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[PATCH] patch for libsysfs sysfs directory handling 

Here's a quick patch to:

1) Add an environment variable "SYSFS_PATH" that libsysfs will check
for when getting mount point before searching system's sysfs mount
point.

2) A quick fix to sysfs_get_link where the bug was.

I have tested this out with libsysfs and with udev. I couldn't test
with klibc because I haven't got the tree to build with klibc without
my changes either. I made the link but get an error finding
linux/linits.h. I will figure that out.

Please have a look at the patch. If it's agreeable, please test it. I
really want to add some generic path manipulation functions for the
sysfs_get_link error, rather than my patch's hack. But, I haven't had
time yet to do that. You really sounded like you needed this for
testing, so I'm sending it out to you. I should probably add a
function to set the env variable(?).
This commit is contained in:
dsteklof@us.ibm.com 2003-11-12 05:37:24 -08:00 committed by Greg KH
parent e308ebb70f
commit 8d8172514d
2 changed files with 30 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
libsysfs/libsysfs.h
View File

@ -40,6 +40,7 @@
#define SYSFS_DRIVERS_NAME "drivers"
#define SYSFS_NAME_ATTRIBUTE "name"
#define SYSFS_UNKNOWN "unknown"
#define SYSFS_PATH_ENV "SYSFS_PATH"
/* Some "block" subsystem specific #defines */
#define SYSFS_QUEUE_NAME "queue"

42
libsysfs/sysfs_utils.c
View File

@ -84,12 +84,18 @@ static int sysfs_get_fs_mnt_path(const unsigned char *fs_type,
*/
int sysfs_get_mnt_path(unsigned char *mnt_path, size_t len)
{
int ret = -1;
char *sysfs_path = NULL;
int ret = 0;
if (mnt_path != NULL)
ret = sysfs_get_fs_mnt_path(SYSFS_FSTYPE_NAME, mnt_path, len);
else
if (mnt_path == NULL) {
errno = EINVAL;
return -1;
}
sysfs_path = getenv(SYSFS_PATH_ENV);
if (sysfs_path != NULL)
strncpy(mnt_path, sysfs_path, len);
else
ret = sysfs_get_fs_mnt_path(SYSFS_FSTYPE_NAME, mnt_path, len);
return ret;
}
@ -130,7 +136,8 @@ int sysfs_get_link(const unsigned char *path, unsigned char *target, size_t len)
{
unsigned char devdir[SYSFS_PATH_MAX];
unsigned char linkpath[SYSFS_PATH_MAX];
unsigned char *d = NULL;
unsigned char *d = NULL, *s = NULL;
int slashes = 0, count = 0;
if (path == NULL || target == NULL) {
errno = EINVAL;
@ -139,12 +146,8 @@ int sysfs_get_link(const unsigned char *path, unsigned char *target, size_t len)
memset(devdir, 0, SYSFS_PATH_MAX);
memset(linkpath, 0, SYSFS_PATH_MAX);
strncpy(devdir, path, SYSFS_PATH_MAX);
if ((sysfs_get_mnt_path(devdir, SYSFS_PATH_MAX)) != 0) {
dprintf("Sysfs not supported on this system\n");
return -1;
}
if ((readlink(path, linkpath, SYSFS_PATH_MAX)) < 0) {
return -1;
}
@ -152,12 +155,25 @@ int sysfs_get_link(const unsigned char *path, unsigned char *target, size_t len)
d = linkpath;
/* getting rid of leading "../.." */
while (*d == '/' || *d == '.')
while (*d == '/' || *d == '.') {
if (*d == '/')
slashes++;
d++;
}
d--;
strcat(devdir, d);
s = &devdir[strlen(devdir)-1];
while (s != NULL && count != (slashes+1)) {
s--;
if (*s == '/')
count++;
}
if (s == NULL)
return -1;
strncpy(s, d, (SYSFS_PATH_MAX-strlen(devdir)));
strncpy(target, devdir, len);
return 0;