[Libguestfs] [PATCH v3 05/19] daemon: Reimplement several devsparts APIs in OCaml.

The reimplemented APIs are: * list_devices * list_partitions * part_to_dev * part_to_partnum * is_whole_device --- daemon/Makefile.am | 2 + daemon/daemon.h | 3 - daemon/devsparts.c | 257 ---------------------------------------------- daemon/devsparts.ml | 109 ++++++++++++++++++++ daemon/devsparts.mli | 25 +++++ daemon/guestfsd.c | 75 -------------- daemon/utils.ml | 84 +++++++++++++++ daemon/utils.mli | 15 +++ generator/actions_core.ml | 5 + generator/daemon.ml | 32 +++++- 10 files changed, 268 insertions(+), 339 deletions(-) create mode 100644 daemon/devsparts.ml create mode 100644 daemon/devsparts.mli diff --git a/daemon/Makefile.am b/daemon/Makefile.am index 4f326177c..6d189b368 100644 --- a/daemon/Makefile.am +++ b/daemon/Makefile.am @@ -253,6 +253,7 @@ SOURCES_MLI = \ chroot.mli \ common_utils.mli \ sysroot.mli \ + devsparts.mli \ file.mli \ mountable.mli \ unix_utils.mli \ @@ -268,6 +269,7 @@ SOURCES_ML = \ mountable.ml \ chroot.ml \ blkid.ml \ + devsparts.ml \ file.ml \ callbacks.ml \ daemon.ml diff --git a/daemon/daemon.h b/daemon/daemon.h index 400116514..42b77f0ca 100644 --- a/daemon/daemon.h +++ b/daemon/daemon.h @@ -114,9 +114,6 @@ extern void sort_strings (char **argv, size_t len); extern void free_strings (char **argv); extern void free_stringslen (char **argv, size_t len); -extern void sort_device_names (char **argv, size_t len); -extern int compare_device_names (const char *a, const char *b); - /* Concatenate strings, optionally with a separator string between * each. On error, these return NULL but do NOT call reply_with_* nor * free anything. diff --git a/daemon/devsparts.c b/daemon/devsparts.c index 82467b92f..1aacb8e16 100644 --- a/daemon/devsparts.c +++ b/daemon/devsparts.c @@ -33,263 +33,6 @@ #include "daemon.h" #include "actions.h" -typedef int (*block_dev_func_t) (const char *dev, struct stringsbuf *r); - -/* Execute a given function for each discovered block device */ -static char ** -foreach_block_device (block_dev_func_t func, bool return_md) -{ - CLEANUP_FREE_STRINGSBUF DECLARE_STRINGSBUF (r); - DIR *dir; - int err = 0; - struct dirent *d; - int fd; - - dir = opendir ("/sys/block"); - if (!dir) { - reply_with_perror ("opendir: /sys/block"); - return NULL; - } - - for (;;) { - errno = 0; - d = readdir (dir); - if (!d) break; - - if (STREQLEN (d->d_name, "sd", 2) || - STREQLEN (d->d_name, "hd", 2) || - STREQLEN (d->d_name, "ubd", 3) || - STREQLEN (d->d_name, "vd", 2) || - STREQLEN (d->d_name, "sr", 2) || - (return_md && - STREQLEN (d->d_name, "md", 2) && c_isdigit (d->d_name[2]))) { - CLEANUP_FREE char *dev_path = NULL; - if (asprintf (&dev_path, "/dev/%s", d->d_name) == -1) { - reply_with_perror ("asprintf"); - closedir (dir); - return NULL; - } - - /* Ignore the root device. */ - if (is_root_device (dev_path)) - continue; - - /* RHBZ#514505: Some versions of qemu <= 0.10 add a - * CD-ROM device even though we didn't request it. Try to - * detect this by seeing if the device contains media. - */ - fd = open (dev_path, O_RDONLY|O_CLOEXEC); - if (fd == -1) { - perror (dev_path); - continue; - } - close (fd); - - /* Call the map function for this device */ - if ((*func)(d->d_name, &r) != 0) { - err = 1; - break; - } - } - } - - /* Check readdir didn't fail */ - if (errno != 0) { - reply_with_perror ("readdir: /sys/block"); - closedir (dir); - return NULL; - } - - /* Close the directory handle */ - if (closedir (dir) == -1) { - reply_with_perror ("closedir: /sys/block"); - return NULL; - } - - if (err) - return NULL; - - /* Sort the devices. */ - if (r.size > 0) - sort_device_names (r.argv, r.size); - - /* NULL terminate the list */ - if (end_stringsbuf (&r) == -1) { - return NULL; - } - - return take_stringsbuf (&r); -} - -/* Add a device to the list of devices */ -static int -add_device (const char *device, struct stringsbuf *r) -{ - char *dev_path; - - if (asprintf (&dev_path, "/dev/%s", device) == -1) { - reply_with_perror ("asprintf"); - return -1; - } - - if (add_string_nodup (r, dev_path) == -1) - return -1; - - return 0; -} - -char ** -do_list_devices (void) -{ - /* For backwards compatibility, don't return MD devices in the list - * returned by guestfs_list_devices. This is because most API users - * expect that this list is effectively the same as the list of - * devices added by guestfs_add_drive. - * - * Also, MD devices are special devices - unlike the devices exposed - * by QEMU, and there is a special API for them, - * guestfs_list_md_devices. - */ - return foreach_block_device (add_device, false); -} - -static int -add_partitions (const char *device, struct stringsbuf *r) -{ - CLEANUP_FREE char *devdir = NULL; - - /* Open the device's directory under /sys/block */ - if (asprintf (&devdir, "/sys/block/%s", device) == -1) { - reply_with_perror ("asprintf"); - return -1; - } - - DIR *dir = opendir (devdir); - if (!dir) { - reply_with_perror ("opendir: %s", devdir); - return -1; - } - - /* Look in /sys/block/<device>/ for entries starting with <device> - * e.g. /sys/block/sda/sda1 - */ - errno = 0; - struct dirent *d; - while ((d = readdir (dir)) != NULL) { - if (STREQLEN (d->d_name, device, strlen (device))) { - CLEANUP_FREE char *part = NULL; - if (asprintf (&part, "/dev/%s", d->d_name) == -1) { - perror ("asprintf"); - closedir (dir); - return -1; - } - - if (add_string (r, part) == -1) { - closedir (dir); - return -1; - } - } - } - - /* Check if readdir failed */ - if (0 != errno) { - reply_with_perror ("readdir: %s", devdir); - closedir (dir); - return -1; - } - - /* Close the directory handle */ - if (closedir (dir) == -1) { - reply_with_perror ("closedir: /sys/block/%s", device); - return -1; - } - - return 0; -} - -char ** -do_list_partitions (void) -{ - return foreach_block_device (add_partitions, true); -} - -char * -do_part_to_dev (const char *part) -{ - int err = 1; - size_t n = strlen (part); - - while (n >= 1 && c_isdigit (part[n-1])) { - err = 0; - n--; - } - - if (err) { - reply_with_error ("device name is not a partition"); - return NULL; - } - - /* Deal with <device>p<N> partition names such as /dev/md0p1. */ - if (part[n-1] == 'p') - n--; - - char *r = strndup (part, n); - if (r == NULL) { - reply_with_perror ("strdup"); - return NULL; - } - - return r; -} - -int -do_part_to_partnum (const char *part) -{ - int err = 1; - size_t n = strlen (part); - - while (n >= 1 && c_isdigit (part[n-1])) { - err = 0; - n--; - } - - if (err) { - reply_with_error ("device name is not a partition"); - return -1; - } - - int r; - if (sscanf (&part[n], "%d", &r) != 1) { - reply_with_error ("could not parse number"); - return -1; - } - - return r; -} - -int -do_is_whole_device (const char *device) -{ - /* A 'whole' block device will have a symlink to the device in its - * /sys/block directory */ - CLEANUP_FREE char *devpath = NULL; - if (asprintf (&devpath, "/sys/block/%s/device", - device + strlen ("/dev/")) == -1) { - reply_with_perror ("asprintf"); - return -1; - } - - struct stat statbuf; - if (stat (devpath, &statbuf) == -1) { - if (errno == ENOENT || errno == ENOTDIR) return 0; - - reply_with_perror ("stat"); - return -1; - } - - return 1; -} - int do_device_index (const char *device) { diff --git a/daemon/devsparts.ml b/daemon/devsparts.ml new file mode 100644 index 000000000..95dc006ca --- /dev/null +++ b/daemon/devsparts.ml @@ -0,0 +1,109 @@ +(* guestfs-inspection + * Copyright (C) 2009-2017 Red Hat Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + *) + +open Printf +open Unix + +open Common_utils + +open Utils + +let map_block_devices ~return_md f = + let devs = Sys.readdir "/sys/block" in + let devs = Array.to_list devs in + let devs = List.filter ( + fun dev -> + String.is_prefix dev "sd" || + String.is_prefix dev "hd" || + String.is_prefix dev "ubd" || + String.is_prefix dev "vd" || + String.is_prefix dev "sr" || + (return_md && String.is_prefix dev "md" && + String.length dev >= 3 && Char.isdigit dev.