freebsd-dev/lib/libc/gen/config.c

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/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@login.dknet.dk> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
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* $Id$
*
*/
#if defined(LIBC_SCCS) && !defined(lint)
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static char rcsid[] = "$Id$";
#endif /* LIBC_SCCS and not lint */
/*
* This file contains four procedures used to read config-files.
*
* char * config_open(const char *filename,int contlines)
* Will open the named file, read it into a private malloc'ed area,
* and close the file again.
* All lines where the first !isspace() char is '#' are deleted.
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* If contlines are non-zero lines where the first char is isspace()
* will be joined to the preceeding line.
* In case of trouble the name of the offending system call will be
* returned. On success NULL is returned.
*
* void config_close()
* This will free the internal malloc'ed area.
*
* char * config_next()
* This will return a pointer to the next entry in the area. NULL is
* returned at "end of file". The return value is '\0' terminated, and
* can be modified, but the contents must be copied somewhere else for
* permanent use.
*
* char * config_skip(char **p)
* This will pick out the next word from the string. The return-value
* points to the word found, and *p is advanced past the word. NULL is
* returned at "end of string".
*
* Many programs have a n*100 bytes config-file and N*1000 bytes of source
* to read it. Doing pointer-aerobics on files that small is a waste of
* time, and bashing around with getchar/ungetc isn't much better. These
* routines implement a simple algorithm and syntax.
*
* config_skip consider a contiguous string of !isspace() chars a word.
*
* 13nov1994 Poul-Henning Kamp phk@login.dknet.dk
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <ctype.h>
#include <string.h>
static char *file_buf;
static char *ptr;
char *
config_open(const char *filename, int contlines)
{
int fd;
struct stat st;
char *p, *q;
if ((fd = open(filename, O_RDONLY)) < 0)
return "open";
if (fstat(fd, &st) < 0) {
close(fd);
return "fstat";
}
if (file_buf)
free(file_buf);
file_buf = malloc(st.st_size + 2);
if (!file_buf) {
close(fd);
return "malloc";
}
if (st.st_size != read(fd, file_buf, st.st_size)) {
free(file_buf);
file_buf = (char *) 0;
close(fd);
return "read";
}
close(fd);
file_buf[st.st_size] = '\n';
file_buf[st.st_size + 1] = '\0';
/*
* /^[ \t]*#[^\n]*$/d
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*
* Delete all lines where the first !isspace() char is '#'
*/
ptr = file_buf;
for (p = ptr; *p;) {
for (q = p; *q != '\n' && isspace(*q); q++)
continue;
if (*q == '#') {
p = strchr(p, '\n');
if (p)
p++;
} else {
q = strchr(p, '\n');
q++;
memcpy(ptr, p, q - p);
ptr += q - p;
p = q;
}
}
*ptr = '\0';
ptr = file_buf;
if (!contlines)
return 0;
/* Join all lines starting with a isspace() char to the preceeding
* line */
for (p = ptr; *p;) {
q = strchr(p, '\n');
if (isspace(*(q + 1)))
*q = ' ';
p = q + 1;
}
return 0;
}
void
config_close(void)
{
if (file_buf)
free(file_buf);
ptr = file_buf = 0;
}
/*
* Get next entry. config_open did all the weird stuff, so just return
* the next line.
*/
char *
config_next(void)
{
char *p;
/* We might be done already ! */
if (!ptr || !*ptr)
return 0;
while (isspace(*ptr))
ptr++;
p = ptr;
ptr = strchr(p, '\n');
if (ptr) {
*ptr = '\0';
ptr++;
}
return p;
}
/*
* Return next word
*/
char *
config_skip(char **p)
{
char *q, *r;
if (!*p || !**p)
return 0;
for (q = *p; isspace(*q); q++);
if (!*q)
return 0;
for (r = q; *r && !isspace(*r); r++);
if (*r)
*r++ = '\0';
*p = r;
return q;
}