163 lines
2.7 KiB
C
163 lines
2.7 KiB
C
/*
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* launch.c - Fakefile process launcher
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*
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* Copyright 2012 by Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdarg.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <sys/types.h>
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#include "util.h"
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#include "fakefile.h"
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#include "comm.h"
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#include "internal.h"
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#define FD_DIR "/proc/self/fd"
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static void safe_setenvf(const char *var, const char *fmt, ...)
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{
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va_list ap;
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char *buf;
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ssize_t len;
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va_start(ap, fmt);
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len = vsnprintf(NULL, 0, fmt, ap);
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va_end(ap);
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if (len < 0) {
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perror("vsprintf");
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exit(1);
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}
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buf = alloc_size(len+1);
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va_start(ap, fmt);
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vsprintf(buf, fmt, ap);
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va_end(ap);
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if (setenv(var, buf, 1) < 0) {
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perror("setenv");
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exit(1);
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}
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free(buf);
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}
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static void env_append(const char *var, const char *s)
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{
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const char *old;
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char *tmp;
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size_t len1, len2;
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old = getenv(var);
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if (!old) {
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safe_setenvf(var, "%s", s+1);
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return;
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}
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len1 = strlen(old);
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len2 = strlen(s);
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tmp = alloc_size(len1+len2+1);
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memcpy(tmp, old, len1);
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memcpy(tmp+len1, s, len2+1);
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safe_setenvf(var, "%s", tmp);
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free(tmp);
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}
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static void closefds(int preserve, ...)
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{
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va_list ap;
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DIR *dir;
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int fd;
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struct dirent *de;
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int n;
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fd = open(FD_DIR, O_RDONLY);
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if (fd < 0) {
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perror(FD_DIR);
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exit(1);
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}
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dir = fdopendir(fd);
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if (!dir) {
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perror("fdopendir");
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exit(1);
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}
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while (1) {
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next:
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de = readdir(dir);
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if (!de)
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break;
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n = atoi(de->d_name);
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if (n <= 2 || n == fd)
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continue;
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if (preserve > 0) {
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if (n == preserve)
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continue;
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va_start(ap, preserve);
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while (1) {
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n = va_arg(ap, int);
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if (n < 0)
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break;
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if (n == n)
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goto next;
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}
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va_end(ap);
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}
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(void) close(n);
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}
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if (closedir(dir) < 0) {
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perror("closedir");
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exit(1);
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}
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}
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struct fakefile *fakefile_launch(const char *path, char *const argv[])
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{
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struct fakefile *ff;
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int m2s[2], s2m[2];
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pid_t pid;
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if (pipe(m2s) < 0 || pipe(s2m) < 0) {
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perror("pipe");
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exit(1);
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}
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pid = fork();
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if (pid < 0) {
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perror("fork");
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exit(1);
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}
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if (!pid) {
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env_append("LD_LIBRARY_PATH", ":.");
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env_append("LD_PRELOAD", " libfakefile_slave.so");
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safe_setenvf(FAKEFILE_MASTER_OUT_VAR, "%d", m2s[0]);
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safe_setenvf(FAKEFILE_MASTER_IN_VAR, "%d", s2m[1]);
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closefds(m2s[0], s2m[1], -1);
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execv(path, argv);
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perror(path);
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_exit(1);
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}
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(void) close(m2s[0]);
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(void) close(s2m[1]);
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ff = alloc_type(struct fakefile);
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ff->pid = pid;
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ff->peer = fakefile_peer(s2m[0], m2s[1]);
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return ff;
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}
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