diff options
Diffstat (limited to 'libnetdata/popen/popen.c')
| -rw-r--r-- | libnetdata/popen/popen.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/libnetdata/popen/popen.c b/libnetdata/popen/popen.c new file mode 100644 index 00000000..845363fd --- /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; +} |