LinuxProcessList: use openat instead of building path strings

openat() is available since Linux 2.6.16
This commit is contained in:
Christian Göttsche 2020-11-17 19:46:12 +01:00 committed by BenBE
parent f704baeb82
commit 638207a2ff
1 changed files with 99 additions and 98 deletions

View File

@ -81,6 +81,20 @@ static ssize_t xread(int fd, void* buf, size_t count) {
}
}
static FILE* fopenat(int dirfd, const char* pathname, const char* mode) {
assert(String_eq(mode, "r")); /* only currently supported mode */
int fd = openat(dirfd, pathname, O_RDONLY);
if (fd < 0)
return NULL;
FILE* stream = fdopen(fd, mode);
if (!stream)
close(fd);
return stream;
}
static int sortTtyDrivers(const void* va, const void* vb) {
const TtyDriver* a = (const TtyDriver*) va;
const TtyDriver* b = (const TtyDriver*) vb;
@ -307,13 +321,11 @@ static inline unsigned long long LinuxProcess_adjustTime(unsigned long long t) {
return t * 100 / jiffy;
}
static bool LinuxProcessList_readStatFile(Process* process, const char* dirname, const char* name, char* command, int* commLen) {
static bool LinuxProcessList_readStatFile(Process* process, int procFd, char* command, int* commLen) {
LinuxProcess* lp = (LinuxProcess*) process;
const int commLenIn = *commLen;
*commLen = 0;
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/stat", dirname, name);
int fd = open(filename, O_RDONLY);
int fd = openat(procFd, "stat", O_RDONLY);
if (fd == -1)
return false;
@ -399,25 +411,17 @@ static bool LinuxProcessList_readStatFile(Process* process, const char* dirname,
}
static bool LinuxProcessList_statProcessDir(Process* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
filename[MAX_NAME] = '\0';
xSnprintf(filename, MAX_NAME, "%s/%s", dirname, name);
static bool LinuxProcessList_statProcessDir(Process* process, int procFd) {
struct stat sstat;
int statok = stat(filename, &sstat);
int statok = fstat(procFd, &sstat);
if (statok == -1)
return false;
process->st_uid = sstat.st_uid;
return true;
}
static void LinuxProcessList_readIoFile(LinuxProcess* process, const char* dirname, const char* name, unsigned long long now) {
char filename[MAX_NAME + 1];
filename[MAX_NAME] = '\0';
xSnprintf(filename, MAX_NAME, "%s/%s/io", dirname, name);
int fd = open(filename, O_RDONLY);
static void LinuxProcessList_readIoFile(LinuxProcess* process, int procFd, unsigned long long now) {
int fd = openat(procFd, "io", O_RDONLY);
if (fd == -1) {
process->io_rate_read_bps = NAN;
process->io_rate_write_bps = NAN;
@ -543,10 +547,8 @@ static void LinuxProcessList_calcLibSize_helper(ATTR_UNUSED hkey_t key, void* va
*d += v->size;
}
static uint64_t LinuxProcessList_calcLibSize(const char* dirname, const char* name) {
char filename[MAX_NAME+1];
xSnprintf(filename, sizeof(filename), "%s/%s/maps", dirname, name);
FILE* mapsfile = fopen(filename, "r");
static uint64_t LinuxProcessList_calcLibSize(int procFd) {
FILE* mapsfile = fopenat(procFd, "maps", "r");
if (!mapsfile)
return 0;
@ -623,10 +625,8 @@ static uint64_t LinuxProcessList_calcLibSize(const char* dirname, const char* na
return total_size / CRT_pageSize;
}
static bool LinuxProcessList_readStatmFile(LinuxProcess* process, const char* dirname, const char* name, bool performLookup, unsigned long long now) {
char filename[MAX_NAME + 1];
xSnprintf(filename, sizeof(filename), "%s/%s/statm", dirname, name);
FILE* statmfile = fopen(filename, "r");
static bool LinuxProcessList_readStatmFile(LinuxProcess* process, int procFd, bool performLookup, unsigned long long now) {
FILE* statmfile = fopenat(procFd, "statm", "r");
if (!statmfile)
return false;
@ -652,7 +652,7 @@ static bool LinuxProcessList_readStatmFile(LinuxProcess* process, const char* di
if(passedTimeInMs > 2000 || passedTimeInMs > recheck) {
process->last_mlrs_calctime = now;
process->m_lrs = LinuxProcessList_calcLibSize(dirname, name);
process->m_lrs = LinuxProcessList_calcLibSize(procFd);
}
} else {
// Keep previous value
@ -662,19 +662,10 @@ static bool LinuxProcessList_readStatmFile(LinuxProcess* process, const char* di
return r == 7;
}
static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* dirname, const char* name, bool haveSmapsRollup) {
static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, int procFd, bool haveSmapsRollup) {
//http://elixir.free-electrons.com/linux/v4.10/source/fs/proc/task_mmu.c#L719
//kernel will return data in chunks of size PAGE_SIZE or less.
