[PATCH] svlogd: implement option to use alternate config file

[Patrick Steinhardt <ps@pks.im>]

Right now, the svlogd daemon will always look up the log configuration
in the target log directory itself. There's reasons though for having
the configuration file located at a different place, e.g. to provide a
global log configuration or to separate data from configuration.

Introduce a new command line option, "-c", that takes as parameter an
alternative log file. It can either be given a relative path, in which
case svlogd will try to open it relative to the log directories, or an
absolute path, where it will try to use a single configuration for each
of the log directories.

Add tests to verify that svlogd is correctly reading the alternative
configuration file.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---

Hi,

I don't quite know whether this is the right place to send
patches to, but runit's homepage didn't mention any way to
contribute patches (or I didn't find it). Please feel free to
redirect me if I've chosen the wrong place.

Regards
Patrick

 man/svlogd.8     | 15 ++++++++++++++-
 src/svlogd.c     | 11 ++++++++---
 src/svlogd.check | 10 ++++++++++
 src/svlogd.dist  |  5 +++++
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/man/svlogd.8 b/man/svlogd.8
index 01b2324..5359d94 100644
--- a/man/svlogd.8
+++ b/man/svlogd.8
@@ -3,7 +3,8 @@
 svlogd \- runit's service logging daemon
 .SH SYNOPSIS
 .B svlogd
-[\-tttv] [\-r
+[\-tttv] [\-c
+.I file\fR] [\-r
 .I c\fR] [\-R
 .I xyz\fR] [\-l
 .I len\fR] [\-b
@@ -377,6 +378,18 @@ the form YYYY-MM-DDTHH:MM:SS.xxxxx when writing to
 .I log
 or to standard error.
 .TP
+.B \-c \fIfile
+config file.
+Use
+.I file
+as configuration instead of the default
+.I log/config
+path.
+.I file
+may either be absolute or relative, in which case it will be relative to the
+.I log
+directory.
+.TP
 .B \-r \fIc
 replace.
 .I c
diff --git a/src/svlogd.c b/src/svlogd.c
index 90a3321..0109684 100644
--- a/src/svlogd.c
+++ b/src/svlogd.c
@@ -49,6 +49,7 @@ unsigned long linemax =1000;
 unsigned long buflen =1024;
 unsigned long linelen;
 
+const char *config = "config";
 const char *replace ="";
 char repl =0;
 
@@ -437,13 +438,14 @@ unsigned int logdir_open(struct logdir *ld, const char *fn) {
   while (! stralloc_copys(&ld->processor, "")) pause_nomem();
 
   /* read config */
-  if ((i =openreadclose("config", &sa, 128)) == -1)
+  if ((i =openreadclose(config, &sa, 128)) == -1)
     warn2("unable to read config", ld->name);
   if (i != 0) {
     int len, c;
     unsigned long port;
 
-    if (verbose) strerr_warn4(INFO, "read: ", ld->name, "/config", 0);
+    if (verbose && *config != '/') strerr_warn5(INFO, "read: ", ld->name, "/", config, 0);
+    else if (verbose) strerr_warn3(INFO, "read: ", config, 0);
     for (i =0; i +1 < sa.len; ++i) {
       len =byte_chr(&sa.s[i], sa.len -i, '\n');
       sa.s[len +i] =0;
@@ -667,8 +669,11 @@ int main(int argc, const char **argv) {
 
   progname =*argv;
 
-  while ((opt =getopt(argc, argv, "R:r:l:b:tvV")) != opteof) {
+  while ((opt =getopt(argc, argv, "c:R:r:l:b:tvV")) != opteof) {
     switch(opt) {
+    case 'c':
+      config =optarg;
+      break;
     case 'R':
       replace =optarg;
       if (! repl) repl ='_';
diff --git a/src/svlogd.check b/src/svlogd.check
index 7d926ef..e9584ee 100755
--- a/src/svlogd.check
+++ b/src/svlogd.check
@@ -24,4 +24,14 @@ echo t2 >"${ctmp}"/config
 echo $?
 cat "${ctmp}"/current
 
+echo prelative-alternate >"${ctmp}"/alternate-config
+echo foo |svlogd -c alternate-config "${ctmp}"
+echo $?
+cat "${ctmp}"/current
+
+echo pabsolute-alternate >>"${ctmp}"/alternate-config
+echo foo |svlogd -c "${ctmp}"/alternate-config "${ctmp}"
+echo $?
+cat "${ctmp}"/current
+
 rm -rf "${ctmp}"
diff --git a/src/svlogd.dist b/src/svlogd.dist
index b3329e6..8570230 100644
--- a/src/svlogd.dist
+++ b/src/svlogd.dist
@@ -19,3 +19,8 @@ baz
 :ar
 :az
 0
+0
+relative-alternatefoo
+0
+relative-alternatefoo
+absolute-alternatefoo
-- 
2.22.0