abuild-fetch: Use User-Agent properly

* Use ABUILD_USER_AGENT environment variable, if present, to customise.
* Default to abuild/VERSION, meeting HTTP spec and preventing us from
  being blocked as a bot by silly upstreams that don't like curl.

Closes: #7

1 files changed, 14 insertions, 1 deletions

diff --git a/abuild-fetch.c b/abuild-fetch.c
index 7145d7e..5adb5fc 100644
--- a/abuild-fetch.c
+++ b/abuild-fetch.c
@@ -81,7 +81,8 @@ int fetch(char *url, const char *destdir)
 {
 	int lockfd, status=0;
 	char outfile[PATH_MAX], partfile[PATH_MAX];
-	char *name, *p;
+	char agent[50];
+	char *name, *p, *env;
 	struct flock fl = {
 		.l_type = F_WRLCK,
 		.l_whence = SEEK_SET,
@@ -140,6 +141,18 @@ int fetch(char *url, const char *destdir)
 		add_opt(&wgetcmd, "-c");
 	}
 
+	add_opt(&curlcmd, "-A");
+	add_opt(&wgetcmd, "-U");
+	env = getenv("ABUILD_USER_AGENT");
+	if (env != NULL) {
+		add_opt(&curlcmd, env);
+		add_opt(&wgetcmd, env);
+	} else {
+		snprintf(agent, sizeof(agent), "abuild/%s", VERSTR);
+		add_opt(&curlcmd, agent);
+		add_opt(&wgetcmd, agent);
+	}
+
 	add_opt(&curlcmd, url);
 	add_opt(&wgetcmd, url);