char buffer[256];
if (haveSmapsRollup) {// only available in Linux 4.14+
xSnprintf(buffer, sizeof(buffer), "%s/%s/smaps_rollup", dirname, name);
} else {
xSnprintf(buffer, sizeof(buffer), "%s/%s/smaps", dirname, name);
}
FILE* f = fopen(buffer, "r");
FILE* f = fopenat(procFd, haveSmapsRollup ? "smaps_rollup" : "smaps", "r");
if (!f)
return false;
@ -682,6 +673,7 @@ static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* di
process->m_swap = 0;
process->m_psswp = 0;
char buffer[256];
while (fgets(buffer, sizeof(buffer), f)) {
if (!strchr(buffer, '\n')) {
// Partial line, skip to end of this line
@ -708,7 +700,7 @@ static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* di
#ifdef HAVE_OPENVZ
static void LinuxProcessList_readOpenVZData(LinuxProcess* process, const char* dirname, const char* name) {
static void LinuxProcessList_readOpenVZData(LinuxProcess* process, int procFd) {
if ( (access(PROCDIR "/vz", R_OK) != 0)) {
free(process->ctid);
process->ctid = NULL;
@ -716,9 +708,7 @@ static void LinuxProcessList_readOpenVZData(LinuxProcess* process, const char* d
return;
}
char filename[MAX_NAME + 1];
xSnprintf(filename, sizeof(filename), "%s/%s/status", dirname, name);
FILE* file = fopen(filename, "r");
FILE* file = fopenat(procFd, "status", "r");
if (!file) {
free(process->ctid);
process->ctid = NULL;
@ -802,10 +792,8 @@ static void LinuxProcessList_readOpenVZData(LinuxProcess* process, const char* d
#endif
static void LinuxProcessList_readCGroupFile(LinuxProcess* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/cgroup", dirname, name);
FILE* file = fopen(filename, "r");
static void LinuxProcessList_readCGroupFile(LinuxProcess* process, int procFd) {
FILE* file = fopenat(procFd, "cgroup", "r");
if (!file) {
if (process->cgroup) {
free(process->cgroup);
@ -842,10 +830,8 @@ static void LinuxProcessList_readCGroupFile(LinuxProcess* process, const char* d
#ifdef HAVE_VSERVER
static void LinuxProcessList_readVServerData(LinuxProcess* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/status", dirname, name);
FILE* file = fopen(filename, "r");
static void LinuxProcessList_readVServerData(LinuxProcess* process, int procFd) {
FILE* file = fopenat(procFd, "status", "r");
if (!file)
return;
@ -874,13 +860,11 @@ static void LinuxProcessList_readVServerData(LinuxProcess* process, const char*
#endif
static void LinuxProcessList_readOomData(LinuxProcess* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/oom_score", dirname, name);
FILE* file = fopen(filename, "r");
if (!file) {
static void LinuxProcessList_readOomData(LinuxProcess* process, int procFd) {
FILE* file = fopenat(procFd, "oom_score", "r");
if (!file)
return;
}
char buffer[PROC_LINE_LENGTH + 1];
if (fgets(buffer, PROC_LINE_LENGTH, file)) {
unsigned int oom;
@ -892,10 +876,8 @@ static void LinuxProcessList_readOomData(LinuxProcess* process, const char* dirn
fclose(file);
}
static void LinuxProcessList_readCtxtData(LinuxProcess* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/status", dirname, name);
FILE* file = fopen(filename, "r");
