name_mask.c

[詳解]

/*++
/* NAME
/*  name_mask 3
/* SUMMARY
/*  map names to bit mask
/* SYNOPSIS
/*  #include <name_mask.h>
/*
/*  int name_mask(context, table, names)
/*  const char *context;
/*  const NAME_MASK *table;
/*  const char *names;
/*
/*  long    long_name_mask(context, table, names)
/*  const char *context;
/*  const LONG_NAME_MASK *table;
/*  const char *names;
/*
/*  const char *str_name_mask(context, table, mask)
/*  const char *context;
/*  const NAME_MASK *table;
/*  int mask;
/*
/*  const char *str_long_name_mask(context, table, mask)
/*  const char *context;
/*  const LONG_NAME_MASK *table;
/*  long    mask;
/*
/*  int name_mask_opt(context, table, names, flags)
/*  const char *context;
/*  const NAME_MASK *table;
/*  const char *names;
/*  int flags;
/*
/*  long    long_name_mask_opt(context, table, names, flags)
/*  const char *context;
/*  const LONG_NAME_MASK *table;
/*  const char *names;
/*  int flags;
/*
/*  int name_mask_delim_opt(context, table, names, delim, flags)
/*  const char *context;
/*  const NAME_MASK *table;
/*  const char *names;
/*  const char *delim;
/*  int flags;
/*
/*  long    long_name_mask_delim_opt(context, table, names, delim, flags)
/*  const char *context;
/*  const LONG_NAME_MASK *table;
/*  const char *names;
/*  const char *delim;
/*  int flags;
/*
/*  const char *str_name_mask_opt(buf, context, table, mask, flags)
/*  VSTRING *buf;
/*  const char *context;
/*  const NAME_MASK *table;
/*  int mask;
/*  int flags;
/*
/*  const char *str_long_name_mask_opt(buf, context, table, mask, flags)
/*  VSTRING *buf;
/*  const char *context;
/*  const LONG_NAME_MASK *table;
/*  long    mask;
/*  int flags;
/* DESCRIPTION
/*  name_mask() takes a null-terminated \fItable\fR with (name, mask)
/*  values and computes the bit-wise OR of the masks that correspond
/*  to the names listed in the \fInames\fR argument, separated by
/*  comma and/or whitespace characters. The "long_" version returns
/*  a "long int" bitmask, rather than an "int" bitmask.
/*
/*  str_name_mask() translates a mask into its equlvalent names.
/*  The result is written to a static buffer that is overwritten
/*  upon each call. The "long_" version converts a "long int"
/*  bitmask, rather than an "int" bitmask.
/*
/*  name_mask_opt() and str_name_mask_opt() are extended versions
/*  with additional fine control. name_mask_delim_opt() supports
/*  non-default delimiter characters.
/*
/*  Arguments:
/* .IP buf
/*  Null pointer or pointer to buffer storage.
/* .IP context
/*  What kind of names and
/*  masks are being manipulated, in order to make error messages
/*  more understandable. Typically, this would be the name of a
/*  user-configurable parameter.
/* .IP table
/*  Table with (name, bit mask) pairs.
/* .IP names
/*  A list of names that is to be converted into a bit mask.
/* .IP mask
/*  A bit mask.
/* .IP delim
/*  Delimiter characters to use instead of whitespace and commas.
/* .IP flags
/*  Bit-wise OR of one or more of the following.  Where features
/*  would have conflicting results (e.g., FATAL versus IGNORE),
/*  the feature that takes precedence is described first.
/*
/*  When converting from string to mask, at least one of the
/*  following must be specified: NAME_MASK_FATAL, NAME_MASK_RETURN,
/*  NAME_MASK_WARN or NAME_MASK_IGNORE.
/*
/*  When converting from mask to string, at least one of the
/*  following must be specified: NAME_MASK_NUMBER, NAME_MASK_FATAL,
/*  NAME_MASK_RETURN, NAME_MASK_WARN or NAME_MASK_IGNORE.
/* .RS
/* .IP NAME_MASK_NUMBER
/*  When converting from string to mask, accept hexadecimal
/*  inputs starting with "0x" followed by hexadecimal digits.
/*  Each hexadecimal input may specify multiple bits.  This
/*  feature is ignored for hexadecimal inputs that cannot be
/*  converted (malformed, out of range, etc.).
/*
/*  When converting from mask to string, represent bits not
/*  defined in \fItable\fR as "0x" followed by hexadecimal
/*  digits. This conversion always succeeds.
/* .IP NAME_MASK_FATAL
/*  Require that all names listed in \fIname\fR exist in
/*  \fItable\fR or that they can be parsed as a hexadecimal
/*  string, and require that all bits listed in \fImask\fR exist
/*  in \fItable\fR or that they can be converted to hexadecimal
/*  string.  Terminate with a fatal run-time error if this
/*  condition is not met.  This feature is enabled by default
/*  when calling name_mask() or str_name_mask().
/* .IP NAME_MASK_RETURN
/*  Require that all names listed in \fIname\fR exist in
/*  \fItable\fR or that they can be parsed as a hexadecimal
/*  string, and require that all bits listed in \fImask\fR exist
/*  in \fItable\fR or that they can be converted to hexadecimal
/*  string.  Log a warning, and return 0 (name_mask()) or a
/*  null pointer (str_name_mask()) if this condition is not
/*  met.  This feature is not enabled by default when calling
/*  name_mask() or str_name_mask().
/* .IP NAME_MASK_WARN
/*  Require that all names listed in \fIname\fR exist in
/*  \fItable\fR or that they can be parsed as a hexadecimal
/*  string, and require that all bits listed in \fImask\fR exist
/*  in \fItable\fR or that they can be converted to hexadecimal
/*  string.  Log a warning if this condition is not met, continue
/*  processing, and return all valid bits or names.  This feature
/*  is not enabled by default when calling name_mask() or
/*  str_name_mask().
/* .IP NAME_MASK_IGNORE
/*  Silently ignore names listed in \fIname\fR that don't exist
/*  in \fItable\fR and that can't be parsed as a hexadecimal
/*  string, and silently ignore bits listed in \fImask\fR that
/*  don't exist in \fItable\fR and that can't be converted to
/*  hexadecimal string.
/* .IP NAME_MASK_ANY_CASE
/*  Enable case-insensitive matching.
/*  This feature is not enabled by default when calling name_mask();
/*  it has no effect with str_name_mask().
/* .IP NAME_MASK_COMMA
/*  Use comma instead of space when converting a mask to string.
/* .IP NAME_MASK_PIPE
/*  Use "|" instead of space when converting a mask to string.
/* .RE
/*  The value NAME_MASK_NONE explicitly requests no features,
/*  and NAME_MASK_DEFAULT enables the default options.
/* DIAGNOSTICS
/*  Fatal: the \fInames\fR argument specifies a name not found in
/*  \fItable\fR, or the \fImask\fR specifies a bit not found in
/*  \fItable\fR.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>

