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src: add new option --link to preserve hard links; use with care

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This commit is contained in:
Markus F.X.J. Oberhumer
2023-09-04 22:34:21 +02:00
parent 62dbf8485f
commit 4f6320d3aa
8 changed files with 181 additions and 82 deletions
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src/work.cpp
+125 -66
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@@ -34,6 +34,7 @@
#include "file.h"
#include "packmast.h"
#include "ui.h"
#include "util/membuffer.h"
#if (ACC_OS_DOS32) && defined(__DJGPP__)
#define USE_FTIME 1
@@ -50,16 +51,94 @@
#define SH_DENYWR (-1)
#endif
/*************************************************************************
// util
**************************************************************************/
// ignore errors in some cases and silence __attribute__((__warn_unused_result__))
#define IGNORE_ERROR(var) ACC_UNUSED(var)
enum WronlyOpenMode { WOM_MUST_EXIST_TRUNCATE, WOM_MUST_CREATE, WOM_CREATE_OR_TRUNCATE };
static constexpr int get_wronly_open_flags(WronlyOpenMode mode) noexcept {
constexpr int flags = O_WRONLY | O_BINARY;
if (mode == WOM_MUST_EXIST_TRUNCATE)
return flags | O_TRUNC; // will cause an error if file does not exist
if (mode == WOM_MUST_CREATE)
return flags | O_CREAT | O_EXCL; // will cause an error if file already exists
// create if not exists, otherwise truncate
return flags | O_CREAT | O_TRUNC;
}
static void copy_file_contents(const char *iname, const char *oname, WronlyOpenMode mode)
may_throw {
InputFile fi;
fi.sopen(iname, O_RDONLY | O_BINARY, SH_DENYWR);
fi.seek(0, SEEK_SET);
int flags = get_wronly_open_flags(mode);
int shmode = SH_DENYWR;
int omode = 0600; // affected by umask; ignored unless O_CREAT
OutputFile fo;
fo.sopen(oname, flags, shmode, omode);
fo.seek(0, SEEK_SET);
MemBuffer buf(256 * 1024 * 1024);
for (;;) {
size_t bytes = fi.read(buf, buf.getSize());
if (bytes == 0)
break;
fo.write(buf, bytes);
}
fi.closex();
fo.closex();
}
static void copy_file_attributes(const struct stat *st, const char *oname, bool preserve_mode,
bool preserve_ownership, bool preserve_timestamp) noexcept {
#if USE_UTIME
// copy time stamp
if (preserve_timestamp) {
struct utimbuf u;
u.actime = st->st_atime;
u.modtime = st->st_mtime;
int r = utime(oname, &u);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHOWN
// copy the group ownership
if (preserve_ownership) {
int r = chown(oname, -1, st->st_gid);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHMOD
// copy permissions
if (preserve_mode) {
int r = chmod(oname, st->st_mode);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHOWN
// copy the user ownership
if (preserve_ownership) {
int r = chown(oname, st->st_uid, -1);
IGNORE_ERROR(r);
}
#endif
// maybe unused
UNUSED(oname);
UNUSED(preserve_mode);
UNUSED(preserve_ownership);
UNUSED(preserve_timestamp);
}
/*************************************************************************
// process one file
**************************************************************************/
void do_one_file(const char *iname, char *oname) {
void do_one_file(const char *const iname, char *const oname) may_throw {
int r;
struct stat st;
struct stat st; // stat of iname
mem_clear(&st);
#if HAVE_LSTAT
r = lstat(iname, &st);
@@ -99,6 +178,7 @@ void do_one_file(const char *iname, char *oname) {
throwIOException("file is write protected -- skipped");
}
// open input file
InputFile fi;
fi.sopen(iname, O_RDONLY | O_BINARY, SH_DENYWR);
@@ -113,6 +193,7 @@ void do_one_file(const char *iname, char *oname) {
// open output file
OutputFile fo;
bool copy_timestamp_only = false;
if (opt->cmd == CMD_COMPRESS || opt->cmd == CMD_DECOMPRESS) {
if (opt->to_stdout) {
if (!fo.openStdout(1, opt->force ? true : false))
@@ -121,33 +202,30 @@ void do_one_file(const char *iname, char *oname) {
char tname[ACC_FN_PATH_MAX + 1];
if (opt->output_name) {
strcpy(tname, opt->output_name);
if (opt->force_overwrite || opt->force >= 2) {
#if HAVE_CHMOD
r = chmod(tname, 0777);
IGNORE_ERROR(r);
#endif
r = unlink(tname);
IGNORE_ERROR(r);
}
if ((opt->force_overwrite || opt->force >= 2) && !opt->preserve_link)
