acl/lib_tls/attr/attr_scan0.c

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/*++
2014-11-19 00:25:21 +08:00
* NAME
* attr_scan0 3
* SUMMARY
* recover attributes from byte stream
* SYNOPSIS
* #include <attr.h>
*
* int attr_scan0(fp, flags, type, name, ..., ATTR_TYPE_END)
* ACL_VSTREAM fp;
* int flags;
* int type;
* char *name;
*
* int attr_vscan0(fp, flags, ap)
* ACL_VSTREAM fp;
* int flags;
* va_list ap;
* DESCRIPTION
* attr_scan0() takes zero or more (name, value) request attributes
* and recovers the attribute values from the byte stream that was
* possibly generated by attr_print0().
*
* attr_vscan0() provides an alternative interface that is convenient
* for calling from within a variadic function.
*
* The input stream is formatted as follows, where (item)* stands
* for zero or more instances of the specified item, and where
* (item1 | item2) stands for choice:
*
* .in +5
* attr-list :== simple-attr* null
* .br
* simple-attr :== attr-name null attr-value null
* .br
* attr-name :== any string not containing null
* .br
* attr-value :== any string not containing null
* .br
* null :== the ASCII null character
* .in
*
* All attribute names and attribute values are sent as null terminated
* strings. Each string must be no longer than 4*var_line_limit
* characters including the terminator.
* These formatting rules favor implementations in C.
*
* Normally, attributes must be received in the sequence as specified with
* the attr_scan0() argument list. The input stream may contain additional
* attributes at any point in the input stream, including additional
* instances of requested attributes.
*
* Additional input attributes or input attribute instances are silently
* skipped over, unless the ATTR_FLAG_EXTRA processing flag is specified
* (see below). This allows for some flexibility in the evolution of
* protocols while still providing the option of being strict where
* this is desirable.
*
* Arguments:
* .IP fp
* Stream to recover the input attributes from.
* .IP flags
* The bit-wise OR of zero or more of the following.
* .RS
* .IP ATTR_FLAG_MISSING
* Log a warning when the input attribute list terminates before all
* requested attributes are recovered. It is always an error when the
* input stream ends without the newline attribute list terminator.
* .IP ATTR_FLAG_EXTRA
* Log a warning and stop attribute recovery when the input stream
* contains an attribute that was not requested. This includes the
* case of additional instances of a requested attribute.
* .IP ATTR_FLAG_MORE
* After recovering the requested attributes, leave the input stream
* in a state that is usable for more attr_scan0() operations from the
* same input attribute list.
* By default, attr_scan0() skips forward past the input attribute list
* terminator.
* .IP ATTR_FLAG_STRICT
* For convenience, this value combines both ATTR_FLAG_MISSING and
* ATTR_FLAG_EXTRA.
* .IP ATTR_FLAG_NONE
* For convenience, this value requests none of the above.
* .RE
* .IP type
* The type argument determines the arguments that follow.
* .RS
* .IP "ATTR_TYPE_INT (char *, int *)"
* This argument is followed by an attribute name and an integer pointer.
* .IP "ATTR_TYPE_LONG (char *, long *)"
* This argument is followed by an attribute name and a long pointer.
* .IP "ATTR_TYPE_STR (char *, ACL_VSTRING *)"
* This argument is followed by an attribute name and a ACL_VSTRING pointer.
* .IP "ATTR_TYPE_DATA (char *, ACL_VSTRING *)"
* This argument is followed by an attribute name and a ACL_VSTRING pointer.
* .IP "ATTR_TYPE_FUNC (ATTR_SCAN_SLAVE_FN, void *)"
* This argument is followed by a function pointer and a generic data
* pointer. The caller-specified function returns < 0 in case of
* error.
* .IP "ATTR_TYPE_HASH (ACL_HTABLE *)"
* .IP "ATTR_TYPE_NAMEVAL (NVTABLE *)"
* All further input attributes are processed as string attributes.
* No specific attribute sequence is enforced.
* All attributes up to the attribute list terminator are read,
* but only the first instance of each attribute is stored.
* There can be no more than 1024 attributes in a hash table.
* .sp
* The attribute string values are stored in the hash table under
* keys equal to the attribute name (obtained from the input stream).
* Values from the input stream are added to the hash table. Existing
* hash table entries are not replaced.
* .sp
* N.B. This construct must be followed by an ATTR_TYPE_END argument.
* .IP ATTR_TYPE_END
* This argument terminates the requested attribute list.
* .RE
* BUGS
* ATTR_TYPE_HASH (ATTR_TYPE_NAMEVAL) accepts attributes with arbitrary
* names from possibly untrusted sources.
