diff options
Diffstat (limited to 'redir.c')
| -rw-r--r-- | redir.c | 1505 |
1 files changed, 1505 insertions, 0 deletions
@@ -0,0 +1,1505 @@ +/* redir.c -- Functions to perform input and output redirection. */ + +/* Copyright (C) 1997-2020 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "config.h" + +#if !defined (__GNUC__) && !defined (HAVE_ALLOCA_H) && defined (_AIX) + #pragma alloca +#endif /* _AIX && RISC6000 && !__GNUC__ */ + +#include <stdio.h> +#include "bashtypes.h" +#if !defined (_MINIX) && defined (HAVE_SYS_FILE_H) +# include <sys/file.h> +#endif +#include "filecntl.h" +#include "posixstat.h" + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif + +#include <errno.h> + +#if !defined (errno) +extern int errno; +#endif + +#include "bashansi.h" +#include "bashintl.h" +#include "memalloc.h" + +#define NEED_FPURGE_DECL + +#include "shell.h" +#include "flags.h" +#include "execute_cmd.h" +#include "redir.h" +#include "trap.h" + +#if defined (BUFFERED_INPUT) +# include "input.h" +#endif + +#include "builtins/pipesize.h" + +/* FreeBSD 13 can reliably handle atomic writes at this capacity without + hanging. */ +#if __FreeBSD__ && !defined (HEREDOC_PIPESIZE) +# define HEREDOC_PIPESIZE 4096 +#endif + +/* Normally set by a build process command that computes pipe capacity */ +#ifndef PIPESIZE +# ifdef PIPE_BUF +# define PIPESIZE PIPE_BUF +# else +# define PIPESIZE 4096 +# endif +#endif + +#ifndef HEREDOC_PIPESIZE +# define HEREDOC_PIPESIZE PIPESIZE +#endif + +#if defined (HEREDOC_PIPEMAX) +# if HEREDOC_PIPESIZE > HEREDOC_PIPEMAX +# define HEREDOC_PIPESIZE HEREDOC_PIPEMAX +# endif +#endif + +#define SHELL_FD_BASE 10 + +int expanding_redir; + +extern REDIRECT *redirection_undo_list; +extern REDIRECT *exec_redirection_undo_list; + +/* Static functions defined and used in this file. */ +static void add_exec_redirect PARAMS((REDIRECT *)); +static int add_undo_redirect PARAMS((int, enum r_instruction, int)); +static int add_undo_close_redirect PARAMS((int)); +static int expandable_redirection_filename PARAMS((REDIRECT *)); +static int stdin_redirection PARAMS((enum r_instruction, int)); +static int undoablefd PARAMS((int)); +static int do_redirection_internal PARAMS((REDIRECT *, int, char **)); + +static char *heredoc_expand PARAMS((WORD_DESC *, enum r_instruction, size_t *)); +static int heredoc_write PARAMS((int, char *, size_t)); +static int here_document_to_fd PARAMS((WORD_DESC *, enum r_instruction)); + +static int redir_special_open PARAMS((int, char *, int, int, enum r_instruction)); +static int noclobber_open PARAMS((char *, int, int, enum r_instruction)); +static int redir_open PARAMS((char *, int, int, enum r_instruction)); + +static int redir_varassign PARAMS((REDIRECT *, int)); +static int redir_varvalue PARAMS((REDIRECT *)); + +/* Spare redirector used when translating [N]>&WORD[-] or [N]<&WORD[-] to + a new redirection and when creating the redirection undo list. */ +static REDIRECTEE rd; + +/* Set to errno when a here document cannot be created for some reason. + Used to print a reasonable error message. */ +static int heredoc_errno; + +#define REDIRECTION_ERROR(r, e, fd) \ +do { \ + if ((r) < 0) \ + { \ + if (fd >= 0) \ + close (fd); \ + set_exit_status (EXECUTION_FAILURE);\ + return ((e) == 0 ? EINVAL : (e));\ + } \ +} while (0) + +void +redirection_error (temp, error, fn) + REDIRECT *temp; + int error; + char *fn; /* already-expanded filename */ +{ + char *filename, *allocname; + int oflags; + + allocname = 0; + if ((temp->rflags & REDIR_VARASSIGN) && error < 0) + filename = allocname = savestring (temp->redirector.filename->word); + else if ((temp->rflags & REDIR_VARASSIGN) == 0 && temp->redirector.dest < 0) + /* This can happen when read_token_word encounters overflow, like in + exec 4294967297>x */ + filename = _("file descriptor out of range"); +#ifdef EBADF + /* This error can never involve NOCLOBBER */ + else if (error != NOCLOBBER_REDIRECT && temp->redirector.dest >= 0 && error == EBADF) + { + /* If we're dealing with two file descriptors, we have to guess about + which one is invalid; in the cases of r_{duplicating,move}_input and + r_{duplicating,move}_output we're here because dup2() failed. */ + switch (temp->instruction) + { + case r_duplicating_input: + case r_duplicating_output: + case r_move_input: + case r_move_output: + filename = allocname = itos (temp->redirectee.dest); + break; + case r_duplicating_input_word: + if (temp->redirector.dest == 0) /* Guess */ + filename = temp->redirectee.filename->word; /* XXX */ + else + filename = allocname = itos (temp->redirector.dest); + break; + case r_duplicating_output_word: + if (temp->redirector.dest == 1) /* Guess */ + filename = temp->redirectee.filename->word; /* XXX */ + else + filename = allocname = itos (temp->redirector.dest); + break; + default: + filename = allocname = itos (temp->redirector.dest); + break; + } + } +#endif + else if (fn) + filename = fn; + else if (expandable_redirection_filename (temp)) + { + oflags = temp->redirectee.filename->flags; + if (posixly_correct && interactive_shell == 0) + temp->redirectee.filename->flags |= W_NOGLOB; + temp->redirectee.filename->flags |= W_NOCOMSUB; + filename = allocname = redirection_expand (temp->redirectee.filename); + temp->redirectee.filename->flags = oflags; + if (filename == 0) + filename = temp->redirectee.filename->word; + } + else if (temp->redirectee.dest < 0) + filename = _("file descriptor out of range"); + else + filename = allocname = itos (temp->redirectee.dest); + + switch (error) + { + case AMBIGUOUS_REDIRECT: + internal_error (_("%s: ambiguous redirect"), filename); + break; + + case NOCLOBBER_REDIRECT: + internal_error (_("%s: cannot overwrite existing file"), filename); + break; + +#if defined (RESTRICTED_SHELL) + case RESTRICTED_REDIRECT: + internal_error (_("%s: restricted: cannot redirect output"), filename); + break; +#endif /* RESTRICTED_SHELL */ + + case HEREDOC_REDIRECT: + internal_error (_("cannot create temp file for here-document: %s"), strerror (heredoc_errno)); + break; + + case BADVAR_REDIRECT: + internal_error (_("%s: cannot assign fd to variable"), filename); + break; + + default: + internal_error ("%s: %s", filename, strerror (error)); + break; + } + + FREE (allocname); +} + +/* Perform the redirections on LIST. If flags & RX_ACTIVE, then actually + make input and output file descriptors, otherwise just do whatever is + necessary for side effecting. flags & RX_UNDOABLE says to remember + how to undo the redirections later, if non-zero. If flags & RX_CLEXEC + is non-zero, file descriptors opened in do_redirection () have their + close-on-exec flag set. */ +int +do_redirections (list, flags) + REDIRECT *list; + int flags; +{ + int error; + REDIRECT *temp; + char *fn; + + if (flags & RX_UNDOABLE) + { + if (redirection_undo_list) + { + dispose_redirects (redirection_undo_list); + redirection_undo_list = (REDIRECT *)NULL; + } + if (exec_redirection_undo_list) + dispose_exec_redirects (); + } + + for (temp = list; temp; temp = temp->next) + { + fn = 0; + error = do_redirection_internal (temp, flags, &fn); + if (error) + { + redirection_error (temp, error, fn); + FREE (fn); + return (error); + } + FREE (fn); + } + return (0); +} + +/* Return non-zero if the redirection pointed to by REDIRECT has a + redirectee.filename that can be expanded. */ +static int +expandable_redirection_filename (redirect) + REDIRECT *redirect; +{ + switch (redirect->instruction) + { + case r_output_direction: + case r_appending_to: + case r_input_direction: + case r_inputa_direction: + case r_err_and_out: + case r_append_err_and_out: + case r_input_output: + case r_output_force: + case r_duplicating_input_word: + case r_duplicating_output_word: + case r_move_input_word: + case r_move_output_word: + return 1; + + default: + return 0; + } +} + +/* Expand the word in WORD returning a string. If WORD expands to + multiple words (or no words), then return NULL. */ +char * +redirection_expand (word) + WORD_DESC *word; +{ + char *result; + WORD_LIST *tlist1, *tlist2; + WORD_DESC *w; + int old; + + w = copy_word (word); + if (posixly_correct) + w->flags |= W_NOSPLIT; + + tlist1 = make_word_list (w, (WORD_LIST *)NULL); + expanding_redir = 1; + /* Now that we've changed the variable search order to ignore the temp + environment, see if we need to change the cached IFS values. */ + sv_ifs ("IFS"); + tlist2 = expand_words_no_vars (tlist1); + expanding_redir = 0; + /* Now we need to change the variable search order back to include the temp + environment. We force the temp environment search by forcing + executing_builtin to 1. This is what makes `read' get the right values + for the IFS-related cached variables, for example. */ + old = executing_builtin; + executing_builtin = 1; + sv_ifs ("IFS"); + executing_builtin = old; + dispose_words (tlist1); + + if (tlist2 == 0 || tlist2->next) + { + /* We expanded to no words, or to more than a single word. + Dispose of the word list and return NULL. */ + if (tlist2) + dispose_words (tlist2); + return ((char *)NULL); + } + result = string_list (tlist2); /* XXX savestring (tlist2->word->word)? */ + dispose_words (tlist2); + return (result); +} + +/* Expand a here-document or here-string (determined by RI) contained in + REDIRECTEE and return the expanded document. If LENP is non-zero, put + the length of the returned string into *LENP. + + This captures everything about expanding here-documents and here-strings: + the returned document should be written directly to whatever file + descriptor is specified. In particular, it adds a newline to the end of + a here-string to preserve previous semantics. */ +static char * +heredoc_expand (redirectee, ri, lenp) + WORD_DESC *redirectee; + enum r_instruction ri; + size_t *lenp; +{ + char *document; + size_t dlen; + int old; + + if (redirectee->word == 0 || redirectee->word[0] == '\0') + { + if (lenp) + *lenp = 0; + return (redirectee->word); + } + + /* Quoted here documents are not expanded */ + if (ri != r_reading_string && (redirectee->flags & W_QUOTED)) + { + if (lenp) + *lenp = STRLEN (redirectee->word); + return (redirectee->word); + } + + expanding_redir = 1; + /* Now that we've changed the variable search order to ignore the temp + environment, see if we need to change the cached IFS values. */ + sv_ifs ("IFS"); + document = (ri == r_reading_string) ? expand_assignment_string_to_string (redirectee->word, 0) + : expand_string_to_string (redirectee->word, Q_HERE_DOCUMENT); + expanding_redir = 0; + /* Now we need to change the variable search order back to include the temp + environment. We force the temp environment search by forcing + executing_builtin to 1. This is what makes `read' get the right values + for the IFS-related cached variables, for example. */ + old = executing_builtin; + executing_builtin = 1; + sv_ifs ("IFS"); + executing_builtin = old; + + dlen = STRLEN (document); + /* XXX - Add trailing newline to here-string */ + if (ri == r_reading_string) + { + document = xrealloc (document, dlen + 2); + document[dlen++] = '\n'; + document[dlen] = '\0'; + } + if (lenp) + *lenp = dlen; + + return document; +} + +/* Write HEREDOC (of length HDLEN) to FD, returning 0 on success and ERRNO on + error. Don't handle interrupts. */ +static int +heredoc_write (fd, heredoc, herelen) + int fd; + char *heredoc; + size_t herelen; +{ + ssize_t nw; + int e; + + errno = 0; + nw = write (fd, heredoc, herelen); + e = errno; + if (nw != herelen) + { + if (e == 0) + e = ENOSPC; + return e; + } + return 0; +} + +/* Create a temporary file or pipe holding the text of the here document + pointed to by REDIRECTEE, and return a file descriptor open for reading + to it. Return -1 on any error, and make sure errno is set appropriately. */ +static int +here_document_to_fd (redirectee, ri) + WORD_DESC *redirectee; + enum r_instruction ri; +{ + char *filename; + int r, fd, fd2, herepipe[2]; + char *document; + size_t document_len; +#if HEREDOC_PARANOID + struct stat st1, st2; +#endif + + /* Expand the here-document/here-string first and then decide what to do. */ + document = heredoc_expand (redirectee, ri, &document_len); + + /* If we have a zero-length document, don't mess with a temp file */ + if (document_len == 0) + { + fd = open ("/dev/null", O_RDONLY); + r = errno; + if (document != redirectee->word) + FREE (document); + errno = r; + return fd; + } + +#if defined (HEREDOC_PIPESIZE) + /* Try to use a pipe internal to this process if the document is shorter + than the system's pipe capacity (computed at build time). We want to + write the entire document without write blocking. */ + if (document_len <= HEREDOC_PIPESIZE) + { + if (pipe (herepipe) < 0) + { + r = errno; + if (document != redirectee->word) + free (document); + errno = r; + return (-1); + } + +#if defined (F_GETPIPE_SZ) + if (fcntl (herepipe[1], F_GETPIPE_SZ, 0) < document_len) + goto use_tempfile; +#endif + + r = heredoc_write (herepipe[1], document, document_len); + if (document != redirectee->word) + free (document); + close (herepipe[1]); + if (r) /* write error */ + { + close (herepipe[0]); + errno = r; + return (-1); + } + return (herepipe[0]); + } +#endif + +use_tempfile: + + fd = sh_mktmpfd ("sh-thd", MT_USERANDOM|MT_USETMPDIR, &filename); + + /* If we failed for some reason other than the file existing, abort */ + if (fd < 0) + { + r = errno; + FREE (filename); + if (document != redirectee->word) + FREE (document); + errno = r; + return (fd); + } + + fchmod (fd, S_IRUSR | S_IWUSR); + SET_CLOSE_ON_EXEC (fd); + + errno = r = 0; /* XXX */ + r = heredoc_write (fd, document, document_len); + if (document != redirectee->word) + FREE (document); + + if (r) + { + close (fd); + unlink (filename); + free (filename); + errno = r; + return (-1); + } + + /* In an attempt to avoid races, we close the first fd only after opening + the second. */ + /* Make the document really temporary. Also make it the input. */ + fd2 = open (filename, O_RDONLY|O_BINARY, 0600); + + if (fd2 < 0) + { + r = errno; + unlink (filename); + free (filename); + close (fd); + errno = r; + return -1; + } + +#if HEREDOC_PARANOID + /* We can use same_file here to check whether or not fd and fd2 refer to + the same file, but we don't do that unless HEREDOC_PARANOID is defined. */ + if (fstat (fd, &st1) < 0 || S_ISREG (st1.st_mode) == 0 || + fstat (fd2, &st2) < 0 || S_ISREG (st2.st_mode) == 0 || + same_file (filename, filename, &st1, &st2) == 0) + { + unlink (filename); + free (filename); + close (fd); + close (fd2); + errno = EEXIST; + return -1; + } +#endif + + close (fd); + if (unlink (filename) < 0) + { + r = errno; + close (fd2); + free (filename); + errno = r; + return (-1); + } + + free (filename); + + fchmod (fd2, S_IRUSR); + return (fd2); +} + +#define RF_DEVFD 1 +#define RF_DEVSTDERR 2 +#define RF_DEVSTDIN 3 +#define RF_DEVSTDOUT 4 +#define RF_DEVTCP 5 +#define RF_DEVUDP 6 + +/* A list of pattern/value pairs for filenames that the redirection + code handles specially. */ +static STRING_INT_ALIST _redir_special_filenames[] = { +#if !defined (HAVE_DEV_FD) + { "/dev/fd/[0-9]*", RF_DEVFD }, +#endif +#if !defined (HAVE_DEV_STDIN) + { "/dev/stderr", RF_DEVSTDERR }, + { "/dev/stdin", RF_DEVSTDIN }, + { "/dev/stdout", RF_DEVSTDOUT }, +#endif +#if defined (NETWORK_REDIRECTIONS) + { "/dev/tcp/*/*", RF_DEVTCP }, + { "/dev/udp/*/*", RF_DEVUDP }, +#endif + { (char *)NULL, -1 } +}; + +static int +redir_special_open (spec, filename, flags, mode, ri) + int spec; + char *filename; + int flags, mode; + enum r_instruction ri; +{ + int fd; +#if !defined (HAVE_DEV_FD) + intmax_t lfd; +#endif + + fd = -1; + switch (spec) + { +#if !defined (HAVE_DEV_FD) + case RF_DEVFD: + if (all_digits (filename+8) && legal_number (filename+8, &lfd) && lfd == (int)lfd) + { + fd = lfd; + fd = fcntl (fd, F_DUPFD, SHELL_FD_BASE); + } + else + fd = AMBIGUOUS_REDIRECT; + break; +#endif + +#if !defined (HAVE_DEV_STDIN) + case RF_DEVSTDIN: + fd = fcntl (0, F_DUPFD, SHELL_FD_BASE); + break; + case RF_DEVSTDOUT: + fd = fcntl (1, F_DUPFD, SHELL_FD_BASE); + break; + case RF_DEVSTDERR: + fd = fcntl (2, F_DUPFD, SHELL_FD_BASE); + break; +#endif + +#if defined (NETWORK_REDIRECTIONS) + case RF_DEVTCP: + case RF_DEVUDP: +#if defined (RESTRICTED_SHELL) + if (restricted) + return (RESTRICTED_REDIRECT); +#endif +#if defined (HAVE_NETWORK) + fd = netopen (filename); +#else + internal_warning (_("/dev/(tcp|udp)/host/port not supported without networking")); + fd = open (filename, flags, mode); +#endif + break; +#endif /* NETWORK_REDIRECTIONS */ + } + + return fd; +} + +/* Open FILENAME with FLAGS in noclobber mode, hopefully avoiding most + race conditions and avoiding the problem where the file is replaced + between the stat(2) and open(2). */ +static int +noclobber_open (filename, flags, mode, ri) + char *filename; + int flags, mode; + enum r_instruction ri; +{ + int r, fd; + struct stat finfo, finfo2; + + /* If the file exists and is a regular file, return an error + immediately. */ + r = stat (filename, &finfo); + if (r == 0 && (S_ISREG (finfo.st_mode))) + return (NOCLOBBER_REDIRECT); + + /* If the file was not present (r != 0), make sure we open it + exclusively so that if it is created before we open it, our open + will fail. Make sure that we do not truncate an existing file. + Note that we don't turn on O_EXCL unless the stat failed -- if + the file was not a regular file, we leave O_EXCL off. */ + flags &= ~O_TRUNC; + if (r != 0) + { + fd = open (filename, flags|O_EXCL, mode); + return ((fd < 0 && errno == EEXIST) ? NOCLOBBER_REDIRECT : fd); + } + fd = open (filename, flags, mode); + + /* If the open failed, return the file descriptor right away. */ + if (fd < 0) + return (errno == EEXIST ? NOCLOBBER_REDIRECT : fd); + + /* OK, the open succeeded, but the file may have been changed from a + non-regular file to a regular file between the stat and the open. + We are assuming that the O_EXCL open handles the case where FILENAME + did not exist and is symlinked to an existing file between the stat + and open. */ + + /* If we can open it and fstat the file descriptor, and neither check + revealed that it was a regular file, and the file has not been replaced, + return the file descriptor. */ + if ((fstat (fd, &finfo2) == 0) && (S_ISREG (finfo2.st_mode) == 0) && + r == 0 && (S_ISREG (finfo.st_mode) == 0) && + same_file (filename, filename, &finfo, &finfo2)) + return fd; + + /* The file has been replaced. badness. */ + close (fd); + errno = EEXIST; + return (NOCLOBBER_REDIRECT); +} + +static int +redir_open (filename, flags, mode, ri) + char *filename; + int flags, mode; + enum r_instruction ri; +{ + int fd, r, e; + + r = find_string_in_alist (filename, _redir_special_filenames, 1); + if (r >= 0) + return (redir_special_open (r, filename, flags, mode, ri)); + + /* If we are in noclobber mode, you are not allowed to overwrite + existing files. Check before opening. */ + if (noclobber && CLOBBERING_REDIRECT (ri)) + { + fd = noclobber_open (filename, flags, mode, ri); + if (fd == NOCLOBBER_REDIRECT) + return (NOCLOBBER_REDIRECT); + } + else + { + do + { + fd = open (filename, flags, mode); + e = errno; + if (fd < 0 && e == EINTR) + { + QUIT; + run_pending_traps (); + } + errno = e; + } + while (fd < 0 && errno == EINTR); + +#if defined (AFS) + if ((fd < 0) && (errno == EACCES)) + { + fd = open (filename, flags & ~O_CREAT, mode); + errno = EACCES; /* restore errno */ + } +#endif /* AFS */ + } + + return fd; +} + +static int +undoablefd (fd) + int fd; +{ + int clexec; + + clexec = fcntl (fd, F_GETFD, 0); + if (clexec == -1 || (fd >= SHELL_FD_BASE && clexec == 1)) + return 0; + return 1; +} + +/* Do the specific redirection requested. Returns errno or one of the + special redirection errors (*_REDIRECT) in case of error, 0 on success. + If flags & RX_ACTIVE is zero, then just do whatever is necessary to + produce the appropriate side effects. flags & RX_UNDOABLE, if non-zero, + says to remember how to undo each redirection. If flags & RX_CLEXEC is + non-zero, then we set all file descriptors > 2 that we open to be + close-on-exec. FNP, if non-null is a pointer to a location where the + expanded filename is stored. The caller will free it. */ +static int +do_redirection_internal (redirect, flags, fnp) + REDIRECT *redirect; + int flags; + char **fnp; +{ + WORD_DESC *redirectee; + int redir_fd, fd, redirector, r, oflags; + intmax_t lfd; + char *redirectee_word; + enum r_instruction ri; + REDIRECT *new_redirect; + REDIRECTEE sd; + + redirectee = redirect->redirectee.filename; + redir_fd = redirect->redirectee.dest; + redirector = redirect->redirector.dest; + ri = redirect->instruction; + + if (redirect->flags & RX_INTERNAL) + flags |= RX_INTERNAL; + + if (TRANSLATE_REDIRECT (ri)) + { + /* We have [N]>&WORD[-] or [N]<&WORD[-] (or {V}>&WORD[-] or {V}<&WORD-). + and WORD, then translate the redirection into a new one and + continue. */ + redirectee_word = redirection_expand (redirectee); + + /* XXX - what to do with [N]<&$w- where w is unset or null? ksh93 + closes N. */ + if (redirectee_word == 0) + return (AMBIGUOUS_REDIRECT); + else if (redirectee_word[0] == '-' && redirectee_word[1] == '\0') + { + sd = redirect->redirector; + rd.dest = 0; + new_redirect = make_redirection (sd, r_close_this, rd, 0); + } + else if (all_digits (redirectee_word)) + { + sd = redirect->redirector; + if (legal_number (redirectee_word, &lfd) && (int)lfd == lfd) + rd.dest = lfd; + else + rd.dest = -1; /* XXX */ + switch (ri) + { + case r_duplicating_input_word: + new_redirect = make_redirection (sd, r_duplicating_input, rd, 0); + break; + case r_duplicating_output_word: + new_redirect = make_redirection (sd, r_duplicating_output, rd, 0); + break; + case r_move_input_word: + new_redirect = make_redirection (sd, r_move_input, rd, 0); + break; + case r_move_output_word: + new_redirect = make_redirection (sd, r_move_output, rd, 0); + break; + default: + break; /* shut up gcc */ + } + } + else if (ri == r_duplicating_output_word && (redirect->rflags & REDIR_VARASSIGN) == 0 && redirector == 1) + { + sd = redirect->redirector; + rd.filename = make_bare_word (redirectee_word); + new_redirect = make_redirection (sd, r_err_and_out, rd, 0); + } + else + { + free (redirectee_word); + return (AMBIGUOUS_REDIRECT); + } + + free (redirectee_word); + + /* Set up the variables needed by the rest of the function from the + new redirection. */ + if (new_redirect->instruction == r_err_and_out) + { + char *alloca_hack; + + /* Copy the word without allocating any memory that must be + explicitly freed. */ + redirectee = (WORD_DESC *)alloca (sizeof (WORD_DESC)); + xbcopy ((char *)new_redirect->redirectee.filename, + (char *)redirectee, sizeof (WORD_DESC)); + + alloca_hack = (char *) + alloca (1 + strlen (new_redirect->redirectee.filename->word)); + redirectee->word = alloca_hack; + strcpy (redirectee->word, new_redirect->redirectee.filename->word); + } + else + /* It's guaranteed to be an integer, and shouldn't be freed. */ + redirectee = new_redirect->redirectee.filename; + + redir_fd = new_redirect->redirectee.dest; + redirector = new_redirect->redirector.dest; + ri = new_redirect->instruction; + + /* Overwrite the flags element of the old redirect with the new value. */ + redirect->flags = new_redirect->flags; + dispose_redirects (new_redirect); + } + + switch (ri) + { + case r_output_direction: + case r_appending_to: + case r_input_direction: + case r_inputa_direction: + case r_err_and_out: /* command &>filename */ + case r_append_err_and_out: /* command &>> filename */ + case r_input_output: + case r_output_force: + if (posixly_correct && interactive_shell == 0) + { + oflags = redirectee->flags; + redirectee->flags |= W_NOGLOB; + } + redirectee_word = redirection_expand (redirectee); + if (posixly_correct && interactive_shell == 0) + redirectee->flags = oflags; + + if (redirectee_word == 0) + return (AMBIGUOUS_REDIRECT); + +#if defined (RESTRICTED_SHELL) + if (restricted && (WRITE_REDIRECT (ri))) + { + free (redirectee_word); + return (RESTRICTED_REDIRECT); + } +#endif /* RESTRICTED_SHELL */ + + fd = redir_open (redirectee_word, redirect->flags, 0666, ri); + if (fnp) + *fnp = redirectee_word; + else + free (redirectee_word); + + if (fd == NOCLOBBER_REDIRECT || fd == RESTRICTED_REDIRECT) + return (fd); + + if (fd < 0) + return (errno); + + if (flags & RX_ACTIVE) + { + if (redirect->rflags & REDIR_VARASSIGN) + { + redirector = fcntl (fd, F_DUPFD, SHELL_FD_BASE); /* XXX try this for now */ + r = errno; + if (redirector < 0) + sys_error (_("redirection error: cannot duplicate fd")); + REDIRECTION_ERROR (redirector, r, fd); + } + + if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0) + { + /* Only setup to undo it if the thing to undo is active. */ + if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1)) + r = add_undo_redirect (redirector, ri, -1); + else + r = add_undo_close_redirect (redirector); + REDIRECTION_ERROR (r, errno, fd); + } + +#if defined (BUFFERED_INPUT) + /* inhibit call to sync_buffered_stream() for async processes */ + if (redirector != 0 || (subshell_environment & SUBSHELL_ASYNC) == 0) + check_bash_input (redirector); +#endif + + /* Make sure there is no pending output before we change the state + of the underlying file descriptor, since the builtins use stdio + for output. */ + if (redirector == 1 && fileno (stdout) == redirector) + { + fflush (stdout); + fpurge (stdout); + } + else if (redirector == 2 && fileno (stderr) == redirector) + { + fflush (stderr); + fpurge (stderr); + } + + if (redirect->rflags & REDIR_VARASSIGN) + { + if ((r = redir_varassign (redirect, redirector)) < 0) + { + close (redirector); + close (fd); + return (r); /* XXX */ + } + } + else if ((fd != redirector) && (dup2 (fd, redirector) < 0)) + { + close (fd); /* dup2 failed? must be fd limit issue */ + return (errno); + } + +#if defined (BUFFERED_INPUT) + /* Do not change the buffered stream for an implicit redirection + of /dev/null to fd 0 for asynchronous commands without job + control (r_inputa_direction). */ + if (ri == r_input_direction || ri == r_input_output) + duplicate_buffered_stream (fd, redirector); +#endif /* BUFFERED_INPUT */ + + /* + * If we're remembering, then this is the result of a while, for + * or until loop with a loop redirection, or a function/builtin + * executing in the parent shell with a redirection. In the + * function/builtin case, we want to set all file descriptors > 2 + * to be close-on-exec to duplicate the effect of the old + * for i = 3 to NOFILE close(i) loop. In the case of the loops, + * both sh and ksh leave the file descriptors open across execs. + * The Posix standard mentions only the exec builtin. + */ + if ((flags & RX_CLEXEC) && (redirector > 2)) + SET_CLOSE_ON_EXEC (redirector); + } + + if (fd != redirector) + { +#if defined (BUFFERED_INPUT) + if (INPUT_REDIRECT (ri)) + close_buffered_fd (fd); + else +#endif /* !BUFFERED_INPUT */ + close (fd); /* Don't close what we just opened! */ + } + + /* If we are hacking both stdout and stderr, do the stderr + redirection here. XXX - handle {var} here? */ + if (ri == r_err_and_out || ri == r_append_err_and_out) + { + if (flags & RX_ACTIVE) + { + if (flags & RX_UNDOABLE) + add_undo_redirect (2, ri, -1); + if (dup2 (1, 2) < 0) + return (errno); + } + } + break; + + case r_reading_until: + case r_deblank_reading_until: + case r_reading_string: + /* REDIRECTEE is a pointer to a WORD_DESC containing the text of + the new input. Place it in a temporary file. */ + if (redirectee) + { + fd = here_document_to_fd (redirectee, ri); + + if (fd < 0) + { + heredoc_errno = errno; + return (HEREDOC_REDIRECT); + } + + if (redirect->rflags & REDIR_VARASSIGN) + { + redirector = fcntl (fd, F_DUPFD, SHELL_FD_BASE); /* XXX try this for now */ + r = errno; + if (redirector < 0) + sys_error (_("redirection error: cannot duplicate fd")); + REDIRECTION_ERROR (redirector, r, fd); + } + + if (flags & RX_ACTIVE) + { + if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0) + { + /* Only setup to undo it if the thing to undo is active. */ + if ((fd != redirector) && (fcntl (redirector, F_GETFD, 0) != -1)) + r = add_undo_redirect (redirector, ri, -1); + else + r = add_undo_close_redirect (redirector); + REDIRECTION_ERROR (r, errno, fd); + } + +#if defined (BUFFERED_INPUT) + check_bash_input (redirector); +#endif + if (redirect->rflags & REDIR_VARASSIGN) + { + if ((r = redir_varassign (redirect, redirector)) < 0) + { + close (redirector); + close (fd); + return (r); /* XXX */ + } + } + else if (fd != redirector && dup2 (fd, redirector) < 0) + { + r = errno; + close (fd); + return (r); + } + +#if defined (BUFFERED_INPUT) + duplicate_buffered_stream (fd, redirector); +#endif + + if ((flags & RX_CLEXEC) && (redirector > 2)) + SET_CLOSE_ON_EXEC (redirector); + } + + if (fd != redirector) +#if defined (BUFFERED_INPUT) + close_buffered_fd (fd); +#else + close (fd); +#endif + } + break; + + case r_duplicating_input: + case r_duplicating_output: + case r_move_input: + case r_move_output: + if ((flags & RX_ACTIVE) && (redirect->rflags & REDIR_VARASSIGN)) + { + redirector = fcntl (redir_fd, F_DUPFD, SHELL_FD_BASE); /* XXX try this for now */ + r = errno; + if (redirector < 0) + sys_error (_("redirection error: cannot duplicate fd")); + REDIRECTION_ERROR (redirector, r, -1); + } + + if ((flags & RX_ACTIVE) && (redir_fd != redirector)) + { + if ((flags & RX_UNDOABLE) && (redirect->rflags & REDIR_VARASSIGN) == 0) + { + /* Only setup to undo it if the thing to undo is active. */ + if (fcntl (redirector, F_GETFD, 0) != -1) + r = add_undo_redirect (redirector, ri, redir_fd); + else + r = add_undo_close_redirect (redirector); + REDIRECTION_ERROR (r, errno, -1); + } + if ((flags & RX_UNDOABLE) && (ri == r_move_input || ri == r_move_output)) + { + /* r_move_input and r_move_output add an additional close() + that needs to be undone */ + if (fcntl (redirector, F_GETFD, 0) != -1) + { + r = add_undo_redirect (redir_fd, r_close_this, -1); + REDIRECTION_ERROR (r, errno, -1); + } + } +#if defined (BUFFERED_INPUT) + /* inhibit call to sync_buffered_stream() for async processes */ + if (redirector != 0 || (subshell_environment & SUBSHELL_ASYNC) == 0) + check_bash_input (redirector); +#endif + if (redirect->rflags & REDIR_VARASSIGN) + { + if ((r = redir_varassign (redirect, redirector)) < 0) + { + close (redirector); + return (r); /* XXX */ + } + } + /* This is correct. 