diff options
Diffstat (limited to 'shell_cmds/sh/redir.c')
| -rw-r--r-- | shell_cmds/sh/redir.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/shell_cmds/sh/redir.c b/shell_cmds/sh/redir.c new file mode 100644 index 0000000..8f415a6 --- /dev/null +++ b/shell_cmds/sh/redir.c @@ -0,0 +1,365 @@ +/*- + * SPDX-License-Identifier: BSD-3-Clause + * + * 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. + */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; +#endif +#endif /* not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: head/bin/sh/redir.c 326025 2017-11-20 19:49:47Z pfg $"); + +#include <sys/types.h> +#include <sys/stat.h> +#include <signal.h> +#include <string.h> +#include <fcntl.h> +#include <errno.h> +#include <unistd.h> +#include <stdlib.h> + +/* + * Code for dealing with input/output redirection. + */ + +#include "shell.h" +#include "nodes.h" +#include "jobs.h" +#include "expand.h" +#include "redir.h" +#include "output.h" +#include "memalloc.h" +#include "error.h" +#include "options.h" + + +#define EMPTY -2 /* marks an unused slot in redirtab */ +#define CLOSED -1 /* fd was not open before redir */ + + +struct redirtab { + struct redirtab *next; + int renamed[10]; + int fd0_redirected; + unsigned int empty_redirs; +}; + + +static 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. +*/ +static int fd0_redirected = 0; + +/* Number of redirtabs that have not been allocated. */ +static unsigned int empty_redirs = 0; + +static void openredirect(union node *, char[10 ]); +static int openhere(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. +* + * We suppress interrupts so that we won't leave open file + * descriptors around. Because the signal handler remains + * installed and we do not use system call restart, interrupts + * will still abort blocking opens such as fifos (they will fail + * with EINTR). There is, however, a race condition if an interrupt + * arrives after INTOFF and before open blocks. + */ + +void +redirect(union node *redir, int flags) +{ + union node *n; + struct redirtab *sv = NULL; + int i; + int fd; + char memory[10]; /* file descriptors to write to memory */ + + INTOFF; + for (i = 10 ; --i >= 0 ; ) + memory[i] = 0; + memory[1] = flags & REDIR_BACKQ; + if (flags & REDIR_PUSH) { + empty_redirs++; + if (redir != NULL) { + sv = ckmalloc(sizeof (struct redirtab)); + for (i = 0 ; i < 10 ; i++) + sv->renamed[i] = EMPTY; + sv->fd0_redirected = fd0_redirected; + sv->empty_redirs = empty_redirs - 1; + sv->next = redirlist; + redirlist = sv; + empty_redirs = 0; + } + } + for (n = redir ; n ; n = n->nfile.next) { + fd = n->nfile.fd; + if (fd == 0) + fd0_redirected = 1; + 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; + if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) { + switch (errno) { + case EBADF: + i = CLOSED; + break; + default: + INTON; + error("%d: %s", fd, strerror(errno)); + break; + } + } + sv->renamed[fd] = i; + INTON; + } + openredirect(n, memory); + INTON; + INTOFF; + } + if (memory[1]) + out1 = &memout; + if (memory[2]) + out2 = &memout; + INTON; +} + + +static void +openredirect(union node *redir, char memory[10]) +{ + struct stat sb; + int fd = redir->nfile.fd; + const char *fname; + int f; + int e; + + memory[fd] = 0; + switch (redir->nfile.type) { + case NFROM: + fname = redir->nfile.expfname; + if ((f = open(fname, O_RDONLY)) < 0) + error("cannot open %s: %s", fname, strerror(errno)); + break; + case NFROMTO: + fname = redir->nfile.expfname; + if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0) + error("cannot create %s: %s", fname, strerror(errno)); + break; + case NTO: + if (Cflag) { + fname = redir->nfile.expfname; + if (stat(fname, &sb) == -1) { + if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0) + error("cannot create %s: %s", fname, strerror(errno)); + } else if (!S_ISREG(sb.st_mode)) { + if ((f = open(fname, O_WRONLY, 0666)) < 0) + error("cannot create %s: %s", fname, strerror(errno)); + if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) { + close(f); + error("cannot create %s: %s", fname, + strerror(EEXIST)); + } + } else + error("cannot create %s: %s", fname, + strerror(EEXIST)); + break; + } + /* FALLTHROUGH */ + case NCLOBBER: + fname = redir->nfile.expfname; + if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) + error("cannot create %s: %s", fname, strerror(errno)); + break; + case NAPPEND: + fname = redir->nfile.expfname; + if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) + error("cannot create %s: %s", fname, strerror(errno)); + break; + case NTOFD: + case NFROMFD: + if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ + if (memory[redir->ndup.dupfd]) + memory[fd] = 1; + else { + if (dup2(redir->ndup.dupfd, fd) < 0) + error("%d: %s", redir->ndup.dupfd, + strerror(errno)); + } + } else { + close(fd); + } + return; + case NHERE: + case NXHERE: + f = openhere(redir); + break; + default: + abort(); + } + if (f != fd) { + if (dup2(f, fd) == -1) { + e = errno; + close(f); + error("%d: %s", fd, strerror(e)); + } + close(f); + } +} + + +/* + * 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(union node *redir) +{ + const char *p; + int pip[2]; + size_t len = 0; + int flags; + ssize_t written = 0; + + if (pipe(pip) < 0) + error("Pipe call failed: %s", strerror(errno)); + + if (redir->type == NXHERE) + p = redir->nhere.expdoc; + else + p = redir->nhere.doc->narg.text; + len = strlen(p); + if (len == 0) + goto out; + flags = fcntl(pip[1], F_GETFL, 0); + if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) { + written = write(pip[1], p, len); + if (written < 0) + written = 0; + if ((size_t)written == len) + goto out; + fcntl(pip[1], F_SETFL, flags); + } + + if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { + close(pip[0]); + signal(SIGINT, SIG_IGN); + signal(SIGQUIT, SIG_IGN); + signal(SIGHUP, SIG_IGN); + signal(SIGTSTP, SIG_IGN); + signal(SIGPIPE, SIG_DFL); + xwrite(pip[1], p + written, len - written); + _exit(0); + } +out: + close(pip[1]); + return pip[0]; +} + + + +/* + * Undo the effects of the last redirection. + */ + +void +popredir(void) +{ + struct redirtab *rp = redirlist; + int i; + + INTOFF; + if (empty_redirs > 0) { + empty_redirs--; + INTON; + return; + } + for (i = 0 ; i < 10 ; i++) { + if (rp->renamed[i] != EMPTY) { + if (rp->renamed[i] >= 0) { + dup2(rp->renamed[i], i); + close(rp->renamed[i]); + } else { + close(i); + } + } + } + fd0_redirected = rp->fd0_redirected; + empty_redirs = rp->empty_redirs; + redirlist = rp->next; + ckfree(rp); + INTON; +} + +/* Return true if fd 0 has already been redirected at least once. */ +int +fd0_redirected_p(void) +{ + return fd0_redirected != 0; +} + +/* + * Discard all saved file descriptors. + */ + +void +clearredir(void) +{ + struct redirtab *rp; + int i; + + for (rp = redirlist ; rp ; rp = rp->next) { + for (i = 0 ; i < 10 ; i++) { + if (rp->renamed[i] >= 0) { + close(rp->renamed[i]); + } + rp->renamed[i] = EMPTY; + } + } +} |