From 8d8172514d8c29cd5b2c51a0825268b823eb8294 Mon Sep 17 00:00:00 2001 From: "dsteklof@us.ibm.com" Date: Wed, 12 Nov 2003 05:37:24 -0800 Subject: [PATCH] [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(?). --- libsysfs/libsysfs.h | 1 + libsysfs/sysfs_utils.c | 42 +++++++++++++++++++++++++++++------------- 2 files changed, 30 insertions(+), 13 deletions(-) diff --git a/libsysfs/libsysfs.h b/libsysfs/libsysfs.h index ccb9898c..b3ffc467 100644 --- a/libsysfs/libsysfs.h +++ b/libsysfs/libsysfs.h @@ -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" diff --git a/libsysfs/sysfs_utils.c b/libsysfs/sysfs_utils.c index f1303cac..3e50bc61 100644 --- a/libsysfs/sysfs_utils.c +++ b/libsysfs/sysfs_utils.c @@ -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; -- 2.39.5