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Support docker cgroup limits (dotnet#13488)
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* Fix cgroup mountinfo parsing

The parsing would find the wrong '-' in lines like this:
354 347 0:28 /system.slice/docker-654dd7b6b8bbfe1739ae3309b471e95ccc82b3a3f56b7879f0a811d68b5c4e1d.scope /sys/fs/cgroup/cpuacct,cpu ro,nosuid,nodev,noexec,relatime - cgroup cgroup rw,cpuacct,cpu

* cgroup: don't append cgroup relative path for reading docker limits
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@tmds
tmds committed Aug 22, 2017
1 parent 0d53e14 commit 5596717
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Showing 2 changed files with 80 additions and 111 deletions.
92 changes: 39 additions & 53 deletions src/gc/unix/cgroup.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,8 @@ class CGroup
public:
CGroup()
{
m_memory_cgroup_path = FindMemoryCgroupPath();
m_cpu_cgroup_path = FindCpuCgroupPath();
m_memory_cgroup_path = FindCgroupPath(&IsMemorySubsystem);
m_cpu_cgroup_path = FindCgroupPath(&IsCpuSubsystem);
}

~CGroup()
Expand Down Expand Up @@ -110,65 +110,45 @@ class CGroup
return strcmp("cpu", strTok) == 0;
}

static char* FindMemoryCgroupPath(){
char *memory_cgroup_path = nullptr;
char *memory_hierarchy_mount = nullptr;
char *mem_cgroup_path_relative_to_mount = nullptr;

memory_hierarchy_mount = FindHierarchyMount(&IsMemorySubsystem);
if (memory_hierarchy_mount == nullptr)
goto done;

mem_cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(&IsMemorySubsystem);
if (mem_cgroup_path_relative_to_mount == nullptr)
goto done;

memory_cgroup_path = (char*)malloc(strlen(memory_hierarchy_mount) + strlen(mem_cgroup_path_relative_to_mount) + 1);
if (memory_cgroup_path == nullptr)
goto done;

strcpy(memory_cgroup_path, memory_hierarchy_mount);
strcat(memory_cgroup_path, mem_cgroup_path_relative_to_mount);

done:
free(memory_hierarchy_mount);
free(mem_cgroup_path_relative_to_mount);
return memory_cgroup_path;
}

static char* FindCpuCgroupPath(){
char *cpu_cgroup_path = nullptr;
char *cpu_hierarchy_mount = nullptr;
char *cpu_cgroup_path_relative_to_mount = nullptr;
static char* FindCgroupPath(bool (*is_subsystem)(const char *)){
char *cgroup_path = nullptr;
char *hierarchy_mount = nullptr;
char *hierarchy_root = nullptr;
char *cgroup_path_relative_to_mount = nullptr;

cpu_hierarchy_mount = FindHierarchyMount(&IsCpuSubsystem);
if (cpu_hierarchy_mount == nullptr)
FindHierarchyMount(is_subsystem, &hierarchy_mount, &hierarchy_root);
if (hierarchy_mount == nullptr || hierarchy_root == nullptr)
goto done;

cpu_cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(&IsCpuSubsystem);
if (cpu_cgroup_path_relative_to_mount == nullptr)
cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(is_subsystem);
if (cgroup_path_relative_to_mount == nullptr)
goto done;

cpu_cgroup_path = (char*)malloc(strlen(cpu_hierarchy_mount) + strlen(cpu_cgroup_path_relative_to_mount) + 1);
if (cpu_cgroup_path == nullptr)
cgroup_path = (char*)malloc(strlen(hierarchy_mount) + strlen(cgroup_path_relative_to_mount) + 1);
if (cgroup_path == nullptr)
goto done;

strcpy(cpu_cgroup_path, cpu_hierarchy_mount);
strcat(cpu_cgroup_path, cpu_cgroup_path_relative_to_mount);
strcpy(cgroup_path, hierarchy_mount);
// For a host cgroup, we need to append the relative path.
// In a docker container, the root and relative path are the same and we don't need to append.
if (strcmp(hierarchy_root, cgroup_path_relative_to_mount) != 0)
strcat(cgroup_path, cgroup_path_relative_to_mount);

done:
free(cpu_hierarchy_mount);
free(cpu_cgroup_path_relative_to_mount);
return cpu_cgroup_path;
free(hierarchy_mount);
free(hierarchy_root);
free(cgroup_path_relative_to_mount);
return cgroup_path;
}

static char* FindHierarchyMount(bool (*is_subsystem)(const char *))
static void FindHierarchyMount(bool (*is_subsystem)(const char *), char** pmountpath, char** pmountroot)
{
char *line = nullptr;
size_t lineLen = 0, maxLineLen = 0;
char *filesystemType = nullptr;
char *options = nullptr;
char *mountpath = nullptr;
char *mountroot = nullptr;

