Blame SOURCES/libcgroup-0.41-size-of-controller-values.patch

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From 5a64a79144e58a62426a34ef51b14e891f042fa2 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
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Date: Tue, 17 Apr 2018 13:54:38 +0200
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Subject: [PATCH 6/6] Increase maximal size of controller values
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Maximal length of a controller value is determined by CG_VALUE_MAX,
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which is equal to 100. That is not sufficient in some cases.
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Add new constant CG_CONTROL_VALUE_MAX (to prevent breaking current API)
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and set it to 4096, which is usually equal to the amount of bytes that
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can be written to a sysctl file directly.
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Add warning message about exceeding the limit while parsing
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configuration file.
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Signed-off-by: Nikola Forró <nforro@redhat.com>
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---
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 src/api.c                |  6 +++---
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 src/libcgroup-internal.h |  5 ++++-
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 src/tools/cgset.c        |  4 ++--
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 src/wrapper.c            | 17 ++++++++++++-----
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 4 files changed, 21 insertions(+), 11 deletions(-)
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diff --git a/src/api.c b/src/api.c
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index efde2d1..1cd30df 100644
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--- a/src/api.c
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+++ b/src/api.c
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@@ -1561,7 +1561,7 @@ static int cgroup_copy_controller_values(struct cgroup_controller *dst,
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 		}
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 		dst_val = dst->values[i];
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-		strncpy(dst_val->value, src_val->value, CG_VALUE_MAX);
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+		strncpy(dst_val->value, src_val->value, CG_CONTROL_VALUE_MAX);
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 		strncpy(dst_val->name, src_val->name, FILENAME_MAX);
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 		dst_val->dirty = src_val->dirty;
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 	}
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@@ -2286,7 +2286,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
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 	if (ctrl_file < 0)
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 		return ECGROUPVALUENOTEXIST;
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-	*value = calloc(CG_VALUE_MAX, 1);
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+	*value = calloc(CG_CONTROL_VALUE_MAX, 1);
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 	if (!*value) {
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 		close(ctrl_file);
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 		last_errno = errno;
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@@ -2297,7 +2297,7 @@ static int cg_rd_ctrl_file(const char *subsys, const char *cgroup,
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 	 * using %as or fread crashes when we try to read from files like
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 	 * memory.stat
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 	 */
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-	ret = read(ctrl_file, *value, CG_VALUE_MAX-1);
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+	ret = read(ctrl_file, *value, CG_CONTROL_VALUE_MAX-1);
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 	if (ret < 0) {
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 		free(*value);
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 		*value = NULL;
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diff --git a/src/libcgroup-internal.h b/src/libcgroup-internal.h
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index 4c0f46c..3a8e336 100644
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--- a/src/libcgroup-internal.h
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+++ b/src/libcgroup-internal.h
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@@ -32,6 +32,9 @@ __BEGIN_DECLS
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 /* Estimated number of groups created */
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 #define MAX_GROUP_ELEMENTS	128
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+/* Maximum length of a value */
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+#define CG_CONTROL_VALUE_MAX 4096
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+
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 #define CG_NV_MAX 100
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 #define CG_CONTROLLER_MAX 100
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 /* Max number of mounted hierarchies. Event if one controller is mounted per
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@@ -73,7 +76,7 @@ __BEGIN_DECLS
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 struct control_value {
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 	char name[FILENAME_MAX];
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-	char value[CG_VALUE_MAX];
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+	char value[CG_CONTROL_VALUE_MAX];
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 	bool dirty;
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 };
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diff --git a/src/tools/cgset.c b/src/tools/cgset.c
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index ea9f90d..3d3c8cc 100644
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--- a/src/tools/cgset.c
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+++ b/src/tools/cgset.c
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@@ -151,8 +151,8 @@ int main(int argc, char *argv[])
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 				goto err;
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 			}
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-			strncpy(name_value[nv_number].value, buf, CG_VALUE_MAX);
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-			name_value[nv_number].value[CG_VALUE_MAX-1] = '\0';
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+			strncpy(name_value[nv_number].value, buf, CG_CONTROL_VALUE_MAX);
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+			name_value[nv_number].value[CG_CONTROL_VALUE_MAX-1] = '\0';
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 			nv_number++;
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 			break;
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diff --git a/src/wrapper.c b/src/wrapper.c
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index c03472a..0952823 100644
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--- a/src/wrapper.c
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+++ b/src/wrapper.c
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@@ -132,10 +132,10 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
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 	if (!controller)
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 		return ECGINVAL;
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-	if (controller->index >= CG_VALUE_MAX)
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+	if (controller->index >= CG_NV_MAX)
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 		return ECGMAXVALUESEXCEEDED;
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-	for (i = 0; i < controller->index && i < CG_VALUE_MAX; i++) {
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+	for (i = 0; i < controller->index && i < CG_NV_MAX; i++) {
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 		if (!strcmp(controller->values[i]->name, name))
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 			return ECGVALUEEXISTS;
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 	}
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@@ -145,8 +145,15 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
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 	if (!cntl_value)
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 		return ECGCONTROLLERCREATEFAILED;
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-	strncpy(cntl_value->name, name, sizeof(cntl_value->name));
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-	strncpy(cntl_value->value, value, sizeof(cntl_value->value));
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+	if (strlen(value) >= sizeof(cntl_value->value)) {
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+		fprintf(stderr, "value exceeds the maximum of %d characters\n",
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+			sizeof(cntl_value->value));
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+		free(cntl_value);
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+		return ECGCONFIGPARSEFAIL;
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+	}
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+
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+	strncpy(cntl_value->name, name, sizeof(cntl_value->name) - 1);
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+	strncpy(cntl_value->value, value, sizeof(cntl_value->value) - 1);
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 	cntl_value->dirty = true;
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 	controller->values[controller->index] = cntl_value;
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 	controller->index++;
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@@ -356,7 +363,7 @@ int cgroup_set_value_string(struct cgroup_controller *controller,
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 	for (i = 0; i < controller->index; i++) {
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 		struct control_value *val = controller->values[i];
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 		if (!strcmp(val->name, name)) {
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-			strncpy(val->value, value, CG_VALUE_MAX);
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+			strncpy(val->value, value, CG_CONTROL_VALUE_MAX - 1);
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 			val->dirty = true;
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 			return 0;
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 		}
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-- 
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2.17.0
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