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authorDaniel Baumann <daniel.baumann@progress-linux.org>2019-10-26 08:29:10 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2019-10-26 08:29:10 +0000
commit66ae4baad173098544603718e9864f0da1c0c7a3 (patch)
treed8e6f387ee9b4d9b6936e3c21208e50b86daea60 /libnetdata/popen/popen.c
parentAdding upstream version 1.18.0. (diff)
downloadnetdata-66ae4baad173098544603718e9864f0da1c0c7a3.tar.xz
netdata-66ae4baad173098544603718e9864f0da1c0c7a3.zip
Adding upstream version 1.18.1.upstream/1.18.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'libnetdata/popen/popen.c')
-rw-r--r--libnetdata/popen/popen.c150
1 files changed, 123 insertions, 27 deletions
diff --git a/libnetdata/popen/popen.c b/libnetdata/popen/popen.c
index 906b10535..1c4ae64d6 100644
--- a/libnetdata/popen/popen.c
+++ b/libnetdata/popen/popen.c
@@ -2,46 +2,79 @@
#include "../libnetdata.h"
-/*
+static pthread_mutex_t myp_lock;
+static int myp_tracking = 0;
+
struct mypopen {
pid_t pid;
- FILE *fp;
struct mypopen *next;
struct mypopen *prev;
};
static struct mypopen *mypopen_root = NULL;
-static void mypopen_add(FILE *fp, pid_t *pid) {
- struct mypopen *mp = malloc(sizeof(struct mypopen));
- if(!mp) {
- fatal("Cannot allocate %zu bytes", sizeof(struct mypopen))
+// myp_add_lock takes the lock if we're tracking.
+static void myp_add_lock(void) {
+ if (myp_tracking == 0)
return;
- }
- mp->fp = fp;
+ netdata_mutex_lock(&myp_lock);
+}
+
+// myp_add_unlock release the lock if we're tracking.
+static void myp_add_unlock(void) {
+ if (myp_tracking == 0)
+ return;
+
+ netdata_mutex_unlock(&myp_lock);
+}
+
+// myp_add_locked adds pid if we're tracking.
+// myp_add_lock must have been called previously.
+static void myp_add_locked(pid_t pid) {
+ struct mypopen *mp;
+
+ if (myp_tracking == 0)
+ return;
+
+ mp = mallocz(sizeof(struct mypopen));
mp->pid = pid;
- mp->next = popen_root;
+
+ mp->next = mypopen_root;
mp->prev = NULL;
- if(mypopen_root) mypopen_root->prev = mp;
+ if (mypopen_root != NULL)
+ mypopen_root->prev = mp;
mypopen_root = mp;
+ netdata_mutex_unlock(&myp_lock);
}
-static void mypopen_del(FILE *fp) {
+// myp_del deletes pid if we're tracking.
+static void myp_del(pid_t pid) {
struct mypopen *mp;
- for(mp = mypopen_root; mp; mp = mp->next)
- if(mp->fd == fp) break;
+ if (myp_tracking == 0)
+ return;
- if(!mp) error("Cannot find mypopen() file pointer in open childs.");
- else {
- if(mp->next) mp->next->prev = mp->prev;
- if(mp->prev) mp->prev->next = mp->next;
- if(mypopen_root == mp) mypopen_root = mp->next;
- free(mp);
+ netdata_mutex_lock(&myp_lock);
+ for (mp = mypopen_root; mp != NULL; mp = mp->next) {
+ if (mp->pid == pid) {
+ if (mp->next != NULL)
+ mp->next->prev = mp->prev;
+ if (mp->prev != NULL)
+ mp->prev->next = mp->next;
+ if (mypopen_root == mp)
+ mypopen_root = mp->next;
+ freez(mp);
+ break;
+ }
}
+
+ if (mp == NULL)
+ error("Cannot find pid %d.", pid);
+
+ netdata_mutex_unlock(&myp_lock);
}
-*/
+
#define PIPE_READ 0
#define PIPE_WRITE 1
@@ -58,7 +91,7 @@ static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, c
posix_spawnattr_t attr;
posix_spawn_file_actions_t fa;
- if(pipe(pipefd) == -1)
+ if (pipe(pipefd) == -1)
return NULL;
if ((fp = fdopen(pipefd[PIPE_READ], "r")) == NULL) {
goto error_after_pipe;
@@ -66,7 +99,7 @@ static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, c
// Mark all files to be closed by the exec() stage of posix_spawn()
int i;
- for(i = (int) (sysconf(_SC_OPEN_MAX) - 1); i >= 0; i--)
+ for (i = (int) (sysconf(_SC_OPEN_MAX) - 1); i >= 0; i--)
if(i != STDIN_FILENO && i != STDERR_FILENO)
(void)fcntl(i, F_SETFD, FD_CLOEXEC);
@@ -92,10 +125,16 @@ static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, c
} else {
error("posix_spawnattr_init() failed.");
}
+
+ // Take the lock while we fork to ensure we don't race with SIGCHLD
+ // delivery on a process which exits quickly.