* This is unsafe, unless the resulting table is queried only with
* known to be good attribute names.
* DIAGNOSTICS
* attr_scan0() and attr_vscan0() return -1 when malformed input is
* detected (string too long, incomplete line, missing end marker).
* Otherwise, the result value is the number of attributes that were
* successfully recovered from the input stream (a hash table counts
* as the number of entries stored into the table).
*
* Panic: interface violation. All system call errors are fatal.
* SEE ALSO
* attr_print0(3) send attributes over byte stream.
* 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
*--*/
#include "StdAfx.h"
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include "attr.h"
/* Application specific. */
#define STR(x) acl_vstring_str(x)
#define LEN(x) ACL_VSTRING_LEN(x)
static void free_vstring(void *arg)
{
ACL_VSTRING *s = (ACL_VSTRING*) arg;
acl_vstring_free(s);
}
/* attr_scan0_string - pull a string from the input stream */
static int attr_scan0_string(ACL_VSTREAM *fp, ACL_VSTRING *plain_buf, const char *context)
{
const char *myname = "attr_scan0_string";
int ch;
if ((ch = acl_vstring_gets_null(plain_buf, fp)) == ACL_VSTREAM_EOF) {
acl_msg_warn("%s: %s on %s while reading %s",
myname, acl_vstream_ftimeout(fp) ? "timeout" : "premature end-of-input",
ACL_VSTREAM_PATH(fp), context);
return (-1);
}
if (ch != 0) {
acl_msg_warn("%s: unexpected end-of-input from %s while reading %s",
myname, ACL_VSTREAM_PATH(fp), context);
return (-1);
}
if (acl_msg_verbose)
acl_msg_info("%s: %s: %s", myname, context, *STR(plain_buf) ? STR(plain_buf) : "(end)");
return (ch);
}
/* attr_scan0_data - pull a data blob from the input stream */
static int attr_scan0_data(ACL_VSTREAM *fp, ACL_VSTRING *str_buf,
const char *context)
{
const char *myname = "attr_scan0_data";
static __thread ACL_VSTRING *base64_buf = 0;
int ch;
if (base64_buf == 0) {
base64_buf = acl_vstring_alloc(10);
acl_pthread_atexit_add(base64_buf, free_vstring);
}
if ((ch = attr_scan0_string(fp, base64_buf, context)) < 0)
return (-1);
if (acl_vstring_base64_decode(str_buf, STR(base64_buf), (int) LEN(base64_buf)) == 0) {
acl_msg_warn("%s: malformed base64 data from %s while reading %s: %.100s",
myname, ACL_VSTREAM_PATH(fp), context, STR(base64_buf));
return (-1);
}
return (ch);
}
/* attr_scan0_number - pull a number from the input stream */
static int attr_scan0_number(ACL_VSTREAM *fp, unsigned *ptr,
ACL_VSTRING *str_buf, const char *context)
{
const char *myname = "attr_scan0_number";
char junk = 0;
int ch;
if ((ch = attr_scan0_string(fp, str_buf, context)) < 0)
return (-1);
if (sscanf(STR(str_buf), "%u%c", ptr, &junk) != 1 || junk != 0) {
acl_msg_warn("%s: malformed numerical data from %s while reading %s: %.100s",
myname, ACL_VSTREAM_PATH(fp), context, STR(str_buf));
return (-1);
}
return (ch);
}
/* attr_scan0_long_number - pull a number from the input stream */
static int attr_scan0_long_number(ACL_VSTREAM *fp, unsigned long *ptr,
ACL_VSTRING *str_buf, const char *context)
{
const char *myname = "attr_scan0_long_number";
char junk = 0;
int ch;
if ((ch = attr_scan0_string(fp, str_buf, context)) < 0)
return (-1);
if (sscanf(STR(str_buf), "%lu%c", ptr, &junk) != 1 || junk != 0) {
acl_msg_warn("%s: malformed numerical data from %s while reading %s: %.100s",
myname, ACL_VSTREAM_PATH(fp), context, STR(str_buf));
return (-1);
}
return (ch);
}
/* attr_vscan0 - receive attribute list from stream */
int attr_vscan0(ACL_VSTREAM *fp, int flags, va_list ap)
{
const char *myname = "attr_scan0";
static __thread ACL_VSTRING *str_buf = 0;
static __thread ACL_VSTRING *name_buf = 0;
int wanted_type = -1;
char *wanted_name = 0;
unsigned int *number;
unsigned long *long_number;
ACL_VSTRING *string;
ACL_HTABLE *hash_table = 0;
int ch;
int conversions;
ATTR_SCAN_SLAVE_FN scan_fn;
void *scan_arg;
/*
* Sanity check.
