Patchwork [V3,2/7] block: Add WIN32 platform support for backing_file_loop_check()

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Submitter Xu Wang
Date July 15, 2013, 9:42 a.m.
Message ID <1373881356-3294-3-git-send-email-cngesaint@gmail.com>
Download mbox | patch
Permalink /patch/258973/
State New
Headers show

Comments

Xu Wang - July 15, 2013, 9:42 a.m.
Method of get_inode is different between Linux and WIN32 plateform.
This patch added inode caculate method on Windows plateform so that
backing file check could work on Windows plateform.

Signed-off-by: Xu Wang <cngesaint@gmail.com>
---
 block.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 101 insertions(+), 8 deletions(-)
Fam Zheng - July 18, 2013, 5:24 a.m.
On Mon, 07/15 05:42, Xu Wang wrote:
> Method of get_inode is different between Linux and WIN32 plateform.
> This patch added inode caculate method on Windows plateform so that
> backing file check could work on Windows plateform.
> 
> Signed-off-by: Xu Wang <cngesaint@gmail.com>
> ---
>  block.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 101 insertions(+), 8 deletions(-)
> 
> diff --git a/block.c b/block.c
> index c1d060d..a06bb08 100644
> --- a/block.c
> +++ b/block.c
> @@ -51,6 +51,10 @@
>  
>  #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
>  
> +#ifdef _WIN32
> +#define MAX_PATH_LEN 8192
> +#endif
> +
>  typedef enum {
>      BDRV_REQ_COPY_ON_READ = 0x1,
>      BDRV_REQ_ZERO_WRITE   = 0x2,
> @@ -4433,6 +4437,96 @@ bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
>      bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
>  }
>  
> +#ifdef _WIN32
> +static int get_lnk_target_file(const char *lnk_file, char *filepath)
> +{
> +    unsigned int flag, offet;
> +    unsigned int sflag;
> +    char uch;
> +    int i = 0;
> +
> +    FILE *fd = fopen(lnk_file, "rb");
> +    if (!fd) {
> +        error_report("Open file %s failed.", lnk_file);
> +        return -1;
> +    }
> +    fread(&flag, 4, 1, fd);
> +    if (flag != 0x4c) {
> +        error_report("%s is not a lnk file.", lnk_file);
> +        fclose(fd);
> +        return -1;
> +    }
> +    fseek(fd, 0x14, SEEK_SET);
> +    fread(&flag, 4, 1, fd);
> +    fseek(fd, 0x4c, SEEK_SET);
> +
> +    if (flag & 0x01) {
> +        fread(&sflag, 2, 1, fd);
> +        fseek(fd, sflag, SEEK_CUR);
> +    }
> +
> +    offset = ftell(fd);
> +    fseek(fd, offset + 0x10, SEEK_SET);
> +    fread(&flag, 4, 1, fd);
> +    fseek(fd, flag + offset, SEEK_SET);
> +
> +    do {
> +        fread(&uch, 1, 1, fd);
> +        filepath[i++] = uch;
> +    } while ((i <= MAX_PATH_LEN) && (uch != '\0'));
> +
> +    fclose(fd);
> +    return 0;
> +}

You didn't check ret value for fseek and fread, what if they are not
succeesful?

> +#endif
> +
> +static long get_inode(const char *filename)
> +{
> +    #ifdef _WIN32
> +    char pbuf[MAX_PATH_LEN], *p;
> +    long inode;
> +    struct stat sbuf;
> +    char path[MAX_PATH_LEN];
> +    int len;
> +
> +    /* If filename contains .lnk, it's a shortcuts. Target file
> +     * need to be parsed.
> +     */
> +    len = strlen(filename);
> +    if (strcmp(filename + len - 4, ".lnk")) {

Don't read out of range: if filename is shorter than 4 chars, (filename +
len - 4) points to address before filename.

> +        if (get_lnk_target_file(filename, path)) {
> +            error_report("Parse .lnk file %s failed.", filename);
> +            return -1;
> +        }
> +    } else {
> +        memcpy(path, filename, sizeof(filename));
> +    }
> +
> +    if (stat(path, &sbuf) == -1) {
> +        error_report("get file %s stat error.", path);
> +        return -1;
> +    }
> +    if (GetFullPathName(path, MAX_PATH_LEN, pbuf, &p) != 0) {
> +        inode = 11003;
> +        for (p = pbuf; *p != '\0'; p++) {
> +            inode = inode * 31 + *(unsigned char *)p;
> +        }
> +        return (inode * 911) & 0x7FFF;
> +    }
> +
> +    return -1;
> +    #else
> +    struct stat sbuf;
> +
> +    if (stat(filename, &sbuf) == -1) {
> +        error_report("get file %s stat error.", filename);
> +        return -1;
> +    }
> +
> +    return sbuf.st_ino;
> +    #endif
> +}
> +
>  static gboolean str_equal_func(gconstpointer a, gconstpointer b)
>  {
>      return strcmp(a, b) == 0;
> @@ -4457,7 +4551,6 @@ bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
>      GHashTable *inodes;
>      BlockDriverState *bs;
>      BlockDriver *drv;
> -    struct stat sbuf;
>      long inode = 0;
>      int ret;
>      char fbuf[1024];
> @@ -4469,11 +4562,11 @@ bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
>          if (access(filename, F_OK)) {
>              inode = -1;
>          } else {
> -            if (stat(filename, &sbuf) == -1) {
> -                error_report("Get file %s stat failed.", filename);
> +            inode = get_inode(filename);
> +            if (inode == -1) {
> +                error_report("Get file %s inode failed.", filename);
>                  goto err;
>              }
> -            inode = (long)sbuf.st_ino;
>          }
>  
>          filename = backing_file;
> @@ -4482,11 +4575,11 @@ bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
>      }
>  
>      while (filename && (filename[0] != '\0')) {
> -        if (stat(filename, &sbuf) == -1) {
> -                error_report("Get file %s stat failed.", filename);
> -                goto err;
> +        inode = get_inode(filename);
> +        if (inode == -1) {
> +            error_report("Get file %s inode failed.", filename);
> +            goto err;
>          }
> -        inode = (long)sbuf.st_ino;
>  
>          if (g_hash_table_lookup_extended(inodes, &inode, NULL, NULL)) {
>              error_report("Backing file '%s' creates an infinite loop.",
> -- 
> 1.8.1.4
>

