From: Richard W.M. Jones Date: Mon, 20 Sep 2010 17:23:58 +0000 (+0100) Subject: New APIs: upload-offset and download-offset X-Git-Tag: 1.5.17~3 X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;h=5d4ae18e2b93073080fbbf8c98b11eec15dbc1e6;p=libguestfs.git New APIs: upload-offset and download-offset These APIs allow you to efficiently write and read parts of files or devices. --- diff --git a/daemon/upload.c b/daemon/upload.c index 604e705..623ad3a 100644 --- a/daemon/upload.c +++ b/daemon/upload.c @@ -39,15 +39,15 @@ write_cb (void *fd_ptr, const void *buf, size_t len) } /* Has one FileIn parameter. */ -int -do_upload (const char *filename) +static int +upload (const char *filename, int flags, int64_t offset) { int err, fd, r, is_dev; is_dev = STRPREFIX (filename, "/dev/"); if (!is_dev) CHROOT_IN; - fd = open (filename, O_WRONLY|O_CREAT|O_TRUNC|O_NOCTTY, 0666); + fd = open (filename, flags, 0666); if (!is_dev) CHROOT_OUT; if (fd == -1) { err = errno; @@ -57,6 +57,16 @@ do_upload (const char *filename) return -1; } + if (offset) { + if (lseek (fd, offset, SEEK_SET) == -1) { + err = errno; + r = cancel_receive (); + errno = err; + if (r != -2) reply_with_perror ("lseek: %s", filename); + return -1; + } + } + r = receive_file (write_cb, &fd); if (r == -1) { /* write error */ err = errno; @@ -85,6 +95,25 @@ do_upload (const char *filename) return 0; } +/* Has one FileIn parameter. */ +int +do_upload (const char *filename) +{ + return upload (filename, O_WRONLY|O_CREAT|O_TRUNC|O_NOCTTY, 0); +} + +/* Has one FileIn parameter. */ +int +do_upload_offset (const char *filename, int64_t offset) +{ + if (offset < 0) { + reply_with_perror ("%s: offset in file is negative", filename); + return -1; + } + + return upload (filename, O_WRONLY|O_CREAT|O_NOCTTY, offset); +} + /* Has one FileOut parameter. */ int do_download (const char *filename) @@ -156,3 +185,83 @@ do_download (const char *filename) return 0; } + +/* Has one FileOut parameter. */ +int +do_download_offset (const char *filename, int64_t offset, int64_t size) +{ + int fd, r, is_dev; + char buf[GUESTFS_MAX_CHUNK_SIZE]; + + if (offset < 0) { + reply_with_perror ("%s: offset in file is negative", filename); + return -1; + } + + if (size < 0) { + reply_with_perror ("%s: size is negative", filename); + return -1; + } + uint64_t usize = (uint64_t) size; + + is_dev = STRPREFIX (filename, "/dev/"); + + if (!is_dev) CHROOT_IN; + fd = open (filename, O_RDONLY); + if (!is_dev) CHROOT_OUT; + if (fd == -1) { + reply_with_perror ("%s", filename); + return -1; + } + + if (offset) { + if (lseek (fd, offset, SEEK_SET) == -1) { + reply_with_perror ("lseek: %s", filename); + return -1; + } + } + + uint64_t total = usize, sent = 0; + + /* Now we must send the reply message, before the file contents. After + * this there is no opportunity in the protocol to send any error + * message back. Instead we can only cancel the transfer. + */ + reply (NULL, NULL); + + while (usize > 0) { + r = read (fd, buf, usize > sizeof buf ? sizeof buf : usize); + if (r == -1) { + perror (filename); + send_file_end (1); /* Cancel. */ + close (fd); + return -1; + } + + if (r == 0) + /* The documentation leaves this case undefined. Currently we + * just read fewer bytes than requested. + */ + break; + + if (send_file_write (buf, r) < 0) { + close (fd); + return -1; + } + + sent += r; + usize -= r; + notify_progress (sent, total); + } + + if (close (fd) == -1) { + perror (filename); + send_file_end (1); /* Cancel. */ + return -1; + } + + if (send_file_end (0)) /* Normal end of file. */ + return -1; + + return 0; +} diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml index d01871f..5a95a6d 100644 --- a/generator/generator_actions.ml +++ b/generator/generator_actions.ml @@ -5117,6 +5117,55 @@ removes the partition number, returning the device name The named partition must exist, for example as a string returned from C."); + ("upload_offset", (RErr, [FileIn "filename"; Dev_or_Path "remotefilename"; Int64 "offset"]), 273, [], + (let md5 = Digest.to_hex (Digest.file "COPYING.LIB") in + [InitBasicFS, Always, TestOutput ( + [["upload_offset"; "../COPYING.LIB"; "/COPYING.LIB"; "0"]; + ["checksum"; "md5"; "/COPYING.LIB"]], md5)]), + "upload a file from the local machine with offset", + "\ +Upload local file C to C on the +filesystem. + +C is overwritten starting at the byte C +specified. The intention is to overwrite parts of existing +files or devices, although if a non-existant file is specified +then it is created with a \"hole\" before C. The +size of the data written is implicit in the size of the +source C. + +Note that there is no limit on the amount of data that +can be uploaded with this call, unlike with C, +and this call always writes the full amount unless an +error occurs. + +See also C, C."); + + ("download_offset", (RErr, [Dev_or_Path "remotefilename"; FileOut "filename"; Int64 "offset"; Int64 "size"]), 274, [Progress], + (let md5 = Digest.to_hex (Digest.file "COPYING.LIB") in + let offset = string_of_int 100 in + let size = string_of_int ((Unix.stat "COPYING.LIB").Unix.st_size - 100) in + [InitBasicFS, Always, TestOutput ( + (* Pick a file from cwd which isn't likely to change. *) + [["upload"; "../COPYING.LIB"; "/COPYING.LIB"]; + ["download_offset"; "/COPYING.LIB"; "testdownload.tmp"; offset; size]; + ["upload_offset"; "testdownload.tmp"; "/COPYING.LIB"; offset]; + ["checksum"; "md5"; "/COPYING.LIB"]], md5)]), + "download a file to the local machine with offset and size", + "\ +Download file C and save it as C +on the local machine. + +C is read for C bytes starting at C +(this region must be within the file or device). + +Note that there is no limit on the amount of data that +can be downloaded with this call, unlike with C, +and this call always reads the full amount unless an +error occurs. + +See also C, C."); + ] let all_functions = non_daemon_functions @ daemon_functions diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR index 31e9cf9..d4d5a4b 100644 --- a/src/MAX_PROC_NR +++ b/src/MAX_PROC_NR @@ -1 +1 @@ -272 +274