1 From 5a64a79144e58a62426a34ef51b14e891f042fa2 Mon Sep 17 00:00:00 2001
2 From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
3 Date: Tue, 17 Apr 2018 13:54:38 +0200
4 Subject: [PATCH 6/6] Increase maximal size of controller values
6 Content-Type: text/plain; charset=UTF-8
7 Content-Transfer-Encoding: 8bit
9 Maximal length of a controller value is determined by CG_VALUE_MAX,
10 which is equal to 100. That is not sufficient in some cases.
12 Add new constant CG_CONTROL_VALUE_MAX (to prevent breaking current API)
13 and set it to 4096, which is usually equal to the amount of bytes that
14 can be written to a sysctl file directly.
16 Add warning message about exceeding the limit while parsing
19 Signed-off-by: Nikola Forró <nforro@redhat.com>
22 src/libcgroup-internal.h | 5 ++++-
23 src/tools/cgset.c | 4 ++--
24 src/wrapper.c | 17 ++++++++++++-----
25 4 files changed, 21 insertions(+), 11 deletions(-)
27 diff --git a/src/api.c b/src/api.c
28 index efde2d1..1cd30df 100644
31 @@ -1561,7 +1561,7 @@ static int cgroup_copy_controller_values(struct cgroup_controller *dst,
34 dst_val = dst->values[i];
35 - strncpy(dst_val->value, src_val->value, CG_VALUE_MAX);
36 + strncpy(dst_val->value, src_val->value, CG_CONTROL_VALUE_MAX);
37 strncpy(dst_val->name, src_val->name, FILENAME_MAX);
38 dst_val->dirty = src_val->dirty;
40 @@ -2286,7 +2286,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
42 return ECGROUPVALUENOTEXIST;
44 - *value = calloc(CG_VALUE_MAX, 1);
45 + *value = calloc(CG_CONTROL_VALUE_MAX, 1);
49 @@ -2297,7 +2297,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
50 * using %as or fread crashes when we try to read from files like
53 - ret = read(ctrl_file, *value, CG_VALUE_MAX-1);
54 + ret = read(ctrl_file, *value, CG_CONTROL_VALUE_MAX-1);
58 diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
59 index 4c0f46c..3a8e336 100644
60 --- a/src/libcgroup-internal.h
61 +++ b/src/libcgroup-internal.h
62 @@ -32,6 +32,9 @@ __BEGIN_DECLS
63 /* Estimated number of groups created */
64 #define MAX_GROUP_ELEMENTS 128
66 +/* Maximum length of a value */
67 +#define CG_CONTROL_VALUE_MAX 4096
70 #define CG_CONTROLLER_MAX 100
71 /* Max number of mounted hierarchies. Event if one controller is mounted per
72 @@ -73,7 +76,7 @@ __BEGIN_DECLS
74 struct control_value {
75 char name[FILENAME_MAX];
76 - char value[CG_VALUE_MAX];
77 + char value[CG_CONTROL_VALUE_MAX];
81 diff --git a/src/tools/cgset.c b/src/tools/cgset.c
82 index ea9f90d..3d3c8cc 100644
83 --- a/src/tools/cgset.c
84 +++ b/src/tools/cgset.c
85 @@ -151,8 +151,8 @@ int main(int argc, char *argv[])
89 - strncpy(name_value[nv_number].value, buf, CG_VALUE_MAX);
90 - name_value[nv_number].value[CG_VALUE_MAX-1] = '\0';
91 + strncpy(name_value[nv_number].value, buf, CG_CONTROL_VALUE_MAX);
92 + name_value[nv_number].value[CG_CONTROL_VALUE_MAX-1] = '\0';
96 diff --git a/src/wrapper.c b/src/wrapper.c
97 index c03472a..0952823 100644
100 @@ -132,10 +132,10 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
104 - if (controller->index >= CG_VALUE_MAX)
105 + if (controller->index >= CG_NV_MAX)
106 return ECGMAXVALUESEXCEEDED;
108 - for (i = 0; i < controller->index && i < CG_VALUE_MAX; i++) {
109 + for (i = 0; i < controller->index && i < CG_NV_MAX; i++) {
110 if (!strcmp(controller->values[i]->name, name))
111 return ECGVALUEEXISTS;
113 @@ -145,8 +145,15 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
115 return ECGCONTROLLERCREATEFAILED;
117 - strncpy(cntl_value->name, name, sizeof(cntl_value->name));
118 - strncpy(cntl_value->value, value, sizeof(cntl_value->value));
119 + if (strlen(value) >= sizeof(cntl_value->value)) {
120 + fprintf(stderr, "value exceeds the maximum of %d characters\n",
121 + sizeof(cntl_value->value));
123 + return ECGCONFIGPARSEFAIL;
126 + strncpy(cntl_value->name, name, sizeof(cntl_value->name) - 1);
127 + strncpy(cntl_value->value, value, sizeof(cntl_value->value) - 1);
128 cntl_value->dirty = true;
129 controller->values[controller->index] = cntl_value;
131 @@ -356,7 +363,7 @@ int cgroup_set_value_string(struct cgroup_controller *controller,
132 for (i = 0; i < controller->index; i++) {
133 struct control_value *val = controller->values[i];
134 if (!strcmp(val->name, name)) {
135 - strncpy(val->value, value, CG_VALUE_MAX);
136 + strncpy(val->value, value, CG_CONTROL_VALUE_MAX - 1);