A_NOACTION },
        { "percent",            A_PERCENT },
        { "pipe",               A_PIPE },
        { "prev-file",          A_PREV_FILE },
        { "prev-tag",           A_PREV_TAG },
        { "quit",               A_QUIT },
        { "remove-file",        A_REMOVE_FILE },
        { "repaint",            A_REPAINT },
        { "repaint-flush",      A_FREPAINT },
        { "repeat-search",      A_AGAIN_SEARCH },
        { "repeat-search-all",  A_T_AGAIN_SEARCH },
        { "reverse-search",     A_REVERSE_SEARCH },
        { "reverse-search-all", A_T_REVERSE_SEARCH },
        { "right-scroll",       A_RSHIFT },
        { "set-mark",           A_SETMARK },
        { "shell",              A_SHELL },
        { "status",             A_STAT },
        { "toggle-flag",        A_OPT_TOGGLE },
        { "toggle-option",      A_OPT_TOGGLE },
        { "undo-hilite",        A_UNDO_SEARCH },
        { "version",            A_VERSION },
        { "visual",             A_VISUAL },
        { NULL, 0 }
};

struct cmdname editnames[] = 
{
        { "back-complete",      EC_B_COMPLETE },
        { "backspace",          EC_BACKSPACE },
        { "delete",             EC_DELETE },
        { "down",               EC_DOWN },
        { "end",                EC_END },
        { "expand",             EC_EXPAND },
        { "forw-complete",      EC_F_COMPLETE },
        { "home",               EC_HOME },
        { "insert",             EC_INSERT },
        { "invalid",            EC_UINVALID },
        { "kill-line",          EC_LINEKILL },
        { "left",               EC_LEFT },
        { "literal",            EC_LITERAL },
        { "right",              EC_RIGHT },
        { "up",                 EC_UP },
        { "word-backspace",     EC_W_BACKSPACE },
        { "word-delete",        EC_W_DELETE },
        { "word-left",          EC_W_LEFT },
        { "word-right",         EC_W_RIGHT },
        { NULL, 0 }
};

struct table
{
        struct cmdname *names;
        char *pbuffer;
        char buffer[MAX_USERCMD];
};

struct table cmdtable;
struct table edittable;
struct table vartable;
struct table *currtable = &cmdtable;

char fileheader[] = {
        C0_LESSKEY_MAGIC, 
        C1_LESSKEY_MAGIC, 
        C2_LESSKEY_MAGIC, 
        C3_LESSKEY_MAGIC
};
char filetrailer[] = {
        C0_END_LESSKEY_MAGIC, 
        C1_END_LESSKEY_MAGIC, 
        C2_END_LESSKEY_MAGIC
};
char cmdsection[1] =    { CMD_SECTION };
char editsection[1] =   { EDIT_SECTION };
char varsection[1] =    { VAR_SECTION };
char endsection[1] =    { END_SECTION };

char *infile = NULL;
char *outfile = NULL ;

int linenum;
int errors;

void terror(char *);

extern char version[];

        void
usage()
{
        fprintf(stderr, "usage: lesskey [-o output] [input]\n");
        exit(1);
}

        char *
mkpathname(dirname, filename)
        char *dirname;
        char *filename;
{
        char *pathname;

        pathname = calloc(strlen(dirname) + strlen(filename) + 2, sizeof(char));
        strcpy(pathname, dirname);
        strcat(pathname, PATHNAME_SEP);
        strcat(pathname, filename);
        return (pathname);
}

/*
 * Figure out the name of a default file (in the user's HOME directory).
 */
        char *
homefile(filename)
        char *filename;
{
        char *p;
        char *pathname;

        if ((p = getenv("HOME")) != NULL && *p != '\0')
                pathname = mkpathname(p, filename);
#if OS2
        else if ((p = getenv("INIT")) != NULL && *p != '\0')
                pathname = mkpathname(p, filename);
#endif
        else
        {
                fprintf(stderr, "cannot find $HOME - using current directory\n");
                pathname = mkpathname(".", filename);
        }
        return (pathname);
}

