/*===========================================================================* * do_exec * *===========================================================================*/ PUBLIC int do_exec() { /* Perform the execve(name, argv, envp) call. The user library builds a * complete stack image, including pointers, args, environ, etc. The stack * is copied to a buffer inside MM, and then to the new core image. */ register struct mproc *rmp; struct mproc *sh_mp; int m, r, fd, ft, sn; static char mbuf[ARG_MAX]; /* buffer for stack and zeroes */ static char name_buf[PATH_MAX]; /* the name of the file to exec */ char *new_sp, *basename; vir_bytes src, dst, text_bytes, data_bytes, bss_bytes, stk_bytes, vsp; phys_bytes tot_bytes; /* total space for program, including gap */ long sym_bytes; vir_clicks sc; struct stat s_buf; vir_bytes pc; /* Do some validity checks. */ rmp = mp; stk_bytes = (vir_bytes) stack_bytes; if (stk_bytes > ARG_MAX) return(ENOMEM); /* stack too big */ if (exec_len <= 0 || exec_len > PATH_MAX) return(EINVAL); /* Get the exec file name and see if the file is executable. */ src = (vir_bytes) exec_name; dst = (vir_bytes) name_buf; r = sys_copy(who, D, (phys_bytes) src, MM_PROC_NR, D, (phys_bytes) dst, (phys_bytes) exec_len); if (r != OK) return(r); /* file name not in user data segment */ tell_fs(CHDIR, who, FALSE, 0); /* switch to the user's FS environ. */ fd = allowed(name_buf, &s_buf, X_BIT); /* is file executable? */ if (fd < 0) return(fd); /* file was not executable */ /* Read the file header and extract the segment sizes. */ sc = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT; m = read_header(fd, &ft, &text_bytes, &data_bytes, &bss_bytes, &tot_bytes, &sym_bytes, sc, &pc); if (m < 0) { close(fd); /* something wrong with header */ return(ENOEXEC); } /* Fetch the stack from the user before destroying the old core image. */ src = (vir_bytes) stack_ptr; dst = (vir_bytes) mbuf; r = sys_copy(who, D, (phys_bytes) src, MM_PROC_NR, D, (phys_bytes) dst, (phys_bytes)stk_bytes); if (r != OK) { close(fd); /* can't fetch stack (e.g. bad virtual addr) */ return(EACCES); } /* Can the process' text be shared with that of one already running? */ sh_mp = find_share(rmp, s_buf.st_ino, s_buf.st_dev, s_buf.st_ctime); /* Allocate new memory and release old memory. Fix map and tell kernel. */ r = new_mem(sh_mp, text_bytes, data_bytes, bss_bytes, stk_bytes, tot_bytes); if (r != OK) { close(fd); /* insufficient core or program too big */ return(r); } /* Save file identification to allow it to be shared. */ rmp->mp_ino = s_buf.st_ino; rmp->mp_dev = s_buf.st_dev; rmp->mp_ctime = s_buf.st_ctime; /* Patch up stack and copy it from MM to new core image. */ vsp = (vir_bytes) rmp->mp_seg[S].mem_vir << CLICK_SHIFT; vsp += (vir_bytes) rmp->mp_seg[S].mem_len << CLICK_SHIFT; vsp -= stk_bytes; patch_ptr(mbuf, vsp); src = (vir_bytes) mbuf; r = sys_copy(MM_PROC_NR, D, (phys_bytes) src, who, D, (phys_bytes) vsp, (phys_bytes)stk_bytes); if (r != OK) panic("do_exec stack copy err", NO_NUM); /* Read in text and data segments. */ if (sh_mp != NULL) { lseek(fd, (off_t) text_bytes, SEEK_CUR); /* shared: skip text */ } else { load_seg(fd, T, text_bytes); } load_seg(fd, D, data_bytes); #if (SHADOWING == 1) if (lseek(fd, (off_t)sym_bytes, SEEK_CUR) == (off_t) -1) ; /* error */ if (relocate(fd, (unsigned char *)mbuf) < 0) ; /* error */ pc += (vir_bytes) rp->mp_seg[T].mem_vir << CLICK_SHIFT; #endif close(fd); /* don't need exec file any more */ /* Take care of setuid/setgid bits. */ if ((rmp->mp_flags & TRACED) == 0) { /* suppress if tracing */ if (s_buf.st_mode & I_SET_UID_BIT) { rmp->mp_effuid = s_buf.st_uid; tell_fs(SETUID,who, (int)rmp->mp_realuid, (int)rmp->mp_effuid); } if (s_buf.st_mode & I_SET_GID_BIT) { rmp->mp_effgid = s_buf.st_gid; tell_fs(SETGID,who, (int)rmp->mp_realgid, (int)rmp->mp_effgid); } } /* Save