#ifdef STRCASECMP_IN_STRINGS_H
#include <strings.h>
#endif

/* Utility library. */

#include <msg.h>
#include <mymalloc.h>
#include <stringops.h>
#include <name_mask.h>
#include <vstring.h>

static int hex_to_ulong(char *, unsigned long, unsigned long *);

#define STR(x) vstring_str(x)

/* name_mask_delim_opt - compute mask corresponding to list of names */

int     name_mask_delim_opt(const char *context, const NAME_MASK *table,
                    const char *names, const char *delim, int flags)
{
    const char *myname = "name_mask";
    char   *saved_names = mystrdup(names);
    char   *bp = saved_names;
    int     result = 0;
    const NAME_MASK *np;
    char   *name;
    int     (*lookup) (const char *, const char *);
    unsigned long ulval;

    if ((flags & NAME_MASK_REQUIRED) == 0)
    msg_panic("%s: missing NAME_MASK_FATAL/RETURN/WARN/IGNORE flag",
          myname);

    if (flags & NAME_MASK_ANY_CASE)
    lookup = strcasecmp;
    else
    lookup = strcmp;

    /*
     * Break up the names string, and look up each component in the table. If
     * the name is found, merge its mask with the result.
     */
    while ((name = mystrtok(&bp, delim)) != 0) {
    for (np = table; /* void */ ; np++) {
        if (np->name == 0) {
        if ((flags & NAME_MASK_NUMBER)
            && hex_to_ulong(name, ~0U, &ulval)) {
            result |= (unsigned int) ulval;
        } else if (flags & NAME_MASK_FATAL) {
            msg_fatal("unknown %s value \"%s\" in \"%s\"",
                  context, name, names);
        } else if (flags & NAME_MASK_RETURN) {
            msg_warn("unknown %s value \"%s\" in \"%s\"",
                 context, name, names);
            myfree(saved_names);
            return (0);
        } else if (flags & NAME_MASK_WARN) {
            msg_warn("unknown %s value \"%s\" in \"%s\"",
                 context, name, names);
        }
        break;
        }
        if (lookup(name, np->name) == 0) {
        if (msg_verbose)
            msg_info("%s: %s", myname, name);
        result |= np->mask;
        break;
        }
    }
    }
    myfree(saved_names);
    return (result);
}