+ myp_add_lock();
if (!posix_spawn(&pid, "/bin/sh", &fa, &attr, spawn_argv, env)) {
*pidptr = pid;
+ myp_add_locked(pid);
debug(D_CHILDS, "Spawned command: '%s' on pid %d from parent pid %d.", command, pid, getpid());
} else {
+ myp_add_unlock();
error("Failed to spawn command: '%s' from parent pid %d.", command, getpid());
fclose(fp);
fp = NULL;
@@ -128,6 +167,60 @@ error_after_pipe:
// See man environ
extern char **environ;
+// myp_init should be called by apps which act as init
+// (pid 1) so that processes created by mypopen and mypopene
+// are tracked. This enables the reaper to ignore processes
+// which will be handled internally, by calling myp_reap, to
+// avoid issues with already reaped processes during wait calls.
+//
+// Callers should call myp_free() to clean up resources.
+void myp_init(void) {
+ info("process tracking enabled.");
+ myp_tracking = 1;
+
+ if (netdata_mutex_init(&myp_lock) != 0) {
+ fatal("myp_init() mutex init failed.");
+ }
+}
+
+// myp_free cleans up any resources allocated for process
+// tracking.
+void myp_free(void) {
+ struct mypopen *mp, *next;
+
+ if (myp_tracking == 0)
+ return;
+
+ netdata_mutex_lock(&myp_lock);
+ for (mp = mypopen_root; mp != NULL; mp = next) {
+ next = mp->next;
+ freez(mp);
+ }
+
+ mypopen_root = NULL;
+ myp_tracking = 0;
+ netdata_mutex_unlock(&myp_lock);
+}
+
+// myp_reap returns 1 if pid should be reaped, 0 otherwise.
+int myp_reap(pid_t pid) {
+ struct mypopen *mp;
+
+ if (myp_tracking == 0)
+ return 0;
+
+ netdata_mutex_lock(&myp_lock);
+ for (mp = mypopen_root; mp != NULL; mp = mp->next) {
+ if (mp->pid == pid) {
+ netdata_mutex_unlock(&myp_lock);
+ return 0;
+ }
+ }
+ netdata_mutex_unlock(&myp_lock);
+
+ return 1;
+}
+
FILE *mypopen(const char *command, volatile pid_t *pidptr) {
return custom_popene(command, pidptr, environ);
}
@@ -137,9 +230,10 @@ FILE *mypopene(const char *command, volatile pid_t *pidptr, char **env) {
}
int mypclose(FILE *fp, pid_t pid) {
- debug(D_EXIT, "Request to mypclose() on pid %d", pid);
+ int ret;
+ siginfo_t info;
- /*mypopen_del(fp);*/
+ debug(D_EXIT, "Request to mypclose() on pid %d", pid);
// close the pipe fd
// this is required in musl
@@ -151,9 +245,11 @@ int mypclose(FILE *fp, pid_t pid) {
errno = 0;
- siginfo_t info;
- if(waitid(P_PID, (id_t) pid, &info, WEXITED) != -1) {
- switch(info.si_code) {
+ ret = waitid(P_PID, (id_t) pid, &info, WEXITED);
+ myp_del(pid);
+
+ if (ret != -1) {
+ switch (info.si_code) {
case CLD_EXITED:
if(info.si_status)
error("child pid %d exited with code %d.", info.si_pid, info.si_status);