Add session configuration save feature to session daemon

[lttng-tools.git] / src / common / utils.c

diff --git a/src/common/utils.c b/src/common/utils.c
index ce25f232d5209b7c08b644ce21a7fa526d70a244..31596ddd36c3a3314daa2de1db6db19690b7800a 100644 (file)
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
  * Copyright (C) 2013 - Raphaël Beamonte <raphael.beamonte@gmail.com>
+ * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License, version 2 only, as
@@ -29,6 +30,7 @@
 #include <inttypes.h>
 #include <regex.h>
 #include <grp.h>
+#include <pwd.h>
 
 #include <common/common.h>
 #include <common/runas.h>
@@ -853,6 +855,46 @@ char *utils_get_home_dir(void)
        return getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
 }
 
+/**
+ * Get user's home directory. Dynamically allocated, must be freed
+ * by the caller.
+ */
+LTTNG_HIDDEN
+char *utils_get_user_home_dir(uid_t uid)
+{
+       struct passwd pwd;
+       struct passwd *result;
+       char *home_dir = NULL;
+       char *buf = NULL;
+       long buflen;
+       int ret;
+
+       buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+       if (buflen == -1) {
+               goto end;
+       }
+retry:
+       buf = zmalloc(buflen);
+       if (!buf) {
+               goto end;
+       }
+
+       ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
+       if (ret || !result) {
+               if (ret == ERANGE) {
+                       free(buf);
+                       buflen *= 2;
+                       goto retry;
+               }
+               goto end;
+       }
+
+       home_dir = strdup(pwd.pw_dir);
+end:
+       free(buf);
+       return home_dir;
+}
+
 /*
  * With the given format, fill dst with the time of len maximum siz.
  *
@@ -900,3 +942,46 @@ gid_t utils_get_group_id(const char *name)
        }
        return grp->gr_gid;
 }
+
+/*
+ * Return a newly allocated option string. This string is to be used as the
+ * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
+ * of elements in the long_options array. Returns NULL if the string's
+ * allocation fails.
+ */
+LTTNG_HIDDEN
+char *utils_generate_optstring(const struct option *long_options,
+               size_t opt_count)
+{
+       int i;
+       size_t string_len = opt_count, str_pos = 0;
+       char *optstring;
+
+       /*
+        * Compute the necessary string length. One letter per option, two when an
+        * argument is necessary, and a trailing NULL.
+        */
+       for (i = 0; i < opt_count; i++) {
+               string_len += long_options[i].has_arg ? 1 : 0;
+       }
+
+       optstring = zmalloc(string_len);
+       if (!optstring) {
+               goto end;
+       }
+
+       for (i = 0; i < opt_count; i++) {
+               if (!long_options[i].name) {
+                       /* Got to the trailing NULL element */
+                       break;
+               }
+
+               optstring[str_pos++] = (char)long_options[i].val;
+               if (long_options[i].has_arg) {
+                       optstring[str_pos++] = ':';
+               }
+       }
+
+end:
+       return optstring;
+}