diff options
| -rw-r--r-- | .gitignore | 54 | ||||
| -rw-r--r-- | 4init/.gitignore | 1 | ||||
| -rw-r--r-- | 4init/4init.c | 82 | ||||
| -rw-r--r-- | 4init/Makefile | 21 | ||||
| -rw-r--r-- | 4init/README.md | 5 | ||||
| -rw-r--r-- | 4init/config.h | 17 | ||||
| -rw-r--r-- | 4init/config.mk | 5 | ||||
| -rw-r--r-- | README.md | 4 |
8 files changed, 134 insertions, 55 deletions
@@ -1,55 +1 @@ -# Prerequisites -*.d - -# Object files *.o -*.ko -*.obj -*.elf - -# Linker output -*.ilk -*.map -*.exp - -# Precompiled Headers -*.gch -*.pch - -# Libraries -*.lib -*.a -*.la -*.lo - -# Shared objects (inc. Windows DLLs) -*.dll -*.so -*.so.* -*.dylib - -# Executables -*.exe -*.out -*.app -*.i*86 -*.x86_64 -*.hex - -# Debug files -*.dSYM/ -*.su -*.idb -*.pdb - -# Kernel Module Compile Results -*.mod* -*.cmd -.tmp_versions/ -modules.order -Module.symvers -Mkfile.old -dkms.conf - -# debug information files -*.dwo diff --git a/4init/.gitignore b/4init/.gitignore new file mode 100644 index 0000000..79cfb58 --- /dev/null +++ b/4init/.gitignore @@ -0,0 +1 @@ +4init
\ No newline at end of file diff --git a/4init/4init.c b/4init/4init.c new file mode 100644 index 0000000..50807b6 --- /dev/null +++ b/4init/4init.c @@ -0,0 +1,82 @@ +#define _POSIX_C_SOURCE 200809L + +#include <signal.h> +#include <stdio.h> +#include <sys/signalfd.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "config.h" + +static void reap(void) +{ + int status; + while (waitpid(-1, &status, WNOHANG) > 0) {} +} + +int main(void) +{ + int sigfd = -1; + pid_t pid = -1; + sigset_t set; + + if (getpid() != 1) { + fprintf(stderr, "4init - you need to run this as PID 1...\n"); + return 1; + } + + sigfillset(&set); + sigdelset(&set, SIGILL); + sigdelset(&set, SIGTRAP); + sigdelset(&set, SIGBUS); + sigdelset(&set, SIGFPE); + sigdelset(&set, SIGSEGV); + + if (sigprocmask(SIG_SETMASK, &set, NULL) < 0) { + perror("sigprocmask"); + return 1; + } + + sigfd = signalfd(-1, &set, SFD_CLOEXEC); + if (sigfd < 0) { + perror("signalfd"); + return 1; + } + + pid = fork(); + if (pid < 0) { + perror("fork"); + return 1; + } + + if (pid == 0) { + sigset_t empty_set; + + sigemptyset(&empty_set); + sigprocmask(SIG_SETMASK, &empty_set, NULL); + + if (setsid() == -1) { + perror("setsid"); + } + + close(sigfd); + + execve(rc_path, rc_argv, rc_envp); + perror("execve"); + _exit(1); + } else { + struct signalfd_siginfo fdsi; + + reap(); + + for (;;) { + if (read(sigfd, &fdsi, sizeof(fdsi)) == sizeof(fdsi)) { + switch (fdsi.ssi_signo) { + case SIGCHLD: + reap(); + break; + } + } + } + } +} diff --git a/4init/Makefile b/4init/Makefile new file mode 100644 index 0000000..e56e105 --- /dev/null +++ b/4init/Makefile @@ -0,0 +1,21 @@ +include config.mk + +BIN = 4init +OBJ = 4init.o + +all: $(BIN) + +$(BIN): $(OBJ) + $(CC) $(LDFLAGS) -o $@ $(OBJ) + +$(OBJ): config.h + +install: all + mkdir -pv $(DESTDIR)$(PREFIX)/bin + cp -fv $(BIN) $(DESTDIR)$(PREFIX)/bin + +uninstall: all + rm -f $(DESTDIR)$(PREFIX)/bin/$(BIN) + +clean: all + rm -f 4init.o 4init diff --git a/4init/README.md b/4init/README.md new file mode 100644 index 0000000..44fbde5 --- /dev/null +++ b/4init/README.md @@ -0,0 +1,5 @@ +# 4init: minimal but functional init + +It's only purpose is to manage processes, it by defaults calls 4rc, but you can change that in `config.h`, it's started as PID 1, and if it crashes, the kernel will panic, read the article in Wikipedia if you want to know more. + +Inspired by [rofl0r](https://gist.github.com/rofl0r/6168719)'s minimal init.
\ No newline at end of file diff --git a/4init/config.h b/4init/config.h new file mode 100644 index 0000000..6c36ccf --- /dev/null +++ b/4init/config.h @@ -0,0 +1,17 @@ +#ifndef CONFIG_H +#define CONFIG_H + +static const char *rc_path = "/usr/bin/4rc"; + +static char *const rc_argv[] = { + "4rc", + NULL +}; + +static char *const rc_envp[] = { + "PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/sbin", + "TERM=linux", + NULL +}; + +#endif // CONFIG_H diff --git a/4init/config.mk b/4init/config.mk new file mode 100644 index 0000000..ab7e752 --- /dev/null +++ b/4init/config.mk @@ -0,0 +1,5 @@ +PREFIX = /usr/local + +CC = musl-gcc +CFLAGS = -std=c99 -Wextra -Wall -Os -fhardened +LDFLAGS = -s -static @@ -1,2 +1,4 @@ # 4suite -A self-contained C boot stack (init, rc, logger, user) with Plan 9 namespace isolation + +A self-contained C boot stack (init, rc, logger, user). +Each component has it's own README.md, worth checking it out. |