mech_krb5/profile/prof_parse.c

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#include "prof_int.h"

#include <stdio.h>
#include <string.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <errno.h>
#include <ctype.h>

#define SECTION_SEP_CHAR '/'

#define STATE_INIT_COMMENT  1
#define STATE_STD_LINE      2
#define STATE_GET_OBRACE    3

struct parse_state {
    int state;
    int group_level;
    struct profile_node *root_section;
    struct profile_node *current_section;
};

static char *skip_over_blanks(char *cp)
{
    while (*cp && isspace((int) (*cp)))
        cp++;
    return cp;
}

static void strip_line(char *line)
{
    char *p = line + strlen(line);
    while (p > line && (p[-1] == '\n' || p[-1] == '\r'))
        *p-- = 0;
}

static void parse_quoted_string(char *str)
{
    char *to, *from;

    to = from = str;

    for (to = from = str; *from && *from != '"'; to++, from++) {
        if (*from == '\\') {
            from++;
            switch (*from) {
            case 'n':
                *to = '\n';
                break;
            case 't':
                *to = '\t';
                break;
            case 'b':
                *to = '\b';
                break;
            default:
                *to = *from;
            }
            continue;
        }
        *to = *from;
    }
    *to = '\0';
}


static errcode_t parse_init_state(struct parse_state *state)
{
    state->state = STATE_INIT_COMMENT;
    state->group_level = 0;

    return profile_create_node("(root)", 0, &state->root_section);
}

static errcode_t parse_std_line(char *line, struct parse_state *state)
{
    char    *cp, ch, *tag, *value;
    char    *p;
    errcode_t retval;
    struct profile_node *node;
    int do_subsection = 0;
    void *iter = 0;

    if (*line == 0)
        return 0;
    cp = skip_over_blanks(line);
    if (cp[0] == ';' || cp[0] == '#')
        return 0;
    strip_line(cp);
    ch = *cp;
    if (ch == 0)
        return 0;
    if (ch == '[') {
        if (state->group_level > 0)
            return PROF_SECTION_NOTOP;
        cp++;
        p = strchr(cp, ']');
        if (p == NULL)
            return PROF_SECTION_SYNTAX;
        *p = '\0';
        retval = profile_find_node_subsection(state->root_section,
                         cp, &iter, 0,
                         &state->current_section);
        if (retval == PROF_NO_SECTION) {
            retval = profile_add_node(state->root_section,
                          cp, 0,
                          &state->current_section);
            if (retval)
                return retval;
        } else if (retval)
            return retval;

        /*
         * Finish off the rest of the line.
         */
        cp = p+1;
        if (*cp == '*') {
            profile_make_node_final(state->current_section);
            cp++;
        }
        /*
         * A space after ']' should not be fatal
         */
        cp = skip_over_blanks(cp);
        if (*cp)
            return PROF_SECTION_SYNTAX;
        return 0;
    }
    if (ch == '}') {
        if (state->group_level == 0)
            return PROF_EXTRA_CBRACE;
        if (*(cp+1) == '*')
            profile_make_node_final(state->current_section);
        retval = profile_get_node_parent(state->current_section,
                         &state->current_section);
        if (retval)
            return retval;
        state->group_level--;
        return 0;
    }
    /*
     * Parse the relations
     */
    tag = cp;
    cp = strchr(cp, '=');
    if (!cp)
        return PROF_RELATION_SYNTAX;
    if (cp == tag)
        return PROF_RELATION_SYNTAX;
    *cp = '\0';
    p = tag;
    /* Look for whitespace on left-hand side.  */
    while (p < cp && !isspace((int)*p))
        p++;
    if (p < cp) {
        /* Found some sort of whitespace.  */
        *p++ = 0;
        /* If we have more non-whitespace, it's an error.  */
        while (p < cp) {
        if (!isspace((int)*p))
            return PROF_RELATION_SYNTAX;
        p++;
        }
    }
    cp = skip_over_blanks(cp+1);
    value = cp;
    if (value[0] == '"') {
        value++;
        parse_quoted_string(value);
    } else if (value[0] == 0) {
        do_subsection++;
        state->state = STATE_GET_OBRACE;
    } else if (value[0] == '{' && *(skip_over_blanks(value+1)) == 0)
        do_subsection++;
    else {
        cp = value + strlen(value) - 1;
        while ((cp > value) && isspace((int) (*cp)))
            *cp-- = 0;
    }
    if (do_subsection) {
        p = strchr(tag, '*');
        if (p)
            *p = '\0';
        retval = profile_add_node(state->current_section,
                      tag, 0, &state->current_section);
        if (retval)
            return retval;
        if (p)
            profile_make_node_final(state->current_section);
        state->group_level++;
        return 0;
    }
    p = strchr(tag, '*');
    if (p)
        *p = '\0';
    profile_add_node(state->current_section, tag, value, &node);
    if (p)
        profile_make_node_final(node);
    return 0;
}

