diff options
Diffstat (limited to 'src/init/s6-linux-init.c')
| -rw-r--r-- | src/init/s6-linux-init.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/src/init/s6-linux-init.c b/src/init/s6-linux-init.c new file mode 100644 index 0000000..e322fa4 --- /dev/null +++ b/src/init/s6-linux-init.c @@ -0,0 +1,189 @@ +/* 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 ] [ -n | -N ]" +#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 + sizeof("/scripts/" STAGE2)] ; + PROG = "s6-linux-init (child)" ; + argv[0] = PROG ; + 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() ; + 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" ; + int mounttype = 1 ; + 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:nN", &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 ; + 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 (mounttype) + { + if (mounttype == 2) + { + if (mount("tmpfs", S6_LINUX_INIT_TMPFS, "tmpfs", MS_REMOUNT | MS_NODEV | MS_NOSUID, "mode=0755") == -1) + strerr_diefu1sys(111, "remount " S6_LINUX_INIT_TMPFS) ; + } + else + { + 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) ; + } +} |