static void LinuxProcessList_readCtxtData(LinuxProcess* process, int procFd) {
FILE* file = fopenat(procFd, "status", "r");
if (!file)
return;
@ -921,15 +903,14 @@ static void LinuxProcessList_readCtxtData(LinuxProcess* process, const char* dir
process->ctxt_total = ctxt;
}
static void LinuxProcessList_readSecattrData(LinuxProcess* process, const char* dirname, const char* name) {
char filename[MAX_NAME + 1];
xSnprintf(filename, sizeof(filename), "%s/%s/attr/current", dirname, name);
FILE* file = fopen(filename, "r");
static void LinuxProcessList_readSecattrData(LinuxProcess* process, int procFd) {
FILE* file = fopenat(procFd, "attr/current", "r");
if (!file) {
free(process->secattr);
process->secattr = NULL;
return;
}
char buffer[PROC_LINE_LENGTH + 1];
char* res = fgets(buffer, sizeof(buffer), file);
fclose(file);
@ -1029,11 +1010,9 @@ static void setCommand(Process* process, const char* command, int len) {
process->commLen = len;
}
static bool LinuxProcessList_readCmdlineFile(Process* process, const char* dirname, const char* name) {
static bool LinuxProcessList_readCmdlineFile(Process* process, int procFd) {
LinuxProcess *lp = (LinuxProcess *)process;
char filename[MAX_NAME + 1];
xSnprintf(filename, MAX_NAME, "%s/%s/cmdline", dirname, name);
int fd = open(filename, O_RDONLY);
int fd = openat(procFd, "cmdline", O_RDONLY);
if (fd == -1)
return false;
@ -1174,8 +1153,7 @@ static bool LinuxProcessList_readCmdlineFile(Process* process, const char* dirna
}
/* /proc/[pid]/comm could change, so should be updated */
xSnprintf(filename, MAX_NAME, "%s/%s/comm", dirname, name);
if ((fd = open(filename, O_RDONLY)) != -1 &&
if ((fd = openat(procFd, "comm", O_RDONLY)) != -1 &&
(amtRead = xread(fd, command, sizeof(command) - 1)) > 0) {
command[amtRead - 1] = 0;
lp->mergedCommand.maxLen += amtRead - 1; /* accommodate comm */
@ -1193,9 +1171,10 @@ static bool LinuxProcessList_readCmdlineFile(Process* process, const char* dirna
if (fd != -1)
close(fd);
char filename[MAX_NAME + 1];
/* execve could change /proc/[pid]/exe, so procExe should be updated */
xSnprintf(command, sizeof(command), "%s/%s/exe", dirname, name);
if ((amtRead = readlink(command, filename, sizeof(filename) - 1)) > 0) {
if ((amtRead = readlinkat(procFd, "exe", filename, sizeof(filename) - 1)) > 0) {
filename[amtRead] = 0;
lp->mergedCommand.maxLen += amtRead; /* accommodate exe */
if (!lp->procExe || strcmp(filename, lp->procExe)) {
@ -1282,21 +1261,23 @@ static char* LinuxProcessList_updateTtyDevice(TtyDriver* ttyDrivers, unsigned in
return out;
}
static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char* dirname, const Process* parent, double period, unsigned long long now) {
static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, int dirFd, const Process* parent, double period, unsigned long long now) {
ProcessList* pl = (ProcessList*) this;
DIR* dir;
const struct dirent* entry;
const Settings* settings = pl->settings;
dir = opendir(dirname);
if (!dir)
DIR* dir = fdopendir(dirFd);
if (!dir) {
close(dirFd);
return false;
}
int cpus = pl->cpuCount;
