[PATCH v4 2/4] x86/ucode: refactor xen-ucode to utilize getopt

[Fouad Hilly <fouad.hilly@xxxxxxxxx>]

Use getopt_long() to handle command line arguments.
Introduce ext_err for common exit with errors.
xc_microcode_update() refactored to accept flags and utilize 
xenpf_microcode_update2
Introducing usage() to handle usage\help messages in a common block.
show_curr_cpu is printed to stdout only.

Signed-off-by: Fouad Hilly <fouad.hilly@xxxxxxxxx>
---
[v4]
1- Merge three patches into one.
2- usage() to print messages to the correct stream.
3- Update commit message and description.
---
 tools/misc/xen-ucode.c | 51 ++++++++++++++++++++++++++++++++----------
 1 file changed, 39 insertions(+), 12 deletions(-)

diff --git a/tools/misc/xen-ucode.c b/tools/misc/xen-ucode.c
index 390969db3d1c..6f9dd2a7e431 100644
--- a/tools/misc/xen-ucode.c
+++ b/tools/misc/xen-ucode.c
@@ -11,12 +11,23 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <xenctrl.h>
+#include <getopt.h>
 
 static xc_interface *xch;
 
 static const char intel_id[] = "GenuineIntel";
 static const char   amd_id[] = "AuthenticAMD";
 
+static void usage(FILE *stream, const char *name)
+{
+    fprintf(stream, "%s: Xen microcode updating tool\n"
+           "Usage: %s [microcode file] [options]\n"
+           "options:\n"
+           "  -h, --help            display this help and exit\n"
+           "  -s, --show-cpu-info   show CPU information and exit\n",
+           name, name);
+}
+
 static void show_curr_cpu(FILE *f)
 {
     int ret;
@@ -77,6 +88,13 @@ int main(int argc, char *argv[])
     char *filename, *buf;
     size_t len;
     struct stat st;
+    int opt;
+
+    static const struct option options[] = {
+        {"help", no_argument, NULL, 'h'},
+        {"show-cpu-info", no_argument, NULL, 's'},
+        {NULL, no_argument, NULL, 0}
+    };
 
     xch = xc_interface_open(NULL, NULL, 0);
     if ( xch == NULL )
@@ -86,22 +104,25 @@ int main(int argc, char *argv[])
         exit(1);
     }
 
-    if ( argc < 2 )
+    while ( (opt = getopt_long(argc, argv, "hs", options, NULL)) != -1 )
     {
-        fprintf(stderr,
-                "xen-ucode: Xen microcode updating tool\n"
-                "Usage: %s [<microcode file> | show-cpu-info]\n", argv[0]);
-        show_curr_cpu(stderr);
-        exit(2);
+        switch (opt)
+        {
+        case 'h':
+            usage(stdout, argv[0]);
+            exit(EXIT_SUCCESS);
+        case 's':
+            show_curr_cpu(stdout);
+            exit(EXIT_SUCCESS);
+        default:
+            goto ext_err;
+        }
     }
 
-    if ( !strcmp(argv[1], "show-cpu-info") )
-    {
-        show_curr_cpu(stdout);
-        return 0;
-    }
+    if ( optind == argc )
+        goto ext_err;
 
-    filename = argv[1];
+    filename = argv[optind];
     fd = open(filename, O_RDONLY);
     if ( fd < 0 )
     {
@@ -146,4 +167,10 @@ int main(int argc, char *argv[])
     close(fd);
 
     return 0;
+
+ ext_err:
+    fprintf(stderr,
+            "%s: unable to process command line arguments\n", argv[0]);
+    usage(stderr, argv[0]);
+    exit(EXIT_FAILURE);
 }
-- 
2.42.0