cgclassify: A command line tool to classify/re-classify already running task

From: Vivek Goyal <vgoyal@redhat.com>

o cgclassify, a command line tool to put a list of pids to the right cgroup
  based on rules in /etc/cgrules.conf. It can be mainly used for
  reclassification of tasks which are already running. Can think of two
  use cases.
        - During initial bootup, after cgroups are mounted, one needs to
          move tasks (started beofore cgroups were mounted) into right
          cgroup.

        - Once can choose to reclassify the tasks if admin has changed the
          rules and thinks a group of tasks should reclassified based on
          new rules.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
git-svn-id: https://libcg.svn.sourceforge.net/svnroot/libcg/trunk@138 4f4bb910-9a46-0410-90c8-c897d4f1cd53

diff --git a/Makefile.in b/Makefile.in
index ba6a7a3bb8a7a1c7956819542e8cb417579f21f2..7fdff9a3cfd37b77d10f38b06bb822c7c56d2208 100644 (file)
--- a/Makefile.in
+++ b/Makefile.in
@@ -29,7 +29,7 @@ PACKAGE_VERSION=@PACKAGE_VERSION@
 CFLAGS=@CFLAGS@ $(INC) -DPACKAGE_VERSION=$(PACKAGE_VERSION)
 VERSION=1
 
-all: libcgroup.so cgconfigparser cgexec
+all: libcgroup.so cgconfigparser cgexec cgclassify
 
 cgconfigparser: libcgroup.so config.c y.tab.c lex.yy.c libcgroup.h file-ops.c
        $(CC) $(CFLAGS) -o $@ y.tab.c lex.yy.c config.c file-ops.c \
@@ -38,6 +38,9 @@ cgconfigparser: libcgroup.so config.c y.tab.c lex.yy.c libcgroup.h file-ops.c
 cgexec: libcgroup.so cgexec.c libcgroup.h
        $(CC) $(CFLAGS) -Wall -o $@ cgexec.c $(LDFLAGS) $(LIBS)
 
+cgclassify: cgclassify.c
+       $(CC) $(CFLAGS) -Wall -o $@ cgclassify.c $(LDFLAGS) $(LIBS)
+
 y.tab.c: parse.y lex.yy.c
        $(YACC) -v -d parse.y
 
@@ -49,13 +52,14 @@ libcgroup.so: api.c libcgroup.h wrapper.c
        wrapper.c
        ln -sf $@ $@.$(VERSION)
 
-install: libcgroup.so cgexec
+install: libcgroup.so cgexec cgclassify
        $(INSTALL_DATA) -D libcgroup.h $(DESTDIR)$(includedir)/libcgroup.h
        $(INSTALL) -D libcgroup.so $(DESTDIR)$(libdir)/libcgroup-$(PACKAGE_VERSION).so
        ln -sf libcgroup-$(PACKAGE_VERSION).so $(DESTDIR)$(libdir)/libcgroup.so.$(VERSION)
        ln -sf libcgroup.so.$(VERSION) $(DESTDIR)$(libdir)/libcgroup.so
        $(INSTALL) -D cgconfigparser $(DESTDIR)$(sbindir)
        $(INSTALL) cgexec $(DESTDIR)$(bindir)/cgexec
+       $(INSTALL) cgclassify $(DESTDIR)$(bindir)/cgclassify
 
 uninstall: libcgroup.so
        rm -f $(DESTDIR)$(includedir)/libcgroup.h
@@ -64,7 +68,8 @@ uninstall: libcgroup.so
        rm -f $(DESTDIR)$(libdir)/libcgroup-$(PACKAGE_VERSION).so
        rm -f $(DESTDIR)$(sbindir)/cgconfigparser
        rm -f $(DESTDIR)$(bindir)/cgexec
+       rm -f $(DESTDIR)$(bindir)/cgclassify
 
 clean:
-       \rm -f y.tab.c y.tab.h lex.yy.c y.output libcgroup.so \
+       \rm -f y.tab.c y.tab.h lex.yy.c y.output libcgroup.so cgclassify\
        libcgroup.so.$(VERSION) cgconfigparser config.log config.status cgexec