FILE *mountinfofile = fopen(PROC_MOUNTINFO_FILENAME, "r");
if (mountinfofile == nullptr)
Expand All @@ -189,11 +169,11 @@ class CGroup
maxLineLen = lineLen;
}

char* separatorChar = strchr(line, '-');
char* separatorChar = strstr(line, " - ");

// See man page of proc to get format for /proc/self/mountinfo file
int sscanfRet = sscanf(separatorChar,
"- %s %*s %s",
" - %s %*s %s",
filesystemType,
options);
if (sscanfRet != 2)
Expand All @@ -213,29 +193,35 @@ class CGroup
mountpath = (char*)malloc(lineLen+1);
if (mountpath == nullptr)
goto done;
mountroot = (char*)malloc(lineLen+1);
if (mountroot == nullptr)
goto done;

sscanfRet = sscanf(line,
"%*s %*s %*s %*s %s ",
"%*s %*s %*s %s %s ",
mountroot,
mountpath);
if (sscanfRet != 1)
{
free(mountpath);
mountpath = nullptr;
if (sscanfRet != 2)
assert(!"Failed to parse mount info file contents with sscanf.");
}

// assign the output arguments and clear the locals so we don't free them.
*pmountpath = mountpath;
*pmountroot = mountroot;
mountpath = mountroot = nullptr;
goto done;
}
strTok = strtok_r(nullptr, ",", &context);
}
}
}
done:
free(mountpath);
free(mountroot);
free(filesystemType);
free(options);
free(line);
if (mountinfofile)
fclose(mountinfofile);
return mountpath;
}

static char* FindCGroupPathForSubsystem(bool (*is_subsystem)(const char *))
Expand Down
99 changes: 41 additions & 58 deletions src/pal/src/misc/cgroup.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,8 @@ class CGroup
public:
CGroup()
{
m_memory_cgroup_path = FindMemoryCgroupPath();
m_cpu_cgroup_path = FindCpuCgroupPath();
m_memory_cgroup_path = FindCgroupPath(&IsMemorySubsystem);
m_cpu_cgroup_path = FindCgroupPath(&IsCpuSubsystem);
}

~CGroup()
Expand Down Expand Up @@ -105,71 +105,48 @@ class CGroup
return strcmp("cpu", strTok) == 0;
}

static char* FindMemoryCgroupPath(){
char *memory_cgroup_path = nullptr;
char *memory_hierarchy_mount = nullptr;
char *mem_cgroup_path_relative_to_mount = nullptr;
size_t len;

memory_hierarchy_mount = FindHierarchyMount(&IsMemorySubsystem);
if (memory_hierarchy_mount == nullptr)
goto done;

mem_cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(&IsMemorySubsystem);
if (mem_cgroup_path_relative_to_mount == nullptr)
goto done;

len = strlen(memory_hierarchy_mount);
len += strlen(mem_cgroup_path_relative_to_mount);
memory_cgroup_path = (char*)PAL_malloc(len+1);
if (memory_cgroup_path == nullptr)
goto done;

strcpy_s(memory_cgroup_path, len+1, memory_hierarchy_mount);
strcat_s(memory_cgroup_path, len+1, mem_cgroup_path_relative_to_mount);

done:
PAL_free(memory_hierarchy_mount);
PAL_free(mem_cgroup_path_relative_to_mount);
return memory_cgroup_path;
}

static char* FindCpuCgroupPath(){
char *cpu_cgroup_path = nullptr;
char *cpu_hierarchy_mount = nullptr;
char *cpu_cgroup_path_relative_to_mount = nullptr;
static char* FindCgroupPath(bool (*is_subsystem)(const char *)){
char *cgroup_path = nullptr;
char *hierarchy_mount = nullptr;
char *hierarchy_root = nullptr;
char *cgroup_path_relative_to_mount = nullptr;
size_t len;

