diff options
Diffstat (limited to 'libnetdata/popen/popen.c')
| -rw-r--r-- | libnetdata/popen/popen.c | 118 |
1 files changed, 84 insertions, 34 deletions
diff --git a/libnetdata/popen/popen.c b/libnetdata/popen/popen.c index 1c4ae64d6..c0135cf40 100644 --- a/libnetdata/popen/popen.c +++ b/libnetdata/popen/popen.c @@ -78,8 +78,16 @@ static void myp_del(pid_t pid) { #define PIPE_READ 0 #define PIPE_WRITE 1 -static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, char **env) { - FILE *fp; +/* custom_popene flag definitions */ +#define FLAG_CREATE_PIPE 1 // Create a pipe like popen() when set, otherwise set stdout to /dev/null +#define FLAG_CLOSE_FD 2 // Close all file descriptors other than STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO + +/* + * Returns -1 on failure, 0 on success. When FLAG_CREATE_PIPE is set, on success set the FILE *fp pointer. + */ +static inline int custom_popene(const char *command, volatile pid_t *pidptr, char **env, uint8_t flags, FILE **fpp) { + FILE *fp = NULL; + int ret = 0; // success by default int pipefd[2], error; pid_t pid; char *const spawn_argv[] = { @@ -91,23 +99,36 @@ 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) - return NULL; - if ((fp = fdopen(pipefd[PIPE_READ], "r")) == NULL) { - goto error_after_pipe; + if (flags & FLAG_CREATE_PIPE) { + if (pipe(pipefd) == -1) + return -1; + if ((fp = fdopen(pipefd[PIPE_READ], "r")) == NULL) { + goto error_after_pipe; + } } - // 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--) - if(i != STDIN_FILENO && i != STDERR_FILENO) - (void)fcntl(i, F_SETFD, FD_CLOEXEC); + if (flags & FLAG_CLOSE_FD) { + // 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--) { + if (i != STDIN_FILENO && i != STDERR_FILENO) + (void) fcntl(i, F_SETFD, FD_CLOEXEC); + } + } if (!posix_spawn_file_actions_init(&fa)) { - // move the pipe to stdout in the child - if (posix_spawn_file_actions_adddup2(&fa, pipefd[PIPE_WRITE], STDOUT_FILENO)) { - error("posix_spawn_file_actions_adddup2() failed"); - goto error_after_posix_spawn_file_actions_init; + if (flags & FLAG_CREATE_PIPE) { + // move the pipe to stdout in the child + if (posix_spawn_file_actions_adddup2(&fa, pipefd[PIPE_WRITE], STDOUT_FILENO)) { + error("posix_spawn_file_actions_adddup2() failed"); + goto error_after_posix_spawn_file_actions_init; + } + } else { + // set stdout to /dev/null + if (posix_spawn_file_actions_addopen(&fa, STDOUT_FILENO, "/dev/null", O_WRONLY, 0)) { + error("posix_spawn_file_actions_addopen() failed"); + // this is not a fatal error + } } } else { error("posix_spawn_file_actions_init() failed."); @@ -136,10 +157,16 @@ static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, c } else { myp_add_unlock(); error("Failed to spawn command: '%s' from parent pid %d.", command, getpid()); - fclose(fp); - fp = NULL; + if (flags & FLAG_CREATE_PIPE) { + fclose(fp); + } + ret = -1; + } + if (flags & FLAG_CREATE_PIPE) { + close(pipefd[PIPE_WRITE]); + if (0 == ret) // on success set FILE * pointer + *fpp = fp; } - close(pipefd[PIPE_WRITE]); if (!error) { // posix_spawnattr_init() succeeded @@ -149,19 +176,21 @@ static inline FILE *custom_popene(const char *command, volatile pid_t *pidptr, c if (posix_spawn_file_actions_destroy(&fa)) error("posix_spawn_file_actions_destroy"); - return fp; + return ret; error_after_posix_spawn_file_actions_init: if (posix_spawn_file_actions_destroy(&fa)) error("posix_spawn_file_actions_destroy"); error_after_pipe: - if (fp) - fclose(fp); - else - close(pipefd[PIPE_READ]); + if (flags & FLAG_CREATE_PIPE) { + if (fp) + fclose(fp); + else + close(pipefd[PIPE_READ]); - close(pipefd[PIPE_WRITE]); - return NULL; + close(pipefd[PIPE_WRITE]); + } + return -1; } // See man environ @@ -222,26 +251,37 @@ int myp_reap(pid_t pid) { } FILE *mypopen(const char *command, volatile pid_t *pidptr) { - return custom_popene(command, pidptr, environ); + FILE *fp = NULL; + (void)custom_popene(command, pidptr, environ, FLAG_CREATE_PIPE | FLAG_CLOSE_FD, &fp); + return fp; } FILE *mypopene(const char *command, volatile pid_t *pidptr, char **env) { - return custom_popene(command, pidptr, env); + FILE *fp = NULL; + (void)custom_popene(command, pidptr, env, FLAG_CREATE_PIPE | FLAG_CLOSE_FD, &fp); + return fp; +} + +// returns 0 on success, -1 on failure +int netdata_spawn(const char *command, volatile pid_t *pidptr) { + return custom_popene(command, pidptr, environ, 0, NULL); } -int mypclose(FILE *fp, pid_t pid) { +int custom_pclose(FILE *fp, pid_t pid) { int ret; siginfo_t info; debug(D_EXIT, "Request to mypclose() on pid %d", pid); - // close the pipe fd - // this is required in musl - // without it the childs do not exit - close(fileno(fp)); + if (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); + // close the pipe file pointer + fclose(fp); + } errno = 0; @@ -285,3 +325,13 @@ int mypclose(FILE *fp, pid_t pid) { return 0; } + +int mypclose(FILE *fp, pid_t pid) +{ + return custom_pclose(fp, pid); +} + +int netdata_spawn_waitpid(pid_t pid) +{ + return custom_pclose(NULL, pid); +}
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