chiark / gitweb /
[PATCH] big libsysfs diet (pre 2.0 version)
[elogind.git] / libsysfs / sysfs_utils.c
index a2410ab..9f6e18f 100644 (file)
@@ -1,9 +1,9 @@
 /*
- * syfs_utils.c
+ * sysfs_utils.c
  *
  * System utility functions for libsysfs
  *
- * Copyright (C) 2003 International Business Machines, Inc.
+ * Copyright (C) IBM Corp. 2003
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
 #include "sysfs.h"
 
 /**
- * sysfs_get_mnt_path: Gets the mount point for specified filesystem.
- * @fs_type: filesystem type to retrieve mount point
- * @mnt_path: place to put the retrieved mount path
- * @len: size of mnt_path
- * returns 0 with success and -1 with error.
- */
-static int sysfs_get_fs_mnt_path(const char *fs_type, char *mnt_path, 
-                                size_t len)
+ * sysfs_remove_trailing_slash: Removes any trailing '/' in the given path
+ * @path: Path to look for the trailing '/'
+ * Returns 0 on success 1 on error
+ */ 
+int sysfs_remove_trailing_slash(char *path)
 {
-       FILE *mnt;
-       struct mntent *mntent;
-       int ret = 0;
-       size_t dirlen = 0;
+       char *c = NULL;
 
-       /* check arg */
-       if (fs_type == NULL || mnt_path == NULL) {
+       if (!path) {
                errno = EINVAL;
-               return -1;
-       }
-
-       if ((mnt = setmntent(SYSFS_PROC_MNTS, "r")) == NULL) {
-               dprintf(stderr, "Error getting mount information\n");
-               return -1;
-       }
-       while (ret == 0 && dirlen == 0 && (mntent = getmntent(mnt)) != NULL) {
-               if (strcmp(mntent->mnt_type, fs_type) == 0) {
-                       dirlen = strlen(mntent->mnt_dir);
-                       if (dirlen <= (len - 1)) {
-                               strcpy(mnt_path, mntent->mnt_dir);
-                       } else {
-                               dprintf(stderr, 
-                                       "Error - mount path too long\n");
-                               ret = -1;
-                       }
-               }
+               return 1;
        }
-       endmntent(mnt);
-       if (dirlen == 0 && ret == 0) {
-               dprintf(stderr, "Filesystem %s not found!\n", fs_type);
+       c = strrchr(path, '/');
+       if (c == NULL) {
+               dprintf("Invalid path %s\n", path);
                errno = EINVAL;
-               ret = -1;
+               return 1;
        }
-       return ret;
+       if (*(c+1) == '\0') 
+               *c = '\0';
+       return 0;
 }
 
 /*
@@ -77,14 +55,21 @@ static int sysfs_get_fs_mnt_path(const char *fs_type, char *mnt_path,
  */
 int sysfs_get_mnt_path(char *mnt_path, size_t len)
 {
-       int ret = -1;
+       static char sysfs_path[SYSFS_PATH_MAX] = "";
+       const char *sysfs_path_env;
 
-       if (mnt_path != NULL)
-               ret = sysfs_get_fs_mnt_path(SYSFS_FSTYPE_NAME, mnt_path, len);
-       else
-               errno = EINVAL;
+       /* evaluate only at the first call */
+       if (sysfs_path[0] == '\0') {
+               /* possible overrride of real mount path */
+               sysfs_path_env = getenv(SYSFS_PATH_ENV);
+               if (sysfs_path_env != NULL) {
+                       safestrcpymax(mnt_path, sysfs_path_env, len);
+                       return 0;
+               }
+               safestrcpymax(mnt_path, SYSFS_MNT_PATH, len);
+       }
 
-       return ret;
+       return 0;
 }
 
 /**
@@ -95,20 +80,30 @@ int sysfs_get_mnt_path(char *mnt_path, size_t len)
  */
 int sysfs_get_name_from_path(const char *path, char *name, size_t len)
 {
+       char tmp[SYSFS_PATH_MAX];
        char *n = NULL;
-                                                                                
-       if (path == NULL || name == NULL) {
+
+       if (!path || !name || len == 0) {
                errno = EINVAL;
                return -1;
        }
-       n = strrchr(path, '/');
+       memset(tmp, 0, SYSFS_PATH_MAX);
+       safestrcpy(tmp, path);
+       n = strrchr(tmp, '/');
        if (n == NULL) {
                errno = EINVAL;
                return -1;
        }
+       if (*(n+1) == '\0') {
+               *n = '\0';
+               n = strrchr(tmp, '/');
+               if (n == NULL) {
+                       errno = EINVAL;
+                       return -1;
+               }
+       }
        n++;
-       strncpy(name, n, len);
-
+       safestrcpymax(name, n, len);
        return 0;
 }
 
@@ -122,35 +117,177 @@ int sysfs_get_link(const char *path, char *target, size_t len)
 {
        char devdir[SYSFS_PATH_MAX];
        char linkpath[SYSFS_PATH_MAX];
-       char *d = NULL;
+       char temp_path[SYSFS_PATH_MAX];
+       char *d = NULL, *s = NULL;
+       int slashes = 0, count = 0;
 