static errcode_t parse_line(char *line, struct parse_state *state)
{
    char    *cp;

    switch (state->state) {
    case STATE_INIT_COMMENT:
        if (line[0] != '[')
            return 0;
        state->state = STATE_STD_LINE;
        /*FALLTHRU*/
    case STATE_STD_LINE:
        return parse_std_line(line, state);
    case STATE_GET_OBRACE:
        cp = skip_over_blanks(line);
        if (*cp != '{')
            return PROF_MISSING_OBRACE;
        state->state = STATE_STD_LINE;
        /*FALLTHRU*/
    }
    return 0;
}

errcode_t profile_parse_file(FILE *f, struct profile_node **root)
{
#define BUF_SIZE    2048
    char *bptr;
    errcode_t retval;
    struct parse_state state;

    bptr = malloc (BUF_SIZE);
    if (!bptr)
        return ENOMEM;

    retval = parse_init_state(&state);
    if (retval) {
        free (bptr);
        return retval;
    }
    while (!feof(f)) {
        if (fgets(bptr, BUF_SIZE, f) == NULL)
            break;
#ifndef PROFILE_SUPPORTS_FOREIGN_NEWLINES
        retval = parse_line(bptr, &state);
        if (retval) {
            /* Solaris Kerberos: check if an unconfigured file */
            if (strstr(bptr, "___"))
                retval = PROF_NO_PROFILE;
            free (bptr);
            return retval;
        }
#else
        {
            char *p, *end;

            if (strlen(bptr) >= BUF_SIZE - 1) {
            /* The string may have foreign newlines and
               gotten chopped off on a non-newline
               boundary.  Seek backwards to the last known
               newline.  */
            long offset;
            char *c = bptr + strlen (bptr);
            for (offset = 0; offset > -BUF_SIZE; offset--) {
                if (*c == '\r' || *c == '\n') {
                *c = '\0';
                fseek (f, offset, SEEK_CUR);
                break;
                }
                c--;
            }
            }

            /* First change all newlines to \n */
            for (p = bptr; *p != '\0'; p++) {
            if (*p == '\r')
                            *p = '\n';
            }
            /* Then parse all lines */
            p = bptr;
            end = bptr + strlen (bptr);
            while (p < end) {
            char* newline;
            char* newp;

            newline = strchr (p, '\n');
            if (newline != NULL)
                *newline = '\0';

            /* parse_line modifies contents of p */
            newp = p + strlen (p) + 1;
            retval = parse_line (p, &state);
            if (retval) {
                free (bptr);
                return retval;
            }

            p = newp;
            }
        }
#endif
    }
    *root = state.root_section;

    free (bptr);
    return 0;
}

/*
 * Return TRUE if the string begins or ends with whitespace
 */
static int need_double_quotes(char *str)
{
    if (!str)
                return 0;
    if (str[0] == '\0')
        return 1;
    if (isspace((int) (*str)) ||isspace((int) (*(str + strlen(str) - 1))))
        return 1;
    if (strchr(str, '\n') || strchr(str, '\t') || strchr(str, '\b'))
        return 1;
    return 0;
}