bool hideKernelThreads = settings->hideKernelThreads;
bool hideUserlandThreads = settings->hideUserlandThreads;
while ((entry = readdir(dir)) != NULL) {
const char* name = entry->d_name;
int procFd = -1;
// Ignore all non-directories
if (entry->d_type != DT_DIR && entry->d_type != DT_UNKNOWN) {
@ -1317,21 +1298,27 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
// filename is a number: process directory
int pid = atoi(name);
if (parent && pid == parent->pid)
continue;
if (pid <= 0)
continue;
bool preExisting = false;
Process* proc = ProcessList_getProcess(pl, pid, &preExisting, LinuxProcess_new);
proc->tgid = parent ? parent->pid : pid;
if (parent && pid == parent->pid)
continue;
bool preExisting;
Process* proc = ProcessList_getProcess(pl, pid, &preExisting, LinuxProcess_new);
LinuxProcess* lp = (LinuxProcess*) proc;
char subdirname[MAX_NAME + 1];
xSnprintf(subdirname, MAX_NAME, "%s/%s/task", dirname, name);
LinuxProcessList_recurseProcTree(this, subdirname, proc, period, now);
proc->tgid = parent ? parent->pid : pid;
procFd = openat(dirFd, name, O_PATH | O_DIRECTORY | O_NOFOLLOW);
if (procFd < 0)
goto errorReadingProcess;
int taskDirFd = openat(procFd, "task", O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
if (taskDirFd >= 0) {
/* LinuxProcessList_recurseProcTree() closes taskDirFd */
LinuxProcessList_recurseProcTree(this, taskDirFd, proc, period, now);
}
/*
* These conditions will not trigger on first occurrence, cause we need to
@ -1344,6 +1331,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
proc->show = false;
pl->kernelThreads++;
pl->totalTasks++;
close(procFd);
continue;
}
if (preExisting && hideUserlandThreads && Process_isUserlandThread(proc)) {
@ -1351,13 +1339,14 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
proc->show = false;
pl->userlandThreads++;
pl->totalTasks++;
close(procFd);
continue;
}
if (settings->flags & PROCESS_FLAG_IO)
LinuxProcessList_readIoFile(lp, dirname, name, now);
LinuxProcessList_readIoFile(lp, procFd, now);
if (!LinuxProcessList_readStatmFile(lp, dirname, name, !!(settings->flags & PROCESS_FLAG_LINUX_LRS_FIX), now))
if (!LinuxProcessList_readStatmFile(lp, procFd, !!(settings->flags & PROCESS_FLAG_LINUX_LRS_FIX), now))
goto errorReadingProcess;
if ((settings->flags & PROCESS_FLAG_LINUX_SMAPS) && !Process_isKernelThread(proc)) {
@ -1365,7 +1354,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
// Read smaps file of each process only every second pass to improve performance
static int smaps_flag = 0;
if ((pid & 1) == smaps_flag) {
LinuxProcessList_readSmapsFile(lp, dirname, name, this->haveSmapsRollup);
LinuxProcessList_readSmapsFile(lp, procFd, this->haveSmapsRollup);
}
if (pid == 1) {
smaps_flag = !smaps_flag;
@ -1379,7 +1368,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
unsigned long long int lasttimes = (lp->utime + lp->stime);
int commLen = sizeof(command);
unsigned int tty_nr = proc->tty_nr;
if (! LinuxProcessList_readStatFile(proc, dirname, name, command, &commLen))
if (! LinuxProcessList_readStatFile(proc, procFd, command, &commLen))
goto errorReadingProcess;
