111 lines
1.9 KiB
C
111 lines
1.9 KiB
C
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/*
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* CORE
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* Copyright (c)2010-2012 the Boeing Company.
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* See the LICENSE file included in this distribution.
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*
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* author: Tom Goff <thomas.goff@boeing.com>
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*
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* netns.c
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*
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* Implements nsfork() and nsexecvp() for forking and executing processes
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* within a network namespace.
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*
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*/
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#include <signal.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/mount.h>
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#include <sys/utsname.h>
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#include "myerr.h"
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#include "netns.h"
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#define NSCLONEFLGS \
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( \
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SIGCHLD | \
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CLONE_NEWNS | \
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CLONE_NEWUTS | \
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CLONE_NEWIPC | \
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CLONE_NEWPID | \
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CLONE_NEWNET \
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)
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#define MOUNT_SYS_MIN_VERSION "2.6.35"
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static void nssetup(void)
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{
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int r;
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struct utsname uts;
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/* Taken from systemd-nspawn. Not sure why needed, but without this,
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* the host system goes a bit crazy under systemd. */
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r = mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL);
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if (r)
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WARN("mounting / failed");
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/* mount per-namespace /proc */
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r = mount(NULL, "/proc", "proc", 0, NULL);
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if (r)
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WARN("mounting /proc failed");
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r = uname(&uts);
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if (r)
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{
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WARN("uname() failed");
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return;
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}
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r = strncmp(uts.release, MOUNT_SYS_MIN_VERSION,
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sizeof(MOUNT_SYS_MIN_VERSION) - 1);
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if (r >= 0)
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{
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/* mount per-namespace /sys */
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r = mount(NULL, "/sys", "sysfs", 0, NULL);
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if (r)
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WARN("mounting /sys failed");
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}
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}
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pid_t nsfork(int flags)
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{
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int pid;
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pid = syscall(SYS_clone, flags | NSCLONEFLGS, NULL, NULL, NULL, NULL);
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if (pid == 0) /* child */
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{
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nssetup();
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}
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return pid;
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}
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pid_t nsexecvp(char *argv[])
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{
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pid_t pid;
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pid = nsfork(CLONE_VFORK);
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switch (pid)
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{
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case -1:
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WARN("nsfork() failed");
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break;
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case 0:
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/* child */
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execvp(argv[0], argv);
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WARN("execvp() failed for '%s'", argv[0]);
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_exit(1);
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break;
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default:
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/* parent */
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if (kill(pid, 0))
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pid = -1;
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break;
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}
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return pid;
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}
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