aboutsummaryrefslogtreecommitdiff
path: root/src/lzma/io.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/lzma/io.c')
-rw-r--r--src/lzma/io.c658
1 files changed, 0 insertions, 658 deletions
diff --git a/src/lzma/io.c b/src/lzma/io.c
deleted file mode 100644
index 0ec63f03..00000000
--- a/src/lzma/io.c
+++ /dev/null
@@ -1,658 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-/// \file io.c
-/// \brief File opening, unlinking, and closing
-//
-// Copyright (C) 2007 Lasse Collin
-//
-// This program is free software; you can redistribute it and/or
-// modify it under the terms of the GNU Lesser General Public
-// License as published by the Free Software Foundation; either
-// version 2.1 of the License, or (at your option) any later version.
-//
-// This program 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
-// Lesser General Public License for more details.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include "private.h"
-
-#include <fcntl.h>
-
-#if defined(HAVE_FUTIMES) || defined(HAVE_FUTIMESAT) || defined(HAVE_UTIMES)
-# include <sys/time.h>
-#elif defined(HAVE_UTIME)
-# include <utime.h>
-#endif
-
-
-/// \brief Unlinks a file
-///
-/// This tries to verify that the file being unlinked really is the file that
-/// we want to unlink by verifying device and inode numbers. There's still
-/// a small unavoidable race, but this is much better than nothing (the file
-/// could have been moved/replaced even hours earlier).
-static void
-io_unlink(const char *name, const struct stat *known_st)
-{
- struct stat new_st;
-
- if (lstat(name, &new_st)
- || new_st.st_dev != known_st->st_dev
- || new_st.st_ino != known_st->st_ino) {
- message_error(_("%s: File seems to be moved, not removing"),
- name);
- } else {
- // There's a race condition between lstat() and unlink()
- // but at least we have tried to avoid removing wrong file.
- if (unlink(name))
- message_error(_("%s: Cannot remove: %s"),
- name, strerror(errno));
- }
-
- return;
-}
-
-
-/// \brief Copies owner/group and permissions
-///
-/// \todo ACL and EA support
-///
-static void
-io_copy_attrs(const file_pair *pair)
-{
- // This function is more tricky than you may think at first.
- // Blindly copying permissions may permit users to access the
- // destination file who didn't have permission to access the
- // source file.
-
- // Simple cache to avoid repeated calls to geteuid().
- static enum {
- WARN_FCHOWN_UNKNOWN,
- WARN_FCHOWN_NO,
- WARN_FCHOWN_YES,
- } warn_fchown = WARN_FCHOWN_UNKNOWN;
-
- // Try changing the owner of the file. If we aren't root or the owner
- // isn't already us, fchown() probably doesn't succeed. We warn
- // about failing fchown() only if we are root.
- if (fchown(pair->dest_fd, pair->src_st.st_uid, -1)
- && warn_fchown != WARN_FCHOWN_NO) {
- if (warn_fchown == WARN_FCHOWN_UNKNOWN)
- warn_fchown = geteuid() == 0
- ? WARN_FCHOWN_YES : WARN_FCHOWN_NO;
-
- if (warn_fchown == WARN_FCHOWN_YES)
- message_warning(_("%s: Cannot set the file owner: %s"),
- pair->dest_name, strerror(errno));
- }
-
- mode_t mode;
-
- if (fchown(pair->dest_fd, -1, pair->src_st.st_gid)) {
- message_warning(_("%s: Cannot set the file group: %s"),
- pair->dest_name, strerror(errno));
- // We can still safely copy some additional permissions:
- // `group' must be at least as strict as `other' and
- // also vice versa.
- //
- // NOTE: After this, the owner of the source file may
- // get additional permissions. This shouldn't be too bad,
- // because the owner would have had permission to chmod
- // the original file anyway.
- mode = ((pair->src_st.st_mode & 0070) >> 3)
- & (pair->src_st.st_mode & 0007);
- mode = (pair->src_st.st_mode & 0700) | (mode << 3) | mode;
- } else {
- // Drop the setuid, setgid, and sticky bits.
