Kerbal Space Program

/* Remove Pulseaudio library reference

 *

 * Copyright (C) 2016 kspflo

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

// Build using: gcc -std=gnu99 -O2 -o pulsenomore pulsenomore.c -ldl

#define _GNU_SOURCE

#include <dlfcn.h>

#include <err.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <linux/memfd.h>

#include <sys/mman.h>

#include <sys/sendfile.h>

#include <sys/syscall.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#define LIBPULSE_SIMPLE                "libpulse-simple.so.0"

#ifdef __NR_memfd_create

static inline int memfd_create(const char *name, unsigned int flags) {

        return syscall(__NR_memfd_create, name, flags);

}

#else

#error "memfd_create syscall missing!"

#endif

static int check_pulseaudio_running(void) {

        void *h;

        pid_t pid;

        int (*pa_pid_file_check_running)(pid_t *, const char *), running;

        if(!(h = dlopen(LIBPULSE_SIMPLE, RTLD_LAZY))) {

                warnx("Failed to resolve " LIBPULSE_SIMPLE);

                return 0;

        }

        if(!(pa_pid_file_check_running = dlsym(h, "pa_pid_file_check_running")))

                errx(1, "Failed to resolve symbol pa_pid_file_check_running");

        running = (pa_pid_file_check_running(&pid, "pulseaudio") < 0) ? 0 : 1;

        dlclose(h);

        return running;

}

int main(int argc, char **argv) {

        int fd, mfd;

        char **args, *mem, *p;

        ssize_t s;

        struct stat stbuf;

        if(argc < 2)

                errx(1, "Usage: %s <program> [<arg1> ... <argN>]", argv[0]);

        args = malloc(sizeof(char *) * argc);

        if(!args)

                err(1, "Failed to allocate argument vector");

        for(int i = 1; i < argc; ++i)

                args[i - 1] = strdup(argv[i]);

        args[argc - 1] = NULL;

        if(check_pulseaudio_running()) {

                warnx("Pulseaudio is running");

                execv(argv[1], args);

                err(1, "Failed to exec '%s'", argv[1]);

        }

        else {

                warnx("Pulseaudio is NOT running");

                if((fd = open(argv[1], O_RDONLY | O_CLOEXEC)) < 0)

                        err(1, "Failed to open executable '%s'", argv[1]);

                if(fstat(fd, &stbuf) < 0)

                        err(1, "Failed to stat executable");

                if((mfd = memfd_create(argv[1], MFD_CLOEXEC)) < 0)

                        err(1, "Failed to create memfd");

                if(ftruncate(mfd, stbuf.st_size) < 0)

                        err(1, "Failed to truncate memfd");

                if((p = mem = mmap(NULL, stbuf.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0)) == MAP_FAILED)

                        err(1, "Failed to mmap memfd");

                while((s = read(fd, p, 64 * 1024 * 1024)) > 0)

                        p += s;

                if(s < 0)

                        err(1, "Failed to load executable into memory");

                if((p = memmem(mem, stbuf.st_size, LIBPULSE_SIMPLE, strlen(LIBPULSE_SIMPLE))) != NULL) {

                        strcpy(p, "/dev/null");

                        p += strlen("/dev/null") + 1;

                        while(*p)

                                *p++ = '\0';

                        warnx(LIBPULSE_SIMPLE " reference replaced");

                }

                else

                        warnx(LIBPULSE_SIMPLE " reference not found");

                munmap(mem, stbuf.st_size);

                fexecve(mfd, args, environ);

                err(1, "Failed to exec '%s'", argv[1]);

        }

}