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passt/arch.c
Stefano Brivio 17689cc9bf arch, passt: Use executable link to form AVX2 binary path
...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>
2022-07-14 01:36:05 +02:00

48 lines
1.1 KiB
C

// SPDX-License-Identifier: AGPL-3.0-or-later
/* PASST - Plug A Simple Socket Transport
* for qemu/UNIX domain socket mode
*
* PASTA - Pack A Subtle Tap Abstraction
* for network namespace/tap device mode
*
* arch.c - Architecture-specific implementations
*
* Copyright (c) 2022 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/**
* arch_avx2_exec() - Switch to AVX2 build if supported
* @argv: Arguments from command line
*/
#ifdef __x86_64__
void arch_avx2_exec(char **argv)
{
char exe[PATH_MAX] = { 0 }, new_path[PATH_MAX + sizeof(".avx2")], *p;
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");
}
}
#else
void arch_avx2_exec(char **argv) { (void)argv; }
#endif