From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 13 Jul 2010 17:00:01 +0000 (+0200)
Subject: cgroup: treat non-existing cgroups like empty ones, to deal with races
X-Git-Tag: v3~7
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=4c633005eacdf964d22107f453ba804868f33a25

cgroup: treat non-existing cgroups like empty ones, to deal with races
---

diff --git a/src/cgroup-util.c b/src/cgroup-util.c
index 26e8f691d..828b30414 100644
--- a/src/cgroup-util.c
+++ b/src/cgroup-util.c
@@ -189,7 +189,7 @@ int cg_kill(const char *controller, const char *path, int sig, bool ignore_self)
                 done = true;
 
                 if ((r = cg_enumerate_processes(controller, path, &f)) < 0) {
-                        if (ret >= 0)
+                        if (ret >= 0 && r != -ENOENT)
                                 ret = r;
 
                         goto finish;
@@ -205,8 +205,8 @@ int cg_kill(const char *controller, const char *path, int sig, bool ignore_self)
 
                         /* If we haven't killed this process yet, kill
                          * it */
-                        if (kill(pid, sig) < 0 && errno != ESRCH) {
-                                if (ret >= 0)
+                        if (kill(pid, sig) < 0) {
+                                if (ret >= 0 && errno != ESRCH)
                                         ret = -errno;
                         } else if (ret == 0)
                                 ret = 1;
@@ -258,7 +258,7 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool ig
         ret = cg_kill(controller, path, sig, ignore_self);
 
         if ((r = cg_enumerate_subgroups(controller, path, &d)) < 0) {
-                if (ret >= 0)
+                if (ret >= 0 && r != -ENOENT)
                         ret = r;
 
                 goto finish;
@@ -289,7 +289,7 @@ int cg_kill_recursive(const char *controller, const char *path, int sig, bool ig
 
         if (rem)
                 if ((r = cg_rmdir(controller, path)) < 0) {
-                        if (ret >= 0)
+                        if (ret >= 0 && r != -ENOENT)
                                 ret = r;
                 }
 
@@ -351,7 +351,7 @@ int cg_migrate(const char *controller, const char *from, const char *to, bool ig
                 done = true;
 
                 if ((r = cg_enumerate_tasks(controller, from, &f)) < 0) {
-                        if (ret >= 0)
+                        if (ret >= 0 && r != -ENOENT)
                                 ret = r;
 
                         goto finish;
@@ -369,7 +369,7 @@ int cg_migrate(const char *controller, const char *from, const char *to, bool ig
                                 continue;
 
                         if ((r = cg_attach(controller, to, pid)) < 0) {
-                                if (ret >= 0)
+                                if (ret >= 0 && r != -ESRCH)
                                         ret = r;
                         } else if (ret == 0)
                                 ret = 1;
@@ -417,7 +417,7 @@ int cg_migrate_recursive(const char *controller, const char *from, const char *t
         ret = cg_migrate(controller, from, to, ignore_self);
 
         if ((r = cg_enumerate_subgroups(controller, from, &d)) < 0) {
-                if (ret >= 0)
+                if (ret >= 0 && r != -ENOENT)
                         ret = r;
                 goto finish;
         }
@@ -447,7 +447,7 @@ int cg_migrate_recursive(const char *controller, const char *from, const char *t
 
         if (rem)
                 if ((r = cg_rmdir(controller, from)) < 0) {
-                        if (ret >= 0)
+                        if (ret >= 0 && r != -ENOENT)
                                 ret = r;
                 }
 
@@ -517,7 +517,7 @@ int cg_trim(const char *controller, const char *path, bool delete_root) {
         r = rm_rf(fs, true, delete_root);
         free(fs);
 
-        return r;
+        return r == -ENOENT ? 0 : r;
 }
 
 int cg_delete(const char *controller, const char *path) {
@@ -533,7 +533,7 @@ int cg_delete(const char *controller, const char *path) {
         r = cg_migrate_recursive(controller, path, parent, false, true);
         free(parent);
 
-        return r;
+        return r == -ENOENT ? 0 : r;
 }
 
 int cg_create(const char *controller, const char *path) {
@@ -646,6 +646,9 @@ int cg_get_by_pid(const char *controller, pid_t pid, char **path) {
         f = fopen(fs, "re");
         free(fs);
 
+        if (!f)
+                return errno == ENOENT ? -ESRCH : -errno;
+
         cs = strlen(controller);
 
         while (!feof(f)) {
@@ -763,7 +766,7 @@ int cg_is_empty(const char *controller, const char *path, bool ignore_self) {
         assert(path);
 
         if ((r = cg_enumerate_tasks(controller, path, &f)) < 0)
-                return r;
+                return r == -ENOENT ? 1 : r;
 
         while ((r = cg_read_pid(f, &pid)) > 0) {
 
@@ -794,7 +797,7 @@ int cg_is_empty_recursive(const char *controller, const char *path, bool ignore_
                 return r;
 
         if ((r = cg_enumerate_subgroups(controller, path, &d)) < 0)
-                return r;
+                return r == -ENOENT ? 1 : r;
 
         while ((r = cg_read_subgroup(d, &fn)) > 0) {
                 char *p = NULL;
diff --git a/src/util.c b/src/util.c
index e5d845609..519d22902 100644
--- a/src/util.c
+++ b/src/util.c
@@ -2565,7 +2565,8 @@ static int rm_rf_children(int fd, bool only_dirs) {
 
         if (!(d = fdopendir(fd))) {
                 close_nointr_nofail(fd);
-                return -errno;
+
+                return errno == ENOENT ? 0 : -errno;
         }
 
         for (;;) {
@@ -2589,7 +2590,7 @@ static int rm_rf_children(int fd, bool only_dirs) {
                         struct stat st;
 
                         if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
-                                if (ret == 0)
+                                if (ret == 0 && errno != ENOENT)
                                         ret = -errno;
                                 continue;
                         }
@@ -2602,7 +2603,7 @@ static int rm_rf_children(int fd, bool only_dirs) {
                         int subdir_fd;
 
                         if ((subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC)) < 0) {
-                                if (ret == 0)
+                                if (ret == 0 && errno != ENOENT)
                                         ret = -errno;
                                 continue;
                         }
@@ -2613,13 +2614,13 @@ static int rm_rf_children(int fd, bool only_dirs) {
                         }
 
                         if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
-                                if (ret == 0)
+                                if (ret == 0 && errno != ENOENT)
                                         ret = -errno;
                         }
                 } else  if (!only_dirs) {
 
                         if (unlinkat(fd, de->d_name, 0) < 0) {
-                                if (ret == 0)
+                                if (ret == 0 && errno != ENOENT)
                                         ret = -errno;
                         }
                 }