Function read_command_output_through_popen

src/butil/popen.cpp:158–194

#include <stdio.h>

int read_command_output_through_popen(std::ostream& os, const char* cmd) {
    FILE* pipe = popen(cmd, "r");
    if (pipe == NULL) {
        return -1;
    }
    char buffer[1024];
    for (;;) {
        size_t nr = fread(buffer, 1, sizeof(buffer), pipe);
        if (nr != 0) {
            os.write(buffer, nr);
        }
        if (nr != sizeof(buffer)) {
            if (feof(pipe)) {
                break;
            } else if (ferror(pipe)) {
                LOG(ERROR) << "Encountered error while reading for the pipe";
                break;
            }
            // retry;
        }
    }

    const int wstatus = pclose(pipe);

    if (wstatus < 0) {
        return wstatus;
    }
    if (WIFEXITED(wstatus)) {
        return WEXITSTATUS(wstatus);
    }
    if (WIFSIGNALED(wstatus)) {
        os << "Child process was killed by signal "
           << WTERMSIG(wstatus);
    }
    errno = ECHILD;
    return -1;
}

int read_command_output(std::ostream& os, const char* cmd) {
#if !defined(OS_LINUX)