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([2602:47:d483:7301:a064:e3f9:a812:973b]) by smtp.gmail.com with ESMTPSA id g14-20020a170902868e00b001bc2831e1a9sm13446584plo.90.2023.08.16.11.03.39 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Aug 2023 11:03:39 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v4 01/18] linux-user: Introduce imgsrc_read, imgsrc_read_alloc Date: Wed, 16 Aug 2023 11:03:21 -0700 Message-Id: <20230816180338.572576-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230816180338.572576-1-richard.henderson@linaro.org> References: <20230816180338.572576-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::62c; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62c.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Introduced and initialized, but not yet really used. These will tidy the current tests vs BPRM_BUF_SIZE. Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé --- linux-user/loader.h | 61 +++++++++++++++++++++++----- linux-user/linuxload.c | 90 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 142 insertions(+), 9 deletions(-) diff --git a/linux-user/loader.h b/linux-user/loader.h index 59cbeacf24..311d20f5d1 100644 --- a/linux-user/loader.h +++ b/linux-user/loader.h @@ -18,6 +18,48 @@ #ifndef LINUX_USER_LOADER_H #define LINUX_USER_LOADER_H +typedef struct { + const void *cache; + unsigned int cache_size; + int fd; +} ImageSource; + +/** + * imgsrc_read: Read from ImageSource + * @dst: destination for read + * @offset: offset within file for read + * @len: size of the read + * @img: ImageSource to read from + * @errp: Error details. + * + * Read into @dst, using the cache when possible. + */ +bool imgsrc_read(void *dst, off_t offset, size_t len, + const ImageSource *img, Error **errp); + +/** + * imgsrc_read_alloc: Read from ImageSource + * @offset: offset within file for read + * @size: size of the read + * @img: ImageSource to read from + * @errp: Error details. + * + * Read into newly allocated memory, using the cache when possible. + */ +void *imgsrc_read_alloc(off_t offset, size_t len, + const ImageSource *img, Error **errp); + +/** + * imgsrc_mmap: Map from ImageSource + * + * If @src has a file descriptor, pass on to target_mmap. Otherwise, + * this is "mapping" from a host buffer, which resolves to memcpy. + * Therefore, flags must be MAP_PRIVATE | MAP_FIXED; the argument is + * retained for clarity. + */ +abi_long imgsrc_mmap(abi_ulong start, abi_ulong len, int prot, + int flags, const ImageSource *src, abi_ulong offset); + /* * Read a good amount of data initially, to hopefully get all the * program headers loaded. @@ -29,15 +71,16 @@ * used when loading binaries. */ struct linux_binprm { - char buf[BPRM_BUF_SIZE] __attribute__((aligned)); - abi_ulong p; - int fd; - int e_uid, e_gid; - int argc, envc; - char **argv; - char **envp; - char *filename; /* Name of binary */ - int (*core_dump)(int, const CPUArchState *); /* coredump routine */ + char buf[BPRM_BUF_SIZE] __attribute__((aligned)); + ImageSource src; + abi_ulong p; + int fd; + int e_uid, e_gid; + int argc, envc; + char **argv; + char **envp; + char *filename; /* Name of binary */ + int (*core_dump)(int, const CPUArchState *); /* coredump routine */ }; void do_init_thread(struct target_pt_regs *regs, struct image_info *infop); diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c index 745cce70ab..3536dd8104 100644 --- a/linux-user/linuxload.c +++ b/linux-user/linuxload.c @@ -3,7 +3,9 @@ #include "qemu/osdep.h" #include "qemu.h" #include "user-internals.h" +#include "user-mmap.h" #include "loader.h" +#include "qapi/error.h" #define NGROUPS 32 @@ -76,6 +78,10 @@ static int prepare_binprm(struct linux_binprm *bprm) /* Make sure the rest of the loader won't read garbage. */ memset(bprm->buf + retval, 0, BPRM_BUF_SIZE - retval); } + + bprm->src.cache = bprm->buf; + bprm->src.cache_size = retval; + return retval; } @@ -139,6 +145,7 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, int retval; bprm->fd = fdexec; + bprm->src.fd = fdexec; bprm->filename = (char *)filename; bprm->argc = count(argv); bprm->argv = argv; @@ -173,3 +180,86 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, return retval; } + +bool imgsrc_read(void *dst, off_t offset, size_t len, + const ImageSource *img, Error **errp) +{ + ssize_t ret; + + if (offset + len <= img->cache_size) { + memcpy(dst, img->cache + offset, len); + return true; + } + + if (img->fd < 0) { + error_setg(errp, "read past end of buffer"); + return false; + } + + ret = pread(img->fd, dst, len, offset); + if (ret == len) { + return true; + } + if (ret < 0) { + error_setg_errno(errp, errno, "Error reading file header"); + } else { + error_setg(errp, "Incomplete read of file header"); + } + return false; +} + +void *imgsrc_read_alloc(off_t offset, size_t len, + const ImageSource *img, Error **errp) +{ + void *alloc = g_malloc(len); + bool ok = imgsrc_read(alloc, offset, len, img, errp); + + if (!ok) { + g_free(alloc); + alloc = NULL; + } + return alloc; +} + +abi_long imgsrc_mmap(abi_ulong start, abi_ulong len, int prot, + int flags, const ImageSource *src, abi_ulong offset) +{ + const int prot_write = PROT_READ | PROT_WRITE; + abi_long ret; + void *haddr; + + assert(flags == (MAP_PRIVATE | MAP_FIXED)); + + if (src->fd >= 0) { + return target_mmap(start, len, prot, flags, src->fd, offset); + } + + /* + * This case is for the vdso; we don't expect bad images. + * The mmap may extend beyond the end of the image, especially + * to the end of the page. Zero fill. + */ + assert(offset < src->cache_size); + + ret = target_mmap(start, len, prot_write, flags | MAP_ANON, -1, 0); + if (ret == -1) { + return ret; + } + + haddr = lock_user(VERIFY_WRITE, start, len, 0); + assert(haddr != NULL); + if (offset + len <= src->cache_size) { + memcpy(haddr, src->cache + offset, len); + } else { + size_t rest = src->cache_size - offset; + memcpy(haddr, src->cache + offset, rest); + memset(haddr + rest, 0, len - rest); + } + unlock_user(haddr, start, len); + + if (prot != prot_write) { + target_mprotect(start, len, prot); + } + + return ret; +}