[PATCH 05/19] fs: implement stat
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Tue Sep 4 15:50:03 EDT 2012
stat() stats the file pointed to by path and fills in buf.
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
fs/fs.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
include/fs.h | 6 ++--
2 files changed, 107 insertions(+), 4 deletions(-)
diff --git a/fs/fs.c b/fs/fs.c
index f46c606..dfe571a 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -26,6 +26,7 @@
#include <errno.h>
#include <malloc.h>
#include <linux/stat.h>
+#include <linux/err.h>
#include <fcntl.h>
#include <xfuncs.h>
#include <init.h>
@@ -111,6 +112,61 @@ static int init_cwd(void)
postcore_initcall(init_cwd);
+char *normalise_link(const char *pathname, const char *symlink)
+{
+ const char *buf = symlink;
+ char *path_free, *path;
+ char *absolute_path;
+ int point = 0;
+ int dir = 1;
+ int len;
+
+ if (symlink[0] == '/')
+ return strdup(symlink);
+
+ while (*buf == '.' || *buf == '/') {
+ if (*buf == '.') {
+ point++;
+ } else if (*buf == '/') {
+ point = 0;
+ dir++;
+ }
+ if (point > 2) {
+ buf -= 2;
+ break;
+ }
+ buf++;
+ }
+
+ path = path_free = strdup(pathname);
+ if (!path)
+ return NULL;
+
+ while(dir) {
+ path = dirname(path);
+ dir--;
+ }
+
+ len = strlen(buf) + strlen(path) + 1;
+ if (buf[0] != '/')
+ len++;
+
+ absolute_path = calloc(sizeof(char), len);
+
+ if (!absolute_path)
+ goto out;
+
+ strcat(absolute_path, path);
+ if (buf[0] != '/')
+ strcat(absolute_path, "/");
+ strcat(absolute_path, buf);
+
+out:
+ free(path_free);
+
+ return absolute_path;
+}
+
char *normalise_path(const char *pathname)
{
char *path = xzalloc(strlen(pathname) + strlen(cwd) + 2);
@@ -512,6 +568,42 @@ out:
}
EXPORT_SYMBOL(unlink);
+static char *realfile(const char *pathname, struct stat *s)
+{
+ char *path = normalise_path(pathname);
+ int ret;
+
+ ret = lstat(path, s);
+ if (ret)
+ goto out;
+
+ if (S_ISLNK(s->st_mode)) {
+ char tmp[PATH_MAX];
+ char *new_path;
+
+ memset(tmp, 0, PATH_MAX);
+
+ ret = readlink(path, tmp, PATH_MAX - 1);
+ if (ret < 0)
+ goto out;
+
+ new_path = normalise_link(path, tmp);
+ free(path);
+ if (!new_path)
+ return ERR_PTR(-ENOMEM);
+ path = new_path;
+
+ ret = lstat(path, s);
+ }
+
+ if (!ret)
+ return path;
+
+out:
+ free(path);
+ return ERR_PTR(ret);
+}
+
int open(const char *pathname, int flags, ...)
{
struct fs_device_d *fsdev;
@@ -1218,6 +1310,19 @@ int closedir(DIR *dir)
}
EXPORT_SYMBOL(closedir);
+int stat(const char *filename, struct stat *s)
+{
+ char *f;
+
+ f = realfile(filename, s);
+ if (IS_ERR(f))
+ return PTR_ERR(f);
+
+ free(f);
+ return 0;
+}
+EXPORT_SYMBOL(stat);
+
int lstat(const char *filename, struct stat *s)
{
struct device_d *dev;
diff --git a/include/fs.h b/include/fs.h
index d96de0e..07976d2 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -107,10 +107,7 @@ int unlink(const char *pathname);
int close(int fd);
int flush(int fd);
int lstat(const char *filename, struct stat *s);
-static inline int stat(const char *filename, struct stat *s)
-{
- return lstat(filename, s);
-}
+int stat(const char *filename, struct stat *s);
int read(int fd, void *buf, size_t count);
int ioctl(int fd, int request, void *buf);
ssize_t write(int fd, const void *buf, size_t count);
@@ -169,6 +166,7 @@ void *read_file(const char *filename, size_t *size);
* of "..", "." and double slashes. The returned string must be freed wit free().
*/
char *normalise_path(const char *path);
+char *normalise_link(const char *pathname, const char* symlink);
/* Register a new filesystem driver */
int register_fs_driver(struct fs_driver_d *fsdrv);
--
1.7.10.4
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