cpu_hierarchy_mount = FindHierarchyMount(&IsCpuSubsystem);
if (cpu_hierarchy_mount == nullptr)
FindHierarchyMount(is_subsystem, &hierarchy_mount, &hierarchy_root);
if (hierarchy_mount == nullptr || hierarchy_root == nullptr)
goto done;

cpu_cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(&IsCpuSubsystem);
if (cpu_cgroup_path_relative_to_mount == nullptr)
cgroup_path_relative_to_mount = FindCGroupPathForSubsystem(is_subsystem);
if (cgroup_path_relative_to_mount == nullptr)
goto done;

len = strlen(cpu_hierarchy_mount);
len += strlen(cpu_cgroup_path_relative_to_mount);
cpu_cgroup_path = (char*)PAL_malloc(len+1);
if (cpu_cgroup_path == nullptr)
len = strlen(hierarchy_mount);
len += strlen(cgroup_path_relative_to_mount);
cgroup_path = (char*)PAL_malloc(len+1);
if (cgroup_path == nullptr)
goto done;

strcpy_s(cpu_cgroup_path, len+1, cpu_hierarchy_mount);
strcat_s(cpu_cgroup_path, len+1, cpu_cgroup_path_relative_to_mount);
strcpy_s(cgroup_path, len+1, hierarchy_mount);
// For a host cgroup, we need to append the relative path.
// In a docker container, the root and relative path are the same and we don't need to append.
if (strcmp(hierarchy_root, cgroup_path_relative_to_mount) != 0)
strcat_s(cgroup_path, len+1, cgroup_path_relative_to_mount);

done:
PAL_free(cpu_hierarchy_mount);
PAL_free(cpu_cgroup_path_relative_to_mount);
return cpu_cgroup_path;
PAL_free(hierarchy_mount);
PAL_free(hierarchy_root);
PAL_free(cgroup_path_relative_to_mount);
return cgroup_path;
}

static char* FindHierarchyMount(bool (*is_subsystem)(const char *))
static void FindHierarchyMount(bool (*is_subsystem)(const char *), char** pmountpath, char** pmountroot)
{
char *line = nullptr;
size_t lineLen = 0, maxLineLen = 0;
char *filesystemType = nullptr;
char *options = nullptr;
char *mountpath = nullptr;
char *mountroot = nullptr;

FILE *mountinfofile = fopen(PROC_MOUNTINFO_FILENAME, "r");
if (mountinfofile == nullptr)
Expand All @@ -189,11 +166,11 @@ class CGroup
goto done;
maxLineLen = lineLen;
}
char* separatorChar = strchr(line, '-');
char* separatorChar = strstr(line, " - ");;

// See man page of proc to get format for /proc/self/mountinfo file
int sscanfRet = sscanf_s(separatorChar,
"- %s %*s %s",
" - %s %*s %s",
filesystemType, lineLen+1,
options, lineLen+1);
if (sscanfRet != 2)
Expand All @@ -213,29 +190,35 @@ class CGroup
mountpath = (char*)PAL_malloc(lineLen+1);
if (mountpath == nullptr)
goto done;
mountroot = (char*)PAL_malloc(lineLen+1);
if (mountroot == nullptr)
goto done;

sscanfRet = sscanf_s(line,
"%*s %*s %*s %*s %s ",
"%*s %*s %*s %s %s ",
mountroot, lineLen+1,
mountpath, lineLen+1);
if (sscanfRet != 1)
{
PAL_free(mountpath);
mountpath = nullptr;
if (sscanfRet != 2)
_ASSERTE(!"Failed to parse mount info file contents with sscanf_s.");
}

// assign the output arguments and clear the locals so we don't free them.
*pmountpath = mountpath;
*pmountroot = mountroot;
mountpath = mountroot = nullptr;
goto done;
}
strTok = strtok_s(nullptr, ",", &context);
}
}
}
done:
PAL_free(mountpath);
PAL_free(mountroot);
PAL_free(filesystemType);
PAL_free(options);
free(line);
if (mountinfofile)
fclose(mountinfofile);
return mountpath;
}

static char* FindCGroupPathForSubsystem(bool (*is_subsystem)(const char *))
Expand Down

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