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gnupg2/common/recsel.c

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/* recsel.c - Record selection
* Copyright (C) 2014, 2016 Werner Koch
*
* This file is part of GnuPG.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either
*
* - the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* or
*
* - the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* or both in parallel, as here.
*
* This file is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include "util.h"
#include "recsel.h"
/* Select operators. */
typedef enum
{
SELECT_SAME,
SELECT_SUB,
SELECT_NONEMPTY,
SELECT_ISTRUE,
SELECT_EQ, /* Numerically equal. */
SELECT_LE,
SELECT_GE,
SELECT_LT,
SELECT_GT,
SELECT_STRLE, /* String is less or equal. */
SELECT_STRGE,
SELECT_STRLT,
SELECT_STRGT
} select_op_t;
/* Definition for a select expression. */
struct recsel_expr_s
{
recsel_expr_t next;
select_op_t op; /* Operation code. */
unsigned int not:1; /* Negate operators. */
unsigned int disjun:1;/* Start of a disjunction. */
unsigned int xcase:1; /* String match is case sensitive. */
const char *value; /* (Points into NAME.) */
long numvalue; /* strtol of VALUE. */
char name[1]; /* Name of the property. */
};
/* Helper */
static inline gpg_error_t
my_error_from_syserror (void)
{
return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
}
/* Helper */
static inline gpg_error_t
my_error (gpg_err_code_t ec)
{
return gpg_err_make (default_errsource, ec);
}
/* This is a case-sensitive version of our memistr. I wonder why no
* standard function memstr exists but I better do not use the name
* memstr to avoid future conflicts.
*
* FIXME: Move this to a stringhelp.c
*/
static const char *
my_memstr (const void *buffer, size_t buflen, const char *sub)
{
const unsigned char *buf = buffer;
const unsigned char *t = (const unsigned char *)buf;
const unsigned char *s = (const unsigned char *)sub;
size_t n = buflen;
for ( ; n ; t++, n-- )
{
if (*t == *s)
{
for (buf = t++, buflen = n--, s++; n && *t ==*s; t++, s++, n--)
;
if (!*s)
return (const char*)buf;
t = (const unsigned char *)buf;
s = (const unsigned char *)sub ;
n = buflen;
}
}
return NULL;
}
/* Return a pointer to the next logical connection operator or NULL if
* none. */
static char *
find_next_lc (char *string)
{
char *p1, *p2;
p1 = strchr (string, '&');
if (p1 && p1[1] != '&')
p1 = NULL;
p2 = strchr (string, '|');
if (p2 && p2[1] != '|')
p2 = NULL;
if (p1 && !p2)
return p1;
if (!p1)
return p2;
return p1 < p2 ? p1 : p2;
}
/* Parse an expression. The expression syntax is:
*
* [<lc>] {{<flag>} PROPNAME <op> VALUE [<lc>]}
*
* A [] indicates an optional part, a {} a repetition. PROPNAME and
* VALUE may not be the empty string. White space between the
* elements is ignored. Numerical values are computed as long int;
* standard C notation applies. <lc> is the logical connection
* operator; either "&&" for a conjunction or "||" for a disjunction.
* A conjunction is assumed at the begin of an expression and
* conjunctions have higher precedence than disjunctions. If VALUE
* starts with one of the characters used in any <op> a space after
* the <op> is required. A VALUE is terminated by an <lc> unless the
* "--" <flag> is used in which case the VALUE spans to the end of the
* expression. <op> may be any of
*
* =~ Substring must match
* !~ Substring must not match
* = The full string must match
* <> The full string must not match
* == The numerical value must match
* != The numerical value must not match
* <= The numerical value of the field must be LE than the value.
* < The numerical value of the field must be LT than the value.
* >= The numerical value of the field must be GT than the value.
* >= The numerical value of the field must be GE than the value.
* -n True if value is not empty (no VALUE parameter allowed).
* -z True if value is empty (no VALUE parameter allowed).
* -t Alias for "PROPNAME != 0" (no VALUE parameter allowed).
* -f Alias for "PROPNAME == 0" (no VALUE parameter allowed).
*
* Values for <flag> must be space separated and any of:
*
* -- VALUE spans to the end of the expression.
* -c The string match in this part is done case-sensitive.
*
* For example four calls to recsel_parse_expr() with these values for
* EXPR
*
* "uid =~ Alfa"
* "&& uid !~ Test"
* "|| uid =~ Alpha"
* "uid !~ Test"
*
* or the equivalent expression
*
* "uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"
*
* are making a selector for records where the "uid" property contains
* the strings "Alfa" or "Alpha" but not the String "test".
*
* The caller must pass the address of a selector variable to this
* function and initialize the value of the function to NULL before
* the first call. recset_release needs to be called to free the
* selector.
