Patch dracut to remove avx2 library paths when installing files to the initrd.
The last barrier towards T4719
Signed-off-by: Peter O'Connor <peter@solus-project.com>
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Details
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- None
- Group Reviewers
Triage Team - Commits
- R661:d2aa854497b4: Prevent dracut from adding avx2 or 32bit libraries
Build initrd locally with repo dracut - includes glibc-2.28 haswell libs that
are installed locally
Build initrd locally with this dracut - no haswell libs included
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- R661 dracut
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Would like review of the C code since I don't have a clue what I'm doing. It suggested that perhaps I strdup somewhere I didn't need to on the valgrind. Small compilable version of the included code.
Updated from below to mostly remove memory leaks.
#include <stdio.h>
#include <string.h>
const char *strip_avx(const char *fullpath, const char *avxpath)
{
int length;
char *spntr = NULL;
char npath[120] = "/usr/lib64/";
// Get pointer to found path
char *qpntr = strstr(fullpath, avxpath);
if(qpntr)
{
// Remove leading path from the pointer
length = strlen(avxpath);
spntr = qpntr + length;
// Join path to /usr/lib64 (dracut default)
strcat(npath, spntr);
char *resultpath = strdup(npath);
return resultpath;
}
return fullpath;
}
int main()
{
char *r = "/haswell/avx512_1/";
char *p = "/haswell/";
const char *result = NULL;
const char *resulttmp = NULL;
char *lib = "/usr/lib64/haswell/avx512_1/libm.so.6";
printf("%s\n", lib);
resulttmp = strip_avx(lib, r);
result = strip_avx(resulttmp, p);
printf("%s\n", result);
return 0;
}The diff of a filesize/file build for old and new dracut.
--- resultsold 2018-08-03 13:30:05.088640215 +1000 +++ resultsnew 2018-08-03 13:30:11.816640421 +1000 @@ -87,7 +87,7 @@ 0etc/fstab.empty 251etc/group 25etc/initrd-release -10384etc/ld.so.cache +9802etc/ld.so.cache 0etc/lvm 44etc/lvm/lvm.conf 0etc/machine-id @@ -891,26 +891,7 @@ 16usr/bin/umount 3080096usr/bin/vim 3usr/bin/vi -0usr/lib32 -0usr/lib32/haswell -171188usr/lib32/ld-2.28.so -10usr/lib32/ld-linux.so.2 -2151824usr/lib32/libc-2.28.so -252usr/lib32/libc.so -12usr/lib32/libc.so.6 -132usr/lib32/libgcc_s.so -116100usr/lib32/libgcc_s.so.1 -50772usr/lib32/libnss_files-2.28.so -20usr/lib32/libnss_files.so.2 -20usr/lib32/libnss_files.so 0usr/lib64 -0usr/lib64/haswell -2049744usr/lib64/haswell/libc-2.28.so -43296usr/lib64/haswell/libcrypt-2.28.so -16usr/lib64/haswell/libcrypt.so.1 -12usr/lib64/haswell/libc.so.6 -1567096usr/lib64/haswell/libm-2.28.so -12usr/lib64/haswell/libm.so.6 135usr/lib64/initrd-release 173616usr/lib64/ld-2.28.so 10usr/lib64/ld-linux-x86-64.so.2 @@ -965,7 +946,6 @@ 17usr/lib64/libexpat.so.1 332176usr/lib64/libext2fs.so.2.4 16usr/lib64/libext2fs.so.2 -0usr/lib64/libfakeroot 34880usr/lib64/libffi.so.6.0.4 15usr/lib64/libffi.so.6 15usr/lib64/libffi.so
Comment Actions
I haven't been using pure C for quite some time but:
- nested functions aren't in C standard, clang will rebuke you for that even with GNU extensions enabled
- void * strip_avx_path(..) is a lie, it works but you should express what type you want to return (char*)
- yep that use of strdup() is a leak, you can see it with clang -g review.c && clang --analyze review.c or valgrind --leak-check=full ./review.out
Maybe somebody better at C could help, this modified code has just one leak compared to 6 it previously had:
#include <stdio.h>
#include <string.h>
const char *strip_avx(const char *fullpath, const char *avxpath)
{
int length;
char *spntr = NULL, *fpath = NULL, *apath = NULL;
char npath[120] = "/usr/lib64/";
if(strstr(fullpath, avxpath))
{
// Get pointer to found path
char *qpntr = strstr(fullpath, avxpath);
// Remove leading path from the pointer
length = strlen(avxpath);
spntr = qpntr + length;
// Join path to /usr/lib64 (dracut default)
strcat(npath, spntr);
char *resultpath = strdup(npath);
return resultpath;
}
return fullpath;
}
int main()
{
char *r = "/haswell/avx512_1/";
char *p = "/haswell/";
const char *result = NULL;
const char *resulttmp = NULL;
char *lib = "/usr/lib64/haswell/avx512_1/libm.so.6";
printf("%s\n", lib);
resulttmp = strip_avx(lib, r);
result = strip_avx(resulttmp, p);
printf("%s\n", result);
return 0;
}Comment Actions
I originally didn't use void and strdup, but at some point in having nfi what I was doing they worked around [courtesy of Google search] whatever issue I was having (I guess one of the returns wasn't a proper char variable). I guess once I tidied everything up, it was actually doing what I had originally intended.
Can also strip out apath and fpath from being initialized now.
Comment Actions
Some fixes based on @mati865 comments
If even I know they're better, then they really must be!
Comment Actions
I originally didn't use void and strdup, but at some point in having nfi what I was doing they worked around [courtesy of Google search] whatever issue I was having (I guess one of the returns wasn't a proper char variable). I guess once I tidied everything up, it was actually doing what I had originally intended.
Know that pain, you spent a lot time investigating why simple code doesn't work and create complicated workaround. Then somebody else removes few lines and the code looks before but this time it works...
Can also strip out apath and fpath from being initialized now.
Ah, just missed it.
| files/0001-Exclude-unwanted-paths-from-initrd-creation.patch | ||
|---|---|---|
| 76–77 | Those would be const char* now (like in modified reduced code), but I haven't tested if dracut builds. | |