OpenSolaris_b135/lib/libdhcpsvc/modules/util/util.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2000-2001 by Sun Microsystems, Inc.
* All rights reserved.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Internal libdhcpsvc public module utility functions: a collection of
* general-purpose routines that are used by assorted public modules.
* Someday we should integrate this into the build process a bit more
* intelligently.
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/isa_defs.h>
#include <dhcp_svc_public.h>
#include <assert.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include <ctype.h>
#include "util.h"
/*
* Open a file at path `pathname'; depending on the flags passed in through
* `dsvc_flags', this file may be optionally created or opened read-only.
* On success, DSVC_SUCCESS is returned and `fdp' points to the opened file
* descriptor. On failure, a DSVC_* error code is returned.
*/
int
open_file(const char *pathname, unsigned int dsvc_flags, int *fdp)
{
int open_flags;
/*
* Note that we always open with read access, independent of
* dsvc_flags, because an update operation (add, delete, modify)
* needs to lookup records to detect collisions.
*/
open_flags = O_RDONLY;
if (dsvc_flags & DSVC_WRITE)
open_flags = O_RDWR;
if (dsvc_flags & DSVC_CREATE)
open_flags |= O_CREAT|O_EXCL;
*fdp = open(pathname, open_flags, 0644);
if (*fdp == -1)
return (syserr_to_dsvcerr(errno));
return (DSVC_SUCCESS);
}
/*
* Read input a chunk at a time, avoiding as much copying as possible. To
* this end, we don't read into a temporary buffer, but rather read
* directly into dynamically reallocated storage (on the assumption that
* most of the time we will have to return something). Returns NULL either
* on failure or EOF; use feof(3C) on `fp' to determine which condition
* occurred.
*/
char *
read_entry(FILE *fp)
{
char *newline, *new_result, *result = NULL;
unsigned int len = 0, size = 0, chunksize = BUFSIZ;
for (;;) {
/*
* See if we need to grow the buffer; we always try to read
* `chunksize' bytes, so we need at least `chunksize' around;
* grab a little more just to avoid constant realloc'ing
*/
if (len + chunksize > size) {
size = len + (chunksize * 2);
new_result = realloc(result, size);
if (new_result == NULL) {
free(result);
return (NULL);
}
}
if (fgets(&new_result[len], chunksize, fp) == NULL) {
/*
* Hit EOF; if we never read any data, then free
* `new_result' and return NULL. If we are
* returning data, it's in `new_result', not
* `result'.
*/
if (result == NULL)
free(new_result);
else
result = new_result;
break;
}
result = new_result;
/*
* If we read a newline, then see if the preceding
* character was an escape. If so, remove the escape and
* continue; otherwise we're done. Note that we need to
* do the strrchr() on `&result[len]' so that NUL's that
* may be lurking elsewhere on the line don't confuse us.
*/
newline = strrchr(&result[len], '\n');
if (newline != NULL) {
len = newline - result;
if (newline == result || newline[-1] != '\\') {
newline[0] = '\0';
break;
}
newline[-1] = '\0';
len -= 2;
} else {
/*
* We either `chunksize' worth of data or we hit a
* NUL somewhere in the data stream. If we hit a
* NUL, then we can't "see" beyond the NUL; just
* advance to the NUL itself and continue.
*/
len += strlen(&result[len]);
}
}
return (result);
}
/*
* Given a buffer `buf' of words separated by one or more of the characters
* in `seps', split it into at most `nfields' fields, by changing the
* separator character following a field to a NUL character. Set
* `fields[i]' to point to the beginning of field i in `buf'. Return the
* number of fields set in `fields[]'. This routine is quite similar to
* bufsplit(3G), but less general, faster, and also handles multiple
* multiple whitespace separator characters differently.