*/
gpg_error_t
recsel_parse_expr (recsel_expr_t *selector, const char *expression)
{
recsel_expr_t se_head = NULL;
recsel_expr_t se, se2;
char *expr_buffer;
char *expr;
char *s0, *s;
int toend = 0;
int xcase = 0;
int disjun = 0;
char *next_lc = NULL;
while (*expression == ' ' || *expression == '\t')
expression++;
expr_buffer = xtrystrdup (expression);
if (!expr_buffer)
return my_error_from_syserror ();
expr = expr_buffer;
if (*expr == '|' && expr[1] == '|')
{
disjun = 1;
expr += 2;
}
else if (*expr == '&' && expr[1] == '&')
expr += 2;
next_term:
while (*expr == ' ' || *expr == '\t')
expr++;
while (*expr == '-')
{
switch (*++expr)
{
case '-': toend = 1; break;
case 'c': xcase = 1; break;
default:
log_error ("invalid flag '-%c' in expression\n", *expr);
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_INV_FLAG);
}
expr++;
while (*expr == ' ' || *expr == '\t')
expr++;
}
next_lc = toend? NULL : find_next_lc (expr);
if (next_lc)
*next_lc = 0; /* Terminate this term. */
se = xtrymalloc (sizeof *se + strlen (expr));
if (!se)
return my_error_from_syserror ();
strcpy (se->name, expr);
se->next = NULL;
se->not = 0;
se->disjun = disjun;
se->xcase = xcase;
if (!se_head)
se_head = se;
else
{
for (se2 = se_head; se2->next; se2 = se2->next)
;
se2->next = se;
}
s = strpbrk (expr, "=<>!~-");
if (!s || s == expr )
{
log_error ("no field name given in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_NO_NAME);
}
s0 = s;
if (!strncmp (s, "=~", 2))
{
se->op = SELECT_SUB;
s += 2;
}
else if (!strncmp (s, "!~", 2))
{
se->op = SELECT_SUB;
se->not = 1;
s += 2;
}
else if (!strncmp (s, "<>", 2))
{
se->op = SELECT_SAME;
se->not = 1;
s += 2;
}
else if (!strncmp (s, "==", 2))
{
se->op = SELECT_EQ;
s += 2;
}
else if (!strncmp (s, "!=", 2))
{
se->op = SELECT_EQ;
se->not = 1;
s += 2;
}
else if (!strncmp (s, "<=", 2))
{
se->op = SELECT_LE;
s += 2;
}
else if (!strncmp (s, ">=", 2))
{
se->op = SELECT_GE;
s += 2;
}
else if (!strncmp (s, "<", 1))
{
se->op = SELECT_LT;
s += 1;
}
else if (!strncmp (s, ">", 1))
{
se->op = SELECT_GT;
s += 1;
}
else if (!strncmp (s, "=", 1))
{
se->op = SELECT_SAME;
s += 1;
}
else if (!strncmp (s, "-z", 2))
{
se->op = SELECT_NONEMPTY;
se->not = 1;
s += 2;
}
else if (!strncmp (s, "-n", 2))
{
se->op = SELECT_NONEMPTY;
s += 2;
}
else if (!strncmp (s, "-f", 2))
{
se->op = SELECT_ISTRUE;
se->not = 1;
s += 2;
}
else if (!strncmp (s, "-t", 2))
{
se->op = SELECT_ISTRUE;
s += 2;
}
else if (!strncmp (s, "-le", 3))
{
se->op = SELECT_STRLE;
s += 3;
}
else if (!strncmp (s, "-ge", 3))
{
se->op = SELECT_STRGE;
s += 3;
}
else if (!strncmp (s, "-lt", 3))
{
se->op = SELECT_STRLT;
s += 3;
}
else if (!strncmp (s, "-gt", 3))
{
se->op = SELECT_STRGT;
s += 3;
}
else
{
log_error ("invalid operator in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_INV_OP);
}
/* We require that a space is used if the value starts with any of
the operator characters. */
if (se->op == SELECT_NONEMPTY || se->op == SELECT_ISTRUE)
;
else if (strchr ("=<>!~", *s))
{
log_error ("invalid operator in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_INV_OP);
}
while (*s == ' ' || *s == '\t')
s++;
if (se->op == SELECT_NONEMPTY || se->op == SELECT_ISTRUE)
{
if (*s)
{
log_error ("value given for -n or -z\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_SYNTAX);
}
}
else
{
if (!*s)
{
log_error ("no value given in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_MISSING_VALUE);
}
}
se->name[s0 - expr] = 0;
trim_spaces (se->name);
if (!se->name[0])
{
log_error ("no field name given in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_NO_NAME);
}
trim_spaces (se->name + (s - expr));
se->value = se->name + (s - expr);
if (!se->value[0] && !(se->op == SELECT_NONEMPTY || se->op == SELECT_ISTRUE))
{
log_error ("no value given in expression\n");
recsel_release (se_head);