/*
 * Parse command line arguments.
 */
        void
parse_args(argc, argv)
        int argc;
        char **argv;
{
        char *arg;

        outfile = NULL;
        while (--argc > 0)
        {
                arg = *++argv;
                if (arg[0] != '-')
                        /* Arg does not start with "-"; it's not an option. */
                        break;
                if (arg[1] == '\0')
                        /* "-" means standard input. */
                        break;
                if (arg[1] == '-' && arg[2] == '\0')
                {
                        /* "--" means end of options. */
                        argc--;
                        argv++;
                        break;
                }
                switch (arg[1])
                {
                case '-':
                        if (strncmp(arg, "--output", 8) == 0)
                        {
                                if (arg[8] == '\0')
                                        outfile = &arg[8];
                                else if (arg[8] == '=')
                                        outfile = &arg[9];
                                else
                                        usage();
                                goto opt_o;
                        }
                        if (strcmp(arg, "--version") == 0)
                        {
                                goto opt_V;
                        }
                        usage();
                        break;
                case 'o':
                        outfile = &argv[0][2];
                opt_o:
                        if (*outfile == '\0')
                        {
                                if (--argc <= 0)
                                        usage();
                                outfile = *(++argv);
                        }
                        break;
                case 'V':
                opt_V:
                        printf("lesskey  version %s\n", version);
                        exit(0);
                default:
                        usage();
                }
        }
        if (argc > 1)
                usage();
        /*
         * Open the input file, or use DEF_LESSKEYINFILE if none specified.
         */
        if (argc > 0)
                infile = *argv;
        else
                infile = homefile(DEF_LESSKEYINFILE);
}

/*
 * Initialize data structures.
 */
        void
init_tables()
{
        cmdtable.names = cmdnames;
        cmdtable.pbuffer = cmdtable.buffer;

        edittable.names = editnames;
        edittable.pbuffer = edittable.buffer;

        vartable.names = NULL;
        vartable.pbuffer = vartable.buffer;
}

/*
 * Parse one character of a string.
 */
        char *
tstr(pp, xlate)
        char **pp;
        int xlate;
{
        register char *p;
        register char ch;
        register int i;
        static char buf[10];
        static char tstr_control_k[] =
                { SK_SPECIAL_KEY, SK_CONTROL_K, 6, 1, 1, 1, '\0' };

        p = *pp;
        switch (*p)
        {
        case '\\':
                ++p;
                switch (*p)
                {
                case '0': case '1': case '2': case '3':
                case '4': case '5': case '6': case '7':
                        /*
                         * Parse an octal number.
                         */
                        ch = 0;
                        i = 0;
                        do
                                ch = 8*ch + (*p - '0');
                        while (*++p >= '0' && *p <= '7' && ++i < 3);
                        *pp = p;
                        if (xlate && ch == CONTROL('K'))
                                return tstr_control_k;
                        buf[0] = ch;
                        buf[1] = '\0';
                        return (buf);
                case 'b':
                        *pp = p+1;
                        return ("\b");
                case 'e':
                        *pp = p+1;
                        buf[0] = ESC;
                        buf[1] = '\0';
                        return (buf);
                case 'n':
                        *pp = p+1;
                        return ("\n");
                case 'r':
                        *pp = p+1;
                        return ("\r");
                case 't':
                        *pp = p+1;
                        return ("\t");
                case 'k':
                        if (xlate)
                        {
                                switch (*++p)
                                {
                                case 'u': ch = SK_UP_ARROW; break;
                                case 'd': ch = SK_DOWN_ARROW; break;
                                case 'r': ch = SK_RIGHT_ARROW; break;
                                case 'l': ch = SK_LEFT_ARROW; break;
                                case 'U': ch = SK_PAGE_UP; break;
                                case 'D': ch = SK_PAGE_DOWN; break;
                                case 'h': ch = SK_HOME; break;
                                case 'e': ch = SK_END; break;
                                case 'x': ch = SK_DELETE; break;
                                default:
                                        terror("illegal char after \\k");
                                        *pp = p+1;
                                        return ("");
                                }
                                *pp = p+1;
                                buf[0] = SK_SPECIAL_KEY;
                                buf[1] = ch;
                                buf[2] = 6;
                                buf[3] = 1;
                                buf[4] = 1;
                                buf[5] = 1;
                                buf[6] = '\0';
                                return (buf);
                        }
                        /* FALLTHRU */
                default:
                        /*
                         * Backslash followed by any other char 
                         * just means that char.
                         */
                        *pp = p+1;
                        buf[0] = *p;
                        buf[1] = '\0';
                        if (xlate && buf[0] == CONTROL('K'))
                                return tstr_control_k;
                        return (buf);
                }
        case '^':
                /*
                 * Carat means CONTROL.
                 */
                *pp = p+2;
                buf[0] = CONTROL(p[1]);
                buf[1] = '\0';
                if (buf[0] == CONTROL('K'))
                        return tstr_control_k;
                return (buf);
        }
        *pp = p+1;
        buf[0] = *p;
        buf[1] = '\0';
        if (xlate && buf[0] == CONTROL('K'))
                return tstr_control_k;
        return (buf);
}