/*
 * Output a string with double quotes, doing appropriate backquoting
 * of characters as necessary.
 */
static void output_quoted_string(char *str, void (*cb)(const char *,void *),
                 void *data)
{
    char    ch;
    char buf[2];

    cb("\"", data);
    if (!str) {
        cb("\"", data);
        return;
    }
    buf[1] = 0;
    while ((ch = *str++)) {
        switch (ch) {
        case '\\':
            cb("\\\\", data);
            break;
        case '\n':
            cb("\\n", data);
            break;
        case '\t':
            cb("\\t", data);
            break;
        case '\b':
            cb("\\b", data);
            break;
        default:
            /* This would be a lot faster if we scanned
               forward for the next "interesting"
               character.  */
            buf[0] = ch;
            cb(buf, data);
            break;
        }
    }
    cb("\"", data);
}


#if defined(_WIN32)
#define EOL "\r\n"
#endif

#ifndef EOL
#define EOL "\n"
#endif

/* Errors should be returned, not ignored!  */
static void dump_profile(struct profile_node *root, int level,
             void (*cb)(const char *, void *), void *data)
{
    int i;
    struct profile_node *p;
    void *iter;
    long retval;
    char *name, *value;

    iter = 0;
    do {
        retval = profile_find_node_relation(root, 0, &iter,
                            &name, &value);
        if (retval)
            break;
        for (i=0; i < level; i++)
            cb("\t", data);
        if (need_double_quotes(value)) {
            cb(name, data);
            cb(" = ", data);
            output_quoted_string(value, cb, data);
            cb(EOL, data);
        } else {
            cb(name, data);
            cb(" = ", data);
            cb(value, data);
            cb(EOL, data);
        }
    } while (iter != 0);

    iter = 0;
    do {
        retval = profile_find_node_subsection(root, 0, &iter,
                              &name, &p);
        if (retval)
            break;
        if (level == 0) { /* [xxx] */
            cb("[", data);
            cb(name, data);
            cb("]", data);
            cb(profile_is_node_final(p) ? "*" : "", data);
            cb(EOL, data);
            dump_profile(p, level+1, cb, data);
            cb(EOL, data);
        } else {    /* xxx = { ... } */
            for (i=0; i < level; i++)
                cb("\t", data);
            cb(name, data);
            cb(" = {", data);
            cb(EOL, data);
            dump_profile(p, level+1, cb, data);
            for (i=0; i < level; i++)
                cb("\t", data);
            cb("}", data);
            cb(profile_is_node_final(p) ? "*" : "", data);
            cb(EOL, data);
        }
    } while (iter != 0);
}

static void dump_profile_to_file_cb(const char *str, void *data)
{
    fputs(str, data);
}

errcode_t profile_write_tree_file(struct profile_node *root, FILE *dstfile)
{
    dump_profile(root, 0, dump_profile_to_file_cb, dstfile);
    return 0;
}

struct prof_buf {
    char *base;
    size_t cur, max;
    int err;
};

static void add_data_to_buffer(struct prof_buf *b, const void *d, size_t len)
{
    if (b->err)
        return;
    if (b->max - b->cur < len) {
        size_t newsize;
        char *newptr;

        newsize = b->max + (b->max >> 1) + len + 1024;
        newptr = realloc(b->base, newsize);
        if (newptr == NULL) {
            b->err = 1;
            return;
        }
        b->base = newptr;
        b->max = newsize;
    }
    memcpy(b->base + b->cur, d, len);
    b->cur += len;      /* ignore overflow */
}

static void dump_profile_to_buffer_cb(const char *str, void *data)
{
    add_data_to_buffer((struct prof_buf *)data, str, strlen(str));
}

errcode_t profile_write_tree_to_buffer(struct profile_node *root,
                       char **buf)
{
    struct prof_buf prof_buf = { 0, 0, 0, 0 };

    dump_profile(root, 0, dump_profile_to_buffer_cb, &prof_buf);
    if (prof_buf.err) {
        *buf = NULL;
        return ENOMEM;
    }
    add_data_to_buffer(&prof_buf, "", 1); /* append nul */
    if (prof_buf.max - prof_buf.cur > (prof_buf.max >> 3)) {
        char *newptr = realloc(prof_buf.base, prof_buf.cur);
        if (newptr)
            prof_buf.base = newptr;
    }
    *buf = prof_buf.base;
    return 0;
}