[2]) + ) devs in + + (* Ignore the root device. *) + let devs = + List.filter (fun dev -> not (is_root_device ("/dev/" ^ dev))) devs in + + (* RHBZ#514505: Some versions of qemu <= 0.10 add a + * CD-ROM device even though we didn't request it. Try to + * detect this by seeing if the device contains media. + *) + let devs = + List.filter ( + fun dev -> + try close (openfile ("/dev/" ^ dev) [O_RDONLY; O_CLOEXEC] 0); true + with _ -> false + ) devs in + + (* Call the map function for the devices left in the list. *) + List.map f devs + +let list_devices () = + (* For backwards compatibility, don't return MD devices in the list + * returned by guestfs_list_devices. This is because most API users + * expect that this list is effectively the same as the list of + * devices added by guestfs_add_drive. + * + * Also, MD devices are special devices - unlike the devices exposed + * by QEMU, and there is a special API for them, + * guestfs_list_md_devices. + *) + let devices = + map_block_devices ~return_md:false (fun dev -> "/dev/" ^ dev) in + sort_device_names devices + +let rec list_partitions () = + let partitions = map_block_devices ~return_md:true add_partitions in + let partitions = List.flatten partitions in + sort_device_names partitions + +and add_partitions dev = + (* Open the device's directory under /sys/block *) + let parts = Sys.readdir ("/sys/block/" ^ dev) in + let parts = Array.to_list parts in + + (* Look in /sys/block/<device>/ for entries starting with + * <device>, eg. /sys/block/sda/sda1. + *) + let parts = List.filter (fun part -> String.is_prefix part dev) parts in + List.map (fun part -> "/dev/" ^ part) parts + +let part_to_dev part = + let dev, part = split_device_partition part in + if part = 0 then + failwithf "device name is not a partition"; + "/dev/" ^ dev + +let part_to_partnum part = + let _, part = split_device_partition part in + if part = 0 then + failwithf "device name is not a partition"; + part + +let is_whole_device device = + (* A 'whole' block device will have a symlink to the device in its + * /sys/block directory + *) + assert (String.is_prefix device "/dev/"); + let device = String.sub device 5 (String.length device - 5) in + let devpath = sprintf "/sys/block/%s/device" device in + + try ignore (stat devpath); true + with Unix_error ((ENOENT|ENOTDIR), _, _) -> false diff --git a/daemon/devsparts.mli b/daemon/devsparts.mli new file mode 100644 index 000000000..4dfaa86e6 --- /dev/null +++ b/daemon/devsparts.mli @@ -0,0 +1,25 @@ +(* guestfs-inspection + * Copyright (C) 2009-2017 Red Hat Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + *) + +val list_devices : unit -> string list +val list_partitions : unit -> string list + +val part_to_dev : string -> string +val part_to_partnum : string -> int + +val is_whole_device : string -> bool diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c index 9b6ae02b1..a54df03c5 100644 --- a/daemon/guestfsd.c +++ b/daemon/guestfsd.c @@ -652,81 +652,6 @@ free_stringslen (char **argv, size_t len) free (argv); } -/** - * Compare device names (including partition numbers if present). - * - * L<https://rwmj.wordpress.com/2011/01/09/how-are-linux-drives-named-bey... - */ -int -compare_device_names (const char *a, const char *b) -{ - size_t alen, blen; - int r; - int a_partnum, b_partnum; - - /* Skip /dev/ prefix if present. */ - if (STRPREFIX (a, "/dev/")) - a += 5; - if (STRPREFIX (b, "/dev/")) - b += 5; - - /* Skip sd/hd/ubd/vd. */ - alen = strcspn (a, "d"); - blen = strcspn (b, "d"); - assert (alen > 0 && alen <= 2); - assert (blen > 0 && blen <= 2); - a += alen + 1; - b += blen + 1; - - /* Get device name part, that is, just 'a', 'ab' etc. */ - alen = strcspn (a, "0123456789"); - blen = strcspn (b, "0123456789"); - - /* If device name part is longer, it is always greater, eg. - * "/dev/sdz" < "/dev/sdaa". - */ - if (alen != blen) - return alen - blen; - - /* Device name parts are the same length, so do a regular compare. */ - r = strncmp (a, b, alen); - if (r != 0) - return r; - - /* Compare partitions numbers. */ - a += alen; - b += alen; - - /* If no partition numbers, bail -- the devices are the same. This - * can happen in one peculiar case: where you have a mix of devices - * with different interfaces (eg. /dev/sda and /dev/vda). - * (RHBZ#858128). - */ - if (!