- mode = pair->src_st.st_mode & 0777;
- }
-
- if (fchmod(pair->dest_fd, mode))
- message_warning(_("%s: Cannot set the file permissions: %s"),
- pair->dest_name, strerror(errno));
-
- // Copy the timestamps. We have several possible ways to do this, of
- // which some are better in both security and precision.
- //
- // First, get the nanosecond part of the timestamps. As of writing,
- // it's not standardized by POSIX, and there are several names for
- // the same thing in struct stat.
- long atime_nsec;
- long mtime_nsec;
-
-# if defined(HAVE_STRUCT_STAT_ST_ATIM_TV_NSEC)
- // GNU and Solaris
- atime_nsec = pair->src_st.st_atim.tv_nsec;
- mtime_nsec = pair->src_st.st_mtim.tv_nsec;
-
-# elif defined(HAVE_STRUCT_STAT_ST_ATIMESPEC_TV_NSEC)
- // BSD
- atime_nsec = pair->src_st.st_atimespec.tv_nsec;
- mtime_nsec = pair->src_st.st_mtimespec.tv_nsec;
-
-# elif defined(HAVE_STRUCT_STAT_ST_ATIMENSEC)
- // GNU and BSD without extensions
- atime_nsec = pair->src_st.st_atimensec;
- mtime_nsec = pair->src_st.st_mtimensec;
-
-# elif defined(HAVE_STRUCT_STAT_ST_UATIME)
- // Tru64
- atime_nsec = pair->src_st.st_uatime * 1000;
- mtime_nsec = pair->src_st.st_umtime * 1000;
-
-# elif defined(HAVE_STRUCT_STAT_ST_ATIM_ST__TIM_TV_NSEC)
- // UnixWare
- atime_nsec = pair->src_st.st_atim.st__tim.tv_nsec;
- mtime_nsec = pair->src_st.st_mtim.st__tim.tv_nsec;
-
-# else
- // Safe fallback
- atime_nsec = 0;
- mtime_nsec = 0;
-# endif
-
- // Construct a structure to hold the timestamps and call appropriate
- // function to set the timestamps.
-#if defined(HAVE_FUTIMENS)
- // Use nanosecond precision.
- struct timespec tv[2];
- tv[0].tv_sec = pair->src_st.st_atime;
- tv[0].tv_nsec = atime_nsec;
- tv[1].tv_sec = pair->src_st.st_mtime;
- tv[1].tv_nsec = mtime_nsec;
-
- (void)futimens(pair->dest_fd, tv);
-
-#elif defined(HAVE_FUTIMES) || defined(HAVE_FUTIMESAT) || defined(HAVE_UTIMES)
- // Use microsecond precision.
- struct timeval tv[2];
- tv[0].tv_sec = pair->src_st.st_atime;
- tv[0].tv_usec = atime_nsec / 1000;
- tv[1].tv_sec = pair->src_st.st_mtime;
- tv[1].tv_usec = mtime_nsec / 1000;
-
-# if defined(HAVE_FUTIMES)
- (void)futimes(pair->dest_fd, tv);
-# elif defined(HAVE_FUTIMESAT)
- (void)futimesat(pair->dest_fd, NULL, tv);
-# else
- // Argh, no function to use a file descriptor to set the timestamp.
- (void)utimes(pair->src_name, tv);
-# endif
-
-#elif defined(HAVE_UTIME)
- // Use one-second precision. utime() doesn't support using file
- // descriptor either.
- const struct utimbuf buf = {
- .actime = pair->src_st.st_atime;
- .modtime = pair->src_st.st_mtime;
- };
-
- // Avoid warnings.
- (void)atime_nsec;
- (void)mtime_nsec;
-
- (void)utime(pair->src_name, &buf);
-#endif
-
- return;
-}
-
-
-/// Opens the source file. Returns false on success, true on error.
-static bool
-io_open_src(file_pair *pair)
-{
- // There's nothing to open when reading from stdin.
- if (pair->src_name == stdin_filename) {
- pair->src_fd = STDIN_FILENO;
- return false;
- }
-
- // We accept only regular files if we are writing the output
- // to disk too, and if --force was not given.
