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-rw-r--r--libnetdata/popen/popen.c206
1 files changed, 206 insertions, 0 deletions
diff --git a/libnetdata/popen/popen.c b/libnetdata/popen/popen.c
new file mode 100644
index 000000000..845363fd2
--- /dev/null
+++ b/libnetdata/popen/popen.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "../libnetdata.h"
+
+/*
+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))
+ return;
+ }
+
+ mp->fp = fp;
+ mp->pid = pid;
+ mp->next = popen_root;
+ mp->prev = NULL;
+ if(mypopen_root) mypopen_root->prev = mp;
+ mypopen_root = mp;
+}
+
+static void mypopen_del(FILE *fp) {
+ struct mypopen *mp;
+
+ for(mp = mypopen_root; mp; mp = mp->next)
+ if(mp->fd == fp) break;
+
+ 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);
+ }
+}
+*/
+#define PIPE_READ 0
+#define PIPE_WRITE 1
+
+FILE *mypopen(const char *command, volatile pid_t *pidptr)
+{
+ int pipefd[2];
+
+ if(pipe(pipefd) == -1) return NULL;
+
+ int pid = fork();
+ if(pid == -1) {
+ close(pipefd[PIPE_READ]);
+ close(pipefd[PIPE_WRITE]);
+ return NULL;
+ }
+ if(pid != 0) {
+ // the parent
+ *pidptr = pid;
+ close(pipefd[PIPE_WRITE]);
+ FILE *fp = fdopen(pipefd[PIPE_READ], "r");
+ /*mypopen_add(fp, pid);*/
+ return(fp);
+ }
+ // the child
+
+ // close all files
+ int i;
+ for(i = (int) (sysconf(_SC_OPEN_MAX) - 1); i >= 0; i--)
+ if(i != STDIN_FILENO && i != STDERR_FILENO && i != pipefd[PIPE_WRITE]) close(i);
+
+ // move the pipe to stdout
+ if(pipefd[PIPE_WRITE] != STDOUT_FILENO) {
+ dup2(pipefd[PIPE_WRITE], STDOUT_FILENO);
+ close(pipefd[PIPE_WRITE]);
+ }
+
+#ifdef DETACH_PLUGINS_FROM_NETDATA
+ // this was an attempt to detach the child and use the suspend mode charts.d
+ // unfortunatelly it does not work as expected.
+
+ // fork again to become session leader
+ pid = fork();
+ if(pid == -1)
+ error("pre-execution of command '%s' on pid %d: Cannot fork 2nd time.", command, getpid());
+
+ if(pid != 0) {
+ // the parent
+ exit(0);
+ }
+
+ // set a new process group id for just this child
+ if( setpgid(0, 0) != 0 )
+ error("pre-execution of command '%s' on pid %d: Cannot set a new process group.", command, getpid());
+
+ if( getpgid(0) != getpid() )
+ error("pre-execution of command '%s' on pid %d: Cannot set a new process group. Process group set is incorrect. Expected %d, found %d", command, getpid(), getpid(), getpgid(0));
+
+ if( setsid() != 0 )
+ error("pre-execution of command '%s' on pid %d: Cannot set session id.", command, getpid());
+
+ fprintf(stdout, "MYPID %d\n", getpid());
+ fflush(NULL);
+#endif
+
+ // reset all signals
+ signals_unblock();
+ signals_reset();
+
+ debug(D_CHILDS, "executing command: '%s' on pid %d.", command, getpid());
+ execl("/bin/sh", "sh", "-c", command, NULL);
+ exit(1);
+}
+
+FILE *mypopene(const char *command, volatile pid_t *pidptr, char **env) {
+ int pipefd[2];
+
+ if(pipe(pipefd) == -1)
+ return NULL;
+
+ int pid = fork();
+ if(pid == -1) {
+ close(pipefd[PIPE_READ]);
+ close(pipefd[PIPE_WRITE]);
+ return NULL;
+ }
+ if(pid != 0) {
+ // the parent
+ *pidptr = pid;
+ close(pipefd[PIPE_WRITE]);
+ FILE *fp = fdopen(pipefd[PIPE_READ], "r");
+ return(fp);
+ }
+ // the child
+
+ // close all files
+ int i;
+ for(i = (int) (sysconf(_SC_OPEN_MAX) - 1); i >= 0; i--)
+ if(i != STDIN_FILENO && i != STDERR_FILENO && i != pipefd[PIPE_WRITE]) close(i);
+
+ // move the pipe to stdout
+ if(pipefd[PIPE_WRITE] != STDOUT_FILENO) {
+ dup2(pipefd[PIPE_WRITE], STDOUT_FILENO);
+ close(pipefd[PIPE_WRITE]);
+ }
+
+ execle("/bin/sh", "sh", "-c", command, NULL, env);
+ exit(1);
+}
+
+int mypclose(FILE *fp, pid_t pid) {
+ debug(D_EXIT, "Request to mypclose() on pid %d", pid);
+
+ /*mypopen_del(fp);*/
+
+ // close the pipe fd
+ // this is required in musl
+ // without it the childs do not exit
+ close(fileno(fp));
+
+ // close the pipe file pointer
+ fclose(fp);
+
+ errno = 0;
+
+ siginfo_t info;
+ if(waitid(P_PID, (id_t) pid, &info, WEXITED) != -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);
+ return(info.si_status);
+
+ case CLD_KILLED:
+ error("child pid %d killed by signal %d.", info.si_pid, info.si_status);
+ return(-1);
+
+ case CLD_DUMPED:
+ error("child pid %d core dumped by signal %d.", info.si_pid, info.si_status);
+ return(-2);
+
+ case CLD_STOPPED:
+ error("child pid %d stopped by signal %d.", info.si_pid, info.si_status);
+ return(0);
+
+ case CLD_TRAPPED:
+ error("child pid %d trapped by signal %d.", info.si_pid, info.si_status);
+ return(-4);
+
+ case CLD_CONTINUED:
+ error("child pid %d continued by signal %d.", info.si_pid, info.si_status);
+ return(0);
+
+ default:
+ error("child pid %d gave us a SIGCHLD with code %d and status %d.", info.si_pid, info.si_code, info.si_status);
+ return(-5);
+ }
+ }
+ else
+ error("Cannot waitid() for pid %d", pid);
+
+ return 0;
+}