systemctl: filter and sort member pid of cgroup

1 files changed, 134 insertions, 0 deletions

diff --git a/src/cgroup-show.c b/src/cgroup-show.c
new file mode 100644
index 0000000000..b637c1c163
--- /dev/null
+++ b/src/cgroup-show.c
@@ -0,0 +1,134 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <string.h>
+
+#include "util.h"
+#include "macro.h"
+#include "cgroup-show.h"
+
+static int compare(const void *a, const void *b) {
+        const pid_t *p = a, *q = b;
+
+        if (*p < *q)
+                return -1;
+        if (*p > *q)
+                return 1;
+        return 0;
+}
+
+void show_cgroup(const char *name, const char *prefix, unsigned columns) {
+        char *fn;
+        FILE *f;
+        size_t n = 0, n_allocated = 0;
+        pid_t *pids = NULL;
+
+        if (!startswith(name, "name=systemd:"))
+                return;
+
+        if (asprintf(&fn, "/cgroup/systemd/%s/cgroup.procs", name + 13) < 0) {
+                log_error("Out of memory");
+                return;
+        }
+
+        f = fopen(fn, "r");
+        free(fn);
+
+        if (!f)
+                return;
+
+        while (!feof(f)) {
+                unsigned long ul;
+
+                if (fscanf(f, "%lu", &ul) != 1)
+                        break;
+
+                if (ul <= 0)
+                        continue;
+
+                if (n >= n_allocated) {
+                        pid_t *npids;
+
+                        n_allocated = MAX(16U, n*2U);
+
+                        if (!(npids = realloc(pids, sizeof(pid_t) * n_allocated))) {
+                                log_error("Out of memory");
+                                goto finish;
+                        }
+
+                        pids = npids;
+                }
+
+                assert(n < n_allocated);
+                pids[n++] = (pid_t) ul;
+        }
+
+        if (n > 0) {
+                unsigned i, m;
+
+                /* Filter duplicates */
+                m = 0;
+                for (i = 0; i < n; i++) {
+                        unsigned j;
+
+                        for (j = i+1; j < n; j++)
+                                if (pids[i] == pids[j])
+                                        break;
+
+                        if (j >= n)
+                                pids[m++] = pids[i];
+                }
+                n = m;
+
+                /* And sort */
+                qsort(pids, n, sizeof(pid_t), compare);
+
+                if (!prefix)
+                        prefix = "";
+
+                if (columns > 8)
+                        columns -= 8;
+                else
+                        columns = 20;
+
+                printf("%s\342\224\202\n", prefix);
+
+                for (i = 0; i < n; i++) {
+                        char *t = NULL;
+
+                        get_process_cmdline(pids[i], columns, &t);
+
+                        printf("%s%s %5lu %s\n",
+                               prefix,
+                               i < n-1 ? "\342\224\234" : "\342\224\224",
+                               (unsigned long) pids[i], strna(t));
+
+                        free(t);
+                }
+        }
+
+finish:
+        free(pids);
+
+        if (f)
+                fclose(f);
+}