*/
unsigned int
field_split(char *buf, unsigned int nfields, char *fields[], const char *seps)
{
unsigned int i = 0;
char *ch;
for (;;) {
fields[i] = buf;
/*
* Look for the field separator, byte-at-a-time; ignore
* separators that have been escaped. Believe it or not,
* strchr(3C) will match `seps' if `*buf' is the NUL byte
* (which indicates we're done).
*/
for (;;) {
ch = strchr(seps, *buf);
if (ch != NULL && *ch == '\0')
return (i + 1);
if (ch != NULL && (buf == fields[i] || buf[-1] != '\\'))
break;
buf++;
}
/*
* If this is the last field, then consider any remaining
* text on the line part of the last field. This is
* similar to how `read' in sh(1) works.
*/
if (++i == nfields)
return (i);
if (*buf == '\0')
return (i);
*buf = '\0';
/*
* If separator is whitespace, then skip all consecutive
* pieces of whitespace.
*/
while (ch != NULL && isspace(*ch)) {
ch = strchr(seps, buf[1]);
if (ch != NULL && isspace(*ch))
buf++;
}
buf++;
}
}
/*
* Map a standard errno into a corresponding DSVC_* code. If there
* is no translation, default to DSVC_INTERNAL.
*/
int
syserr_to_dsvcerr(int error)
{
switch (error) {
case EEXIST:
return (DSVC_TABLE_EXISTS);
case ENOMEM:
return (DSVC_NO_MEMORY);
case ENOSPC:
return (DSVC_NO_RESOURCES);
case EROFS:
case EPERM:
case EACCES:
return (DSVC_ACCESS);
case ENOENT:
return (DSVC_NO_TABLE);
default:
break;
}
return (DSVC_INTERNAL);
}
/*
* Convert an object of `len' bytes pointed to by `srcraw' between
* network-order and host-order and store in `dstraw'. The length `len'
* must be the actual length of the objects pointed to by `srcraw' and
* `dstraw' (or zero) or the results are undefined. Note that `srcraw' and
* `dstraw' may be the same, in which case the object is converted
* in-place. This routine will convert from host-order to network-order or
* network-order to host-order, since the conversion is the same.
*/
void
nhconvert(void *dstraw, const void *srcraw, size_t len)
{
#ifdef _LITTLE_ENDIAN
uint8_t b1, b2;
uint8_t *dst, *src;
size_t i;
/*
* If both `srcraw' and `dstraw' are 32-bit aligned and `len' is 4,
* then use ntohl() to do the byteswap, since it's hand-tuned.
*/
if (IS_P2ALIGNED(dstraw, 4) && IS_P2ALIGNED(srcraw, 4) && len == 4) {
*(uint32_t *)dstraw = ntohl(*(uint32_t *)srcraw);
return;
}
dst = (uint8_t *)dstraw;
src = (uint8_t *)srcraw;
for (i = 0; i < len / 2; i++) {
b1 = src[i];
b2 = src[len - i - 1];
dst[i] = b2;
dst[len - i - 1] = b1;
}
#else
if (srcraw != dstraw)
(void) memmove(dstraw, srcraw, len);
#endif
}
/*
* Positioned n-byte read: read `buflen' bytes at offset `off' at open file
* `fd' into `buffer', or "read" none at all. Returns -1 if all `buflen'
* bytes cannot be read; otherwise, returns 0.
*/
int
pnread(int fd, void *buffer, size_t buflen, off_t off)
{
size_t nread;
ssize_t nbytes;
char *buf = buffer;
for (nread = 0; nread < buflen; nread += nbytes) {
nbytes = pread(fd, &buf[nread], buflen - nread, off + nread);
if (nbytes == -1)
return (-1);
if (nbytes == 0) {
errno = EIO;
return (-1);
}
}
assert(nread == buflen);
return (0);
}
/*
* Positioned n-byte write: write `buflen' bytes from `buffer' to offset
* `off' in open file `fd'. Tries to write all `buflen' bytes, but does
* not attempt to "undo" what it has done in the case of failure. Returns
* -1 if all `buflen' bytes cannot be written, otherwise returns 0.