/* str_name_mask_opt - mask to string */

const char *str_name_mask_opt(VSTRING *buf, const char *context,
                          const NAME_MASK *table,
                          int mask, int flags)
{
    const char *myname = "name_mask";
    const NAME_MASK *np;
    ssize_t len;
    static VSTRING *my_buf = 0;
    int     delim = (flags & NAME_MASK_COMMA ? ',' :
             (flags & NAME_MASK_PIPE ? '|' : ' '));

    if ((flags & STR_NAME_MASK_REQUIRED) == 0)
    msg_panic("%s: missing NAME_MASK_NUMBER/FATAL/RETURN/WARN/IGNORE flag",
          myname);

    if (buf == 0) {
    if (my_buf == 0)
        my_buf = vstring_alloc(1);
    buf = my_buf;
    }
    VSTRING_RESET(buf);

    for (np = table; mask != 0; np++) {
    if (np->name == 0) {
        if (flags & NAME_MASK_NUMBER) {
        vstring_sprintf_append(buf, "0x%x%c", mask, delim);
        } else if (flags & NAME_MASK_FATAL) {
        msg_fatal("%s: unknown %s bit in mask: 0x%x",
              myname, context, mask);
        } else if (flags & NAME_MASK_RETURN) {
        msg_warn("%s: unknown %s bit in mask: 0x%x",
             myname, context, mask);
        return (0);
        } else if (flags & NAME_MASK_WARN) {
        msg_warn("%s: unknown %s bit in mask: 0x%x",
             myname, context, mask);
        }
        break;
    }
    if (mask & np->mask) {
        mask &= ~np->mask;
        vstring_sprintf_append(buf, "%s%c", np->name, delim);
    }
    }
    if ((len = VSTRING_LEN(buf)) > 0)
    vstring_truncate(buf, len - 1);
    VSTRING_TERMINATE(buf);

    return (STR(buf));
}

/* long_name_mask_delim_opt - compute mask corresponding to list of names */

long    long_name_mask_delim_opt(const char *context,
                         const LONG_NAME_MASK * table,
                           const char *names, const char *delim,
                         int flags)
{
    const char *myname = "name_mask";
    char   *saved_names = mystrdup(names);
    char   *bp = saved_names;
    long    result = 0;
    const LONG_NAME_MASK *np;
    char   *name;
    int     (*lookup) (const char *, const char *);
    unsigned long ulval;

    if ((flags & NAME_MASK_REQUIRED) == 0)
    msg_panic("%s: missing NAME_MASK_FATAL/RETURN/WARN/IGNORE flag",
          myname);

    if (flags & NAME_MASK_ANY_CASE)
    lookup = strcasecmp;
    else
    lookup = strcmp;

    /*
     * Break up the names string, and look up each component in the table. If
     * the name is found, merge its mask with the result.
     */
    while ((name = mystrtok(&bp, delim)) != 0) {
    for (np = table; /* void */ ; np++) {
        if (np->name == 0) {
        if ((flags & NAME_MASK_NUMBER)
            && hex_to_ulong(name, ~0UL, &ulval)) {
            result |= ulval;
        } else if (flags & NAME_MASK_FATAL) {
            msg_fatal("unknown %s value \"%s\" in \"%s\"",
                  context, name, names);
        } else if (flags & NAME_MASK_RETURN) {
            msg_warn("unknown %s value \"%s\" in \"%s\"",
                 context, name, names);
            myfree(saved_names);
            return (0);
        } else if (flags & NAME_MASK_WARN) {
            msg_warn("unknown %s value \"%s\" in \"%s\"",
                 context, name, names);
        }
        break;
        }
        if (lookup(name, np->name) == 0) {
        if (msg_verbose)
            msg_info("%s: %s", myname, name);
        result |= np->mask;
        break;
        }
    }
    }

    myfree(saved_names);
    return (result);
}

/* str_long_name_mask_opt - mask to string */

const char *str_long_name_mask_opt(VSTRING *buf, const char *context,
                           const LONG_NAME_MASK * table,
                           long mask, int flags)
{
    const char *myname = "name_mask";
    ssize_t len;
    static VSTRING *my_buf = 0;
    int     delim = (flags & NAME_MASK_COMMA ? ',' :
             (flags & NAME_MASK_PIPE ? '|' : ' '));
    const LONG_NAME_MASK *np;

