In this patch, the xc_domain_dumpcore_via_callback() in xc_core.c of

libxc is modified. Previously, the xc_domain_dumpcore_via_callback()
did not respond to error when copy_from_domain_page() failed.
In other words, the dump core remained silent even if mapping the domain
memory failed and its page could not be copied. When this happened,
erroneous data had been dumped to the file without the user realizing it.
Now, it has been modified so that if copy_from_domain_page fails,
this fact is recorded in the logfile and make imcoplerte-list.
However even in such cases, the dumping will continue as before.

Signed-off-by: Ken Hironaka <hironaka.ken@soft.fujitsu.com>
Signed-off-by: Akio Takebe <takebe_akio@jp.fujitsu.com>

diff --git a/tools/libxc/xc_core.c b/tools/libxc/xc_core.c
index efaf397abf55bb1968442afd0efcd2f7a608e4eb..eddba6304b05de43f8931f049c76a2e90f2b9f61 100644 (file)
--- a/tools/libxc/xc_core.c
+++ b/tools/libxc/xc_core.c
@@ -6,6 +6,12 @@
 #define DUMP_INCREMENT (4 * 1024)
 #define round_pgup(_p)    (((_p)+(PAGE_SIZE-1))&PAGE_MASK)
 
+/* Callback args for writing to a local dump file. */
+struct dump_args {
+    int     fd;
+    int     incomp_fd;
+};
+
 static int
 copy_from_domain_page(int xc_handle,
                       uint32_t domid,
@@ -27,7 +33,7 @@ xc_domain_dumpcore_via_callback(int xc_handle,
                                 void *args,
                                 dumpcore_rtn_t dump_rtn)
 {
-    unsigned long nr_pages;
+    unsigned long n, nr_pages;
     xen_pfn_t *page_array = NULL;
     xc_dominfo_t info;
     int i, nr_vcpus = 0;
@@ -37,6 +43,12 @@ xc_domain_dumpcore_via_callback(int xc_handle,
     char dummy[PAGE_SIZE];
     int dummy_len;
     int sts;
+    unsigned int cpy_err_cnt = 0;
+    struct dump_args *da = args;
+    int fd = da->fd;
+    int incomp_fd = da->incomp_fd;
+    char cpy_err_mesg[64];
+    int mesg_bytes;
 
     if ( (dump_mem_start = malloc(DUMP_INCREMENT*PAGE_SIZE)) == NULL )
     {
@@ -73,11 +85,11 @@ xc_domain_dumpcore_via_callback(int xc_handle,
                  (nr_pages * sizeof(xen_pfn_t)));
     header.xch_pages_offset = round_pgup(dummy_len);
 
-    sts = dump_rtn(args, (char *)&header, sizeof(struct xc_core_header));
+    sts = dump_rtn(fd, (char *)&header, sizeof(struct xc_core_header));
     if ( sts != 0 )
         goto error_out;
 
-    sts = dump_rtn(args, (char *)&ctxt, sizeof(ctxt[0]) * nr_vcpus);
+    sts = dump_rtn(fd, (char *)&ctxt, sizeof(ctxt[0]) * nr_vcpus);
     if ( sts != 0 )
         goto error_out;
 
@@ -91,28 +103,40 @@ xc_domain_dumpcore_via_callback(int xc_handle,
         IPRINTF("Could not get the page frame list\n");
         goto error_out;
     }
-    sts = dump_rtn(args, (char *)page_array, nr_pages * sizeof(xen_pfn_t));
+    sts = dump_rtn(fd, (char *)page_array, nr_pages * sizeof(xen_pfn_t));
     if ( sts != 0 )
         goto error_out;
 
     /* Pad the output data to page alignment. */
     memset(dummy, 0, PAGE_SIZE);
-    sts = dump_rtn(args, dummy, header.xch_pages_offset - dummy_len);
+    sts = dump_rtn(fd, dummy, header.xch_pages_offset - dummy_len);
     if ( sts != 0 )
         goto error_out;
 
