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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-23 21:35:29 +03:00

Add support functions for analysis of config sections,

and hence, on-disk LVM2 metadata.

--
This commit is contained in:
Dave Wysochanski 2007-04-25 20:38:39 +00:00
parent 1c2360b335
commit 8fc854f38e
3 changed files with 71 additions and 5 deletions

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@ -1,5 +1,6 @@
Version 2.02.25 - Version 2.02.25 -
================================= =================================
Add support functions for analysis of config sections
Update pvck to read labels on disk, with --labelsector parameter Update pvck to read labels on disk, with --labelsector parameter
Add count_chars and count_chars_len functions Add count_chars and count_chars_len functions
Add /sys/block listings to lvm_dump.sh Add /sys/block listings to lvm_dump.sh

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@ -19,6 +19,7 @@
#include "device.h" #include "device.h"
#include "str_list.h" #include "str_list.h"
#include "toolcontext.h" #include "toolcontext.h"
#include "lvm-string.h"
#include <sys/stat.h> #include <sys/stat.h>
#include <sys/mman.h> #include <sys/mman.h>
@ -26,6 +27,9 @@
#include <fcntl.h> #include <fcntl.h>
#include <ctype.h> #include <ctype.h>
#define SECTION_B_CHAR '{'
#define SECTION_E_CHAR '}'
enum { enum {
TOK_INT, TOK_INT,
TOK_FLOAT, TOK_FLOAT,
@ -474,7 +478,7 @@ static struct config_node *_file(struct parser *p)
static struct config_node *_section(struct parser *p) static struct config_node *_section(struct parser *p)
{ {
/* IDENTIFIER '{' VALUE* '}' */ /* IDENTIFIER SECTION_B_CHAR VALUE* SECTION_E_CHAR */
struct config_node *root, *n, *l = NULL; struct config_node *root, *n, *l = NULL;
if (!(root = _create_node(p))) { if (!(root = _create_node(p))) {
stack; stack;
@ -623,12 +627,12 @@ static void _get_token(struct parser *p, int tok_prev)
p->t = TOK_INT; /* fudge so the fall through for p->t = TOK_INT; /* fudge so the fall through for
floats works */ floats works */
switch (*p->te) { switch (*p->te) {
case '{': case SECTION_B_CHAR:
p->t = TOK_SECTION_B; p->t = TOK_SECTION_B;
p->te++; p->te++;
break; break;
case '}': case SECTION_E_CHAR:
p->t = TOK_SECTION_E; p->t = TOK_SECTION_E;
p->te++; p->te++;
break; break;
@ -708,8 +712,9 @@ static void _get_token(struct parser *p, int tok_prev)
default: default:
p->t = TOK_IDENTIFIER; p->t = TOK_IDENTIFIER;
while ((p->te != p->fe) && (*p->te) && !isspace(*p->te) && while ((p->te != p->fe) && (*p->te) && !isspace(*p->te) &&
(*p->te != '#') && (*p->te != '=') && (*p->te != '{') && (*p->te != '#') && (*p->te != '=') &&
(*p->te != '}')) (*p->te != SECTION_B_CHAR) &&
(*p->te != SECTION_E_CHAR))
p->te++; p->te++;
break; break;
} }
@ -1146,3 +1151,61 @@ int merge_config_tree(struct cmd_context *cmd, struct config_tree *cft,
return 1; return 1;
} }
/*
* Convert a token type to the char it represents.
*/
static char _token_type_to_char(int type)
{
switch (type) {
case TOK_SECTION_B:
return SECTION_B_CHAR;
case TOK_SECTION_E:
return SECTION_E_CHAR;
default:
return 0;
}
}
/*
* Returns:
* # of 'type' tokens in 'str'.
*/
static unsigned _count_tokens (const char *str, unsigned len, int type)
{
char c;
c = _token_type_to_char(type);
return(count_chars_len(str, len, c));
}
/*
* Heuristic function to make a quick guess as to whether a text
* region probably contains a valid config "section". (Useful for
* scanning areas of the disk for old metadata.)
* Config sections contain various tokens, may contain other sections
* and strings, and are delimited by begin (type 'TOK_SECTION_B') and
* end (type 'TOK_SECTION_E') tokens. As a quick heuristic, we just
* count the number of begin and end tokens, and see if they are
* non-zero and the counts match.
* Full validation of the section should be done with another function
* (for example, read_config_fd).
*
* Returns:
* 0 - probably is not a valid config section
* 1 - probably _is_ a valid config section
*/
unsigned maybe_config_section(const char *str, unsigned len)
{
int begin_count;
int end_count;
begin_count = _count_tokens(str, len, TOK_SECTION_B);
end_count = _count_tokens(str, len, TOK_SECTION_E);
if (begin_count && end_count && (begin_count - end_count == 0))
return 1;
else
return 0;
}

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@ -108,4 +108,6 @@ int get_config_uint64(const struct config_node *cn, const char *path,
int get_config_str(const struct config_node *cn, const char *path, int get_config_str(const struct config_node *cn, const char *path,
char **result); char **result);
unsigned maybe_config_section(const char *str, unsigned len);
#endif #endif