/*
 * Skip leading spaces in a string.
 */
        public char *
skipsp(s)
        register char *s;
{
        while (*s == ' ' || *s == '\t') 
                s++;
        return (s);
}

/*
 * Skip non-space characters in a string.
 */
        public char *
skipnsp(s)
        register char *s;
{
        while (*s != '\0' && *s != ' ' && *s != '\t')
                s++;
        return (s);
}

/*
 * Clean up an input line:
 * strip off the trailing newline & any trailing # comment.
 */
        char *
clean_line(s)
        char *s;
{
        register int i;

        s = skipsp(s);
        for (i = 0;  s[i] != '\n' && s[i] != '\r' && s[i] != '\0';  i++)
                if (s[i] == '#' && (i == 0 || s[i-1] != '\\'))
                        break;
        s[i] = '\0';
        return (s);
}

/*
 * Add a byte to the output command table.
 */
        void
add_cmd_char(c)
        int c;
{
        if (currtable->pbuffer >= currtable->buffer + MAX_USERCMD)
        {
                terror("too many commands");
                exit(1);
        }
        *(currtable->pbuffer)++ = c;
}

/*
 * Add a string to the output command table.
 */
        void
add_cmd_str(s)
        char *s;
{
        for ( ;  *s != '\0';  s++)
                add_cmd_char(*s);
}

/*
 * See if we have a special "control" line.
 */
        int
control_line(s)
        char *s;
{
#define PREFIX(str,pat) (strncmp(str,pat,strlen(pat)-1) == 0)

        if (PREFIX(s, "#line-edit"))
        {
                currtable = &edittable;
                return (1);
        }
        if (PREFIX(s, "#command"))
        {
                currtable = &cmdtable;
                return (1);
        }
        if (PREFIX(s, "#env"))
        {
                currtable = &vartable;
                return (1);
        }
        if (PREFIX(s, "#stop"))
        {
                add_cmd_char('\0');
                add_cmd_char(A_END_LIST);
                return (1);
        }
        return (0);
}

/*
 * Output some bytes.
 */
        void
fputbytes(fd, buf, len)
        FILE *fd;
        char *buf;
        int len;
{
        while (len-- > 0)
        {
                fwrite(buf, sizeof(char), 1, fd);
                buf++;
        }
}

/*
 * Output an integer, in special KRADIX form.
 */
        void
fputint(fd, val)
        FILE *fd;
        unsigned int val;
{
        char c;

        if (val >= KRADIX*KRADIX)
        {
                fprintf(stderr, "error: integer too big (%d > %d)\n", 
                        val, KRADIX*KRADIX);
                exit(1);
        }
        c = val % KRADIX;
        fwrite(&c, sizeof(char), 1, fd);
        c = val / KRADIX;
        fwrite(&c, sizeof(char), 1, fd);
}

/*
 * Find an action, given the name of the action.
 */
        int
findaction(actname)
        char *actname;
{
        int i;

        for (i = 0;  currtable->names[i].cn_name != NULL;  i++)
                if (strcmp(currtable->names[i].cn_name, actname) == 0)
                        return (currtable->names[i].cn_action);
        terror("unknown action");
        return (A_INVALID);
}

        void
terror(s)
        char *s;
{
        fprintf(stderr, "line %d: %s\n", linenum, s);
        errors++;
}


        void
parse_cmdline(p)
        char *p;
{
        int cmdlen;
        char *actname;
        int action;
        char *s;
        char c;

        /*
         * Parse the command string and store it in the current table.
         */
        cmdlen = 0;
        do
        {
                s = tstr(&p, 1);
                cmdlen += strlen(s);
                if (cmdlen > MAX_CMDLEN)
                        terror("command too long");
                else
                        add_cmd_str(s);
        } while (*p != ' ' && *p != '\t' && *p != '\0');
        /*
         * Terminate the command string with a null byte.
         */
        add_cmd_char('\0');

        /*
         * Skip white space between the command string
         * and the action name.
         * Terminate the action name with a null byte.
         */
        p = skipsp(p);
        if (*p == '\0')
        {
                terror("missing action");
                return;
        }
        actname = p;
        p = skipnsp(p);
        c = *p;
        *p = '\0';

        /*
         * Parse the action name and store it in the current table.
         */
        action = findaction(actname);

