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/* ISC license. */
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <sys/stat.h>
#include <skalibs/types.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/stralloc.h>
#include <skalibs/sig.h>
#include <skalibs/env.h>
#include <skalibs/djbunix.h>
#include <skalibs/exec.h>
#include <s6/config.h>
#include <s6-linux-init/config.h>
#include "os.h"
#include "defaults.h"
#include "initctl.h"
#define USAGE "s6-linux-init [ -c basedir ] [ -p initpath ] [ -s envdumpdir ] [ -m umask ] [ -d devtmpfs ] [ -D initdefault ] [ -n | -N ] [ -C ] [ -B ]"
#define dieusage() strerr_dieusage(100, USAGE)
#define BANNER "\n s6-linux-init version " S6_LINUX_INIT_VERSION "\n\n"
static int inns = 0 ;
static int nologger = 0 ;
static int notifpipe[2] ;
static inline char const *scan_cmdline (char const *initdefault, char const *const *argv, unsigned int argc)
{
if (!inns)
{
static char const *valid[] = { "default", "1", "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 wait_for_notif (int fd)
{
char buf[16] ;
for (;;)
{
ssize_t r = read(fd, buf, 16) ;
if (r < 0) strerr_diefu1sys(111, "read from notification pipe") ;
if (!r)
{
strerr_warnw1x("s6-svscan failed to send a notification byte!") ;
break ;
}
if (memchr(buf, '\n', r)) break ;
}
close(fd) ;
}
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 + sizeof("/scripts/" STAGE2)] ;
PROG = "s6-linux-init (child)" ;
memcpy(fn, basedir, dirlen) ;
memcpy(fn + dirlen, "/scripts/" STAGE2, sizeof("/scripts/" STAGE2)) ;
childargv[0] = fn ;
childargv[1] = scan_cmdline(initdefault, argv, argc) ;
for (unsigned int i = 0 ; i < argc ; i++)
childargv[i+2] = argv[i] ;
childargv[argc + 2] = 0 ;
setsid() ;
if (nologger)
{
close(notifpipe[1]) ;
wait_for_notif(notifpipe[0]) ;
}
else
{
/* block on opening the log fifo until the catch-all logger is up */
close(1) ;
if (open(LOGFIFO, O_WRONLY) != 1)
strerr_diefu1sys(111, "open " LOGFIFO " for writing") ;
if (fd_copy(2, 1) == -1)
strerr_diefu1sys(111, "fd_copy stdout to stderr") ;
}
xmexec_fm(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" ;
int mounttype = 1 ;
stralloc envmodifs = STRALLOC_ZERO ;
PROG = "s6-linux-init" ;
if (getpid() != 1)
{
argv[0] = S6_LINUX_INIT_BINPREFIX "s6-linux-init-telinit" ;
xexec_e(argv, envp) ;
}
{
subgetopt_t l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "c:p:s:m:d:D:nNCB", &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 ;
case 'n' : mounttype = 2 ; break ;
case 'N' : mounttype = 0 ; break ;
case 'C' : inns = 1 ; break ;
case 'B' : nologger = 1 ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
}
if (inns)
{ /* If there's a Docker synchronization pipe, wait on it */
char c ;
ssize_t r = read(3, &c, 1) ;
if (r < 0)
{
if (errno != EBADF) strerr_diefu1sys(111, "read from fd 3") ;
}
else
{
if (r) strerr_warnw1x("parent wrote to fd 3!") ;
close(3) ;
}
}
else allwrite(1, BANNER, sizeof(BANNER) - 1) ;
if (chdir("/") == -1) strerr_diefu1sys(111, "chdir to /") ;
umask(mask) ;
setpgid(0, 0) ;
close(0) ;
if (slashdev)
{
int nope, e ;
close(1) ;
close(2) ;
/* at this point we're totally in the dark, hoping /dev/console will work */
nope = os_mount_devtmpfs(slashdev) < 0 ;
e = errno ;
if (open("/dev/console", O_WRONLY)
|| fd_move(2, 0) < 0
|| fd_copy(1, 2) < 0) return 111 ;
if (nope)
{
errno = e ;
strerr_diefu1sys(111, "mount a devtmpfs on /dev") ;
}
}
if (open("/dev/null", O_RDONLY))
{ /* ghetto /dev/null to the rescue */
int p[2] ;
strerr_warnwu1sys("open /dev/null") ;
if (pipe(p) < 0) strerr_diefu1sys(111, "pipe") ;
close(p[1]) ;
if (fd_move(0, p[0]) < 0) strerr_diefu1sys(111, "fd_move to stdin") ;
}
os_mount_tmpfs(S6_LINUX_INIT_TMPFS, mounttype) ;
{
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) ;
if (!nologger)
{
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) ;
}
{
char const *newenvp[2] = { 0, 0 } ;
size_t pathlen = path ? strlen(path) : 0 ;
pid_t pid ;
char fmtfd[2 + UINT_FMT] = "-" ;
char const *newargv[5] = { S6_EXTBINPREFIX "s6-svscan", fmtfd, "--", S6_LINUX_INIT_TMPFS "/" SCANDIR, 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 ;
}
if (nologger && pipe(notifpipe) < 0) strerr_diefu1sys(111, "pipe") ;
pid = fork() ;
if (pid == -1) strerr_diefu1sys(111, "fork") ;
if (!pid) run_stage2(basedir, argv, argc, newenvp, !!path, envmodifs.s, envmodifs.len, initdefault) ;
if (nologger)
{
close(notifpipe[0]) ;
fmtfd[1] = 'd' ;
fmtfd[2 + uint_fmt(fmtfd + 2, notifpipe[1])] = 0 ;
os_kbspecials(inns) ;
}
else
{
int fd = dup(2) ;
if (fd < 0) strerr_diefu1sys(111, "dup stderr") ;
fmtfd[1] = 'X' ;
fmtfd[2 + uint_fmt(fmtfd + 2, (unsigned int)fd)] = 0 ;
os_kbspecials(inns) ;
if (fd_copy(2, 1) == -1)
strerr_diefu1sys(111, "redirect output file descriptor") ;
}
xmexec_fm(newargv, newenvp, !!path, envmodifs.s, envmodifs.len) ;
}
}
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