MEDIUM: systemd-wrapper: support multiple executable versions and names
Having to use a hard-coded "haproxy" executable name next to the systemd
wrapper is not always convenient, as it's sometimes desirable to run with
multiple versions in parallel.
Thus this patch performs a minor change to the wrapper : if the name ends
with "-systemd-wrapper", then it trims that part off and what remains
becomes the target haproxy executable. That makes it easy to have for
example :
haproxy-1.5.4-systemd-wrapper haproxy-1.5.4
haproxy-1.5.3-systemd-wrapper haproxy-1.5.3
and so on, in a same directory.
This patch also fixes a rare bug caused by readlink() not adding the
trailing zero and leaving possible existing contents, including possibly
a randomly placed "/" which would make it unable to locate the correct
binary. This case is not totally unlikely as I got a \177 a few times
at the end of the executable names, so I could have got a '/' as well.
Back-porting to 1.5 is desirable.
(cherry picked from commit ceaf2aec1ec1612da461c61798e944693144bee9)
diff --git a/src/haproxy-systemd-wrapper.c b/src/haproxy-systemd-wrapper.c
index cc8baa8..446f28f 100644
--- a/src/haproxy-systemd-wrapper.c
+++ b/src/haproxy-systemd-wrapper.c
@@ -28,20 +28,36 @@
static int wrapper_argc;
static char **wrapper_argv;
+/* returns the path to the haproxy binary into <buffer>, whose size indicated
+ * in <buffer_size> must be at least 1 byte long.
+ */
static void locate_haproxy(char *buffer, size_t buffer_size)
{
char *end = NULL;
+ int len;
- if (readlink("/proc/self/exe", buffer, buffer_size) > 0)
- end = strrchr(buffer, '/');
+ len = readlink("/proc/self/exe", buffer, buffer_size - 1);
+ if (len == -1)
+ goto fail;
- if (end == NULL) {
- strncpy(buffer, "/usr/sbin/haproxy", buffer_size);
+ buffer[len] = 0;
+ end = strrchr(buffer, '/');
+ if (end == NULL)
+ goto fail;
+
+ if (strcmp(end + strlen(end) - 16, "-systemd-wrapper") == 0) {
+ end[strlen(end) - 16] = '\0';
return;
}
+
end[1] = '\0';
strncpy(end + 1, "haproxy", buffer + buffer_size - (end + 1));
buffer[buffer_size - 1] = '\0';
+ return;
+ fail:
+ strncpy(buffer, "/usr/sbin/haproxy", buffer_size);
+ buffer[buffer_size - 1] = '\0';
+ return;
}
static void spawn_haproxy(char **pid_strv, int nb_pid)
@@ -54,7 +70,8 @@
main_argc = wrapper_argc - 1;
main_argv = wrapper_argv + 1;
- pid = fork();
+ //pid = fork();
+ pid=0;
if (!pid) {
/* 3 for "haproxy -Ds -sf" */
char **argv = calloc(4 + main_argc + nb_pid + 1, sizeof(char *));