*/
if (flags & ~ATTR_FLAG_ALL)
acl_msg_panic("%s: bad flags: 0x%x", myname, flags);
/*
* EOF check.
*/
if ((ch = ACL_VSTREAM_GETC(fp)) == ACL_VSTREAM_EOF)
return (0);
acl_vstream_ungetc(fp, ch);
/*
* Initialize.
*/
if (str_buf == 0) {
str_buf = acl_vstring_alloc(10);
name_buf = acl_vstring_alloc(10);
acl_pthread_atexit_add(str_buf, free_vstring);
acl_pthread_atexit_add(name_buf, free_vstring);
}
/*
* Iterate over all (type, name, value) triples.
*/
for (conversions = 0; /* void */ ; conversions++) {
/*
* Determine the next attribute type and attribute name on the
* caller's wish list.
*
* If we're reading into a hash table, we already know that the
* attribute value is string-valued, and we get the attribute name
* from the input stream instead. This is secure only when the
* resulting table is queried with known to be good attribute names.
*/
if (wanted_type != ATTR_TYPE_HASH) {
wanted_type = va_arg(ap, int);
if (wanted_type == ATTR_TYPE_END) {
if ((flags & ATTR_FLAG_MORE) != 0)
return (conversions);
wanted_name = "(list terminator)";
} else if (wanted_type == ATTR_TYPE_HASH) {
wanted_name = "(any attribute name or list terminator)";
hash_table = va_arg(ap, ACL_HTABLE *);
if (va_arg(ap, int) != ATTR_TYPE_END)
acl_msg_panic("%s: ATTR_TYPE_HASH not followed by ATTR_TYPE_END",
myname);
} else if (wanted_type != ATTR_TYPE_FUNC) {
wanted_name = va_arg(ap, char *);
}
}
/*
* Locate the next attribute of interest in the input stream.
*/
while (wanted_type != ATTR_TYPE_FUNC) {
/*
* Get the name of the next attribute. Hitting EOF is always bad.
* Hitting the end-of-input early is OK if the caller is prepared
* to deal with missing inputs.
*/
if (acl_msg_verbose)
acl_msg_info("%s: wanted attribute: %s",
ACL_VSTREAM_PATH(fp), wanted_name);
if ((ch = attr_scan0_string(fp, name_buf,
"input attribute name")) < 0)
return (-1);
if (LEN(name_buf) == 0) {
if (wanted_type == ATTR_TYPE_END
|| wanted_type == ATTR_TYPE_HASH)
return (conversions);
if ((flags & ATTR_FLAG_MISSING) != 0)
acl_msg_warn("%s: missing attribute %s in input from %s",
myname, wanted_name, ACL_VSTREAM_PATH(fp));
return (conversions);
}
/*
* See if the caller asks for this attribute.
*/
if (wanted_type == ATTR_TYPE_HASH
|| (wanted_type != ATTR_TYPE_END
&& strcmp(wanted_name, STR(name_buf)) == 0))
break;
if ((flags & ATTR_FLAG_EXTRA) != 0) {
acl_msg_warn("%s: unexpected attribute %s from %s (expecting: %s)",
myname, STR(name_buf), ACL_VSTREAM_PATH(fp), wanted_name);
return (conversions);
}
/*
* Skip over this attribute. The caller does not ask for it.
*/
(void) attr_scan0_string(fp, str_buf, "input attribute value");
}
/*
* Do the requested conversion.