*a && !*b) - return 0; - - r = sscanf (a, "%d", &a_partnum); - assert (r == 1); - r = sscanf (b, "%d", &b_partnum); - assert (r == 1); - - return a_partnum - b_partnum; -} - -static int -compare_device_names_vp (const void *vp1, const void *vp2) -{ - char * const *p1 = (char * const *) vp1; - char * const *p2 = (char * const *) vp2; - return compare_device_names (*p1, *p2); -} - -void -sort_device_names (char **argv, size_t len) -{ - qsort (argv, len, sizeof (char *), compare_device_names_vp); -} - char * concat_strings (char *const *argv) { diff --git a/daemon/utils.ml b/daemon/utils.ml index 3a5363063..d80a6947e 100644 --- a/daemon/utils.ml +++ b/daemon/utils.ml @@ -129,6 +129,90 @@ let is_root_device device = device func arg (error_message err); false +(* XXX This function is copied from C, but is misconceived. It + * cannot by design work for devices like /dev/md0. It would be + * better if it checked for the existence of devices and partitions + * in /sys/block so we know what the kernel thinks is a device or + * partition. The same applies to APIs such as part_to_partnum + * and part_to_dev which rely on this function. + *) +let split_device_partition dev = + (* Skip /dev/ prefix if present. *) + let dev = + if String.is_prefix dev "/dev/" then + String.sub dev 5 (String.length dev - 5) + else dev in + + (* Find the partition number (if present). *) + let dev, part = + let n = String.length dev in + let i = ref n in + while !i >= 1 && Char.isdigit dev.[!i-1] do + decr i + done; + let i = !i in + if i = n then + dev, 0 (* no partition number, whole device *) + else + String.sub dev 0 i, int_of_string (String.sub dev i (n-i)) in + + (* Deal with device names like /dev/md0p1. *) + (* XXX This function is buggy (as was the old C function) when + * presented with a whole device like /dev/md0. + *) + let dev = + let n = String.length dev in + if n < 2 || dev.[n-1] <> 'p' || not (Char.isdigit dev.[n-2]) then + dev + else ( + let i = ref (n-1) in + while !i >= 0 && Char.isdigit dev.[!i] do + decr i; + done; + let i = !i in + String.sub dev 0 i + ) in + + dev, part + +let rec sort_device_names devs = + List.sort compare_device_names devs + +and compare_device_names a b = + (* This takes the device name like "/dev/sda1" and returns ("sda", 1). *) + let dev_a, part_a = split_device_partition a + and dev_b, part_b = split_device_partition b in + + (* Skip "sd|hd|ubd..." so that /dev/sda and /dev/vda sort together. + * (This is what the old C function did, but it's not clear if it + * is still relevant. XXX) + *) + let skip_prefix dev = + let n = String.length dev in + if n >= 2 && dev.[1] = 'd' then + String.sub dev 2 (String.length dev - 2) + else if n >= 3 && dev.[2] = 'd' then + String.sub dev 3 (String.length dev - 3) + else + dev in + let dev_a = skip_prefix dev_a + and dev_b = skip_prefix dev_b in + + (* If device name part is longer, it is always greater, eg. + * "/dev/sdz" < "/dev/sdaa". + *) + let r = compare (String.length dev_a) (String.length dev_b) in + if r <> 0 then r + else ( + (* Device name parts are the same length, so do a regular compare. *) + let r = compare dev_a dev_b in + if r <> 0 then r + else ( + (* Device names are identical, so compare partition numbers. *) + compare part_a part_b + ) + ) + let proc_unmangle_path path = let n = String.length path in let b = Buffer.create n in diff --git a/daemon/utils.mli b/daemon/utils.mli index 57f703c6c..a1f956be3 100644 --- a/daemon/utils.mli +++ b/daemon/utils.mli @@ -41,6 +41,21 @@ val is_root_device_stat : Unix.stats -> bool (** As for {!is_root_device} but operates on a statbuf instead of a device name. *) +val split_device_partition : string -> string * int +(** Split a device name