offset to initial argc (for ps) */ rmp->mp_procargs = vsp; /* Fix 'mproc' fields, tell kernel that exec is done, reset caught sigs. */ for (sn = 1; sn <= _NSIG; sn++) { if (sigismember(&rmp->mp_catch, sn)) { sigdelset(&rmp->mp_catch, sn); rmp->mp_sigact[sn].sa_handler = SIG_DFL; sigemptyset(&rmp->mp_sigact[sn].sa_mask); } } rmp->mp_flags &= ~SEPARATE; /* turn off SEPARATE bit */ rmp->mp_flags |= ft; /* turn it on for separate I & D files */ new_sp = (char *) vsp; tell_fs(EXEC, who, 0, 0); /* allow FS to handle FD_CLOEXEC files */ /* System will save command line for debugging, ps(1) output, etc. */ basename = strrchr(name_buf, '/'); if (basename == NULL) basename = name_buf; else basename++; sys_exec(who, new_sp, rmp->mp_flags & TRACED, basename, pc); return(OK); }
static int process_share(sa_handle_impl_t impl_handle, sa_share_impl_t impl_share, char *pathname, char *resource, char *proto, char *options, char *description, char *dataset, boolean_t from_sharetab) { struct stat statbuf; int rc; char *resource_dup = NULL, *dataset_dup = NULL; boolean_t new_share; sa_fstype_t *fstype; new_share = B_FALSE; if (impl_share == NULL) impl_share = find_share(impl_handle, pathname); if (impl_share == NULL) { if (lstat(pathname, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode)) return (SA_BAD_PATH); impl_share = alloc_share(pathname); if (impl_share == NULL) { rc = SA_NO_MEMORY; goto err; } new_share = B_TRUE; } if (dataset != NULL) { dataset_dup = strdup(dataset); if (dataset_dup == NULL) { rc = SA_NO_MEMORY; goto err; } } free(impl_share->dataset); impl_share->dataset = dataset_dup; rc = SA_INVALID_PROTOCOL; fstype = fstypes; while (fstype != NULL) { if (strcmp(fstype->name, proto) == 0) { if (resource != NULL) { resource_dup = strdup(resource); if (resource_dup == NULL) { rc = SA_NO_MEMORY; goto err; } } free(FSINFO(impl_share, fstype)->resource); FSINFO(impl_share, fstype)->resource = resource_dup; rc = fstype->ops->update_shareopts(impl_share, resource, options); if (rc == SA_OK && from_sharetab) FSINFO(impl_share, fstype)->active = B_TRUE; break; } fstype = fstype->next; } if (rc != SA_OK) goto err; if (new_share) { impl_share->handle = impl_handle; impl_share->next = impl_handle->shares; impl_handle->shares = impl_share; } err: if (rc != SA_OK) { if (new_share) free_share(impl_share); } return (rc); }
sa_share_t sa_find_share(sa_handle_t handle, char *sharepath) { return ((sa_share_t)find_share((sa_handle_impl_t)handle, sharepath)); }
/*===========================================================================* * do_exec * *===========================================================================*/ PUBLIC int do_exec() { /* Perform the execve(name, argv, envp) call. The user library builds a * complete stack image, including pointers, args, environ, etc. The stack * is copied to a buffer inside PM, and then to the new core image. */ /* * 执行 execve(name, argv, envp) 调用. 用户库函数构造了一个完整的栈映像, * 包括指针, 命令行参数, 环境变量等等. 栈先复制到 PM 内的一个缓冲区中, * 再复制给新的堆栈映像. */ register struct mproc *rmp; struct mproc *sh_mp; int m, r, fd, ft, sn; static char mbuf[ARG_MAX]; /* buffer for stack and zeroes */ static char name_buf[PATH_MAX]; /* the name of the file to exec */ char *new_sp, *name, *basename; vir_bytes src, dst, text_bytes, data_bytes, bss_bytes, stk_bytes, vsp; phys_bytes tot_bytes; /* total space for program, including gap */ long sym_bytes; vir_clicks sc; struct stat s_buf[2], *s_p; vir_bytes pc; /* Do some validity checks. */ rmp = mp; // rmp = mp = 当前进程的 struct mproc 结构 stk_bytes = (vir_bytes) m_in.stack_bytes; if (stk_bytes > ARG_MAX) return(ENOMEM); /* stack too big */ if (m_in.exec_len <= 0 || m_in.exec_len > PATH_MAX) return(EINVAL); /* Get the exec file name and see if the file is executable. */ src = (vir_bytes) m_in.exec_name; dst = (vir_bytes) name_buf; // 将可执行文件的路径名从主调进程复制到 PM 的 