diff --git a/cgclassify.c b/cgclassify.c
new file mode 100644 (file)
index 0000000..556ed3f
--- /dev/null
+++ b/cgclassify.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright RedHat Inc. 2008
+ *
+ * Authors:    Vivek Goyal <vgoyal@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <libcgroup.h>
+#include <limits.h>
+#include <pwd.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#define TEMP_BUF       81
+
+/*
+ * Go through /proc/<pid>/status file to determine the euid of the
+ * process.
+ * It returns 0 on success and negative values on failure.
+ */
+
+int euid_of_pid(pid_t pid)
+{
+       FILE *fp;
+       char path[FILENAME_MAX];
+       char buf[TEMP_BUF];
+       uid_t ruid, euid, suid, fsuid;
+
+       sprintf(path, "/proc/%d/status", pid);
+       fp = fopen(path, "r");
+       if (!fp) {
+               fprintf(stderr, "Error in opening file %s:%s\n", path,
+                               strerror(errno));
+               return -1;
+       }
+
+       while (fgets(buf, TEMP_BUF, fp)) {
+               if (!strncmp(buf, "Uid:", 4)) {
+                       sscanf((buf + 5), "%d%d%d%d", (int *)&ruid,
+                               (int *)&euid, (int *)&suid, (int *)&fsuid);
+                       dbg("Scanned proc values are %d %d %d %d\n",
+                               ruid, euid, suid, fsuid);
+                       return euid;
+               }
+       }
+
+       /* If we are here, we could not find euid. Return error. */
+       return -1;
+}
+
+/*
+ * Go through /proc/<pid>/status file to determine the egid of the
+ * process.
+ * It returns 0 on success and negative values on failure.
+ */
+
+int egid_of_pid(pid_t pid)
+{
+       FILE *fp;
+       char path[FILENAME_MAX];
+       char buf[TEMP_BUF];
+       gid_t rgid, egid, sgid, fsgid;
+
+       sprintf(path, "/proc/%d/status", pid);
+       fp = fopen(path, "r");
+       if (!fp) {
+               fprintf(stderr, "Error in opening file %s:%s\n", path,
+                               strerror(errno));
+               return -1;
+       }
+
+       while (fgets(buf, TEMP_BUF, fp)) {
+               if (!strncmp(buf, "Gid:", 4)) {
+                       sscanf((buf + 5), "%d%d%d%d", (int *)&rgid,
+                               (int *)&egid, (int *)&sgid, (int *)&fsgid);
+                       dbg("Scanned proc values are %d %d %d %d\n",
+                               rgid, egid, sgid, fsgid);
+                       return egid;
+               }
+       }
+
+       /* If we are here, we could not find egid. Return error. */
+       return -1;
+}
+
+int main(int argc, char *argv[])
+{
+       int ret = 0, i;
+       uid_t euid;
+       gid_t egid;
+       pid_t pid;
+
+       if (argc < 2) {
+               fprintf(stderr, "usage is %s <list of pids>  \n",
+                       argv[0]);
+               exit(2);
+       }
+
+
+       /* Initialize libcg */
+       ret = cgroup_init();
+       if (ret) {
+               fprintf(stderr, "libcgroup initialization failed:%d\n", ret);
+               return ret;
+       }
+
+       /* Put pids into right cgroups as per rules in /etc/cgrules.conf */
+       for (i = 1; i < argc; i++) {
+               pid = (uid_t) atoi(argv[i]);
+               euid = euid_of_pid(pid);
+               if (euid == -1) {
+                       fprintf(stderr, "Error in determining euid of"
+                                       " pid %d\n", pid);
+                       return -1;
+               }
+
+               egid = egid_of_pid(pid);
+               if (egid == -1) {
+                       fprintf(stderr, "Error in determining egid of"
+                                       " pid %d\n", pid);
+                       return -1;
+               }
+
+               /* Change the cgroup by determining the rules based on uid */
+               ret = cgroup_change_cgroup_uid_gid(euid, egid, pid);
+               if (ret) {
+                       fprintf(stderr, "Error: change of cgroup failed for"
+                                       " pid %d\n", pid);
+                       return ret;
+               }
+       }
+       return 0;
+}