--autosysroot option uses suggestions to user on how to mount filesystems and change root suggested by --suggest option in virt-rescue. Commands are passed on kernel command line in format guestfs_command=command;. Command ends with a semicolon and there can be multiple commands specified. These are executed just before bash starts. On successfull run user is presented directly with bash in chroot environment. Resolves RFE: RHBZ#1183493 --- appliance/init | 5 ++ rescue/rescue.c | 169 +++++++++++++++++++++++++++++++++++++++++++++----------- 2 files changed, 143 insertions(+), 31 deletions(-) diff --git a/appliance/init b/appliance/init index 3fdf4d0..0a76398 100755 --- a/appliance/init +++ b/appliance/init @@ -192,6 +192,11 @@ else echo "You have to mount the guest's partitions under /sysroot" echo "before you can examine them." echo + echo 'Executing commands from kernel cmdline' + + grep -Eo 'guestfs_command=([^;]+);[[:space:]]*' /proc/cmdline | sed -n 's/guestfs_command=\(.*;\)/\1/p' + eval $(grep -Eo 'guestfs_command=([^;]+);[[:space:]]*' /proc/cmdline | sed -n 's/guestfs_command=\(.*;\)/\1/p') + bash -i echo echo "virt-rescue: Syncing the disk now before exiting ..." diff --git a/rescue/rescue.c b/rescue/rescue.c index 135c9e6..77b6544 100644 --- a/rescue/rescue.c +++ b/rescue/rescue.c @@ -37,7 +37,7 @@ #include "options.h" static void add_scratch_disks (int n, struct drv **drvs); -static void do_suggestion (struct drv *drvs); +static char ** do_suggestion (struct drv *drvs); /* Currently open libguestfs handle. */ guestfs_h *g; @@ -50,6 +50,9 @@ int echo_keys = 0; const char *libvirt_uri = NULL; int inspector = 0; +static void use_suggestions (char **cmds); +static void parse_opts(int argc, char * argv[]); + static void __attribute__((noreturn)) usage (int status) { @@ -65,6 +68,8 @@ usage (int status) "Options:\n" " -a|--add image Add image\n" " --append kernelopts Append kernel options\n" + " --autosysroot Automatically use suggested mount commands\n" + " and chroot to guest. Needs --suggest to work\n" " -c|--connect uri Specify libvirt URI for -d option\n" " -d|--domain guest Add disks from libvirt guest\n" " --format[=raw|..] Force disk format for -a option\n" @@ -87,21 +92,30 @@ usage (int status) exit (status); } -int -main (int argc, char *argv[]) -{ - setlocale (LC_ALL, ""); - bindtextdomain (PACKAGE, LOCALEBASEDIR); - textdomain (PACKAGE); - - parse_config (); +struct drv *drvs = NULL; +struct drv *drv; +char **cmds = NULL; +const char *format = NULL; +bool format_consumed = true; +int c; +int option_index; +int network = 0; +char *append = NULL; +int memsize = 0; +int smp = 0; +int suggest = 0; +int autosysroot = 0; +static void +parse_opts(int argc, char * argv[]) +{ enum { HELP_OPTION = CHAR_MAX + 1 }; static const char *options = "a:c:d:m:rvVx"; static const struct option long_options[] = { { "add", 1, 0, 'a' }, { "append", 1, 0, 0 }, + { "autosysroot", 0, 0, 0 }, { "connect", 1, 0, 'c' }, { "domain", 1, 0, 'd' }, { "format", 2, 0, 0 }, @@ -120,22 +134,10 @@ main (int argc, char *argv[]) { "version", 0, 0, 'V' }, { 0, 0, 0, 0 } }; - struct drv *drvs = NULL; - struct drv *drv; - const char *format = NULL; - bool format_consumed = true; - int c; - int option_index; - int network = 0; - const char *append = NULL; - int memsize = 0; - int smp = 0; - int suggest = 0; - g = guestfs_create (); - if (g == NULL) - error (EXIT_FAILURE, errno, "guestfs_create"); + option_index = 0; + optind = 0; for (;;) { c = getopt_long (argc, argv, options, long_options, &option_index); if (c == -1) break; @@ -150,7 +152,9 @@ main (int argc, char *argv[]) if (guestfs_set_selinux (g, 1) == -1) exit (EXIT_FAILURE); } else if (STREQ (long_options[option_index].name, "append")) { - append = optarg; + append = strdup (optarg); + } else if (STREQ (long_options[option_index].name, "autosysroot")) { + autosysroot = 1; } else if (STREQ (long_options[option_index].name, "network")) { network = 1; } else if (STREQ (long_options[option_index].name, "format")) { @@ -259,10 +263,71 @@ main (int argc, char *argv[]) } } +} + +int +main (int argc, char *argv[]) +{ + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEBASEDIR); + textdomain (PACKAGE); + + parse_config (); + g = guestfs_create (); + if (g == NULL) + error (EXIT_FAILURE, errno, "guestfs_create"); + + parse_opts (argc, argv); + /* --suggest flag */ if (suggest) { - do_suggestion (drvs); - exit (EXIT_SUCCESS); + cmds = do_suggestion (drvs); + if (!autosysroot) { + exit (EXIT_SUCCESS); + } else { + /* Shut down libguestfs so we can start a new one */ + guestfs_shutdown (g); + guestfs_close (g); + + /* remove --suggest flag */ + size_t newcount = argc; + for (int i = 0; i < argc; i++) { + if (strcmp (argv[i], "--suggest") == 0) { + newcount--; + } + } + + char ** args = malloc (sizeof (char*) * (newcount)); + for (int i = 0, j = 0; i < argc; i++) { + if (strcmp (argv[i], "--suggest") != 0) { + args[j] = strdup (argv[i]); + j++; + } + } + + /* clear options */ + drvs = NULL; + format_consumed = true; + c = 0; + option_index = 0; + network = 0; + if (append) free(append); + memsize = 0; + smp = 0; + suggest = 0; + autosysroot = 0; + + /* Create new guestfs handle, this time for rescue instead of OS detection */ + g = guestfs_create (); + /* Parse options with --suggest flag removed */ + parse_opts (newcount, args); + argc = newcount; + } + } else { + if (autosysroot) { + fprintf (stderr, _("%s: warning: --autosysroot used without --suggest.