2>&1 means dup2 (1, 2); */ + else if (dup2 (redir_fd, redirector) < 0) + return (errno); + +#if defined (BUFFERED_INPUT) + if (ri == r_duplicating_input || ri == r_move_input) + duplicate_buffered_stream (redir_fd, redirector); +#endif /* BUFFERED_INPUT */ + + /* First duplicate the close-on-exec state of redirectee. dup2 + leaves the flag unset on the new descriptor, which means it + stays open. Only set the close-on-exec bit for file descriptors + greater than 2 in any case, since 0-2 should always be open + unless closed by something like `exec 2<&-'. It should always + be safe to set fds > 2 to close-on-exec if they're being used to + save file descriptors < 2, since we don't need to preserve the + state of the close-on-exec flag for those fds -- they should + always be open. */ + /* if ((already_set || set_unconditionally) && (ok_to_set)) + set_it () */ +#if 0 + if (((fcntl (redir_fd, F_GETFD, 0) == 1) || redir_fd < 2 || (flags & RX_CLEXEC)) && + (redirector > 2)) +#else + if (((fcntl (redir_fd, F_GETFD, 0) == 1) || (redir_fd < 2 && (flags & RX_INTERNAL)) || (flags & RX_CLEXEC)) && + (redirector > 2)) +#endif + SET_CLOSE_ON_EXEC (redirector); + + /* When undoing saving of non-standard file descriptors (>=3) using + file descriptors >= SHELL_FD_BASE, we set the saving fd to be + close-on-exec and use a flag to decide how to set close-on-exec + when the fd is restored. */ + if ((redirect->flags & RX_INTERNAL) && (redirect->flags & RX_SAVCLEXEC) && redirector >= 3 && (redir_fd >= SHELL_FD_BASE || (redirect->flags & RX_SAVEFD))) + SET_OPEN_ON_EXEC (redirector); + + /* dup-and-close redirection */ + if (ri == r_move_input || ri == r_move_output) + { + xtrace_fdchk (redir_fd); + + close (redir_fd); +#if defined (COPROCESS_SUPPORT) + coproc_fdchk (redir_fd); /* XXX - loses coproc fds */ +#endif + } + } + break; + + case r_close_this: + if (flags & RX_ACTIVE) + { + if (redirect->rflags & REDIR_VARASSIGN) + { + redirector = redir_varvalue (redirect); + if (redirector < 0) + return AMBIGUOUS_REDIRECT; + } + + r = 0; + /* XXX - only if REDIR_VARASSIGN not set? */ + if (flags & RX_UNDOABLE) + { + if (fcntl (redirector, F_GETFD, 0) != -1) + r = add_undo_redirect (redirector, ri, -1); + else + r = add_undo_close_redirect (redirector); + REDIRECTION_ERROR (r, errno, redirector); + } + +#if defined (COPROCESS_SUPPORT) + coproc_fdchk (redirector); +#endif + xtrace_fdchk (redirector); + +#if defined (BUFFERED_INPUT) + /* inhibit call to sync_buffered_stream() for async processes */ + if (redirector != 0 || (subshell_environment & SUBSHELL_ASYNC) == 0) + check_bash_input (redirector); + r = close_buffered_fd (redirector); +#else /* !BUFFERED_INPUT */ + r = close (redirector); +#endif /* !BUFFERED_INPUT */ + + if (r < 0 && (flags & RX_INTERNAL) && (errno == EIO || errno == ENOSPC)) + REDIRECTION_ERROR (r, errno, -1); + } + break; + + case r_duplicating_input_word: + case r_duplicating_output_word: + case r_move_input_word: + case r_move_output_word: + break; + } + return (0); +} + +/* Remember the file descriptor associated with the slot FD, + on REDIRECTION_UNDO_LIST. Note that the list will be reversed + before it is executed. Any redirections that need to be undone + even if REDIRECTION_UNDO_LIST is discarded by the exec builtin + are also saved on EXEC_REDIRECTION_UNDO_LIST. FDBASE says where to + start the duplicating. If it's less than SHELL_FD_BASE, we're ok, + and can use SHELL_FD_BASE (-1 == don't care). If it's >= SHELL_FD_BASE, + we have to make sure we don't use fdbase to save a file descriptor, + since we're going to use it later (e.g., make sure we don't save fd 0 + to fd 10 if we have a redirection like 0<&10). If the value of fdbase + puts the process over its fd limit, causing fcntl to fail, we try + again with SHELL_FD_BASE. Return 0 on success, -1 on error. */ +static int +add_undo_redirect (fd, ri, fdbase) + int fd; + enum r_instruction ri; + int fdbase; +{ + int new_fd, clexec_flag, savefd_flag; + REDIRECT *new_redirect, *closer, *dummy_redirect; + REDIRECTEE sd; + + savefd_flag = 0; + new_fd = fcntl (fd, F_DUPFD, (fdbase < SHELL_FD_BASE) ? SHELL_FD_BASE : fdbase+1); + if (new_fd < 0) + new_fd = fcntl (fd, F_DUPFD, SHELL_FD_BASE); + if (new_fd < 0) + { + new_fd = fcntl (fd, F_DUPFD, 0); + savefd_flag = 1; + } + + if (new_fd < 0) + { + sys_error (_("redirection error: cannot duplicate fd")); + return (-1); + } + + clexec_flag = fcntl (fd, F_GETFD, 0); + + sd.dest = new_fd; + rd.dest = 0; + closer = make_redirection (sd, r_close_this, rd, 0); + closer->flags |= RX_INTERNAL; + dummy_redirect = copy_redirects (closer); + + sd.dest = fd; + rd.dest = new_fd; + if (fd == 0) + new_redirect = make_redirection (sd, r_duplicating_input, rd, 0); + else + new_redirect = make_redirection (sd, r_duplicating_output, rd, 0); + new_redirect->flags |= RX_INTERNAL; + if (savefd_flag) + new_redirect->flags |= RX_SAVEFD; + if (clexec_flag == 0 && fd >= 3 && (new_fd >= SHELL_FD_BASE || savefd_flag)) + new_redirect->flags |= RX_SAVCLEXEC; + new_redirect->next = closer; + + closer->next = redirection_undo_list; + redirection_undo_list = new_redirect; + + /* Save redirections that need to be undone even if the undo list + is thrown away by the `exec' builtin. */ + add_exec_redirect (dummy_redirect); + + /* experimental: if we're saving a redirection to undo for a file descriptor + above SHELL_FD_BASE, add a redirection to be undone if the exec builtin + causes redirections to be discarded. There needs to be a difference + between fds that are used to save other fds and then are the target of + user redirections and fds that are just the target of user redirections. + We use the close-on-exec flag to tell the difference; fds > SHELL_FD_BASE + that have the close-on-exec flag set are assumed to be fds used internally + to save others. */ + if (fd >= SHELL_FD_BASE && ri != r_close_this && clexec_flag) + { + sd.dest = fd; + rd.dest = new_fd; + new_redirect = make_redirection (sd, r_duplicating_output, rd, 0); + new_redirect->flags |= RX_INTERNAL; + + add_exec_redirect (new_redirect); + } + + /* File descriptors used only for saving others should always be + marked close-on-exec. Unfortunately, we have to preserve the + close-on-exec state of the file descriptor we are saving, since + fcntl (F_DUPFD) sets the new file descriptor to remain open + across execs. If, however, the file descriptor whose state we + are saving is <= 2, we can just set the close-on-exec flag, + because file descriptors 0-2 should always be open-on-exec, + and the restore above in do_redirection() will take care of it. */ + if (clexec_flag || fd < 3) + SET_CLOSE_ON_EXEC (new_fd); + else if (redirection_undo_list->flags & RX_SAVCLEXEC) + SET_CLOSE_ON_EXEC (new_fd); + + return (0); +} + +/* Set up to close FD when we are finished with the current command + and its redirections. Return 0 on success, -1 on error. */ +static int +add_undo_close_redirect (fd) + int fd; +{ + REDIRECT *closer; + REDIRECTEE sd; + + sd.dest = fd; + rd.dest = 0; + closer = make_redirection (sd, r_close_this, rd, 0); + closer->flags |= RX_INTERNAL; + closer->next = redirection_undo_list; + redirection_undo_list = closer; + + return 0; +} + +static void +add_exec_redirect (dummy_redirect) + REDIRECT *dummy_redirect; +{ + dummy_redirect->next = exec_redirection_undo_list; + exec_redirection_undo_list = dummy_redirect; +} + +/* Return 1 if the redirection specified by RI and REDIRECTOR alters the + standard input. */ +static int +stdin_redirection (ri, redirector) + enum r_instruction ri; + int redirector; +{ + switch (ri) + { + case r_input_direction: + case r_inputa_direction: + case r_input_output: + case r_reading_until: + case r_deblank_reading_until: + case r_reading_string: + return (1); + case r_duplicating_input: + case r_duplicating_input_word: + case r_close_this: + return (redirector == 0); + case r_output_direction: + case r_appending_to: + case r_duplicating_output: + case r_err_and_out: + case r_append_err_and_out: + case r_output_force: + case r_duplicating_output_word: + case r_move_input: + case r_move_output: + case r_move_input_word: + case r_move_output_word: + return (0); + } + return (0); +} + +/* Return non-zero if any of the redirections in REDIRS alter the standard + input. */ +int +stdin_redirects (redirs) + REDIRECT *redirs; +{ + REDIRECT *rp; + int n; + + for (n = 0, rp = redirs; rp; rp = rp->next) + if ((rp->rflags & REDIR_VARASSIGN) == 0) + n += stdin_redirection (rp->instruction, rp->redirector.dest); + return n; +} +/* bind_var_to_int handles array references */ +static int +redir_varassign (redir, fd) + REDIRECT *redir; + int fd; +{ + WORD_DESC *w; + SHELL_VAR *v; + + w = redir->redirector.filename; + v = bind_var_to_int (w->word, fd); + if (v == 0 || readonly_p (v) || noassign_p (v)) + return BADVAR_REDIRECT; + + stupidly_hack_special_variables (w->word); + return 0; +} + +/* Handles {array[ind]} for redirection words */ +static int +redir_varvalue (redir) + REDIRECT *redir; +{ + SHELL_VAR *v; + char *val, *w; + intmax_t vmax; + int i; +#if defined (ARRAY_VARS) + char *sub; + int len, vr; +#endif + + w = redir->redirector.filename->word; /* shorthand */ + /* XXX - handle set -u here? */ +#if defined (ARRAY_VARS) + if (vr = valid_array_reference (w, 0)) + { + v = array_variable_part (w, 0, &sub, &len); + } + else +#endif + { + v = find_variable (w); +#if defined (ARRAY_VARS) + if (v == 0) + { + v = find_variable_last_nameref (w, 0); + if (v && nameref_p (v)) + { + w = nameref_cell (v); + if (vr = valid_array_reference (w, 0)) + v = array_variable_part (w, 0, &sub, &len); + else + v = find_variable (w); + } + } +#endif + } + + if (v == 0 || invisible_p (v)) + return -1; + +#if defined (ARRAY_VARS) + /* get_variable_value handles references to array variables without + subscripts */ + if (vr && (array_p (v) || assoc_p (v))) + val = get_array_value (w, 0, (int *)NULL, (arrayind_t *)0); + else +#endif + val = get_variable_value (v); + if (val == 0 || *val == 0) + return -1; + + if (legal_number (val, &vmax) < 0) + return -1; + + i = vmax; /* integer truncation */ + return i; +} |