Bug#810367: [PATCH] depmod: Don't insert comment in modules.devname if otherwise empty

[Josh Triplett]

This allows tools to detect the file as empty, such as via systemd's
ConditionFileNotEmpty.
---

The string constant extends past 80 columns, per CODING-STYLE.

The motivation for this patch came from Debian bug 810367.  This change
would allow kmod-static-nodes.service to use ConditionFileNotEmpty
instead of ConditionPathExists.

 tools/depmod.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/tools/depmod.c b/tools/depmod.c
index a585d47..6e9bb4d 100644
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -1999,8 +1999,7 @@ static int output_builtin_bin(struct depmod *depmod, FILE 
*out)
 static int output_devname(struct depmod *depmod, FILE *out)
 {
        size_t i;
-
-       fputs("# Device nodes to trigger on-demand module loading.\n", out);
+       bool empty = true;
 
        for (i = 0; i < depmod->modules.count; i++) {
                const struct mod *mod = depmod->modules.array[i];
@@ -2036,10 +2035,15 @@ static int output_devname(struct depmod *depmod, FILE 
*out)
                }
 
                if (devname != NULL) {
-                       if (type != '\0')
+                       if (type != '\0') {
+                               if (empty) {
+                                       fputs("# Device nodes to trigger 
on-demand module loading.\n",
+                                             out);
+                                       empty = false;
+                               }
                                fprintf(out, "%s %s %c%u:%u\n", mod->modname,
                                        devname, type, major, minor);
-                       else
+                        } else
                                ERR("Module '%s' has devname (%s) but "
                                    "lacks major and minor information. "
                                    "Ignoring.\n", mod->modname, devname);
-- 
2.7.0.rc3