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Add devname_r(3) which takes a buffer as argument.

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This commit is contained in:
phk 2003-06-20 09:52:27 +00:00
parent 4d61d2249d
commit 9dbf18e118
3 changed files with 22 additions and 56 deletions
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1
include/stdlib.h
View File

@ -258,6 +258,7 @@ int cgetustr(char *, const char *, char **);
int daemon(int, int);
char *devname(int, int);
char *devname_r(int, int, char *buf, int len);
int getloadavg(double [], int);
__const char *
getprogname(void);

20
lib/libc/gen/devname.3
View File

@ -45,6 +45,8 @@
.In stdlib.h
.Ft char *
.Fn devname "dev_t dev" "mode_t type"
.Ft char *
.Fn devname_r "dev_t dev" "mode_t type" "char *buf" "int len"
.Sh DESCRIPTION
The
.Fn devname
@ -61,27 +63,25 @@ or
.Dv S_IFCHR .
To find the right name,
.Fn devname
first searches the device database created by
.Xr dev_mkdb 8 ;
if that fails, it asks the kernel via the
asks the kernel via the
.Va kern.devname
sysctl.
If it was still unable to come up with a suitable name,
If it is unable to come up with a suitable name,
it will format the information encapsulated in
.Fa dev
and
.Fa type
in a human-readable format.
.Pp
.Fn devname
returns the name stored in a static buffer which will be overwritten
on subsequent calls.
.Fn devname_r
takes a buffer and length as argument to avoid this problem.
.Sh SEE ALSO
.Xr stat 2 ,
.Xr dev_mkdb 8
.Sh HISTORY
The
.Fn devname
function appeared in
.Bx 4.4 .
.Sh BUGS
The
.Fn devname
function returns a pointer to an internal static object;
thus, subsequent calls will modify the same buffer.

57
lib/libc/gen/devname.c
View File

@ -40,65 +40,22 @@ __FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/sysctl.h>
#include <db.h>
#include <err.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
static char *
xdevname(dev, type)
dev_t dev;
mode_t type;
{
struct {
mode_t type;
dev_t dev;
} bkey;
static DB *db;
static int failure;
DBT data, key;
if (!db && !failure &&
!(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)))
failure = 1;
if (failure)
return (NULL);
/*
* Keys are a mode_t followed by a dev_t. The former is the type of
* the file (mode & S_IFMT), the latter is the st_rdev field. Be
* sure to clear any padding that may be found in bkey.
*/
memset(&bkey, 0, sizeof(bkey));
bkey.dev = dev;
bkey.type = type;
key.data = &bkey;
key.size = sizeof(bkey);
return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
}
char *
devname(dev, type)
dev_t dev;
mode_t type;
devname_r(dev_t dev, mode_t type, char *buf, int len)
{
static char buf[SPECNAMELEN + 1];
int i;
size_t j;
char *r;
/* First check the DB file. */
r = xdevname(dev, type);
if (r != NULL)
return (r);
/* Then ask the kernel. */
if ((type & S_IFMT) == S_IFCHR) {
j = sizeof(buf);
j = len;
i = sysctlbyname("kern.devname", buf, &j, &dev, sizeof (dev));
if (i == 0)
return (buf);
@ -109,7 +66,15 @@ devname(dev, type)
r = "#NODEV";
else
r = "#%c:%d:0x%x";
snprintf(buf, SPECNAMELEN + 1, r,
snprintf(buf, len, r,
(type & S_IFMT) == S_IFCHR ? 'C' : 'B', major(dev), minor(dev));
return (buf);
}
char *
devname(dev_t dev, mode_t type)
{
static char buf[SPECNAMELEN + 1];
return(devname_r(dev, type, buf, sizeof(buf)));
}