-    for ( dump_mem = dump_mem_start, i = 0; i < nr_pages; i++ )
+    for ( dump_mem = dump_mem_start, n = 0; n < nr_pages; n++ )
     {
-        copy_from_domain_page(xc_handle, domid, page_array[i], dump_mem);
+        sts = copy_from_domain_page(xc_handle, domid, page_array[i], dump_mem);
+        if( sts != 0 ){
+            memset(dump_mem, 0, PAGE_SIZE);
+            cpy_err_cnt++;
+            memset(cpy_err_mesg, 0, sizeof(cpy_err_mesg));
+            mesg_bytes = sprintf(cpy_err_mesg, "Cannot copy_from_domain_page (%lu)\n", n);
+            dump_rtn(incomp_fd, (char *)cpy_err_mesg, mesg_bytes);
+        }
+
         dump_mem += PAGE_SIZE;
-        if ( ((i + 1) % DUMP_INCREMENT == 0) || ((i + 1) == nr_pages) )
+        if ( ((n + 1) % DUMP_INCREMENT == 0) || ((n + 1) == nr_pages) )
         {
-            sts = dump_rtn(args, dump_mem_start, dump_mem - dump_mem_start);
+            sts = dump_rtn(fd, dump_mem_start, dump_mem - dump_mem_start);
             if ( sts != 0 )
                 goto error_out;
             dump_mem = dump_mem_start;
         }
     }
+    if( cpy_err_cnt != 0 ){
+        IPRINTF("Could not copy from domid=%d (%d)pages\n", domid, cpy_err_cnt);
+        goto error_out;
+    }
 
     free(dump_mem_start);
     free(page_array);
@@ -124,20 +148,14 @@ xc_domain_dumpcore_via_callback(int xc_handle,
     return -1;
 }
 
-/* Callback args for writing to a local dump file. */
-struct dump_args {
-    int     fd;
-};
-
 /* Callback routine for writing to a local dump file. */
-static int local_file_dump(void *args, char *buffer, unsigned int length)
+static int local_file_dump(int fd, char *buffer, unsigned int length)
 {
-    struct dump_args *da = args;
     int bytes, offset;
 
     for ( offset = 0; offset < length; offset += bytes )
     {
-        bytes = write(da->fd, &buffer[offset], length-offset);
+        bytes = write(fd, &buffer[offset], length-offset);
         if ( bytes <= 0 )
         {
             PERROR("Failed to write buffer: %s", strerror(errno));
@@ -154,6 +172,7 @@ xc_domain_dumpcore(int xc_handle,
                    const char *corename)
 {
     struct dump_args da;
+    char *incomp_file;
     int sts;
 
     if ( (da.fd = open(corename, O_CREAT|O_RDWR, S_IWUSR|S_IRUSR)) < 0 )
@@ -162,10 +181,28 @@ xc_domain_dumpcore(int xc_handle,
         return -errno;
     }
 
+    
+    if ( (incomp_file = (char *)malloc(sizeof(corename) + 12)) == NULL )
+    {
+        PERROR("Could not allocate incomp_file");
+        return -errno;
+    }
+
+    sprintf(incomp_file, "%s-incomp.list", corename);
+    if ( (da.incomp_fd = open(incomp_file, O_CREAT|O_RDWR, S_IWUSR|S_IRUSR)) < 0 )
+    {
+        PERROR("Could not open corefile %s: %s", incomp_file, strerror(errno));
+        return -errno;
+    }
+
     sts = xc_domain_dumpcore_via_callback(
         xc_handle, domid, &da, &local_file_dump);
 
     close(da.fd);
+    close(da.incomp_fd);
+
+    if( sts == 0)
+        unlink(incomp_file);
 
     return sts;
 }

diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
index 0a5cfadd3d1ec48a9448a09e35c488c536e36139..f7242913210a85cf4b2facdcb6f6c0500ec3de98 100644 (file)
--- a/tools/libxc/xenctrl.h
+++ b/tools/libxc/xenctrl.h
@@ -166,7 +166,7 @@ int xc_domain_dumpcore(int xc_handle,
  * and passes an opaque object for the use of the function and
  * created by the caller of xc_domain_dumpcore_via_callback.
  */
-typedef int (dumpcore_rtn_t)(void *arg, char *buffer, unsigned int length);
+typedef int (dumpcore_rtn_t)(int fd, char *buffer, unsigned int length);
 
 int xc_domain_dumpcore_via_callback(int xc_handle,
                                     uint32_t domid,