/* $NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * 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. * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. */ #if 0 #ifndef lint static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; #else __RCSID("$NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $"); #endif /* not lint */ #endif #include #include /* PIPE_BUF */ #include #include #include /* * Code for dealing with input/output redirection. */ #include "main.h" #include "shell.h" #include "nodes.h" #include "jobs.h" #include "options.h" #include "expand.h" #include "redir.h" #include "output.h" #include "memalloc.h" #include "error.h" #include "shinstance.h" #define EMPTY -2 /* marks an unused slot in redirtab */ #ifndef PIPE_BUF # define PIPESIZE 4096 /* amount of buffering in a pipe */ #else # define PIPESIZE PIPE_BUF #endif MKINIT struct redirtab { struct redirtab *next; short renamed[10]; }; //MKINIT struct redirtab *redirlist; /* * We keep track of whether or not fd0 has been redirected. This is for * background commands, where we want to redirect fd0 to /dev/null only * if it hasn't already been redirected. */ //int fd0_redirected = 0; STATIC void openredirect(shinstance *, union node *, char[10], int); STATIC int openhere(shinstance *, union node *); /* * Process a list of redirection commands. If the REDIR_PUSH flag is set, * old file descriptors are stashed away so that the redirection can be * undone by calling popredir. If the REDIR_BACKQ flag is set, then the * standard output, and the standard error if it becomes a duplicate of * stdout, is saved in memory. */ void redirect(shinstance *psh, union node *redir, int flags) { union node *n; struct redirtab *sv = NULL; int i; int fd; int try; char memory[10]; /* file descriptors to write to memory */ for (i = 10 ; --i >= 0 ; ) memory[i] = 0; memory[1] = flags & REDIR_BACKQ; if (flags & REDIR_PUSH) { /* We don't have to worry about REDIR_VFORK here, as * flags & REDIR_PUSH is never true if REDIR_VFORK is set. */ sv = ckmalloc(psh, sizeof (struct redirtab)); for (i = 0 ; i < 10 ; i++) sv->renamed[i] = EMPTY; sv->next = psh->redirlist; psh->redirlist = sv; } for (n = redir ; n ; n = n->nfile.next) { fd = n->nfile.fd; try = 0; if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && n->ndup.dupfd == fd) continue; /* redirect from/to same file descriptor */ if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { INTOFF; again: if ((i = shfile_fcntl(&psh->fdtab, fd, F_DUPFD, 10)) == -1) { switch (errno) { case EBADF: if (!try) { openredirect(psh, n, memory, flags); try++; goto again; } /* FALLTHROUGH*/ default: INTON; error(psh, "%d: %s", fd, sh_strerror(psh, errno)); /* NOTREACHED */ } } if (!try) { sv->renamed[fd] = i; shfile_close(&psh->fdtab, fd); } INTON; } else { shfile_close(&psh->fdtab, fd); } if (fd == 0) psh->fd0_redirected++; if (!try) openredirect(psh, n, memory, flags); } if (memory[1]) psh->out1 = &psh->memout; if (memory[2]) psh->out2 = &psh->memout; } STATIC void openredirect(shinstance *psh, union node *redir, char memory[10], int flags) { int fd = redir->nfile.fd; char *fname; int f; int oflags = O_WRONLY|O_CREAT|O_TRUNC, eflags; /* * We suppress interrupts so that we won't leave open file * descriptors around. This may not be such a good idea because * an open of a device or a fifo can block indefinitely. */ INTOFF; memory[fd] = 0; switch (redir->nfile.type) { case NFROM: fname = redir->nfile.expfname; if (flags & REDIR_VFORK) eflags = O_NONBLOCK; else eflags = 0; if ((f = shfile_open(&psh->fdtab, fname, O_RDONLY|eflags, 0)) < 0) goto eopen; if (eflags) (void)shfile_fcntl(&psh->fdtab, f, F_SETFL, shfile_fcntl(&psh->fdtab, f, F_GETFL, 0) & ~eflags); break; case NFROMTO: fname = redir->nfile.expfname; if ((f = shfile_open(&psh->fdtab, fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0) goto ecreate; break; case NTO: if (Cflag(psh)) oflags |= O_EXCL; /* FALLTHROUGH */ case NCLOBBER: fname = redir->nfile.expfname; if ((f = shfile_open(&psh->fdtab, fname, oflags, 0666)) < 0) goto ecreate; break; case NAPPEND: fname = redir->nfile.expfname; if ((f = shfile_open(&psh->fdtab, fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) goto ecreate; break; case NTOFD: case NFROMFD: if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ if (memory[redir->ndup.dupfd]) memory[fd] = 1; else copyfd(psh, redir->ndup.dupfd, fd); } INTON; return; case NHERE: case NXHERE: f = openhere(psh, redir); break; default: sh_abort(psh); } if (f != fd) { movefd(psh, f, fd); } INTON; return; ecreate: error(psh, "cannot create %s: %s", fname, errmsg(psh, errno, E_CREAT)); eopen: error(psh, "cannot open %s: %s", fname, errmsg(psh, errno, E_OPEN)); } /* * Handle here documents. Normally we fork off a process to write the * data to a pipe. If the document is short, we can stuff the data in * the pipe without forking. */ STATIC int openhere(shinstance *psh, union node *redir) { int pip[2]; size_t len = 0; if (shfile_pipe(&psh->fdtab, pip) < 0) error(psh, "Pipe call failed"); if (redir->type == NHERE) { len = strlen(redir->nhere.doc->narg.text); if (len <= PIPESIZE) { xwrite(psh, pip[1], redir->nhere.doc->narg.text, len); goto out; } } if (forkshell(psh, (struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { shfile_close(&psh->fdtab, pip[0]); sh_signal(psh, SIGINT, SH_SIG_IGN); sh_signal(psh, SIGQUIT, SH_SIG_IGN); sh_signal(psh, SIGHUP, SH_SIG_IGN); #ifdef SIGTSTP sh_signal(psh, SIGTSTP, SH_SIG_IGN); #endif sh_signal(psh, SIGPIPE, SH_SIG_DFL); if (redir->type == NHERE) xwrite(psh, pip[1], redir->nhere.doc->narg.text, len); else expandhere(psh, redir->nhere.doc, pip[1]); sh__exit(psh, 0); } out: shfile_close(&psh->fdtab, pip[1]); return pip[0]; } /* * Undo the effects of the last redirection. */ void popredir(shinstance *psh) { struct redirtab *rp = psh->redirlist; int i; for (i = 0 ; i < 10 ; i++) { if (rp->renamed[i] != EMPTY) { if (i == 0) psh->fd0_redirected--; if (rp->renamed[i] >= 0) { movefd(psh, rp->renamed[i], i); } else { shfile_close(&psh->fdtab, i); } } } INTOFF; psh->redirlist = rp->next; ckfree(psh, rp); INTON; } /* * Undo all redirections. Called on error or interrupt. */ #ifdef mkinit INCLUDE "redir.h" RESET { while (psh->redirlist) popredir(psh); } SHELLPROC { clearredir(psh, 0); } #endif /* Return true if fd 0 has already been redirected at least once. */ int fd0_redirected_p(shinstance *psh) { return psh->fd0_redirected != 0; } /* * Discard all saved file descriptors. */ void clearredir(shinstance *psh, int vforked) { struct redirtab *rp; int i; for (rp = psh->redirlist ; rp ; rp = rp->next) { for (i = 0 ; i < 10 ; i++) { if (rp->renamed[i] >= 0) { shfile_close(&psh->fdtab, rp->renamed[i]); } if (!vforked) rp->renamed[i] = EMPTY; } } } /* * Copy a file descriptor to be >= to. Returns -1 * if the source file descriptor is closed, EMPTY if there are no unused * file descriptors left. */ int copyfd(shinstance *psh, int from, int to) { int newfd; newfd = shfile_fcntl(&psh->fdtab, from, F_DUPFD, to); if (newfd < 0) { if (errno == EMFILE) return EMPTY; error(psh, "%d: %s", from, sh_strerror(psh, errno)); } return newfd; } /* * Move a file descriptor to be == to. Returns -1 * if the source file descriptor is closed, EMPTY if there are no unused * file descriptors left. */ int movefd(shinstance *psh, int from, int to) { int newfd; newfd = shfile_movefd(&psh->fdtab, from, to); if (newfd < 0) { if (errno == EMFILE) return EMPTY; error(psh, "%d: %s", from, sh_strerror(psh, errno)); } return newfd; } /* * Move a file descriptor to be >= to. Returns -1 * if the source file descriptor is closed, EMPTY if there are no unused * file descriptors left. */ int movefd_above(shinstance *psh, int from, int to) { int newfd; newfd = shfile_movefd_above(&psh->fdtab, from, to); if (newfd < 0) { if (errno == EMFILE) return EMPTY; error(psh, "%d: %s", from, sh_strerror(psh, errno)); } return newfd; }