[Xen-devel] [PATCH v1 7/7] tools/livepatch: Exit with 2 if a timeout occurs

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

Exit with 0 for success.
Exit with 1 for an error.
Exit with 2 if the operation should be retried for any reason (e.g. a
timeout or because another operation was in progress).

This allows a program or script driving xen-livepatch to determine if
the operation should be retried without parsing the output.

Fix a number of incorrect uses of errno after an operation that could
set it (e.g. fprintf, close).

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 tools/misc/xen-livepatch.c | 60 +++++++++++++++++++++++++++++++---------------
 1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/tools/misc/xen-livepatch.c b/tools/misc/xen-livepatch.c
index 9633c4a..370ad60 100644
--- a/tools/misc/xen-livepatch.c
+++ b/tools/misc/xen-livepatch.c
@@ -101,9 +101,10 @@ static int list_func(int argc, char *argv[])
         rc = xc_livepatch_list(xch, MAX_LEN, idx, info, name, len, &done, 
&left);
         if ( rc )
         {
+            rc = errno;
             fprintf(stderr, "Failed to list %d/%d.\n"
                             "Error %d: %s\n",
-                    idx, left, errno, strerror(errno));
+                    idx, left, rc, strerror(rc));
             break;
         }
         if ( !idx )
@@ -175,37 +176,40 @@ static int upload_func(int argc, char *argv[])
     fd = open(filename, O_RDONLY);
     if ( fd < 0 )
     {
+        int saved_errno = errno;
         fprintf(stderr, "Could not open %s.\n"
                         "Error %d: %s\n",
-                filename, errno, strerror(errno));
-        return errno;
+                filename, saved_errno, strerror(saved_errno));
+        return saved_errno;
     }
     if ( stat(filename, &buf) != 0 )
     {
+        int saved_errno = errno;
         fprintf(stderr, "Could not get size of %s.\n"
                         "Error %d: %s\n",
-                filename, errno, strerror(errno));
+                filename, saved_errno, strerror(saved_errno));
         close(fd);
-        return errno;
+        return saved_errno;
     }
 
     len = buf.st_size;
     fbuf = mmap(0, len, PROT_READ, MAP_PRIVATE, fd, 0);
     if ( fbuf == MAP_FAILED )
     {
+        int saved_errno = errno;
         fprintf(stderr, "Could not map %s.\n"
                         "Error %d: %s\n",
-                filename, errno, strerror(errno));
+                filename, saved_errno, strerror(saved_errno));
         close (fd);
-        return errno;
+        return saved_errno;
     }
     printf("Uploading %s... ", filename);
     rc = xc_livepatch_upload(xch, name, fbuf, len);
     if ( rc )
     {
+        rc = errno;
         printf("failed\n");
-        fprintf(stderr, "Error %d: %s\n",
-                errno, strerror(errno));
+        fprintf(stderr, "Error %d: %s\n", rc, strerror(rc));
     }
     else
         printf("completed\n");
@@ -216,8 +220,6 @@ static int upload_func(int argc, char *argv[])
         fprintf(stderr, "Could not unmap %s.\n"
                         "Error %d: %s\n",
                 filename, errno, strerror(errno));
-        if ( !rc )
-            rc = errno;
     }
     close(fd);
 
@@ -307,17 +309,18 @@ int action_func(int argc, char *argv[], unsigned int idx)
     rc = xc_livepatch_get(xch, name, &status);
     if ( rc )
     {
+        int saved_errno = errno;
         fprintf(stderr, "Failed to get status of %s.\n"
                         "Error %d: %s\n",
-                name, errno, strerror(errno));
-        return -1;
+                name, saved_errno, strerror(saved_errno));
+        return saved_errno;
     }
     if ( status.rc == -XEN_EAGAIN )
     {
         fprintf(stderr,
                 "Cannot execute %s.\n"
                 "Operation already in progress.\n", action_options[idx].name);
-        return -1;
+        return EAGAIN;
     }
 
     if ( status.state == action_options[idx].expected )
@@ -333,9 +336,11 @@ int action_func(int argc, char *argv[], unsigned int idx)
         rc = action_options[idx].function(xch, name, HYPERVISOR_TIMEOUT);
         if ( rc )
         {
+            int saved_errno = errno;
             printf("failed\n");
-            fprintf(stderr, "Error %d: %s\n", errno, strerror(errno));
-            return -1;
+            fprintf(stderr, "Error %d: %s\n",
+                    saved_errno, strerror(saved_errno));
+            return saved_errno;
         }
     }
     else
@@ -360,7 +365,7 @@ int action_func(int argc, char *argv[], unsigned int idx)
     {
         printf("failed\n");
         fprintf(stderr, "Operation didn't complete.\n");
-        return -1;
+        return EAGAIN;
     }
 
     if ( rc == 0 )
@@ -372,7 +377,7 @@ int action_func(int argc, char *argv[], unsigned int idx)
     {
         printf("failed\n");
         fprintf(stderr, "Error %d: %s\n", -rc, strerror(-rc));
-        return -1;
+        return -rc;
     }
     else
     {
@@ -485,7 +490,24 @@ int main(int argc, char *argv[])
 
     xc_interface_close(xch);
 
-    return !!ret;
+    /*
+     * Exitcode 0 for success.
+     * Exitcode 1 for an error.
+     * Exitcode 2 if the operation should be retried for any reason (e.g. a
+     * timeout or because another operation was in progress).
+     */
+
+#define EXIT_TIMEOUT (EXIT_FAILURE + 1)
+    switch ( ret )
+    {
+    case 0:
+        return EXIT_SUCCESS;
+    case EAGAIN:
+    case EBUSY:
+        return EXIT_TIMEOUT;
+    default:
+        return EXIT_FAILURE;
+    }
 }
 
 /*
-- 
2.7.4


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