- const bool reg_files_only = !opt_stdout && !opt_force;
-
- // Flags for open()
- int flags = O_RDONLY | O_NOCTTY;
-
- // If we accept only regular files, we need to be careful to avoid
- // problems with special files like devices and FIFOs. O_NONBLOCK
- // prevents blocking when opening such files. When we want to accept
- // special files, we must not use O_NONBLOCK, or otherwise we won't
- // block waiting e.g. FIFOs to become readable.
- if (reg_files_only)
- flags |= O_NONBLOCK;
-
-#ifdef O_NOFOLLOW
- if (reg_files_only)
- flags |= O_NOFOLLOW;
-#else
- // Some POSIX-like systems lack O_NOFOLLOW (it's not required
- // by POSIX). Check for symlinks with a separate lstat() on
- // these systems.
- if (reg_files_only) {
- struct stat st;
- if (lstat(pair->src_name, &st)) {
- message_error("%s: %s", pair->src_name,
- strerror(errno));
- return true;
-
- } else if (S_ISLNK(st.st_mode)) {
- message_warning(_("%s: Is a symbolic link, "
- "skipping"), pair->src_name);
- return true;
- }
- }
-#endif
-
- // Try to open the file. If we are accepting non-regular files,
- // unblock the caught signals so that open() can be interrupted
- // if it blocks e.g. due to a FIFO file.
- if (!reg_files_only)
- signals_unblock();
-
- // Maybe this wouldn't need a loop, since all the signal handlers for
- // which we don't use SA_RESTART set user_abort to true. But it
- // doesn't hurt to have it just in case.
- do {
- pair->src_fd = open(pair->src_name, flags);
- } while (pair->src_fd == -1 && errno == EINTR && !user_abort);
-
- if (!reg_files_only)
- signals_block();
-
- if (pair->src_fd == -1) {
- // If we were interrupted, don't display any error message.
- if (errno == EINTR) {
- // All the signals that don't have SA_RESTART
- // set user_abort.
- assert(user_abort);
- return true;
- }
-
-#ifdef O_NOFOLLOW
- // Give an understandable error message in if reason
- // for failing was that the file was a symbolic link.
- //
- // Note that at least Linux, OpenBSD, Solaris, and Darwin
- // use ELOOP to indicate if O_NOFOLLOW was the reason
- // that open() failed. Because there may be
- // directories in the pathname, ELOOP may occur also
- // because of a symlink loop in the directory part.
- // So ELOOP doesn't tell us what actually went wrong.
- //
- // FreeBSD associates EMLINK with O_NOFOLLOW and
- // Tru64 uses ENOTSUP. We use these directly here
- // and skip the lstat() call and the associated race.
- // I want to hear if there are other kernels that
- // fail with something else than ELOOP with O_NOFOLLOW.
- bool was_symlink = false;
-
-# if defined(__FreeBSD__) || defined(__DragonFly__)
- if (errno == EMLINK)
- was_symlink = true;
-
-# elif defined(__digital__) && defined(__unix__)
- if (errno == ENOTSUP)
- was_symlink = true;
-
-# else
- if (errno == ELOOP && reg_files_only) {
- const int saved_errno = errno;
- struct stat st;
- if (lstat(pair->src_name, &st) == 0
- && S_ISLNK(st.st_mode))
- was_symlink = true;
-
- errno = saved_errno;
- }
-# endif
-
- if (was_symlink)
- message_warning(_("%s: Is a symbolic link, "
- "skipping"), pair->src_name);
- else
-#endif
- // Something else than O_NOFOLLOW failing
- // (assuming that the race conditions didn't
- // confuse us).
- message_error("%s: %s", pair->src_name,
- strerror(errno));
-
- return true;
- }
-
- // Drop O_NONBLOCK, which is used only when we are accepting only
- // regular files. After the open() call, we want things to block
- // instead of giving EAGAIN.
- if (reg_files_only) {
- flags = fcntl(pair->src_fd, F_GETFL);
- if (flags == -1)
- goto error_msg;
-
- flags &= ~O_NONBLOCK;
-
- if (fcntl(pair->src_fd, F_SETFL, flags))
- goto error_msg;
- }
-
- // Stat the source file. We need the result also when we copy
- // the permissions, and when unlinking.