xfree (expr_buffer);
return my_error (GPG_ERR_MISSING_VALUE);
}
se->numvalue = strtol (se->value, NULL, 0);
if (next_lc)
{
disjun = next_lc[1] == '|';
expr = next_lc + 2;
goto next_term;
}
/* Read:y Append to passes last selector. */
if (!*selector)
*selector = se_head;
else
{
for (se2 = *selector; se2->next; se2 = se2->next)
;
se2->next = se_head;
}
xfree (expr_buffer);
return 0;
}
void
recsel_release (recsel_expr_t a)
{
while (a)
{
recsel_expr_t tmp = a->next;
xfree (a);
a = tmp;
}
}
void
recsel_dump (recsel_expr_t selector)
{
recsel_expr_t se;
log_debug ("--- Begin selectors ---\n");
for (se = selector; se; se = se->next)
{
log_debug ("%s %s %s %s '%s'\n",
se==selector? " ": (se->disjun? "||":"&&"),
se->xcase? "-c":" ",
se->name,
se->op == SELECT_SAME? (se->not? "<>":"= "):
se->op == SELECT_SUB? (se->not? "!~":"=~"):
se->op == SELECT_NONEMPTY?(se->not? "-z":"-n"):
se->op == SELECT_ISTRUE? (se->not? "-f":"-t"):
se->op == SELECT_EQ? (se->not? "!=":"=="):
se->op == SELECT_LT? "< ":
se->op == SELECT_LE? "<=":
se->op == SELECT_GT? "> ":
se->op == SELECT_GE? ">=":
se->op == SELECT_STRLT? "-lt":
se->op == SELECT_STRLE? "-le":
se->op == SELECT_STRGT? "-gt":
se->op == SELECT_STRGE? "-ge":
/**/ "[oops]",
se->value);
}
log_debug ("--- End selectors ---\n");
}
/* Return true if the record RECORD has been selected. The GETVAL
* function is called with COOKIE and the NAME of a property used in
* the expression. */
int
recsel_select (recsel_expr_t selector,
const char *(*getval)(void *cookie, const char *propname),
void *cookie)
{
recsel_expr_t se;
const char *value;
size_t selen, valuelen;
long numvalue;
int result = 1;
se = selector;
while (se)
{
value = getval? getval (cookie, se->name) : NULL;
if (!value)
value = "";
if (!*value)
{
/* Field is empty. */
result = 0;
}
else /* Field has a value. */
{
valuelen = strlen (value);
numvalue = strtol (value, NULL, 0);
selen = strlen (se->value);
switch (se->op)
{
case SELECT_SAME:
if (se->xcase)
result = (valuelen==selen && !memcmp (value,se->value,selen));
else
result = (valuelen==selen && !memicmp (value,se->value,selen));
break;
case SELECT_SUB:
if (se->xcase)
result = !!my_memstr (value, valuelen, se->value);
else
result = !!memistr (value, valuelen, se->value);
break;
case SELECT_NONEMPTY:
result = !!valuelen;
break;
case SELECT_ISTRUE:
result = !!numvalue;
break;
case SELECT_EQ:
result = (numvalue == se->numvalue);
break;
case SELECT_GT:
result = (numvalue > se->numvalue);
break;
case SELECT_GE:
result = (numvalue >= se->numvalue);
break;
case SELECT_LT:
result = (numvalue < se->numvalue);
break;
case SELECT_LE:
result = (numvalue <= se->numvalue);
break;
case SELECT_STRGT:
if (se->xcase)
result = strcmp (value, se->value) > 0;
else
result = strcasecmp (value, se->value) > 0;
break;
case SELECT_STRGE:
if (se->xcase)
result = strcmp (value, se->value) >= 0;
else
result = strcasecmp (value, se->value) >= 0;
break;
case SELECT_STRLT:
if (se->xcase)
result = strcmp (value, se->value) < 0;
else
result = strcasecmp (value, se->value) < 0;
break;
case SELECT_STRLE:
if (se->xcase)
result = strcmp (value, se->value) <= 0;
else
result = strcasecmp (value, se->value) <= 0;
break;
}
}
if (se->not)
result = !result;
if (result)
{
/* This expression evaluated to true. See whether there are
remaining expressions in this conjunction. */
if (!se->next || se->next->disjun)
break; /* All expressions are true. Return True. */
se = se->next; /* Test the next. */
}
else
{
/* This expression evaluated to false and thus the
* conjunction evaluates to false. We skip over the
* remaining expressions of this conjunction and continue
* with the next disjunction if any. */
do
se = se->next;
while (se && !se->disjun);
}
}
return result;
}
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