-       if (path == NULL || target == NULL) {
+       if (!path || !target || len == 0) {
                errno = EINVAL;
                return -1;
        }
 
        memset(devdir, 0, SYSFS_PATH_MAX);
        memset(linkpath, 0, SYSFS_PATH_MAX);
+       memset(temp_path, 0, SYSFS_PATH_MAX);
+       safestrcpy(devdir, path);
 
-       if ((sysfs_get_mnt_path(devdir, SYSFS_PATH_MAX)) != 0) {
-               dprintf(stderr, "Sysfs not supported on this system\n");
-               return -1;
-       }
-                                                                       
        if ((readlink(path, linkpath, SYSFS_PATH_MAX)) < 0) {
                return -1;
        }
-                                                                               
        d = linkpath;
+       /*
+        * Three cases here:
+        * 1. relative path => format ../..
+        * 2. absolute path => format /abcd/efgh
+        * 3. relative path _from_ this dir => format abcd/efgh
+        */
+       switch (*d) {
+               case '.': 
+                       /*
+                        * handle the case where link is of type ./abcd/xxx
+                        */
+                       safestrcpy(temp_path, devdir);
+                       if (*(d+1) == '/')
+                               d += 2;
+                       else if (*(d+1) == '.')
+                               goto parse_path;
+                       s = strrchr(temp_path, '/');
+                       if (s != NULL) {
+                               *(s+1) = '\0';
+                               safestrcat(temp_path, d);
+                       } else {
+                               safestrcpy(temp_path, d);
+                       }
+                       safestrcpymax(target, temp_path, len);
+                       break;
+                       /*
+                        * relative path, getting rid of leading "../.."
+                        */
+parse_path:
+                       while (*d == '/' || *d == '.') {
+                               if (*d == '/')
+                                       slashes++;
+                               d++;
+                       }
+                       d--;
+                       s = &devdir[strlen(devdir)-1];
+                       while (s != NULL && count != (slashes+1)) {
+                               s--;
+                               if (*s == '/')
+                                       count++;
+                       }
+                       safestrcpymax(s, d, (SYSFS_PATH_MAX-strlen(devdir)));
+                       safestrcpymax(target, devdir, len);
+                       break;
+               case '/':
+                       /* absolute path - copy as is */
+                       safestrcpymax(target, linkpath, len);
+                       break;
+               default:
+                       /* relative path from this directory */
+                       safestrcpy(temp_path, devdir);
+                       s = strrchr(temp_path, '/');
+                       if (s != NULL) {
+                               *(s+1) = '\0';
+                               safestrcat(temp_path, linkpath);
+                       } else {
+                               safestrcpy(temp_path, linkpath);
+                       }
+                       safestrcpymax(target, temp_path, len);
+       }
+       return 0;
+}
 
-       /* getting rid of leading "../.." */    
-       while (*d == '/' || *d == '.')
-               d++;
+/**
+ * sysfs_close_list: generic list free routine
+ * @list: dlist to free
+ * Returns nothing
+ */
+void sysfs_close_list(struct dlist *list)
+{
+       if (list)
+               dlist_destroy(list);
+}
 
-       d--;
-       
-       strcat(devdir, d);
-       strncpy(target, devdir, len);
+/**
+ * sysfs_open_directory_list: gets a list of all directories under "path"
+ * @path: path to read
+ * Returns a dlist of supported names or NULL no directories (errno is set
+ *     in case of error
+ */
+struct dlist *sysfs_open_directory_list(const char *path)
+{
+       if (!path)
+               return NULL;
 
-       return 0;
+       return (read_dir_subdirs(path));
+}
+
+/**
+ * sysfs_path_is_dir: Check if the path supplied points to a directory
+ * @path: path to validate
+ * Returns 0 if path points to dir, 1 otherwise
+ */
+int sysfs_path_is_dir(const char *path)
+{
+       struct stat astats;
+
+       if (!path) {
+               errno = EINVAL;
+               return 1;
+       }
+       if ((lstat(path, &astats)) != 0) {
+               dprintf("stat() failed\n");
+               return 1;
+       }
+       if (S_ISDIR(astats.st_mode))
+               return 0;
+
+       return 1;
+}
+
+/**
+ * sysfs_path_is_link: Check if the path supplied points to a link
+ * @path: path to validate
+ * Returns 0 if path points to link, 1 otherwise
+ */
+int sysfs_path_is_link(const char *path)
+{
+       struct stat astats;
+
+       if (!path) {
+               errno = EINVAL;
+               return 1;
+       }
+       if ((lstat(path, &astats)) != 0) {
+               dprintf("stat() failed\n");
+               return 1;
+       }
+       if (S_ISLNK(astats.st_mode))
+               return 0;
+
+       return 1;
+}
+
+/**
+ * sysfs_path_is_file: Check if the path supplied points to a file
+ * @path: path to validate
+ * Returns 0 if path points to file, 1 otherwise
+ */
+int sysfs_path_is_file(const char *path)
+{
+       struct stat astats;
+
+       if (!path) {
+               errno = EINVAL;
+               return 1;
+       }
+       if ((lstat(path, &astats)) != 0) {
+               dprintf("stat() failed\n");
+               return 1;
+       }
+       if (S_ISREG(astats.st_mode))
+               return 0;
+
+       return 1;
 }