- if (fstat(pair->src_fd, &pair->src_st))
- goto error_msg;
-
- if (S_ISDIR(pair->src_st.st_mode)) {
- message_warning(_("%s: Is a directory, skipping"),
- pair->src_name);
- goto error;
- }
-
- if (reg_files_only) {
- if (!S_ISREG(pair->src_st.st_mode)) {
- message_warning(_("%s: Not a regular file, "
- "skipping"), pair->src_name);
- goto error;
- }
-
- if (pair->src_st.st_mode & (S_ISUID | S_ISGID)) {
- // gzip rejects setuid and setgid files even
- // when --force was used. bzip2 doesn't check
- // for them, but calls fchown() after fchmod(),
- // and many systems automatically drop setuid
- // and setgid bits there.
- //
- // We accept setuid and setgid files if
- // --force was used. We drop these bits
- // explicitly in io_copy_attr().
- message_warning(_("%s: File has setuid or "
- "setgid bit set, skipping"),
- pair->src_name);
- goto error;
- }
-
- if (pair->src_st.st_mode & S_ISVTX) {
- message_warning(_("%s: File has sticky bit "
- "set, skipping"),
- pair->src_name);
- goto error;
- }
-
- if (pair->src_st.st_nlink > 1) {
- message_warning(_("%s: Input file has more "
- "than one hard link, "
- "skipping"), pair->src_name);
- goto error;
- }
- }
-
- return false;
-
-error_msg:
- message_error("%s: %s", pair->src_name, strerror(errno));
-error:
- (void)close(pair->src_fd);
- return true;
-}
-
-
-/// \brief Closes source file of the file_pair structure
-///
-/// \param pair File whose src_fd should be closed
-/// \param success If true, the file will be removed from the disk if
-/// closing succeeds and --keep hasn't been used.
-static void
-io_close_src(file_pair *pair, bool success)
-{
- if (pair->src_fd != STDIN_FILENO && pair->src_fd != -1) {
- // If we are going to unlink(), do it before closing the file.
- // This way there's no risk that someone replaces the file and
- // happens to get same inode number, which would make us
- // unlink() wrong file.
- if (success && !opt_keep_original)
- io_unlink(pair->src_name, &pair->src_st);
-
- (void)close(pair->src_fd);
- }
-
- return;
-}
-
-
-static bool
-io_open_dest(file_pair *pair)
-{
- if (opt_stdout || pair->src_fd == STDIN_FILENO) {
- // We don't modify or free() this.
- pair->dest_name = (char *)"(stdout)";
- pair->dest_fd = STDOUT_FILENO;
- return false;
- }
-
- pair->dest_name = suffix_get_dest_name(pair->src_name);
- if (pair->dest_name == NULL)
- return true;
-
- // If --force was used, unlink the target file first.
- if (opt_force && unlink(pair->dest_name) && errno != ENOENT) {
- message_error("%s: Cannot unlink: %s",
- pair->dest_name, strerror(errno));
- free(pair->dest_name);
- return true;
- }
-
- if (opt_force && unlink(pair->dest_name) && errno != ENOENT) {
- message_error("%s: Cannot unlink: %s", pair->dest_name,
- strerror(errno));
- free(pair->dest_name);
- return true;
- }
-
- // Open the file.
- const int flags = O_WRONLY | O_NOCTTY | O_CREAT | O_EXCL;
- const mode_t mode = S_IRUSR | S_IWUSR;
- pair->dest_fd = open(pair->dest_name, flags, mode);
-
- if (pair->dest_fd == -1) {
- // Don't bother with error message if user requested
- // us to exit anyway.
- if (!user_abort)
- message_error("%s: %s", pair->dest_name,
- strerror(errno));
-
- free(pair->dest_name);
- return true;
- }
-
- // If this really fails... well, we have a safe fallback.
- if (fstat(pair->dest_fd, &pair->dest_st)) {
- pair->dest_st.st_dev = 0;
- pair->dest_st.st_ino = 0;
- }
-
- return false;
-}
-
-
-/// \brief Closes destination file of the file_pair structure
-///
-/// \param pair File whose dest_fd should be closed
-/// \param success If false, the file will be removed from the disk.
-///
-/// \return Zero if closing succeeds. On error, -1 is returned and
-/// error message printed.