if (tty_nr != proc->tty_nr && this->ttyDrivers) {
@ -1397,24 +1386,24 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
if (!preExisting) {
if (! LinuxProcessList_statProcessDir(proc, dirname, name))
if (! LinuxProcessList_statProcessDir(proc, procFd))
goto errorReadingProcess;
proc->user = UsersTable_getRef(pl->usersTable, proc->st_uid);
#ifdef HAVE_OPENVZ
if (settings->flags & PROCESS_FLAG_LINUX_OPENVZ) {
LinuxProcessList_readOpenVZData(lp, dirname, name);
LinuxProcessList_readOpenVZData(lp, procFd);
}
#endif
#ifdef HAVE_VSERVER
if (settings->flags & PROCESS_FLAG_LINUX_VSERVER) {
LinuxProcessList_readVServerData(lp, dirname, name);
LinuxProcessList_readVServerData(lp, procFd);
}
#endif
if (! LinuxProcessList_readCmdlineFile(proc, dirname, name)) {
if (! LinuxProcessList_readCmdlineFile(proc, procFd)) {
goto errorReadingProcess;
}
@ -1423,7 +1412,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
ProcessList_add(pl, proc);
} else {
if (settings->updateProcessNames && proc->state != 'Z') {
if (! LinuxProcessList_readCmdlineFile(proc, dirname, name)) {
if (! LinuxProcessList_readCmdlineFile(proc, procFd)) {
goto errorReadingProcess;
}
}
@ -1443,19 +1432,19 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
#endif
if (settings->flags & PROCESS_FLAG_LINUX_CGROUP) {
LinuxProcessList_readCGroupFile(lp, dirname, name);
LinuxProcessList_readCGroupFile(lp, procFd);
}
if (settings->flags & PROCESS_FLAG_LINUX_OOM) {
LinuxProcessList_readOomData(lp, dirname, name);
LinuxProcessList_readOomData(lp, procFd);
}
if (settings->flags & PROCESS_FLAG_LINUX_CTXT) {
LinuxProcessList_readCtxtData(lp, dirname, name);
LinuxProcessList_readCtxtData(lp, procFd);
}
if (settings->flags & PROCESS_FLAG_LINUX_SECATTR) {
LinuxProcessList_readSecattrData(lp, dirname, name);
LinuxProcessList_readSecattrData(lp, procFd);
}
if (proc->state == 'Z' && (proc->basenameOffset == 0)) {
@ -1466,7 +1455,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
proc->basenameOffset = -1;
setCommand(proc, command, commLen);
} else if (settings->showThreadNames) {
if (! LinuxProcessList_readCmdlineFile(proc, dirname, name)) {
if (! LinuxProcessList_readCmdlineFile(proc, procFd)) {
goto errorReadingProcess;
}
}
@ -1484,12 +1473,18 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
if (proc->state == 'R')
pl->runningTasks++;
proc->updated = true;
close(procFd);
continue;
// Exception handler.
errorReadingProcess:
{
if (procFd >= 0)
close(procFd);
if (preExisting) {
ProcessList_remove(pl, proc);
} else {
@ -1940,5 +1935,11 @@ void ProcessList_goThroughEntries(ProcessList* super, bool pauseProcessUpdate) {
gettimeofday(&tv, NULL);
unsigned long long now = tv.tv_sec * 1000ULL + tv.tv_usec / 1000ULL;
LinuxProcessList_recurseProcTree(this, PROCDIR, NULL, period, now);
int procDirfd = open(PROCDIR, O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
if (procDirfd < 0) {
CRT_fatalError("Can not open the root process directory " PROCDIR);
}
/* LinuxProcessList_recurseProcTree() closes procDirfd */
LinuxProcessList_recurseProcTree(this, procDirfd, NULL, period, now);
}