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/*-
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Jordan K. Hubbard
* 29 August 1998
*
* The meat of the simple parser.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include <string.h>
#include "bootstrap.h"
static void clean(void);
static int insert(int *argcp, char *buf);
static char *variable_lookup(char *name);
#define PARSE_BUFSIZE 1024 /* maximum size of one element */
#define MAXARGS 20 /* maximum number of elements */
static char *args[MAXARGS];
/*
* parse: accept a string of input and "parse" it for backslash
* substitutions and environment variable expansions (${var}),
* returning an argc/argv style vector of whitespace separated
* arguments. Returns 0 on success, 1 on failure (ok, ok, so I
* wimped-out on the error codes! :).
*
* Note that the argv array returned must be freed by the caller, but
* we own the space allocated for arguments and will free that on next
* invocation. This allows argv consumers to modify the array if
* required.
*
* NB: environment variables that expand to more than one whitespace
* separated token will be returned as a single argv[] element, not
* split in turn. Expanded text is also immune to further backslash
* elimination or expansion since this is a one-pass, non-recursive
* parser. You didn't specify more than this so if you want more, ask
* me. - jkh
*/
#define PARSE_FAIL(expr) \
if (expr) { \
printf("fail at line %d\n", __LINE__); \
clean(); \
free(copy); \
free(buf); \
return 1; \
}
/* Accept the usual delimiters for a variable, returning counterpart */
static char
isdelim(int ch)
{
if (ch == '{')
return '}';
else if (ch == '(')
return ')';
return '\0';
}
static int
isquote(int ch)
{
return (ch == '\'' || ch == '"');
}
int
parse(int *argc, char ***argv, char *str)
{
int ac;
char *val, *p, *q, *copy = NULL;
size_t i = 0;
char token, tmp, quote, *buf;
enum { STR, VAR, WHITE } state;
ac = *argc = 0;
quote = 0;
if (!str || (p = copy = backslash(str)) == NULL)
return 1;
/* Initialize vector and state */
clean();
state = STR;
buf = (char *)malloc(PARSE_BUFSIZE);
token = 0;
/* And awaaaaaaaaay we go! */
while (*p) {
switch (state) {
case STR:
if ((*p == '\\') && p[1]) {
p++;
PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
buf[i++] = *p++;
} else if (isquote(*p)) {
quote = quote ? 0 : *p;
++p;
}
else if (isspace(*p) && !quote) {
state = WHITE;
if (i) {
buf[i] = '\0';
PARSE_FAIL(insert(&ac, buf));
i = 0;
}
++p;
} else if (*p == '$') {
token = isdelim(*(p + 1));
if (token)
p += 2;
else
++p;
state = VAR;
} else {
PARSE_FAIL(i == (PARSE_BUFSIZE - 1));
buf[i++] = *p++;
}
break;
case WHITE:
if (isspace(*p))
++p;
else
state = STR;
break;
case VAR:
if (token) {
PARSE_FAIL((q = strchr(p, token)) == NULL);
} else {
q = p;
while (*q && !isspace(*q))
++q;
}
tmp = *q;
*q = '\0';
if ((val = variable_lookup(p)) != NULL) {
size_t len = strlen(val);
strncpy(buf + i, val, PARSE_BUFSIZE - (i + 1));
i += min(len, PARSE_BUFSIZE - 1);
}
*q = tmp; /* restore value */
p = q + (token ? 1 : 0);
state = STR;
break;
}
}
/* If at end of token, add it */
if (i && state == STR) {
buf[i] = '\0';
PARSE_FAIL(insert(&ac, buf));
}
args[ac] = NULL;
*argc = ac;
*argv = (char **)malloc((sizeof(char *) * ac + 1));
bcopy(args, *argv, sizeof(char *) * ac + 1);
free(buf);
free(copy);
return 0;
}
#define MAXARGS 20
/* Clean vector space */
static void
clean(void)
{
int i;
for (i = 0; i < MAXARGS; i++) {
if (args[i] != NULL) {
free(args[i]);
args[i] = NULL;
}
}
}
static int
insert(int *argcp, char *buf)
{
if (*argcp >= MAXARGS)
return 1;
args[(*argcp)++] = strdup(buf);
return 0;
}
static char *
variable_lookup(char *name)
{
/* XXX search "special variable" space first? */
return (char *)getenv(name);
}
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