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([2a01:e0a:e17:9700:16d2:7456:6634:9626]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-36b36862549sm14577757f8f.106.2024.07.30.05.24.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jul 2024 05:24:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1722351939; x=1722956739; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=MD3SZjQaELpHhaRRsED0fgSL5OizI87LWpY75t1A8Zw=; b=YbQO36ClSzLyvQLjUcQpdnXnnPoq6A/FD0NDRyT+9Wwy+9zoImhAXqkbOIoIB/YqWH O6IpmOi25bRGzrG8kJYfdDeARXzTilZdSs0AG7BWIzr1toQDfGoaq9qFyQWJLd11hQP3 n1wsx+kwvzzDj/52/+j/bY0eRwlbEHZ47IHN0PC08QTYAxTQruubghHCqriWrg97v9vX APWYt683uuItJpWAL1Ex9rXT/c0tl63J42sxqa8irYsOtjsBGPPK5KasMFIF2bHLUqnS BCUIwjjWu9xKLQVeqS8b+F5U5J7/KTSSG8DF8BDR0eQuTz5KyR2zvgtu8xF2/C35QtE9 xjyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722351939; x=1722956739; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=MD3SZjQaELpHhaRRsED0fgSL5OizI87LWpY75t1A8Zw=; b=Ci0IrINsOQHqa9wZppv8vFS7MtdIa92wxWDRnjrY490h6hxOcI7M5MUKxYv0GMZ6XY 3flXkuOoDUC4v4ezy6N7U+R5RP/tE00ZHjVuvbNPtmfP64eJbC4GAkjX0l+X2s66x1ou ilTKlBEcoPQpCK8QNXDctZVUd8cWC+oNU7XTr2AE8G22Ycp8jhC0qCDuUEPTFaRkSuEt ujwpAbcp28wpWRQ62tBsLEfTav0/bdmDEkTyqtoojXf5DlQ9IjKYP0WWJbyxiKCOSFef hvFx/yyRrarvhYOc46I7jm7ZUDHzFlBTYOPd7S4AEbPkPAQpm4WgSqeW1OCW22BSUpms Uznw== X-Gm-Message-State: AOJu0YzPDqKdfoq5nwHek2IrojGZVko6Gth6+4eYJaLWqF1wJLQlIKJt ajT363YkhLqLQTY9Y1NjHS/jViuHHhbEPePKVH49ToniGQKRryZM/Ad+9Wwx5CHeMFbHu2qhThn Mqpk= X-Google-Smtp-Source: AGHT+IHriaT1wvvutTP7Qzjy0U75fJZvDUaiSh3bdM3D+wHZsXRb9cA2f7bzk4c+4JC/Js4jE2GHRg== X-Received: by 2002:a5d:5f49:0:b0:360:8490:74d with SMTP id ffacd0b85a97d-36b34d240a7mr7415237f8f.5.1722342285039; Tue, 30 Jul 2024 05:24:45 -0700 (PDT) From: =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Cl=C3=A9ment=20L=C3=A9ger?= , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Peter Maydell , Jason Wang , Richard Henderson , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Subject: [PATCH v6 4/5] qemu/osdep: Add excluded fd parameter to qemu_close_all_open_fd() Date: Tue, 30 Jul 2024 14:24:27 +0200 Message-ID: <20240730122437.1749603-5-cleger@rivosinc.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240730122437.1749603-1-cleger@rivosinc.com> References: <20240730122437.1749603-1-cleger@rivosinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::234; envelope-from=cleger@rivosinc.com; helo=mail-lj1-x234.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @rivosinc-com.20230601.gappssmtp.com) X-ZM-MESSAGEID: 1722352000493116600 In order for this function to be usable by tap.c code, add a list of file descriptors that should not be closed. Signed-off-by: Cl=C3=A9ment L=C3=A9ger --- include/qemu/osdep.h | 8 +++- system/async-teardown.c | 2 +- util/oslib-posix.c | 99 ++++++++++++++++++++++++++++++++++------- 3 files changed, 91 insertions(+), 18 deletions(-) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 5cd8517380..0bf6f0a356 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -760,9 +760,13 @@ int qemu_fdatasync(int fd); /** * qemu_close_all_open_fd: * - * Close all open file descriptors + * Close all open file descriptors except the ones supplied in the @skip a= rray + * + * @skip: ordered array of distinct file descriptors that should not be cl= osed + * if any, or NULL. + * @nskip: number of entries in the @skip array or 0 if @skip is NULL. */ -void qemu_close_all_open_fd(void); +void qemu_close_all_open_fd(const int *skip, unsigned int nskip); =20 /** * Sync changes made to the memory mapped file back to the backing diff --git a/system/async-teardown.c b/system/async-teardown.c index edf49e1007..9148ee8d04 100644 --- a/system/async-teardown.c +++ b/system/async-teardown.c @@ -52,7 +52,7 @@ static int async_teardown_fn(void *arg) * Close all file descriptors that might have been inherited from the * main qemu process when doing clone, needed to make libvirt happy. */ - qemu_close_all_open_fd(); + qemu_close_all_open_fd(NULL, 0); =20 /* Set up a handler for SIGHUP and unblock SIGHUP. */ sigaction(SIGHUP, &sa, NULL); diff --git a/util/oslib-posix.c b/util/oslib-posix.c index a6749d9f9b..e7bffaea16 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -808,11 +808,14 @@ int qemu_msync(void *addr, size_t length, int fd) return msync(addr, length, MS_SYNC); } =20 -static bool qemu_close_all_open_fd_proc(void) + +static bool qemu_close_all_open_fd_proc(const int *skip, unsigned int nski= p) { struct dirent *de; int fd, dfd; + bool close_fd; DIR *dir; + unsigned int i, skip_start =3D 0, skip_end =3D nskip; =20 dir =3D opendir("/proc/self/fd"); if (!dir) { @@ -823,8 +826,31 @@ static bool qemu_close_all_open_fd_proc(void) dfd =3D dirfd(dir); =20 for (de =3D readdir(dir); de; de =3D readdir(dir)) { + if (de->d_name[0] =3D=3D '.') { + continue; + } fd =3D atoi(de->d_name); - if (fd !=3D dfd) { + close_fd =3D true; + if (fd =3D=3D dfd) { + close_fd =3D false; + } else { + for (i =3D skip_start; i < skip_end; i++) { + if (fd < skip[i]) { + /* We are below the next skipped fd, break */ + break; + } else if (fd =3D=3D skip[i]) { + close_fd =3D false; + /* Restrict the range as we found fds matching start/e= nd */ + if (i =3D=3D skip_start) { + skip_start++; + } else if (i =3D=3D skip_end) { + skip_end--; + } + break; + } + } + } + if (close_fd) { close(fd); } } @@ -833,36 +859,79 @@ static bool qemu_close_all_open_fd_proc(void) return true; } =20 -static bool qemu_close_all_open_fd_close_range(void) +static bool qemu_close_all_open_fd_close_range(const int *skip, + unsigned int nskip) { #ifdef CONFIG_CLOSE_RANGE - int r =3D close_range(0, ~0U, 0); - if (!r) { - /* Success, no need to try other ways. */ - return true; - } -#endif + int max_fd =3D sysconf(_SC_OPEN_MAX) - 1; + int first =3D 0, last =3D max_fd; + unsigned int cur_skip =3D 0; + int ret; + + do { + /* Find the start boundary of the range to close */ + while (cur_skip < nskip && first =3D=3D skip[cur_skip]) { + cur_skip++; + first++; + } + + /* Find the upper boundary of the range to close */ + if (cur_skip < nskip) { + last =3D skip[cur_skip] - 1; + } + /* + * Adjust the maximum fd to close if it's above what the system + * supports + */ + if (last > max_fd) { + last =3D max_fd; + /* + * We can directly skip the remaining skip fds since the curre= nt + * one is already above the maximum supported one. + */ + cur_skip =3D nskip; + } + /* If last was adjusted, we might be > first, bail out */ + if (first > last) { + break; + } + + ret =3D close_range(first, last, 0); + if (ret < 0) { + return false; + } + first =3D last + 1; + last =3D max_fd; + } while (cur_skip < nskip); + + return true; +#else return false; +#endif } =20 -/* - * Close all open file descriptors. - */ -void qemu_close_all_open_fd(void) +void qemu_close_all_open_fd(const int *skip, unsigned int nskip) { int open_max =3D sysconf(_SC_OPEN_MAX); + unsigned int cur_skip =3D 0; int i; =20 - if (qemu_close_all_open_fd_close_range()) { + assert(skip !=3D NULL || nskip =3D=3D 0); + + if (qemu_close_all_open_fd_close_range(skip, nskip)) { return; } =20 - if (qemu_close_all_open_fd_proc()) { + if (qemu_close_all_open_fd_proc(skip, nskip)) { return; } =20 /* Fallback */ for (i =3D 0; i < open_max; i++) { + if (cur_skip < nskip && i =3D=3D skip[cur_skip]) { + cur_skip++; + continue; + } close(i); } } --=20 2.45.2