        /*
         * See if an extra string follows the action name.
         */
        *p = c;
        p = skipsp(p);
        if (*p == '\0')
        {
                add_cmd_char(action);
        } else
        {
                /*
                 * OR the special value A_EXTRA into the action byte.
                 * Put the extra string after the action byte.
                 */
                add_cmd_char(action | A_EXTRA);
                while (*p != '\0')
                        add_cmd_str(tstr(&p, 0));
                add_cmd_char('\0');
        }
}

        void
parse_varline(p)
        char *p;
{
        char *s;

        do
        {
                s = tstr(&p, 0);
                add_cmd_str(s);
        } while (*p != ' ' && *p != '\t' && *p != '=' && *p != '\0');
        /*
         * Terminate the variable name with a null byte.
         */
        add_cmd_char('\0');

        p = skipsp(p);
        if (*p++ != '=')
        {
                terror("missing =");
                return;
        }

        add_cmd_char(EV_OK|A_EXTRA);

        p = skipsp(p);
        while (*p != '\0')
        {
                s = tstr(&p, 0);
                add_cmd_str(s);
        }
        add_cmd_char('\0');
}

/*
 * Parse a line from the lesskey file.
 */
        void
parse_line(line)
        char *line;
{
        char *p;

        /*
         * See if it is a control line.
         */
        if (control_line(line))
                return;
        /*
         * Skip leading white space.
         * Replace the final newline with a null byte.
         * Ignore blank lines and comments.
         */
        p = clean_line(line);
        if (*p == '\0')
                return;

        if (currtable == &vartable)
                parse_varline(p);
        else
                parse_cmdline(p);
}

        int
main(argc, argv)
        int argc;
        char *argv[];
{
        FILE *desc;
        FILE *out;
        char line[1024];

#ifdef WIN32
        if (getenv("HOME") == NULL)
        {
                /*
                 * If there is no HOME environment variable,
                 * try the concatenation of HOMEDRIVE + HOMEPATH.
                 */
                char *drive = getenv("HOMEDRIVE");
                char *path  = getenv("HOMEPATH");
                if (drive != NULL && path != NULL)
                {
                        char *env = (char *) calloc(strlen(drive) + 
                                        strlen(path) + 6, sizeof(char));
                        strcpy(env, "HOME=");
                        strcat(env, drive);
                        strcat(env, path);
                        putenv(env);
                }
        }
#endif /* WIN32 */

        /*
         * Process command line arguments.
         */
        parse_args(argc, argv);
        init_tables();

        /*
         * Open the input file.
         */
        if (strcmp(infile, "-") == 0)
                desc = stdin;
        else if ((desc = fopen(infile, "r")) == NULL)
        {
#if HAVE_PERROR
                perror(infile);
#else
                fprintf(stderr, "Cannot open %s\n", infile);
#endif
                usage();
        }

        /*
         * Read and parse the input file, one line at a time.
         */
        errors = 0;
        linenum = 0;
        while (fgets(line, sizeof(line), desc) != NULL)
        {
                ++linenum;
                parse_line(line);
        }

        /*
         * Write the output file.
         * If no output file was specified, use "$HOME/.less"
         */
        if (errors > 0)
        {
                fprintf(stderr, "%d errors; no output produced\n", errors);
                exit(1);
        }

        if (outfile == NULL)
                outfile = getenv("LESSKEY");
        if (outfile == NULL)
                outfile = homefile(LESSKEYFILE);
        if ((out = fopen(outfile, "wb")) == NULL)
        {
#if HAVE_PERROR
                perror(outfile);
#else
                fprintf(stderr, "Cannot open %s\n", outfile);
#endif
                exit(1);
        }

        /* File header */
        fputbytes(out, fileheader, sizeof(fileheader));

        /* Command key section */
        fputbytes(out, cmdsection, sizeof(cmdsection));
        fputint(out, cmdtable.pbuffer - cmdtable.buffer);
        fputbytes(out, (char *)cmdtable.buffer, cmdtable.pbuffer-cmdtable.buffer);
        /* Edit key section */
        fputbytes(out, editsection, sizeof(editsection));
        fputint(out, edittable.pbuffer - edittable.buffer);
        fputbytes(out, (char *)edittable.buffer, edittable.pbuffer-edittable.buffer);

        /* Environment variable section */
        fputbytes(out, varsection, sizeof(varsection)); 
        fputint(out, vartable.pbuffer - vartable.buffer);
        fputbytes(out, (char *)vartable.buffer, vartable.pbuffer-vartable.buffer);

        /* File trailer */
        fputbytes(out, endsection, sizeof(endsection));
        fputbytes(out, filetrailer, sizeof(filetrailer));
        return (0);
}