    if ((flags & STR_NAME_MASK_REQUIRED) == 0)
    msg_panic("%s: missing NAME_MASK_NUMBER/FATAL/RETURN/WARN/IGNORE flag",
          myname);

    if (buf == 0) {
    if (my_buf == 0)
        my_buf = vstring_alloc(1);
    buf = my_buf;
    }
    VSTRING_RESET(buf);

    for (np = table; mask != 0; np++) {
    if (np->name == 0) {
        if (flags & NAME_MASK_NUMBER) {
        vstring_sprintf_append(buf, "0x%lx%c", mask, delim);
        } else if (flags & NAME_MASK_FATAL) {
        msg_fatal("%s: unknown %s bit in mask: 0x%lx",
              myname, context, mask);
        } else if (flags & NAME_MASK_RETURN) {
        msg_warn("%s: unknown %s bit in mask: 0x%lx",
             myname, context, mask);
        return (0);
        } else if (flags & NAME_MASK_WARN) {
        msg_warn("%s: unknown %s bit in mask: 0x%lx",
             myname, context, mask);
        }
        break;
    }
    if (mask & np->mask) {
        mask &= ~np->mask;
        vstring_sprintf_append(buf, "%s%c", np->name, delim);
    }
    }
    if ((len = VSTRING_LEN(buf)) > 0)
    vstring_truncate(buf, len - 1);
    VSTRING_TERMINATE(buf);

    return (STR(buf));
}

/* hex_to_ulong - 0x... to unsigned long or smaller */

static int hex_to_ulong(char *value, unsigned long mask, unsigned long *ulp)
{
    unsigned long result;
    char   *cp;

    if (strncasecmp(value, "0x", 2) != 0)
    return (0);

    /*
     * Check for valid hex number. Since the value starts with 0x, strtoul()
     * will not allow a negative sign before the first nibble. So we don't
     * need to worry about explicit +/- signs.
     */
    errno = 0;
    result = strtoul(value, &cp, 16);
    if (*cp != '\0' || errno == ERANGE)
    return (0);

    *ulp = (result & mask);
    return (*ulp == result);
}

#ifdef TEST

 /*
  * Stand-alone test program.
  */
#include <stdlib.h>
#include <vstream.h>
#include <vstring_vstream.h>

int     main(int argc, char **argv)
{
    static const NAME_MASK demo_table[] = {
    "zero", 1 << 0,
    "one", 1 << 1,
    "two", 1 << 2,
    "three", 1 << 3,
    0, 0,
    };
    static const NAME_MASK feature_table[] = {
    "DEFAULT", NAME_MASK_DEFAULT,
    "FATAL", NAME_MASK_FATAL,
    "ANY_CASE", NAME_MASK_ANY_CASE,
    "RETURN", NAME_MASK_RETURN,
    "COMMA", NAME_MASK_COMMA,
    "PIPE", NAME_MASK_PIPE,
    "NUMBER", NAME_MASK_NUMBER,
    "WARN", NAME_MASK_WARN,
    "IGNORE", NAME_MASK_IGNORE,
    0,
    };
    int     in_feature_mask;
    int     out_feature_mask;
    int     demo_mask;
    const char *demo_str;
    VSTRING *out_buf = vstring_alloc(1);
    VSTRING *in_buf = vstring_alloc(1);

    if (argc != 3)
    msg_fatal("usage: %s in-feature-mask out-feature-mask", argv[0]);
    in_feature_mask = name_mask(argv[1], feature_table, argv[1]);
    out_feature_mask = name_mask(argv[2], feature_table, argv[2]);
    while (vstring_get_nonl(in_buf, VSTREAM_IN) != VSTREAM_EOF) {
    demo_mask = name_mask_opt("name", demo_table,
                  STR(in_buf), in_feature_mask);
    demo_str = str_name_mask_opt(out_buf, "mask", demo_table,
                     demo_mask, out_feature_mask);
    vstream_printf("%s -> 0x%x -> %s\n",
               STR(in_buf), demo_mask,
               demo_str ? demo_str : "(null)");
    vstream_fflush(VSTREAM_OUT);
    }
    vstring_free(in_buf);
    vstring_free(out_buf);
    exit(0);
}

#endif