*/
switch (wanted_type) {
case ATTR_TYPE_INT:
number = va_arg(ap, unsigned int *);
if ((ch = attr_scan0_number(fp, number, str_buf, "input attribute value")) < 0)
return (-1);
break;
case ATTR_TYPE_LONG:
long_number = va_arg(ap, unsigned long *);
if ((ch = attr_scan0_long_number(fp, long_number, str_buf, "input attribute value")) < 0)
return (-1);
break;
case ATTR_TYPE_STR:
string = va_arg(ap, ACL_VSTRING *);
if ((ch = attr_scan0_string(fp, string, "input attribute value")) < 0)
return (-1);
break;
case ATTR_TYPE_DATA:
string = va_arg(ap, ACL_VSTRING *);
if ((ch = attr_scan0_data(fp, string, "input attribute value")) < 0)
return (-1);
break;
case ATTR_TYPE_FUNC:
scan_fn = va_arg(ap, ATTR_SCAN_SLAVE_FN);
scan_arg = va_arg(ap, void *);
if (scan_fn(attr_scan0, fp, flags | ATTR_FLAG_MORE, scan_arg) < 0)
return (-1);
break;
case ATTR_TYPE_HASH:
if ((ch = attr_scan0_string(fp, str_buf,
"input attribute value")) < 0)
return (-1);
if (acl_htable_locate(hash_table, STR(name_buf)) != 0) {
if ((flags & ATTR_FLAG_EXTRA) != 0) {
acl_msg_warn("%s: duplicate attribute %s in input from %s",
myname, STR(name_buf), ACL_VSTREAM_PATH(fp));
return (conversions);
}
} else if (acl_htable_used(hash_table) >= ATTR_HASH_LIMIT) {
acl_msg_warn("%s: attribute count exceeds limit %d in input from %s",
myname, ATTR_HASH_LIMIT, ACL_VSTREAM_PATH(fp));
return (conversions);
} else {
acl_htable_enter(hash_table, STR(name_buf),
acl_mystrdup(STR(str_buf)));
}
break;
default:
acl_msg_panic("%s: unknown type code: %d", myname, wanted_type);
}
}
}
/* attr_scan0 - read attribute list from stream */
int attr_scan0(ACL_VSTREAM *fp, int flags,...)
{
va_list ap;
int ret;
va_start(ap, flags);
ret = attr_vscan0(fp, flags, ap);
va_end(ap);
return (ret);
}
#ifdef TEST
/*
* Proof of concept test program. Mirror image of the attr_scan0 test
* program.
*/
int var_line_limit = 2048;
int main(int unused_argc, char **used_argv)
{
ACL_VSTRING *data_val = acl_vstring_alloc(1);
ACL_VSTRING *str_val = acl_vstring_alloc(1);
ACL_HTABLE *table = acl_htable_create(1);
ACL_HTABLE_INFO **ht_info_list;
ACL_HTABLE_INFO **ht;
int int_val;
long long_val;
int ret;
acl_msg_verbose = 1;
if ((ret = attr_scan0(ACL_VSTREAM_IN,
ATTR_FLAG_STRICT,
ATTR_TYPE_INT, ATTR_NAME_INT, &int_val,
ATTR_TYPE_LONG, ATTR_NAME_LONG, &long_val,
ATTR_TYPE_STR, ATTR_NAME_STR, str_val,
ATTR_TYPE_DATA, ATTR_NAME_DATA, data_val,
ATTR_TYPE_HASH, table,
ATTR_TYPE_END)) > 4) {
acl_vstream_printf("%s %d\n", ATTR_NAME_INT, int_val);
acl_vstream_printf("%s %ld\n", ATTR_NAME_LONG, long_val);
acl_vstream_printf("%s %s\n", ATTR_NAME_STR, STR(str_val));
acl_vstream_printf("%s %s\n", ATTR_NAME_DATA, STR(str_val));
ht_info_list = acl_htable_list(table);
for (ht = ht_info_list; *ht; ht++)
acl_vstream_printf("(hash) %s %s\n", ht[0]->key, ht[0]->value);
acl_myfree((char *) ht_info_list);
} else {
acl_vstream_printf("return: %d\n", ret);
}
if ((ret = attr_scan0(ACL_VSTREAM_IN,
ATTR_FLAG_STRICT,
ATTR_TYPE_INT, ATTR_NAME_INT, &int_val,
ATTR_TYPE_LONG, ATTR_NAME_LONG, &long_val,
ATTR_TYPE_STR, ATTR_NAME_STR, str_val,
ATTR_TYPE_DATA, ATTR_NAME_DATA, data_val,
ATTR_TYPE_END)) == 4) {
acl_vstream_printf("%s %d\n", ATTR_NAME_INT, int_val);
acl_vstream_printf("%s %ld\n", ATTR_NAME_LONG, long_val);
acl_vstream_printf("%s %s\n", ATTR_NAME_STR, STR(str_val));
acl_vstream_printf("%s %s\n", ATTR_NAME_DATA, STR(data_val));
ht_info_list = acl_htable_list(table);
for (ht = ht_info_list; *ht; ht++)
acl_vstream_printf("(hash) %s %s\n", ht[0]->key, ht[0]->value);
acl_myfree((char *) ht_info_list);
} else {
acl_vstream_printf("return: %d\n", ret);
}
if (acl_vstream_fflush(ACL_VSTREAM_OUT) == ACL_VSTREAM_EOF)
acl_msg_fatal("%s: write error: %s", __FUNCTION__, acl_last_serror());
acl_vstring_free(data_val);
acl_vstring_free(str_val);
acl_htable_free(table, myfree);
return (0);
}
#endif