*/
int
pnwrite(int fd, const void *buffer, size_t buflen, off_t off)
{
size_t nwritten;
ssize_t nbytes;
const char *buf = buffer;
for (nwritten = 0; nwritten < buflen; nwritten += nbytes) {
nbytes = pwrite(fd, &buf[nwritten], buflen - nwritten,
off + nwritten);
if (nbytes == -1)
return (-1);
if (nbytes == 0) {
errno = EIO;
return (-1);
}
}
assert(nwritten == buflen);
return (0);
}
/*
* Copy `nbytes' efficiently from offset `srcoff' in `srcfd' to offset
* `dstoff' in `dstfd'; returns a DSVC_* return code. Note that we make
* `nbytes' a uint64_t (rather than a size_t) so that we can copy 2^64
* bits even when compiled ILP32.
*/
int
copy_range(int srcfd, off_t srcoff, int dstfd, off_t dstoff, uint64_t nbytes)
{
const size_t chunksize = 16 * PAGESIZE;
size_t validsize;
size_t skip;
uint64_t nwritten = 0;
int mflags = MAP_PRIVATE;
char *buf = NULL;
int error;
/*
* Handle trivial copy specially so we don't call munmap() below.
*/
if (nbytes == 0)
return (DSVC_SUCCESS);
/*
* The `off' argument to mmap(2) must be page-aligned, so align it;
* compute how many bytes we need to skip over in the mmap()'d
* buffer as a result.
*/
skip = srcoff % PAGESIZE;
srcoff -= skip;
while (nwritten < nbytes) {
buf = mmap(buf, chunksize, PROT_READ, mflags, srcfd, srcoff);
if (buf == MAP_FAILED)
return (DSVC_INTERNAL);
mflags |= MAP_FIXED;
validsize = MIN(chunksize, nbytes - nwritten + skip);
if (pnwrite(dstfd, &buf[skip], validsize - skip, dstoff)
== -1) {
error = errno;
(void) munmap(buf, chunksize);
return (syserr_to_dsvcerr(error));
}
nwritten += validsize - skip;
dstoff += validsize - skip;
srcoff += validsize;
skip = 0;
}
(void) munmap(buf, chunksize);
return (DSVC_SUCCESS);
}
/*
* Unescape all instances of `delimiter' in `buffer' and store result in
* `unescaped', which is `size' bytes. To guarantee that all data is
* copied, `unescaped' should be at least as long as `buffer'.
*/
void
unescape(char delimiter, const char *buffer, char *unescaped, size_t size)
{
int i, j;
size--;
for (i = 0, j = 0; buffer[i] != '\0' && j < size; i++, j++) {
if (buffer[i] == '\\' && buffer[i + 1] == delimiter)
i++;
unescaped[j] = buffer[i];
}
unescaped[j] = '\0';
}
/*
* Escape all instances of `delimiter' in `buffer' and store result in
* `escaped', which is `size' bytes. To guarantee that all data is
* copied, `escaped' should be at least twice as long as `buffer'.
*/
void
escape(char delimiter, const char *buffer, char *escaped, size_t size)
{
int i, j;
size--;
for (i = 0, j = 0; buffer[i] != '\0' && j < size; i++, j++) {
if (buffer[i] == delimiter)
escaped[j++] = '\\';
escaped[j] = buffer[i];
}
escaped[j] = '\0';
}
/*
* Generate a signature for a new record. The signature is conceptually
* divided into two pieces: a random 16-bit "generation number" and a
* 48-bit monotonically increasing integer. The generation number protects
* against stale updates to records that have been deleted and since
* recreated.
*/
uint64_t
gensig(void)
{
static int seeded = 0;
if (seeded == 0) {
srand48((long)gethrtime());
seeded++;
}
return ((uint64_t)lrand48() << 48 | 1);
}