-static int
-io_close_dest(file_pair *pair, bool success)
-{
- if (pair->dest_fd == -1 || pair->dest_fd == STDOUT_FILENO)
- return 0;
-
- if (close(pair->dest_fd)) {
- message_error(_("%s: Closing the file failed: %s"),
- pair->dest_name, strerror(errno));
-
- // Closing destination file failed, so we cannot trust its
- // contents. Get rid of junk:
- io_unlink(pair->dest_name, &pair->dest_st);
- free(pair->dest_name);
- return -1;
- }
-
- // If the operation using this file wasn't successful, we git rid
- // of the junk file.
- if (!success)
- io_unlink(pair->dest_name, &pair->dest_st);
-
- free(pair->dest_name);
-
- return 0;
-}
-
-
-extern file_pair *
-io_open(const char *src_name)
-{
- if (is_empty_filename(src_name))
- return NULL;
-
- // Since we have only one file open at a time, we can use
- // a statically allocated structure.
- static file_pair pair;
-
- pair = (file_pair){
- .src_name = src_name,
- .dest_name = NULL,
- .src_fd = -1,
- .dest_fd = -1,
- .src_eof = false,
- };
-
- // Block the signals, for which we have a custom signal handler, so
- // that we don't need to worry about EINTR.
- signals_block();
-
- file_pair *ret = NULL;
- if (!io_open_src(&pair)) {
- // io_open_src() may have unblocked the signals temporarily,
- // and thus user_abort may have got set even if open()
- // succeeded.
- if (user_abort || io_open_dest(&pair))
- io_close_src(&pair, false);
- else
- ret = &pair;
- }
-
- signals_unblock();
-
- return ret;
-}
-
-
-extern void
-io_close(file_pair *pair, bool success)
-{
- signals_block();
-
- if (success && pair->dest_fd != STDOUT_FILENO)
- io_copy_attrs(pair);
-
- // Close the destination first. If it fails, we must not remove
- // the source file!
- if (io_close_dest(pair, success))
- success = false;
-
- // Close the source file, and unlink it if the operation using this
- // file pair was successful and we haven't requested to keep the
- // source file.
- io_close_src(pair, success);
-
- signals_unblock();
-
- return;
-}
-
-
-extern size_t
-io_read(file_pair *pair, uint8_t *buf, size_t size)
-{
- // We use small buffers here.
- assert(size < SSIZE_MAX);
-
- size_t left = size;
-
- while (left > 0) {
- const ssize_t amount = read(pair->src_fd, buf, left);
-
- if (amount == 0) {
- pair->src_eof = true;
- break;
- }
-
- if (amount == -1) {
- if (errno == EINTR) {
- if (user_abort)
- return SIZE_MAX;
-
- continue;
- }
-
- message_error(_("%s: Read error: %s"),
- pair->src_name, strerror(errno));
-
- // FIXME Is this needed?
- pair->src_eof = true;
-
- return SIZE_MAX;
- }
-
- buf += (size_t)(amount);
- left -= (size_t)(amount);
- }
-
- return size - left;
-}
-
-
-extern bool
-io_write(const file_pair *pair, const uint8_t *buf, size_t size)
-{
- assert(size < SSIZE_MAX);
-
- while (size > 0) {
- const ssize_t amount = write(pair->dest_fd, buf, size);
- if (amount == -1) {
- if (errno == EINTR) {
- if (user_abort)
- return -1;
-
- continue;
- }
-
- // Handle broken pipe specially. gzip and bzip2
- // don't print anything on SIGPIPE. In addition,
- // gzip --quiet uses exit status 2 (warning) on
- // broken pipe instead of whatever raise(SIGPIPE)
- // would make it return. It is there to hide "Broken
- // pipe" message on some old shells (probably old
- // GNU bash).
- //
- // We don't do anything special with --quiet, which
- // is what bzip2 does too. If we get SIGPIPE, we
- // will handle it like other signals by setting
- // user_abort, and get EPIPE here.
- if (errno != EPIPE)
- message_error(_("%s: Write error: %s"),
- pair->dest_name, strerror(errno));
-
- return true;
- }
-
- buf += (size_t)(amount);
- size -= (size_t)(amount);
- }
-
- return false;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-12 14:36:32 +0000