like [/dev/sda1] into a device name and + partition number, eg. ["sda", 1]. + + The [/dev/] prefix is skipped and removed, if present. + + If the partition number is not present (a whole device), 0 is returned. + + This function splits [/dev/md0p1] to ["md0", 1]. *) + +val sort_device_names : string list -> string list +(** Sort device names correctly so that /dev/sdaa appears after /dev/sdz. + This also deals with partition numbers, and works whether or not + [/dev/] is present. *) + val proc_unmangle_path : string -> string (** Reverse kernel path escaping done in fs/seq_file.c:mangle_path. This is inconsistently used for /proc fields. *) diff --git a/generator/actions_core.ml b/generator/actions_core.ml index a6eb2c273..94391288f 100644 --- a/generator/actions_core.ml +++ b/generator/actions_core.ml @@ -1817,6 +1817,7 @@ is I<not> intended that you try to parse the output string." }; { defaults with name = "list_devices"; added = (0, 0, 4); style = RStringList (RDevice, "devices"), [], []; + impl = OCaml "Devsparts.list_devices"; tests = [ InitEmpty, Always, TestResult ( [["list_devices"]], @@ -1833,6 +1834,7 @@ See also C<guestfs_list_filesystems>." }; { defaults with name = "list_partitions"; added = (0, 0, 4); style = RStringList (RDevice, "partitions"), [], []; + impl = OCaml "Devsparts.list_partitions"; tests = [ InitBasicFS, Always, TestResult ( [["list_partitions"]], @@ -6086,6 +6088,7 @@ See also C<guestfs_stat>." }; { defaults with name = "part_to_dev"; added = (1, 5, 15); style = RString (RDevice, "device"), [String (Device, "partition")], []; + impl = OCaml "Devsparts.part_to_dev"; tests = [ InitPartition, Always, TestResultDevice ( [["part_to_dev"; "/dev/sda1"]], "/dev/sda"), []; @@ -6533,6 +6536,7 @@ as in C<guestfs_compress_out>." }; { defaults with name = "part_to_partnum"; added = (1, 13, 25); style = RInt "partnum", [String (Device, "partition")], []; + impl = OCaml "Devsparts.part_to_partnum"; tests = [ InitPartition, Always, TestResult ( [["part_to_partnum"; "/dev/sda1"]], "ret == 1"), []; @@ -8480,6 +8484,7 @@ you are better to use C<guestfs_mv> instead." }; { defaults with name = "is_whole_device"; added = (1, 21, 9); style = RBool "flag", [String (Device, "device")], []; + impl = OCaml "Devsparts.is_whole_device"; tests = [ InitEmpty, Always, TestResultTrue ( [["is_whole_device"; "/dev/sda"]]), []; diff --git a/generator/daemon.ml b/generator/daemon.ml index ef388850f..c37ffdab0 100644 --- a/generator/daemon.ml +++ b/generator/daemon.ml @@ -549,6 +549,26 @@ copy_mountable (const mountable_t *mountable) CAMLreturn (r); } +/* Implement RStringList. */ +static char ** +return_string_list (value retv) +{ + CLEANUP_FREE_STRINGSBUF DECLARE_STRINGSBUF (ret); + value v; + + while (retv != Val_int (0)) { + v = Field (retv, 0); + if (add_string (&ret, String_val (v)) == -1) + return NULL; + retv = Field (retv, 1); + } + + if (end_stringsbuf (&ret) == -1) + return NULL; + + return take_stringsbuf (&ret); /* caller frees */ +} + "; List.iter ( @@ -665,12 +685,14 @@ copy_mountable (const mountable_t *mountable) (match ret with | RErr -> assert false - | RInt _ -> assert false + | RInt _ -> + pr " CAMLreturnT (int, Int_val (retv));\n" | RInt64 _ -> assert false - | RBool _ -> assert false + | RBool _ -> + pr " CAMLreturnT (int, Bool_val (retv));\n" | RConstString _ -> assert false | RConstOptString _ -> assert false - | RString (RPlainString, _) -> + | RString ((RPlainString|RDevice), _) -> pr " char *ret = strdup (String_val (retv));\n"; pr " if (ret == NULL) {\n"; pr " reply_with_perror (\"strdup\");\n"; @@ -678,7 +700,9 @@ copy_mountable (const mountable_t *mountable) pr " }\n"; pr " CAMLreturnT (char *, ret); /* caller frees */\n" | RString _ -> assert false - | RStringList _ -> assert false + | RStringList _ -> + pr " char **ret = return_string_list (retv);\n"; + pr " CAMLreturnT (char **, ret); /* caller frees */\n" | RStruct _ -> assert false | RStructList _ -> assert false | RHashtable _ -> assert false -- 2.13.0