daemon: collect list of called external commands

guestfsd calls many different tools. Keeping track of all of them is
error prone. This patch introduces a new helper macro to put the command
string into its own ELF section:

GUESTFSD_EXT_CMD(C_variable, command_name);

This syntax makes it still possible to grep for used command names.

The actual usage of the collected list could be like this:

  objcopy -j .guestfsd_ext_cmds -O binary daemon/guestfsd /dev/stdout |
  tr '\0' '\n' | sort -u

The resulting output will be used to tell mkinitrd which programs to
copy into the initrd.

Signed-off-by: Olaf Hering <olaf@aepfle.de>

RWMJ:
 - Move str_vgchange at request of author.
 - Fix snprintf call in daemon/debug.c

1 files changed, 5 insertions, 2 deletions

diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index 80175e08..e6d5fde4 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -53,6 +53,9 @@
 
 #include "daemon.h"
 
+GUESTFSD_EXT_CMD(str_udevadm, udevadm);
+GUESTFSD_EXT_CMD(str_udevsettle, udevsettle);
+
 static char *read_cmdline (void);
 
 #ifndef MAX
@@ -1294,6 +1297,6 @@ random_name (char *template)
 void
 udev_settle (void)
 {
-  (void) command (NULL, NULL, "udevadm", "settle", NULL);
-  (void) command (NULL, NULL, "udevsettle", NULL);
+  (void) command (NULL, NULL, str_udevadm, "settle", NULL);
+  (void) command (NULL, NULL, str_udevsettle, NULL);
 }