[Qemu-devel] [PATCH 5/5] opts: produce valid command line in qemu_opts_print

[Kővágó, Zoltán]

This will let us print options in a format that the user would actually
write it on the command line (foo=bar,baz=asd,etc=def), without
prepending a spurious comma at the beginning of the list, or quoting
values unnecessarily.  This patch provides the following changes:
* write and id=, if the option has an id
* do not print separator before the first element
* do not quote string arguments which only contains letters or numbers
* properly escape commas (,) for QEMU, apostrophe (') for shell

Signed-off-by: Kővágó, Zoltán <dirty.ice...@gmail.com>

---

Chages from v1 -audiodev patch:
* print id=
* proper value escaping (apostrophe and comma)
* renamed d_sep -> separator


 block.c            |  2 +-
 util/qemu-option.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index e2e33fd..a18af00 100644
--- a/block.c
+++ b/block.c
@@ -3825,7 +3825,7 @@ void bdrv_img_create(const char *filename, const char 
*fmt,
     }
 
     if (!quiet) {
-        printf("Formatting '%s', fmt=%s", filename, fmt);
+        printf("Formatting '%s', fmt=%s ", filename, fmt);
         qemu_opts_print(opts, " ");
         puts("");
     }
diff --git a/util/qemu-option.c b/util/qemu-option.c
index efe9d27..db60ac9 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -730,14 +730,53 @@ void qemu_opts_del(QemuOpts *opts)
     g_free(opts);
 }
 
-void qemu_opts_print(QemuOpts *opts, const char *sep)
+/* print value properly escaping it for the shell (at least for bash) */
+static void escaped_print(const char *value)
+{
+    const char *ptr;
+    bool need_quote = false;
+
+    for (ptr = value; *ptr; ++ptr) {
+        if (!qemu_isalnum(*ptr)) {
+            need_quote = true;
+            break;
+        }
+    }
+
+    if (need_quote) {
+        putchar('\'');
+        for (ptr = value; *ptr; ++ptr) {
+            if (*ptr == '\'') {
+                printf("'\\''");
+            } else if (*ptr == ',') {
+                printf(",,");
+            } else {
+                putchar(*ptr);
+            }
+        }
+        putchar('\'');
+    } else {
+        printf("%s", value);
+    }
+}
+
+void qemu_opts_print(QemuOpts *opts, const char *separator)
 {
     QemuOpt *opt;
     QemuOptDesc *desc = opts->list->desc;
+    const char *sep = "";
+
+    if (opts->id) {
+        printf("id=");
+        escaped_print(opts->id);
+        sep = separator;
+    }
 
     if (desc[0].name == NULL) {
         QTAILQ_FOREACH(opt, &opts->head, next) {
-            printf("%s%s=\"%s\"", sep, opt->name, opt->str);
+            printf("%s%s=", sep, opt->name);
+            escaped_print(opt->str);
+            sep = separator;
         }
         return;
     }
@@ -750,13 +789,15 @@ void qemu_opts_print(QemuOpts *opts, const char *sep)
             continue;
         }
         if (desc->type == QEMU_OPT_STRING) {
-            printf("%s%s='%s'", sep, desc->name, value);
+            printf("%s%s=", sep, desc->name);
+            escaped_print(value);
         } else if ((desc->type == QEMU_OPT_SIZE ||
                     desc->type == QEMU_OPT_NUMBER) && opt) {
             printf("%s%s=%" PRId64, sep, desc->name, opt->value.uint);
         } else {
             printf("%s%s=%s", sep, desc->name, value);
         }
+        sep = separator;
     }
 }
 
-- 
2.4.3