d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Preserve hard & symbolic links when modifying source file

Browse Source 
Strip is often used to modify existing files, rather than creating new
files. If the existing file has hard links or is a symbolic link, act as
if editing the file in place and preserve the links.

Reported by:	luigi
Reviewed by:	imp, rpaulo
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D1682
This commit is contained in:
Ed Maste 2015-01-28 18:37:09 +00:00
parent 54edb5043c
commit 272a972b88
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=277843
1 changed files with 33 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
contrib/elftoolchain/elfcopy/main.c
View File

@ -210,7 +210,7 @@ static struct {
};
static int copy_from_tempfile(const char *src, const char *dst,
int infd, int *outfd);
int infd, int *outfd, int in_place);
static void create_file(struct elfcopy *ecp, const char *src,
const char *dst);
static void elfcopy_main(struct elfcopy *ecp, int argc, char **argv);
@ -523,33 +523,39 @@ create_tempfile(char **fn, int *fd)
#undef _TEMPFILEPATH
}
/*
* Copy temporary file with path src and file descriptor infd to path dst.
* If in_place is set act as if editing the file in place, avoiding rename()
* to preserve hard and symbolic links. Output file remains open, with file
* descriptor returned in outfd.
*/
static int
copy_from_tempfile(const char *src, const char *dst, int infd, int *outfd)
copy_from_tempfile(const char *src, const char *dst, int infd, int *outfd,
int in_place)
{
int tmpfd;
/*
* First, check if we can use rename().
*/
if (rename(src, dst) >= 0) {
*outfd = infd;
return (0);
} else if (errno != EXDEV)
return (-1);
if (in_place == 0) {
if (rename(src, dst) >= 0) {
*outfd = infd;
return (0);
} else if (errno != EXDEV)
return (-1);
/*
* If the rename() failed due to 'src' and 'dst' residing in
* two different file systems, invoke a helper function in
* libelftc to do the copy.
*/
/*
* If the rename() failed due to 'src' and 'dst' residing in
* two different file systems, invoke a helper function in
* libelftc to do the copy.
*/
if (unlink(dst) < 0)
return (-1);
}
if (unlink(dst) < 0)
return (-1);
if ((tmpfd = open(dst, O_CREAT | O_WRONLY, 0755)) < 0)
return (-1);
if (lseek(infd, 0, SEEK_SET) < 0)
if ((tmpfd = open(dst, O_CREAT | O_TRUNC | O_WRONLY, 0755)) < 0)
return (-1);
if (elftc_copyfile(infd, tmpfd) < 0)
@ -578,6 +584,7 @@ create_file(struct elfcopy *ecp, const char *src, const char *dst)
struct stat sb;
char *tempfile, *elftemp;
int efd, ifd, ofd, ofd0, tfd;
int in_place;
tempfile = NULL;
@ -718,10 +725,15 @@ create_file(struct elfcopy *ecp, const char *src, const char *dst)
#endif
if (tempfile != NULL) {
if (dst == NULL)
in_place = 0;
if (dst == NULL) {
dst = src;
if (lstat(dst, &sb) != -1 &&
(sb.st_nlink > 1 || S_ISLNK(sb.st_mode)))
in_place = 1;
}
if (copy_from_tempfile(tempfile, dst, ofd, &tfd) < 0)
if (copy_from_tempfile(tempfile, dst, ofd, &tfd, in_place) < 0)
err(EXIT_FAILURE, "creation of %s failed", dst);
free(tempfile);