diff --git a/grep.c b/grep.c index 1687f65b64..0690ed9b89 100644 --- a/grep.c +++ b/grep.c @@ -262,6 +262,31 @@ static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data) free(pointer); } +static int pcre2_jit_functional(void) +{ + static int jit_working = -1; + pcre2_code *code; + size_t off; + int err; + + if (jit_working != -1) + return jit_working; + + /* + * Try to JIT compile a simple pattern to probe if the JIT is + * working in general. It might fail for systems where creating + * memory mappings for runtime code generation is restricted. + */ + code = pcre2_compile((PCRE2_SPTR)".", 1, 0, &err, &off, NULL); + if (!code) + return 0; + + jit_working = pcre2_jit_compile(code, PCRE2_JIT_COMPLETE) == 0; + pcre2_code_free(code); + + return jit_working; +} + static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt) { int error; @@ -317,8 +342,29 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt pcre2_config(PCRE2_CONFIG_JIT, &p->pcre2_jit_on); if (p->pcre2_jit_on) { jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE); - if (jitret) - die("Couldn't JIT the PCRE2 pattern '%s', got '%d'\n", p->pattern, jitret); + if (jitret == PCRE2_ERROR_NOMEMORY && !pcre2_jit_functional()) { + /* + * Even though pcre2_config(PCRE2_CONFIG_JIT, ...) + * indicated JIT support, the library might still + * fail to generate JIT code for various reasons, + * e.g. when SELinux's 'deny_execmem' or PaX's + * MPROTECT prevent creating W|X memory mappings. + * + * Instead of faling hard, fall back to interpreter + * mode, just as if the pattern was prefixed with + * '(*NO_JIT)'. + */ + p->pcre2_jit_on = 0; + return; + } else if (jitret) { + int need_clip = p->patternlen > 64; + int clip_len = need_clip ? 64 : p->patternlen; + die("Couldn't JIT the PCRE2 pattern '%.*s'%s, got '%d'%s", + clip_len, p->pattern, need_clip ? "..." : "", jitret, + pcre2_jit_functional() + ? "\nPerhaps prefix (*NO_JIT) to your pattern?" + : ""); + } /* * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just