name_buf[] 中. r = sys_datacopy(who, (vir_bytes) src, PM_PROC_NR, (vir_bytes) dst, (phys_bytes) m_in.exec_len); if (r != OK) return(r); /* file name not in user data segment */ /* Fetch the stack from the user before destroying the old core image. */ // 将主调进程的栈复制到 mbuf[], 在毁掉旧的核心映像之前 src = (vir_bytes) m_in.stack_ptr; dst = (vir_bytes) mbuf; r = sys_datacopy(who, (vir_bytes) src, PM_PROC_NR, (vir_bytes) dst, (phys_bytes)stk_bytes); /* can't fetch stack (e.g. bad virtual addr) */ if (r != OK) return(EACCES); r = 0; /* r = 0 (first attempt), or 1 (interpreted script) */ name = name_buf; /* name of file to exec. */ do { s_p = &s_buf[r]; // 切换到主调进程的当前工作目录 tell_fs(CHDIR, who, FALSE, 0); /* switch to the user's FS environ */ // 检查文件是否可执行, 如果可执行, 返回文件描述符 fd = allowed(name, s_p, X_BIT); /* is file executable? */ if (fd < 0) return(fd); /* file was not executable */ /* Read the file header and extract the segment sizes. */ sc = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT; // 读取文件头部数据, 并赋值给相应参数 m = read_header(fd, &ft, &text_bytes, &data_bytes, &bss_bytes, &tot_bytes, &sym_bytes, sc, &pc); if (m != ESCRIPT || ++r > 1) break; } while ((name = patch_stack(fd, mbuf, &stk_bytes, name_buf)) != NULL); if (m < 0) { close(fd); /* something wrong with header */ return(stk_bytes > ARG_MAX ? ENOMEM : ENOEXEC); } /* Can the process' text be shared with that of one already running? */ sh_mp = find_share(rmp, s_p->st_ino, s_p->st_dev, s_p->st_ctime); /* Allocate new memory and release old memory. Fix map and tell kernel. */ r = new_mem(sh_mp, text_bytes, data_bytes, bss_bytes, stk_bytes, tot_bytes); if (r != OK) { close(fd); /* insufficient core or program too big */ return(r); } /* Save file identification to allow it to be shared. */ rmp->mp_ino = s_p->st_ino; rmp->mp_dev = s_p->st_dev; rmp->mp_ctime = s_p->st_ctime; /* Patch up stack and copy it from PM to new core image. */ vsp = (vir_bytes) rmp->mp_seg[S].mem_vir << CLICK_SHIFT; vsp += (vir_bytes) rmp->mp_seg[S].mem_len << CLICK_SHIFT; vsp -= stk_bytes; patch_ptr(mbuf, vsp); src = (vir_bytes) mbuf; r = sys_datacopy(PM_PROC_NR, (vir_bytes) src, who, (vir_bytes) vsp, (phys_bytes)stk_bytes); if (r != OK) panic(__FILE__,"do_exec stack copy err on", who); /* Read in text and data segments. */ if (sh_mp != NULL) { lseek(fd, (off_t) text_bytes, SEEK_CUR); /* shared: skip text */ } else { rw_seg(0, fd, who, T, text_bytes); } rw_seg(0, fd, who, D, data_bytes); close(fd); /* don't need exec file any more */ /* Take care of setuid/setgid bits. */ if ((rmp->mp_flags & TRACED) == 0) { /* suppress if tracing */ if (s_buf[0].st_mode & I_SET_UID_BIT) { rmp->mp_effuid = s_buf[0].st_uid; tell_fs(SETUID,who, (int)rmp->mp_realuid, (int)rmp->mp_effuid); } if (s_buf[0].st_mode & I_SET_GID_BIT) { rmp->mp_effgid = s_buf[0].st_gid; tell_fs(SETGID,who, (int)rmp->mp_realgid, (int)rmp->mp_effgid); } } /* Save offset to initial argc (for ps) */ rmp->mp_procargs = vsp; /* Fix 'mproc' fields, tell kernel that exec is done, reset caught sigs. */ for (sn = 1; sn <= _NSIG; sn++) { if (sigismember(&rmp->mp_catch, sn)) { sigdelset(&rmp->mp_catch, sn); rmp->mp_sigact[sn].sa_handler = SIG_DFL; sigemptyset(&rmp->mp_sigact[sn].sa_mask); } } rmp->mp_flags &= ~SEPARATE; /* turn off SEPARATE bit */ rmp->mp_flags |= ft; /* turn it on for separate I & D files */ new_sp = (char *) vsp; tell_fs(EXEC, who, 0, 0); /* allow FS to handle FD_CLOEXEC files */ /* System will save command line for debugging, ps(1) output, etc. */ basename = strrchr(name, '/'); if (basename == NULL) basename = name; else basename++; strncpy(rmp->mp_name, basename, PROC_NAME_LEN-1); rmp->mp_name[PROC_NAME_LEN] = '\0'; sys_exec(who, new_sp, basename, pc); /* Cause a signal if this process is traced. */ if (rmp->mp_flags & TRACED) check_sig(rmp->mp_pid, SIGTRAP); return(SUSPEND); /* no reply, new program just runs */ }