shithub: neoventi

ref: 0a0dc432673d0c5f0902b0d053e08c8fe41a0eea
dir: /venti/config.c/

#include "platform.h"
#include "dat.h"
#include "fns.h"

#include <stdio.h>

static char magic[] = "venti config\n";
static uint8_t magiclen = sizeof(magic);

// Precondition: buf points to an array of >= MaxConfig+1 bytes
void
readconfig(char *path, char *buf)
{
	size_t fsize, n = 0, offset = 0;
	int fd = open(path, OREAD);
	if(fd < 0)
		sysfatal("Unable to open '%s' for config file", path);
	fsize = fdsize(fd);
	if(fsize > PartBlank)
		offset = PartBlank - MaxConfig;
	else if(fsize > MaxConfig)
		sysfatal("Config file '%s' too large (size %lu, max %lu)!", path, fsize, MaxConfig);
	n = pread(fd, buf, MaxConfig, offset);
	if(n == 0)
		sysfatal("Config file '%s' empty!", path);
	if(offset != 0){
		if(memcmp(buf, magic, magiclen) != 0)
			sysfatal("bad venti config magic in '%s'", path);
		memmove(buf, buf + magiclen, MaxConfig - magiclen);
		n -= magiclen;
	}
	buf[n] = 0;
}

/* Skips to the next part of the string with meaning - i.e. skips comments and whitespace */
/* *line indicates whether a line was found */
static char*
skip(char *c, int *line)
{
	if(c == NULL)
		return NULL;
	if(line != NULL)
		*line = 0;
	while(*c == '#' || isspace(*c)){
		if(*c == '#'){
			while(*c != '\n' && *c != 0)
				c += 1;
			/* either at a newline or end-of-string */
		}
		while(isspace(*c)){
			if(*c == '\n' && line != NULL)
				*line = 1;
			c += 1;
		}
	}
	if(*c == 0)
		return NULL;
	return c;
}

static int
confis(char **c, char *test, char **out)
{
	int lined;
	if(!strbegins(*c, test))
		return 0;
	*c += strlen(test) + 1;
	*out = untilspace(*c);
	*c += strlen(*out);
	if(*out == NULL)
		sysfatal("Out of memory");
	*c = skip(*c, &lined);
	if(lined == 0)
		sysfatal("config error: garbage found after '%s' line", test);
	return 1;
}

static void
indexname(config *conf, char *name)
{
	if(conf->index != NULL)
		sysfatal("configuration error: multiple names specified for index");
	if(!nameok(name))
		sysfatal("Invalid name specified for index: '%s'", name);
	conf->index = name;
}

static void
parseconfig(config *conf, char *buf)
{
	char *c = buf, *tmp;
	while((c = skip(c, NULL)) != NULL){
		if(confis(&c, "index", &tmp))
			indexname(conf, tmp);
		else if(confis(&c, "isect", &tmp))
			sysfatal("TODO isect '%s'", tmp);
		else if(strbegins(c, "arenas "))
			sysfatal("TODO arenas");
		else
			sysfatal("TODO load config from '%s' (offset %d)", c, c - buf);
	}
}

config
loadconfig(char *path)
{
	char buf[MaxConfig + 1];
	config conf;
	memset(&conf, 0, sizeof(conf));
	readconfig(path, buf);
	parseconfig(&conf, buf);
	return conf;
}