/*- * Copyright (c) 1994-1996 Søren Schmidt * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer * in this position and unchanged. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software withough specific prior written permission * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD$ */ /* XXX we use functions that might not exist. */ #include "opt_compat.h" #ifndef COMPAT_43 #error "Unable to compile Linux-emulator due to missing COMPAT_43 option!" #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_VERSION(linux, 1); MALLOC_DEFINE(M_LINUX, "linux", "Linux mode structures"); #if BYTE_ORDER == LITTLE_ENDIAN #define SHELLMAGIC 0x2123 /* #! */ #else #define SHELLMAGIC 0x2321 #endif extern char linux_sigcode[]; extern int linux_szsigcode; extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL]; extern struct linker_set linux_ioctl_handler_set; static int linux_fixup __P((register_t **stack_base, struct image_params *iparams)); static int elf_linux_fixup __P((register_t **stack_base, struct image_params *iparams)); static void linux_prepsyscall __P((struct trapframe *tf, int *args, u_int *code, caddr_t *params)); static void linux_sendsig __P((sig_t catcher, int sig, sigset_t *mask, u_long code)); /* * Linux syscalls return negative errno's, we do positive and map them */ static int bsd_to_linux_errno[ELAST + 1] = { -0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -35, -12, -13, -14, -15, -16, -17, -18, -19, -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, -30, -31, -32, -33, -34, -11,-115,-114, -88, -89, -90, -91, -92, -93, -94, -95, -96, -97, -98, -99, -100,-101,-102,-103,-104,-105,-106,-107,-108,-109, -110,-111, -40, -36,-112,-113, -39, -11, -87,-122, -116, -66, -6, -6, -6, -6, -6, -37, -38, -9, -6, -6, -43, -42, -75, -6, -84 }; int bsd_to_linux_signal[LINUX_SIGTBLSZ] = { LINUX_SIGHUP, LINUX_SIGINT, LINUX_SIGQUIT, LINUX_SIGILL, LINUX_SIGTRAP, LINUX_SIGABRT, 0, LINUX_SIGFPE, LINUX_SIGKILL, LINUX_SIGBUS, LINUX_SIGSEGV, 0, LINUX_SIGPIPE, LINUX_SIGALRM, LINUX_SIGTERM, LINUX_SIGURG, LINUX_SIGSTOP, LINUX_SIGTSTP, LINUX_SIGCONT, LINUX_SIGCHLD, LINUX_SIGTTIN, LINUX_SIGTTOU, LINUX_SIGIO, LINUX_SIGXCPU, LINUX_SIGXFSZ, LINUX_SIGVTALRM, LINUX_SIGPROF, LINUX_SIGWINCH, 0, LINUX_SIGUSR1, LINUX_SIGUSR2 }; int linux_to_bsd_signal[LINUX_SIGTBLSZ] = { SIGHUP, SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGABRT, SIGBUS, SIGFPE, SIGKILL, SIGUSR1, SIGSEGV, SIGUSR2, SIGPIPE, SIGALRM, SIGTERM, SIGBUS, SIGCHLD, SIGCONT, SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGURG, SIGXCPU, SIGXFSZ, SIGVTALRM, SIGPROF, SIGWINCH, SIGIO, SIGURG, 0 }; /* * If FreeBSD & Linux have a difference of opinion about what a trap * means, deal with it here. */ static int translate_traps(int signal, int trap_code) { if (signal != SIGBUS) return signal; switch (trap_code) { case T_PROTFLT: case T_TSSFLT: case T_DOUBLEFLT: case T_PAGEFLT: return SIGSEGV; default: return signal; } } static int linux_fixup(register_t **stack_base, struct image_params *imgp) { register_t *argv, *envp; argv = *stack_base; envp = *stack_base + (imgp->argc + 1); (*stack_base)--; **stack_base = (intptr_t)(void *)envp; (*stack_base)--; **stack_base = (intptr_t)(void *)argv; (*stack_base)--; **stack_base = imgp->argc; return 0; } static int elf_linux_fixup(register_t **stack_base, struct image_params *imgp) { Elf32_Auxargs *args = (Elf32_Auxargs *)imgp->auxargs; register_t *pos; pos = *stack_base + (imgp->argc + imgp->envc + 2); if (args->trace) { AUXARGS_ENTRY(pos, AT_DEBUG, 1); } if (args->execfd != -1) { AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd); } AUXARGS_ENTRY(pos, AT_PHDR, args->phdr); AUXARGS_ENTRY(pos, AT_PHENT, args->phent); AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum); AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz); AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); AUXARGS_ENTRY(pos, AT_BASE, args->base); AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_cred->p_ruid); AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_cred->p_svuid); AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_cred->p_rgid); AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_cred->p_svgid); AUXARGS_ENTRY(pos, AT_NULL, 0); free(imgp->auxargs, M_TEMP); imgp->auxargs = NULL; (*stack_base)--; **stack_base = (long)imgp->argc; return 0; } extern int _ucodesel, _udatasel; /* * Send an interrupt to process. * * Stack is set up to allow sigcode stored * in u. to call routine, followed by kcall * to sigreturn routine below. After sigreturn * resets the signal mask, the stack, and the * frame pointer, it returns to the user * specified pc, psl. */ static void linux_sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code) { register struct proc *p = curproc; register struct trapframe *regs; struct linux_sigframe *fp, frame; struct sigacts *psp = p->p_sigacts; int oonstack; regs = p->p_md.md_regs; oonstack = p->p_sigstk.ss_flags & SS_ONSTACK; #ifdef DEBUG printf("Linux-emul(%ld): linux_sendsig(%p, %d, %p, %lu)\n", (long)p->p_pid, catcher, sig, (void*)mask, code); #endif /* * Allocate space for the signal handler context. */ if ((p->p_flag & P_ALTSTACK) && !oonstack && SIGISMEMBER(psp->ps_sigonstack, sig)) { fp = (struct linux_sigframe *)(p->p_sigstk.ss_sp + p->p_sigstk.ss_size - sizeof(struct linux_sigframe)); p->p_sigstk.ss_flags |= SS_ONSTACK; } else { fp = (struct linux_sigframe *)regs->tf_esp - 1; } /* * grow() will return FALSE if the fp will not fit inside the stack * and the stack can not be grown. useracc will return FALSE * if access is denied. */ if ((grow_stack (p, (int)fp) == FALSE) || !useracc((caddr_t)fp, sizeof (struct linux_sigframe), VM_PROT_WRITE)) { /* * Process has trashed its stack; give it an illegal * instruction to halt it in its tracks. */ SIGACTION(p, SIGILL) = SIG_DFL; SIGDELSET(p->p_sigignore, SIGILL); SIGDELSET(p->p_sigcatch, SIGILL); SIGDELSET(p->p_sigmask, SIGILL); psignal(p, SIGILL); return; } /* * Build the argument list for the signal handler. */ if (p->p_sysent->sv_sigtbl) if (sig <= p->p_sysent->sv_sigsize) sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)]; frame.sf_handler = catcher; frame.sf_sig = sig; /* * Build the signal context to be used by sigreturn. */ frame.sf_sc.sc_mask = mask->__bits[0]; frame.sf_sc.sc_gs = rgs(); frame.sf_sc.sc_fs = regs->tf_fs; frame.sf_sc.sc_es = regs->tf_es; frame.sf_sc.sc_ds = regs->tf_ds; frame.sf_sc.sc_edi = regs->tf_edi; frame.sf_sc.sc_esi = regs->tf_esi; frame.sf_sc.sc_ebp = regs->tf_ebp; frame.sf_sc.sc_ebx = regs->tf_ebx; frame.sf_sc.sc_edx = regs->tf_edx; frame.sf_sc.sc_ecx = regs->tf_ecx; frame.sf_sc.sc_eax = regs->tf_eax; frame.sf_sc.sc_eip = regs->tf_eip; frame.sf_sc.sc_cs = regs->tf_cs; frame.sf_sc.sc_eflags = regs->tf_eflags; frame.sf_sc.sc_esp_at_signal = regs->tf_esp; frame.sf_sc.sc_ss = regs->tf_ss; frame.sf_sc.sc_err = regs->tf_err; frame.sf_sc.sc_trapno = code; /* XXX ???? */ if (copyout(&frame, fp, sizeof(frame)) != 0) { /* * Process has trashed its stack; give it an illegal * instruction to halt it in its tracks. */ sigexit(p, SIGILL); /* NOTREACHED */ } /* * Build context to run handler in. */ regs->tf_esp = (int)fp; regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode); regs->tf_eflags &= ~PSL_VM; regs->tf_cs = _ucodesel; regs->tf_ds = _udatasel; regs->tf_es = _udatasel; regs->tf_fs = _udatasel; load_gs(_udatasel); regs->tf_ss = _udatasel; } /* * System call to cleanup state after a signal * has been taken. Reset signal mask and * stack state from context left by sendsig (above). * Return to previous pc and psl as specified by * context left by sendsig. Check carefully to * make sure that the user has not modified the * psl to gain improper privileges or to cause * a machine fault. */ int linux_sigreturn(p, args) struct proc *p; struct linux_sigreturn_args *args; { struct linux_sigcontext context; register struct trapframe *regs; int eflags; regs = p->p_md.md_regs; #ifdef DEBUG printf("Linux-emul(%ld): linux_sigreturn(%p)\n", (long)p->p_pid, (void *)args->scp); #endif /* * The trampoline code hands us the context. * It is unsafe to keep track of it ourselves, in the event that a * program jumps out of a signal handler. */ if (copyin((caddr_t)args->scp, &context, sizeof(context)) != 0) return (EFAULT); /* * Check for security violations. */ #define EFLAGS_SECURE(ef, oef) ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0) eflags = context.sc_eflags; /* * XXX do allow users to change the privileged flag PSL_RF. The * cpu sets PSL_RF in tf_eflags for faults. Debuggers should * sometimes set it there too. tf_eflags is kept in the signal * context during signal handling and there is no other place * to remember it, so the PSL_RF bit may be corrupted by the * signal handler without us knowing. Corruption of the PSL_RF * bit at worst causes one more or one less debugger trap, so * allowing it is fairly harmless. */ if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) { return(EINVAL); } /* * Don't allow users to load a valid privileged %cs. Let the * hardware check for invalid selectors, excess privilege in * other selectors, invalid %eip's and invalid %esp's. */ #define CS_SECURE(cs) (ISPL(cs) == SEL_UPL) if (!CS_SECURE(context.sc_cs)) { trapsignal(p, SIGBUS, T_PROTFLT); return(EINVAL); } p->p_sigstk.ss_flags &= ~SS_ONSTACK; SIGSETOLD(p->p_sigmask, context.sc_mask); SIG_CANTMASK(p->p_sigmask); /* * Restore signal context. */ /* %gs was restored by the trampoline. */ regs->tf_fs = context.sc_fs; regs->tf_es = context.sc_es; regs->tf_ds = context.sc_ds; regs->tf_edi = context.sc_edi; regs->tf_esi = context.sc_esi; regs->tf_ebp = context.sc_ebp; regs->tf_ebx = context.sc_ebx; regs->tf_edx = context.sc_edx; regs->tf_ecx = context.sc_ecx; regs->tf_eax = context.sc_eax; regs->tf_eip = context.sc_eip; regs->tf_cs = context.sc_cs; regs->tf_eflags = eflags; regs->tf_esp = context.sc_esp_at_signal; regs->tf_ss = context.sc_ss; return (EJUSTRETURN); } static void linux_prepsyscall(struct trapframe *tf, int *args, u_int *code, caddr_t *params) { args[0] = tf->tf_ebx; args[1] = tf->tf_ecx; args[2] = tf->tf_edx; args[3] = tf->tf_esi; args[4] = tf->tf_edi; *params = NULL; /* no copyin */ } /* * If a linux binary is exec'ing something, try this image activator * first. We override standard shell script execution in order to * be able to modify the interpreter path. We only do this if a linux * binary is doing the exec, so we do not create an EXEC module for it. */ static int exec_linux_imgact_try __P((struct image_params *iparams)); static int exec_linux_imgact_try(imgp) struct image_params *imgp; { const char *head = (const char *)imgp->image_header; int error = -1; /* * The interpreter for shell scripts run from a linux binary needs * to be located in /compat/linux if possible in order to recursively * maintain linux path emulation. */ if (((const short *)head)[0] == SHELLMAGIC) { /* * Run our normal shell image activator. If it succeeds attempt * to use the alternate path for the interpreter. If an alternate * path is found, use our stringspace to store it. */ if ((error = exec_shell_imgact(imgp)) == 0) { char *rpath = NULL; linux_emul_find(imgp->proc, NULL, linux_emul_path, imgp->interpreter_name, &rpath, 0); if (rpath != imgp->interpreter_name) { int len = strlen(rpath) + 1; if (len <= MAXSHELLCMDLEN) { memcpy(imgp->interpreter_name, rpath, len); } free(rpath, M_TEMP); } } } return(error); } struct sysentvec linux_sysvec = { LINUX_SYS_MAXSYSCALL, linux_sysent, 0xff, LINUX_SIGTBLSZ, bsd_to_linux_signal, ELAST + 1, bsd_to_linux_errno, translate_traps, linux_fixup, linux_sendsig, linux_sigcode, &linux_szsigcode, linux_prepsyscall, "Linux a.out", aout_coredump, exec_linux_imgact_try }; struct sysentvec elf_linux_sysvec = { LINUX_SYS_MAXSYSCALL, linux_sysent, 0xff, LINUX_SIGTBLSZ, bsd_to_linux_signal, ELAST + 1, bsd_to_linux_errno, translate_traps, elf_linux_fixup, linux_sendsig, linux_sigcode, &linux_szsigcode, linux_prepsyscall, "Linux ELF", elf_coredump, exec_linux_imgact_try }; static Elf32_Brandinfo linux_brand = { ELFOSABI_LINUX, "/compat/linux", "/lib/ld-linux.so.1", &elf_linux_sysvec }; static Elf32_Brandinfo linux_glibc2brand = { ELFOSABI_LINUX, "/compat/linux", "/lib/ld-linux.so.2", &elf_linux_sysvec }; Elf32_Brandinfo *linux_brandlist[] = { &linux_brand, &linux_glibc2brand, NULL }; static int linux_elf_modevent(module_t mod, int type, void *data) { Elf32_Brandinfo **brandinfo; int error; error = 0; switch(type) { case MOD_LOAD: for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; ++brandinfo) if (elf_insert_brand_entry(*brandinfo) < 0) error = EINVAL; if (error) printf("cannot insert Linux elf brand handler\n"); else { linux_ioctl_register_handlers(&linux_ioctl_handler_set); if (bootverbose) printf("Linux-ELF exec handler installed\n"); } break; case MOD_UNLOAD: linux_ioctl_unregister_handlers(&linux_ioctl_handler_set); for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; ++brandinfo) if (elf_brand_inuse(*brandinfo)) error = EBUSY; if (error == 0) { for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL; ++brandinfo) if (elf_remove_brand_entry(*brandinfo) < 0) error = EINVAL; } if (error) printf("Could not deinstall ELF interpreter entry\n"); else if (bootverbose) printf("Linux-elf exec handler removed\n"); break; default: break; } return error; } static moduledata_t linux_elf_mod = { "linuxelf", linux_elf_modevent, 0 }; DECLARE_MODULE(linuxelf, linux_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);