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/* ISC license. */
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <skalibs/types.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/stralloc.h>
#include <skalibs/env.h>
#include <skalibs/djbunix.h>
#include <s6/config.h>
#include <s6-linux-init/config.h>
#include "defaults.h"
#include "initctl.h"
#define USAGE "s6-linux-init [ -c basedir ] [ -p initpath ] [ -s envdumpdir ] [ -m umask ] [ -d devtmpfs ] [ -D initdefault ]"
#define dieusage() strerr_dieusage(100, USAGE)
#define BANNER "\n s6-linux-init version " S6_LINUX_INIT_VERSION "\n\n"
static inline char const *scan_cmdline (char const *initdefault, char const *const *argv, unsigned int argc)
{
static char const *valid[] = { "default", "2", "3", "4", "5", 0 } ;
for (unsigned int i = 0 ; i < argc ; i++)
for (char const *const *p = valid ; *p ; p++)
if (!strcmp(argv[i], *p)) return argv[i] ;
return initdefault ;
}
static inline void run_stage2 (char const *basedir, char const **argv, unsigned int argc, char const *const *envp, size_t envlen, char const *modifs, size_t modiflen, char const *initdefault)
{
size_t dirlen = strlen(basedir) ;
char const *childargv[argc + 3] ;
char fn[dirlen + 1 + sizeof(STAGE2)] ;
PROG = "s6-linux-init (child)" ;
argv[0] = PROG ;
memcpy(fn, basedir, dirlen) ;
fn[dirlen] = '/' ;
memcpy(fn + dirlen + 1, STAGE2, sizeof(STAGE2)) ;
childargv[0] = fn ;
childargv[1] = scan_cmdline(initdefault, argv + 1, argc - 1) ;
for (unsigned int i = 0 ; i < argc ; i++)
childargv[i+2] = argv[i] ;
childargv[argc + 2] = 0 ;
setsid() ;
fd_close(1) ;
if (open(LOGFIFO, O_WRONLY) != 1) /* blocks until catch-all logger is up */
strerr_diefu1sys(111, "open " LOGFIFO " for writing") ;
if (fd_copy(2, 1) == -1)
strerr_diefu1sys(111, "fd_copy stdout to stderr") ;
xpathexec_r(childargv, envp, envlen, modifs, modiflen) ;
}
int main (int argc, char const **argv, char const *const *envp)
{
mode_t mask = 0022 ;
char const *basedir = BASEDIR ;
char const *path = INITPATH ;
char const *slashdev = 0 ;
char const *envdumpdir = 0 ;
char const *initdefault = "default" ;
stralloc envmodifs = STRALLOC_ZERO ;
PROG = "s6-linux-init" ;
if (getpid() != 1)
{
argv[0] = S6_LINUX_INIT_BINPREFIX "/s6-linux-init-telinit" ;
pathexec_run(argv[0], argv, envp) ;
strerr_dieexec(111, argv[0]) ;
}
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "c:p:s:m:d:D:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'c' : basedir = l.arg ; break ;
case 'p' : path = l.arg ; break ;
case 's' : envdumpdir = l.arg ; break ;
case 'm' : if (!uint0_oscan(l.arg, &mask)) dieusage() ; break ;
case 'd' : slashdev = l.arg ; break ;
case 'D' : initdefault = l.arg ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
allwrite(1, BANNER, sizeof(BANNER) - 1) ;
if (chdir("/") == -1) strerr_diefu1sys(111, "chdir to /") ;
umask(mask) ;
setpgid(0, 0) ;
fd_close(0) ;
if (slashdev)
{
fd_close(1) ;
fd_close(2) ;
if (mount("dev", slashdev, "devtmpfs", MS_NOSUID | MS_NOEXEC, "") == -1)
{
int e = errno ;
open("/dev/null", O_RDONLY) ;
open("/dev/console", O_WRONLY) ;
fd_copy(2, 1) ;
errno = e ;
strerr_diefu2sys(111, "mount ", slashdev) ;
}
if (open("/dev/console", O_WRONLY)
|| fd_copy(1, 0) == -1
|| fd_move(2, 0) == -1) return 111 ;
}
if (open("/dev/null", O_RDONLY)) strerr_diefu1sys(111, "open /dev/null") ;
if (umount(S6_LINUX_INIT_TMPFS) == -1)
{
if (errno != EINVAL)
strerr_warnwu1sys("umount " S6_LINUX_INIT_TMPFS) ;
}
if (mount("tmpfs", S6_LINUX_INIT_TMPFS, "tmpfs", MS_NODEV | MS_NOSUID, "mode=0755") == -1)
strerr_diefu1sys(111, "mount tmpfs on " S6_LINUX_INIT_TMPFS) ;
{
size_t dirlen = strlen(basedir) ;
char fn[dirlen + 1 + (sizeof(RUNIMAGE) > sizeof(ENVSTAGE1) ? sizeof(RUNIMAGE) : sizeof(ENVSTAGE1))] ;
memcpy(fn, basedir, dirlen) ;
fn[dirlen] = '/' ;
memcpy(fn + dirlen + 1, RUNIMAGE, sizeof(RUNIMAGE)) ;
if (!hiercopy(fn, S6_LINUX_INIT_TMPFS))
strerr_diefu3sys(111, "copy ", fn, " to " S6_LINUX_INIT_TMPFS) ;
memcpy(fn + dirlen + 1, ENVSTAGE1, sizeof(ENVSTAGE1)) ;
if (envdir(fn, &envmodifs) == -1)
strerr_warnwu2sys("envdir ", fn) ;
}
if (envdumpdir && !env_dump(envdumpdir, 0700, envp))
strerr_warnwu2sys("dump kernel environment to ", envdumpdir) ;
{
int fdr = open_read(LOGFIFO) ;
if (fdr == -1) strerr_diefu1sys(111, "open " LOGFIFO) ;
fd_close(1) ;
if (open(LOGFIFO, O_WRONLY) != 1) strerr_diefu1sys(111, "open " LOGFIFO) ;
fd_close(fdr) ;
}
{
static char const *const newargv[5] = { S6_EXTBINPREFIX "s6-svscan", "-st0", "--", S6_LINUX_INIT_TMPFS "/" SCANDIR, 0 } ;
char const *newenvp[2] = { 0, 0 } ;
pid_t pid ;
size_t pathlen = path ? strlen(path) : 0 ;
char pathvar[6 + pathlen] ;
if (path)
{
if (setenv("PATH", path, 1) == -1)
strerr_diefu1sys(111, "set initial PATH") ;
memcpy(pathvar, "PATH=", 5) ;
memcpy(pathvar + 5, path, pathlen + 1) ;
newenvp[0] = pathvar ;
}
pid = fork() ;
if (pid == -1) strerr_diefu1sys(111, "fork") ;
if (!pid) run_stage2(basedir, argv, argc, newenvp, !!path, envmodifs.s, envmodifs.len, initdefault) ;
if (fd_copy(2, 1) == -1)
strerr_diefu1sys(111, "redirect output file descriptor") ;
xpathexec_r(newargv, newenvp, !!path, envmodifs.s, envmodifs.len) ;
}
}
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