[ltt-dev] [UST PATCH 5/6] Make root see all available pids

[Nils Carlson]

Changes since v1:
	* Fix a whitespace
	* Make functions that should be static static

Allow root (geteuid() == 0) to see all pids. This way the super-user
can connect to any program. A step on the way of carefully outlining
what UST does and doesn't.

Signed-off-by: Nils Carlson <nils.carlson at ericsson.com>
---
 libustcomm/ustcomm.h  |    4 ++-
 libustctl/libustctl.c |   61 ++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/libustcomm/ustcomm.h b/libustcomm/ustcomm.h
index d16aec7..9952958 100644
--- a/libustcomm/ustcomm.h
+++ b/libustcomm/ustcomm.h
@@ -25,7 +25,9 @@
 #include <ust/kcompat/kcompat.h>
 
 #define SOCK_DIR "/tmp/ust-app-socks"
-#define USER_SOCK_DIR "/tmp/ust-socks-"
+#define USER_TMP_DIR "/tmp"
+#define USER_SOCK_DIR_BASE "ust-socks-"
+#define USER_SOCK_DIR USER_TMP_DIR "/" USER_SOCK_DIR_BASE
 
 struct ustcomm_sock {
 	struct cds_list_head list;
diff --git a/libustctl/libustctl.c b/libustctl/libustctl.c
index 5625f43..356d5ef 100644
--- a/libustctl/libustctl.c
+++ b/libustctl/libustctl.c
@@ -121,7 +121,7 @@ static void get_pids_in_dir(DIR *dir, pid_t **pid_list,
 	(*pid_list)[*pid_list_size - 1] = 0; /* Array end */
 }
 
-pid_t *ustctl_get_online_pids(void)
+static pid_t *get_pids_non_root(void)
 {
 	char *dir_name;
 	DIR *dir;
@@ -139,6 +139,9 @@ pid_t *ustctl_get_online_pids(void)
 	}
 
 	pid_list = malloc(pid_list_size * sizeof(pid_t));
+	if (!pid_list) {
+		goto close_dir;
+	}
 
 	get_pids_in_dir(dir, &pid_list, &pid_list_size);
 
@@ -158,6 +161,62 @@ free_dir_name:
 	return pid_list;
 }
 
+static pid_t *get_pids_root(void)
+{
+	char *dir_name;
+	DIR *tmp_dir, *dir;
+	unsigned int pid_list_size = 1;
+	pid_t *pid_list = NULL;
+	struct dirent *dirent;
+
+	tmp_dir = opendir(USER_TMP_DIR);
+	if (!tmp_dir) {
+		return NULL;
+	}
+
+	pid_list = malloc(pid_list_size * sizeof(pid_t));
+	if (!pid_list) {
+		goto close_tmp_dir;
+	}
+
+	while ((dirent = readdir(tmp_dir))) {
+		/* Compare the dir to check for the USER_SOCK_DIR_BASE prefix */
+		if (!strncmp(dirent->d_name, USER_SOCK_DIR_BASE,
+			     strlen(USER_SOCK_DIR_BASE))) {
+
+			if (asprintf(&dir_name, USER_TMP_DIR "/%s", dirent->d_name) < 0) {
+				goto close_tmp_dir;
+			}
+
+			dir = opendir(dir_name);
+
+			free(dir_name);
+
+			if (!dir) {
+				continue;
+			}
+
+			get_pids_in_dir(dir, &pid_list, &pid_list_size);
+
+			closedir(dir);
+		}
+	}
+
+close_tmp_dir:
+	closedir(tmp_dir);
+
+	return pid_list;
+}
+
+pid_t *ustctl_get_online_pids(void)
+{
+	if (geteuid()) {
+		return get_pids_non_root();
+	} else {
+		return get_pids_root();
+	}
+}
+
 /**
  * Sets marker state (USTCTL_MS_ON or USTCTL_MS_OFF).
  *
-- 
1.7.1