FileBase::unlink(tname, false);
} else {
if (!maketempname(tname, sizeof(tname), iname, ".upx"))
throwIOException("could not create a temporary file name");
}
int flags = O_CREAT | O_WRONLY | O_BINARY;
if (opt->force_overwrite || opt->force)
flags |= O_TRUNC;
else
flags |= O_EXCL;
int flags = get_wronly_open_flags(WOM_MUST_CREATE);
if (opt->output_name && opt->preserve_link) {
flags = get_wronly_open_flags(WOM_CREATE_OR_TRUNCATE);
if (file_exists(opt->output_name)) {
flags = get_wronly_open_flags(WOM_MUST_EXIST_TRUNCATE);
copy_timestamp_only = true;
}
} else if (opt->force_overwrite || opt->force)
flags = get_wronly_open_flags(WOM_CREATE_OR_TRUNCATE);
int shmode = SH_DENYWR;
#if (ACC_ARCH_M68K && ACC_OS_TOS && ACC_CC_GNUC) && defined(__MINT__)
// TODO later: check current mintlib if this hack is still needed
flags |= O_TRUNC;
shmode = O_DENYRW;
#endif
// cannot rely on open() because of umask
// int omode = st.st_mode | 0600;
int omode = 0600;
if (!opt->preserve_mode)
omode = 0666;
int omode = opt->preserve_mode ? 0600 : 0666; // affected by umask; only for O_CREAT
fo.sopen(tname, flags, shmode, omode);
// open succeeded - now set oname[]
strcpy(oname, tname);
@@ -187,59 +265,45 @@ void do_one_file(const char *iname, char *oname) {
fo.closex();
fi.closex();
// rename or delete files
// rename or copy files
// NOTE: only use "preserve_link" if you really need it, e.g. it can fail
// with ETXTBSY and other unexpected errors; renaming files is much safer
if (oname[0] && !opt->output_name) {
// both iname and oname do exist; rename oname to iname
if (opt->backup) {
char bakname[ACC_FN_PATH_MAX + 1];
if (!makebakname(bakname, sizeof(bakname), iname))
throwIOException("could not create a backup file name");
FileBase::rename(iname, bakname);
if (opt->preserve_link) {
copy_file_contents(iname, bakname, WOM_MUST_CREATE);
copy_file_attributes(&st, bakname, true, true, true);
copy_file_contents(oname, iname, WOM_MUST_EXIST_TRUNCATE);
FileBase::unlink(oname);
copy_timestamp_only = true;
} else {
FileBase::rename(iname, bakname);
FileBase::rename(oname, iname);
}
} else if (opt->preserve_link) {
copy_file_contents(oname, iname, WOM_MUST_EXIST_TRUNCATE);
FileBase::unlink(oname);
copy_timestamp_only = true;
} else {
#if HAVE_CHMOD
r = chmod(iname, 0777);
IGNORE_ERROR(r);
#endif
FileBase::unlink(iname);
FileBase::rename(oname, iname);
}
FileBase::rename(oname, iname);
// now iname is the new packed/unpacked file and oname does not exist any longer
}
// copy file attributes
if (oname[0]) {
oname[0] = 0; // done with oname
const char *name = opt->output_name ? opt->output_name : iname;
UNUSED(name);
#if USE_UTIME
// copy time stamp
if (opt->preserve_timestamp) {
struct utimbuf u;
u.actime = st.st_atime;
u.modtime = st.st_mtime;
r = utime(name, &u);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHOWN
// copy the group ownership
if (opt->preserve_ownership) {
r = chown(name, -1, st.st_gid);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHMOD
// copy permissions
if (opt->preserve_mode) {
r = chmod(name, st.st_mode);
IGNORE_ERROR(r);
}
#endif
#if HAVE_CHOWN
// copy the user ownership
if (opt->preserve_ownership) {
r = chown(name, st.st_uid, -1);
IGNORE_ERROR(r);
}
#endif
if (copy_timestamp_only)
copy_file_attributes(&st, name, false, false, opt->preserve_timestamp);
else
copy_file_attributes(&st, name, opt->preserve_mode, opt->preserve_ownership,
opt->preserve_timestamp);
}
UiPacker::uiConfirmUpdate();
@@ -251,17 +315,12 @@ void do_one_file(const char *iname, char *oname) {
static void unlink_ofile(char *oname) noexcept {
if (oname && oname[0]) {
#if HAVE_CHMOD
int r;
r = chmod(oname, 0777);
IGNORE_ERROR(r);
#endif
if (unlink(oname) == 0)
oname[0] = 0; // done with oname
FileBase::unlink(oname, false);
oname[0] = 0; // done with oname
}
}
int do_files(int i, int argc, char *argv[]) {
int do_files(int i, int argc, char *argv[]) may_throw {
upx_compiler_sanity_check();
if (opt->verbose >= 1) {
show_header();
@@ -271,7 +330,7 @@ int do_files(int i, int argc, char *argv[]) {
for (; i < argc; i++) {
infoHeader();
const char *iname = argv[i];
const char *const iname = argv[i];
char oname[ACC_FN_PATH_MAX + 1];
oname[0] = 0;