pam-modules/lib/transform.c
Sergey Poznyakoff c20d0e4bf3 Happy GNU Year
2018-01-01 11:22:40 +02:00

570 lines
13 KiB
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/* This file is part of pam_modules.
Copyright (C) 2006-2008, 2010-2012, 2014-2015, 2018 Sergey Poznyakoff.
(using my implementation for the GNU tar).
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any later
version.
This program 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, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <graypam.h>
enum transform_type
{
transform_first,
transform_global
};
enum replace_segm_type
{
segm_literal, /* Literal segment */
segm_backref, /* Back-reference segment */
segm_case_ctl /* Case control segment (GNU extension) */
};
enum case_ctl_type
{
ctl_stop, /* Stop case conversion */
ctl_upcase_next,/* Turn the next character to uppercase */
ctl_locase_next,/* Turn the next character to lowercase */
ctl_upcase, /* Turn the replacement to uppercase until ctl_stop */
ctl_locase /* Turn the replacement to lowercase until ctl_stop */
};
struct replace_segm
{
struct replace_segm *next;
enum replace_segm_type type;
union
{
struct
{
char *ptr;
size_t size;
} literal; /* type == segm_literal */
size_t ref; /* type == segm_backref */
enum case_ctl_type ctl; /* type == segm_case_ctl */
} v;
};
struct transform
{
struct transform *next;
enum transform_type transform_type;
unsigned match_number;
regex_t regex;
int has_regex;
/* Compiled replacement expression */
struct replace_segm *repl_head, *repl_tail;
size_t segm_count; /* Number of elements in the above list */
};
static struct transform *transform_head, *transform_tail;
static struct transform *
new_transform ()
{
struct transform *p = gray_zalloc (sizeof *p);
if (transform_tail)
transform_tail->next = p;
else
transform_head = p;
transform_tail = p;
return p;
}
static void free_segment (struct replace_segm *segm);
static void
free_transform (struct transform *tr)
{
struct replace_segm *segm;
if (tr->has_regex)
regfree (&tr->regex);
for (segm = tr->repl_head; segm; )
{
struct replace_segm *next = segm->next;
free_segment (segm);
segm = next;
}
}
static struct replace_segm *
add_segment (struct transform *tf)
{
struct replace_segm *segm = gray_malloc (sizeof *segm);
segm->next = NULL;
if (tf->repl_tail)
tf->repl_tail->next = segm;
else
tf->repl_head = segm;
tf->repl_tail = segm;
tf->segm_count++;
return segm;
}
static void
free_segment (struct replace_segm *segm)
{
if (segm->type == segm_literal)
free (segm->v.literal.ptr);
free (segm);
}
static void
add_literal_segment (struct transform *tf, char *str, char *end)
{
size_t len = end - str;
if (len)
{
struct replace_segm *segm = add_segment (tf);
segm->type = segm_literal;
segm->v.literal.ptr = gray_malloc (len + 1);
memcpy (segm->v.literal.ptr, str, len);
segm->v.literal.ptr[len] = 0;
segm->v.literal.size = len;
}
}
static void
add_char_segment (struct transform *tf, int chr)
{
struct replace_segm *segm = add_segment (tf);
segm->type = segm_literal;
segm->v.literal.ptr = gray_malloc (2);
segm->v.literal.ptr[0] = chr;
segm->v.literal.ptr[1] = 0;
segm->v.literal.size = 1;
}
static void
add_backref_segment (struct transform *tf, size_t ref)
{
struct replace_segm *segm = add_segment (tf);
segm->type = segm_backref;
segm->v.ref = ref;
}
static void
add_case_ctl_segment (struct transform *tf, enum case_ctl_type ctl)
{
struct replace_segm *segm = add_segment (tf);
segm->type = segm_case_ctl;
segm->v.ctl = ctl;