\n"), + guestfs_int_program_name); + } } /* These are really constants, but they have to be variables for the @@ -313,6 +378,11 @@ main (int argc, char *argv[]) } } + /* Now it's time to set suggestions. */ + if (autosysroot) { + use_suggestions (cmds); + } + /* Set other features. */ if (memsize > 0) if (guestfs_set_memsize (g, memsize) == -1) @@ -367,14 +437,34 @@ compare_keys_len (const void *p1, const void *p2) return strlen (key1) - strlen (key2); } +/* Use autodetected suggested filesystems */ +static void +use_suggestions (char **cmds) +{ + size_t i; + if (cmds == NULL) return; + read_only = 0; + + /* Craft kernel command line from suggested commands */ + for (i = 0; cmds[i] != NULL; i++) { + char *old_append = append; + append = xasprintf ("%s guestfs_command=%s;", append == NULL? "" : append, cmds[i]); + if (old_append != NULL) + free (old_append); + } +} + /* virt-rescue --suggest flag does a kind of inspection on the * drives and suggests mount commands that you should use. */ -static void +static char ** do_suggestion (struct drv *drvs) { CLEANUP_FREE_STRING_LIST char **roots = NULL; size_t i; + char **cmds = malloc (sizeof (char*)); + cmds[0] = NULL; + /* For inspection, force add_drives to add the drives read-only. */ read_only = 1; @@ -401,7 +491,7 @@ do_suggestion (struct drv *drvs) if (roots[0] == NULL) { suggest_filesystems (); - return; + return NULL; } printf (_("This disk contains one or more operating systems. You can use these mount\n" @@ -436,10 +526,16 @@ do_suggestion (struct drv *drvs) qsort (mps, guestfs_int_count_strings (mps) / 2, 2 * sizeof (char *), compare_keys_len); - for (j = 0; mps[j] != NULL; j += 2) - printf ("mount %s /sysroot%s\n", mps[j+1], mps[j]); + /* First we save commands to mount system root. */ + for (j = 0; mps[j] != NULL; j += 2) { + int cnt = guestfs_int_count_strings (cmds); + cmds = realloc (cmds, sizeof (char *) * (cnt + 2)); + + cmds[cnt] = xasprintf ("mount %s /sysroot%s", mps[j+1], mps[j]); + cmds[cnt+1] = NULL; + } - /* If it's Linux, print the bind-mounts and a chroot command. */ + /* If it's Linux, print the bind-mounts and a chroot command and save them. */ if (type && STREQ (type, "linux")) { printf ("mount --rbind /dev /sysroot/dev\n"); printf ("mount --rbind /proc /sysroot/proc\n"); @@ -447,10 +543,21 @@ do_suggestion (struct drv *drvs) printf ("\n"); printf ("cd /sysroot\n"); printf ("chroot /sysroot\n"); + + int cnt = guestfs_int_count_strings (cmds); + cmds = realloc (cmds, sizeof (char *) * (cnt + 6)); + + cmds[cnt+0] = xasprintf ("mount --rbind /dev /sysroot/dev"); + cmds[cnt+1] = xasprintf ("mount --rbind /proc /sysroot/proc"); + cmds[cnt+2] = xasprintf ("mount --rbind /sys /sysroot/sys"); + cmds[cnt+3] = xasprintf ("cd /sysroot"); + cmds[cnt+4] = xasprintf ("chroot /sysroot"); + cmds[cnt+5] = NULL; } printf ("\n"); } + return cmds; } /* Inspection failed, so it doesn't contain any OS that we recognise. -- 2.5.5

On 06/09/2016 03:18 PM, Pino Toscano wrote: We can call it -i, I don't mind, I've implemented this as was in RFE. What about escaping, have you found a counter-example? I don't see much problem with this limit either, have we run into an issue? It seems that max allowed size is about 4KiB (between 256 and 4KiB) and we're running a VM so I don't ever expect this to be a problem. Hm, this introduces another type of splitter (:) and we would have to think about escaping it too (but this time it's not done by bash itself) - what if : is included in filename? I don't get this, --autosysroot is meant to be "optimization" so one doesn't have to copy-paste any commands and this feature is what was requested in RFE, and user doesn't have to use this automagic. These are filled in option parser and used elsewhere, it didn't seem to make sense to make it more complicated for this simple program. These were used as if they were global variables before, difference was that they were used in one large function (main) and their initialization was not factored out to function so their 'global' sense/semantics didn't really change. yup Because we need to reinitialize stuff - library and so - and options should be constructed a bit different when we want to just inspect and when we need r/w access. Thank you for reviewing! I'll be back with corrections. - m