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arch, passt: Use executable link to form AVX2 binary path

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...instead of argv[0], which might or might not contain a valid path
to the executable itself. Instead of mangling argv[0], use the same
link to find out if we're already running the AVX2 build where
supported.

Alternatively, we could use execvpe(), but that might result in
running a different installed version, in case e.g. the set of
binaries is present in both /usr/bin and /usr/local/bin, with both
being in $PATH.

Reported-by: Wenli Quan <wquan@redhat.com>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2101310
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2022-07-13 03:20:45 +02:00
parent 30ac86823b
commit 17689cc9bf
2 changed files with 21 additions and 13 deletions
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25
arch.c
View file

@ -14,26 +14,31 @@
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/**
* arch_avx2_exec() - Run AVX2 build if supported, drop suffix from argv[0]
* arch_avx2_exec() - Switch to AVX2 build if supported
* @argv: Arguments from command line
*/
#ifdef __x86_64__
static char avx2_path[PATH_MAX];
void arch_avx2_exec(char **argv)
{
char *p = strstr(argv[0], ".avx2");
char exe[PATH_MAX] = { 0 }, new_path[PATH_MAX + sizeof(".avx2")], *p;
if (p) {
*p = 0;
} else if (__builtin_cpu_supports("avx2")) {
snprintf(avx2_path, PATH_MAX, "%s.avx2", argv[0]);
argv[0] = avx2_path;
execve(avx2_path, argv, environ);
if (readlink("/proc/self/exe", exe, PATH_MAX - 1) < 0) {
perror("readlink /proc/self/exe");
exit(EXIT_FAILURE);
}
p = strstr(exe, ".avx2");
if (p && strlen(p) == strlen(".avx2"))
return;
if (__builtin_cpu_supports("avx2")) {
snprintf(new_path, PATH_MAX + sizeof(".avx2"), "%s.avx2", exe);
execve(new_path, argv, environ);
perror("Can't run AVX2 build, using non-AVX2 version");
}
}

9
passt.c
View file

@ -35,6 +35,7 @@
#include <sys/mount.h>
#include <netinet/ip.h>
#include <net/ethernet.h>
#include <libgen.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
@ -283,11 +284,11 @@ int main(int argc, char **argv)
{
int nfds, i, devnull_fd = -1, pidfile_fd = -1, quit_fd;
struct epoll_event events[EPOLL_EVENTS];
char *log_name, argv0[PATH_MAX], *name;
struct ctx c = { 0 };
struct rlimit limit;
struct timespec now;
struct sigaction sa;
char *log_name;
arch_avx2_exec(argv);
@ -304,14 +305,16 @@ int main(int argc, char **argv)
if (argc < 1)
exit(EXIT_FAILURE);
if (strstr(argv[0], "pasta")) {
strncpy(argv0, argv[0], PATH_MAX - 1);
name = basename(argv0);
if (strstr(name, "pasta")) {
sa.sa_handler = pasta_child_handler;
sigaction(SIGCHLD, &sa, NULL);
signal(SIGPIPE, SIG_IGN);
c.mode = MODE_PASTA;
log_name = "pasta";
} else if (strstr(argv[0], "passt")) {
} else if (strstr(name, "passt")) {
c.mode = MODE_PASST;
log_name = "passt";
} else {