[collectd] [PATCH 1/2] exec plugin: Added support to specify a group as well.

[Sebastian Harl]

Now, the user and group as which the process should be executed can be
specified as the first argument to the "Exec" config option. The syntax is
identical to the one used by GNU's chown(1).

Signed-off-by: Sebastian Harl <sh at tokkee.org>
---
 src/exec.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/src/exec.c b/src/exec.c
index 3502794..e416c8f 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -26,6 +26,7 @@
 
 #include <sys/types.h>
 #include <pwd.h>
+#include <grp.h>
 #include <signal.h>
 
 #include <pthread.h>
@@ -38,6 +39,7 @@ typedef struct program_list_s program_list_t;
 struct program_list_s
 {
   char           *user;
+  char           *group;
   char           *exec;
   int             pid;
   program_list_t *next;
@@ -96,6 +98,12 @@ static int exec_config (const char *key, const char *value)
 
     pl->next = pl_head;
     pl_head = pl;
+
+    pl->group = strchr (pl->user, ':');
+    if (NULL != pl->group) {
+      *pl->group = '\0';
+      pl->group++;
+    }
   }
   else
   {
@@ -109,15 +117,16 @@ static void exec_child (program_list_t *pl)
 {
   int status;
   int uid;
+  int gid;
   char *arg0;
 
   struct passwd *sp_ptr;
   struct passwd sp;
-  char pwnambuf[2048];
+  char nambuf[2048];
   char errbuf[1024];
 
   sp_ptr = NULL;
-  status = getpwnam_r (pl->user, &sp, pwnambuf, sizeof (pwnambuf), &sp_ptr);
+  status = getpwnam_r (pl->user, &sp, nambuf, sizeof (nambuf), &sp_ptr);
   if (status != 0)
   {
     ERROR ("exec plugin: getpwnam_r failed: %s",
@@ -145,6 +154,41 @@ static void exec_child (program_list_t *pl)
     exit (-1);
   }
 
+  if (NULL != pl->group)
+  {
+    if ('\0' != *pl->group) {
+      struct group *gr_ptr = NULL;
+      struct group gr;
+
+      status = getgrnam_r (pl->group, &gr, nambuf, sizeof (nambuf), &gr_ptr);
+      if (0 != status)
+      {
+	ERROR ("exec plugin: getgrnam_r failed: %s",
+	    sstrerror (errno, errbuf, sizeof (errbuf)));
+	exit (-1);
+      }
+      if (NULL == gr_ptr)
+      {
+	ERROR ("exec plugin: No such group: `%s'", pl->group);
+	exit (-1);
+      }
+
+      gid = gr.gr_gid;
+    }
+    else
+    {
+      gid = sp.pw_gid;
+    }
+
+    status = setgid (gid);
+    if (0 != status)
+    {
+      ERROR ("exec plugin: setgid failed: %s",
+	  sstrerror (errno, errbuf, sizeof (errbuf)));
+      exit (-1);
+    }
+  }
+
   arg0 = strrchr (pl->exec, '/');
   if (arg0 != NULL)
     arg0++;
-- 
1.5.2.1

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