Patch

diff --git a/block.c b/block.c
index c1d060d..a06bb08 100644
--- a/block.c
+++ b/block.c
@@ -51,6 +51,10 @@ 
 
 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
 
+#ifdef _WIN32
+#define MAX_PATH_LEN 8192
+#endif
+
 typedef enum {
     BDRV_REQ_COPY_ON_READ = 0x1,
     BDRV_REQ_ZERO_WRITE   = 0x2,
@@ -4433,6 +4437,96 @@  bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
     bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
 }
 
+#ifdef _WIN32
+static int get_lnk_target_file(const char *lnk_file, char *filepath)
+{
+    unsigned int flag, offet;
+    unsigned int sflag;
+    char uch;
+    int i = 0;
+
+    FILE *fd = fopen(lnk_file, "rb");
+    if (!fd) {
+        error_report("Open file %s failed.", lnk_file);
+        return -1;
+    }
+    fread(&flag, 4, 1, fd);
+    if (flag != 0x4c) {
+        error_report("%s is not a lnk file.", lnk_file);
+        fclose(fd);
+        return -1;
+    }
+    fseek(fd, 0x14, SEEK_SET);
+    fread(&flag, 4, 1, fd);
+    fseek(fd, 0x4c, SEEK_SET);
+
+    if (flag & 0x01) {
+        fread(&sflag, 2, 1, fd);
+        fseek(fd, sflag, SEEK_CUR);
+    }
+
+    offset = ftell(fd);
+    fseek(fd, offset + 0x10, SEEK_SET);
+    fread(&flag, 4, 1, fd);
+    fseek(fd, flag + offset, SEEK_SET);
+
+    do {
+        fread(&uch, 1, 1, fd);
+        filepath[i++] = uch;
+    } while ((i <= MAX_PATH_LEN) && (uch != '\0'));
+
+    fclose(fd);
+    return 0;
+}
+#endif
+
+static long get_inode(const char *filename)
+{
+    #ifdef _WIN32
+    char pbuf[MAX_PATH_LEN], *p;
+    long inode;
+    struct stat sbuf;
+    char path[MAX_PATH_LEN];
+    int len;
+
+    /* If filename contains .lnk, it's a shortcuts. Target file
+     * need to be parsed.
+     */
+    len = strlen(filename);
+    if (strcmp(filename + len - 4, ".lnk")) {
+        if (get_lnk_target_file(filename, path)) {
+            error_report("Parse .lnk file %s failed.", filename);
+            return -1;
+        }
+    } else {
+        memcpy(path, filename, sizeof(filename));
+    }
+
+    if (stat(path, &sbuf) == -1) {
+        error_report("get file %s stat error.", path);
+        return -1;
+    }
+    if (GetFullPathName(path, MAX_PATH_LEN, pbuf, &p) != 0) {
+        inode = 11003;
+        for (p = pbuf; *p != '\0'; p++) {
+            inode = inode * 31 + *(unsigned char *)p;
+        }
+        return (inode * 911) & 0x7FFF;
+    }
+
+    return -1;
+    #else
+    struct stat sbuf;
+
+    if (stat(filename, &sbuf) == -1) {
+        error_report("get file %s stat error.", filename);
+        return -1;
+    }
+
+    return sbuf.st_ino;
+    #endif
+}
+
 static gboolean str_equal_func(gconstpointer a, gconstpointer b)
 {
     return strcmp(a, b) == 0;
@@ -4457,7 +4551,6 @@  bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
     GHashTable *inodes;
     BlockDriverState *bs;
     BlockDriver *drv;
-    struct stat sbuf;
     long inode = 0;
     int ret;
     char fbuf[1024];
@@ -4469,11 +4562,11 @@  bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
         if (access(filename, F_OK)) {
             inode = -1;
         } else {
-            if (stat(filename, &sbuf) == -1) {
-                error_report("Get file %s stat failed.", filename);
+            inode = get_inode(filename);
+            if (inode == -1) {
+                error_report("Get file %s inode failed.", filename);
                 goto err;
             }
-            inode = (long)sbuf.st_ino;
         }
 
         filename = backing_file;
@@ -4482,11 +4575,11 @@  bool bdrv_backing_file_loop_check(const char *filename, const char *fmt,
     }
 
     while (filename && (filename[0] != '\0')) {
-        if (stat(filename, &sbuf) == -1) {
-                error_report("Get file %s stat failed.", filename);
-                goto err;
+        inode = get_inode(filename);
+        if (inode == -1) {
+            error_report("Get file %s inode failed.", filename);
+            goto err;
         }
-        inode = (long)sbuf.st_ino;
 
         if (g_hash_table_lookup_extended(inodes, &inode, NULL, NULL)) {
             error_report("Backing file '%s' creates an infinite loop.",