}
static const char *
parse_transform_expr (const char *expr)
{
int delim;
int i, j, rc;
char *str, *beg, *cur;
const char *p;
int cflags = 0;
struct transform *tf = new_transform ();
if (expr[0] != 's')
gray_raise ("Invalid transform expression");
delim = expr[1];
/* Scan regular expression */
for (i = 2; expr[i] && expr[i] != delim; i++)
if (expr[i] == '\\' && expr[i+1])
i++;
if (expr[i] != delim)
gray_raise ("Invalid transform expression");
/* Scan replacement expression */
for (j = i + 1; expr[j] && expr[j] != delim; j++)
if (expr[j] == '\\' && expr[j+1])
j++;
if (expr[j] != delim)
gray_raise ("Invalid transform expression");
/* Check flags */
tf->transform_type = transform_first;
for (p = expr + j + 1; *p && *p != ';'; p++)
switch (*p)
{
case 'g':
tf->transform_type = transform_global;
break;
case 'i':
cflags |= REG_ICASE;
break;
case 'x':
cflags |= REG_EXTENDED;
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
tf->match_number = strtoul (p, (char**) &p, 0);
p--;
break;
default:
gray_raise("Unknown flag in transform expression: %c", *p);
}
if (*p == ';')
p++;
/* Extract and compile regex */
str = gray_malloc (i - 1);
memcpy (str, expr + 2, i - 2);
str[i - 2] = 0;
rc = regcomp (&tf->regex, str, cflags);
if (rc)
{
char errbuf[512];
regerror (rc, &tf->regex, errbuf, sizeof (errbuf));
gray_raise("Invalid transform expression: %s", errbuf);
}
tf->has_regex = 1;
if (str[0] == '^' || str[strlen (str) - 1] == '$')
tf->transform_type = transform_first;
free (str);
/* Extract and compile replacement expr */
i++;
str = gray_malloc (j - i + 1);
memcpy (str, expr + i, j - i);
str[j - i] = 0;
for (cur = beg = str; *cur;)
{
if (*cur == '\\')
{
size_t n;
add_literal_segment (tf, beg, cur);
switch (*++cur)
{
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
n = strtoul (cur, &cur, 10);
if (n > tf->regex.re_nsub)
gray_raise ("Invalid transform replacement: "
"back reference out of range");
add_backref_segment (tf, n);
break;
case '\\':
add_char_segment (tf, '\\');
cur++;
break;
case 'a':
add_char_segment (tf, '\a');
cur++;
break;
case 'b':
add_char_segment (tf, '\b');
cur++;
break;
case 'f':
add_char_segment (tf, '\f');
cur++;
break;
case 'n':
add_char_segment (tf, '\n');
cur++;
break;
case 'r':
add_char_segment (tf, '\r');
cur++;
break;
case 't':
add_char_segment (tf, '\t');
cur++;
break;
case 'v':
add_char_segment (tf, '\v');
cur++;
break;
case '&':
add_char_segment (tf, '&');
cur++;
break;
case 'L':
/* Turn the replacement to lowercase until a `\U' or `\E'
is found, */
add_case_ctl_segment (tf, ctl_locase);
cur++;
break;
case 'l':
/* Turn the next character to lowercase, */
add_case_ctl_segment (tf, ctl_locase_next);
cur++;
break;
case 'U':
/* Turn the replacement to uppercase until a `\L' or `\E'
is found, */
add_case_ctl_segment (tf, ctl_upcase);
cur++;
break;
case 'u':
/* Turn the next character to uppercase, */
add_case_ctl_segment (tf, ctl_upcase_next);
cur++;
break;
case 'E':
/* Stop case conversion started by `\L' or `\U'. */
add_case_ctl_segment (tf, ctl_stop);
cur++;
break;
default:
/* Try to be nice */
{
char buf[2];
buf[0] = '\\';
buf[1] = *cur;
add_literal_segment (tf, buf, buf + 2);
}
cur++;
break;
}
beg = cur;
}
else if (*cur == '&')
{
add_literal_segment (tf, beg, cur);
add_backref_segment (tf, 0);
beg = ++cur;
}
else
cur++;
}
add_literal_segment (tf, beg, cur);
return p;
}
void
gray_set_transform_expr (const char *expr)
{
while (*expr)
expr = parse_transform_expr (expr);
}
void
