From bc8f8e4e6e7a648e8c6357307d614be8fdcfdf2a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Tue, 7 Apr 2020 22:28:53 +0200 Subject: [PATCH] um: Add a generic "fd" vector transport MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Learn to take a pre-opened file-descriptor for vector IO. Instead of teaching the driver to open a FD in multiple ways, it can rely on management layer to do it on its behalf. For example, this allows inheriting a preconfigured device fd or a simple socketpair() setup, without further arguments, privileges or system access by UML. Signed-off-by: Marc-André Lureau Acked-By: Anton Ivanov Signed-off-by: Richard Weinberger --- arch/um/drivers/vector_user.c | 59 +++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c index aa28e9eecb7b..c4a0f26b2824 100644 --- a/arch/um/drivers/vector_user.c +++ b/arch/um/drivers/vector_user.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include "vector_user.h" @@ -42,6 +43,9 @@ #define TRANS_RAW "raw" #define TRANS_RAW_LEN strlen(TRANS_RAW) +#define TRANS_FD "fd" +#define TRANS_FD_LEN strlen(TRANS_FD) + #define VNET_HDR_FAIL "could not enable vnet headers on fd %d" #define TUN_GET_F_FAIL "tapraw: TUNGETFEATURES failed: %s" #define L2TPV3_BIND_FAIL "l2tpv3_open : could not bind socket err=%i" @@ -347,6 +351,59 @@ unix_cleanup: return NULL; } +static int strtofd(const char *nptr) +{ + long fd; + char *endptr; + + if (nptr == NULL) + return -1; + + errno = 0; + fd = strtol(nptr, &endptr, 10); + if (nptr == endptr || + errno != 0 || + *endptr != '\0' || + fd < 0 || + fd > INT_MAX) { + return -1; + } + return fd; +} + +static struct vector_fds *user_init_fd_fds(struct arglist *ifspec) +{ + int fd = -1; + char *fdarg = NULL; + struct vector_fds *result = NULL; + + fdarg = uml_vector_fetch_arg(ifspec, "fd"); + fd = strtofd(fdarg); + if (fd == -1) { + printk(UM_KERN_ERR "fd open: bad or missing fd argument"); + goto fd_cleanup; + } + + result = uml_kmalloc(sizeof(struct vector_fds), UM_GFP_KERNEL); + if (result == NULL) { + printk(UM_KERN_ERR "fd open: allocation failed"); + goto fd_cleanup; + } + + result->rx_fd = fd; + result->tx_fd = fd; + result->remote_addr_size = 0; + result->remote_addr = NULL; + return result; + +fd_cleanup: + if (fd >= 0) + os_close_file(fd); + if (result != NULL) + kfree(result); + return NULL; +} + static struct vector_fds *user_init_raw_fds(struct arglist *ifspec) { int rxfd = -1, txfd = -1; @@ -578,6 +635,8 @@ struct vector_fds *uml_vector_user_open( return user_init_socket_fds(parsed, ID_L2TPV3); if (strncmp(transport, TRANS_BESS, TRANS_BESS_LEN) == 0) return user_init_unix_fds(parsed, ID_BESS); + if (strncmp(transport, TRANS_FD, TRANS_FD_LEN) == 0) + return user_init_fd_fds(parsed); return NULL; }