gray_free_transform_expr ()
{
while (transform_head)
{
struct transform *next = transform_head->next;
free_transform (transform_head);
transform_head = next;
}
transform_tail = NULL;
}
/* Run case conversion specified by CASE_CTL on array PTR of SIZE
characters. Returns pointer to statically allocated storage. */
static char *
run_case_conv (enum case_ctl_type case_ctl, char *ptr, size_t size)
{
static char *case_ctl_buffer;
static size_t case_ctl_bufsize;
char *p;
if (case_ctl_bufsize < size)
{
case_ctl_bufsize = size;
case_ctl_buffer = gray_realloc (case_ctl_buffer, case_ctl_bufsize);
}
memcpy (case_ctl_buffer, ptr, size);
switch (case_ctl)
{
case ctl_upcase_next:
case_ctl_buffer[0] = toupper (case_ctl_buffer[0]);
break;
case ctl_locase_next:
case_ctl_buffer[0] = tolower (case_ctl_buffer[0]);
break;
case ctl_upcase:
for (p = case_ctl_buffer; p < case_ctl_buffer + size; p++)
*p = toupper (*p);
break;
case ctl_locase:
for (p = case_ctl_buffer; p < case_ctl_buffer + size; p++)
*p = tolower (*p);
break;
case ctl_stop:
break;
}
return case_ctl_buffer;
}
void
_single_transform_name_to_slist (struct transform *tf, gray_slist_t slist,
char *input)
{
regmatch_t *rmp;
int rc;
size_t nmatches = 0;
enum case_ctl_type case_ctl = ctl_stop, /* Current case conversion op */
save_ctl = ctl_stop; /* Saved case_ctl for \u and \l */
/* Reset case conversion after a single-char operation */
#define CASE_CTL_RESET() if (case_ctl == ctl_upcase_next \
|| case_ctl == ctl_locase_next) \
{ \
case_ctl = save_ctl; \
save_ctl = ctl_stop; \
}
rmp = gray_malloc ((tf->regex.re_nsub + 1) * sizeof (*rmp));
while (*input)
{
size_t disp;
char *ptr;
rc = regexec (&tf->regex, input, tf->regex.re_nsub + 1, rmp, 0);
if (rc == 0)
{
struct replace_segm *segm;
disp = rmp[0].rm_eo;
if (rmp[0].rm_so)
gray_slist_append (slist, input, rmp[0].rm_so);
nmatches++;
if (tf->match_number && nmatches < tf->match_number)
{
gray_slist_append (slist, input, disp);
input += disp;
continue;
}
for (segm = tf->repl_head; segm; segm = segm->next)
{
switch (segm->type)
{
case segm_literal: /* Literal segment */
if (case_ctl == ctl_stop)
ptr = segm->v.literal.ptr;
else
{
ptr = run_case_conv (case_ctl,
segm->v.literal.ptr,
segm->v.literal.size);
CASE_CTL_RESET();
}
gray_slist_append (slist, ptr, segm->v.literal.size);
break;
case segm_backref: /* Back-reference segment */
if (rmp[segm->v.ref].rm_so != -1
&& rmp[segm->v.ref].rm_eo != -1)
{
size_t size = rmp[segm->v.ref].rm_eo
- rmp[segm->v.ref].rm_so;
ptr = input + rmp[segm->v.ref].rm_so;
if (case_ctl != ctl_stop)
{
ptr = run_case_conv (case_ctl, ptr, size);
CASE_CTL_RESET();
}
gray_slist_append (slist, ptr, size);
}
break;
case segm_case_ctl:
switch (segm->v.ctl)
{
case ctl_upcase_next:
case ctl_locase_next:
switch (save_ctl)
{
case ctl_stop:
case ctl_upcase:
case ctl_locase:
save_ctl = case_ctl;
default:
break;
}
/*FALL THROUGH*/
case ctl_upcase:
case ctl_locase:
case ctl_stop:
case_ctl = segm->v.ctl;
}
}
}
}
else
{
disp = strlen (input);
gray_slist_append (slist, input, disp);
}
input += disp;
if (tf->transform_type == transform_first)
{
gray_slist_append (slist, input, strlen (input));
break;
}
}
gray_slist_append_char (slist, 0);
free (rmp);
}
int
gray_transform_name_to_slist (gray_slist_t slist, char *input, char **output)
{
struct transform *tf;
for (tf = transform_head; tf; tf = tf->next)
{
_single_transform_name_to_slist (tf, slist, input);
input = gray_slist_finish (slist);
}
*output = input;
return transform_head != NULL;
}