This patch changes appliance search using paths with multiple directories. Now all appliance checks will be done separately for each directory. For example if the path LIBGUESTFS_PATH=/a:/b:/c, then all applainces are searched first in /a, then in /b and then in /c. It allows to flexibly configure the libguestfs to interact with different appliances. Signed-off-by: Pavel Butsykin <pbutsykin(a)virtuozzo.com&gt; --- lib/appliance.c | 227 +++++++++++++++++++++++++------------------------------- 1 file changed, 102 insertions(+), 125 deletions(-) diff --git a/lib/appliance.c b/lib/appliance.c index 5738e4e7f..66f91cb0a 100644 --- a/lib/appliance.c +++ b/lib/appliance.c @@ -37,18 +37,23 @@ #include "guestfs.h" #include "guestfs-internal.h" +struct appliance_files { + char *kernel; + char *initrd; + char *image; +}; + /* Old-style appliance is going to be obsoleted. */ static const char kernel_name[] = "vmlinuz." host_cpu; static const char initrd_name[] = "initramfs." host_cpu ".img"; -static int build_appliance (guestfs_h *g, char **kernel, char **initrd, char **appliance); -static int find_path (guestfs_h *g, int (*pred) (guestfs_h *g, const char *pelem, void *data), void *data, char **pelem); +static int search_appliance (guestfs_h *g, struct appliance_files *appliance); static int dir_contains_file (guestfs_h *g, const char *dir, const char *file); static int dir_contains_files (guestfs_h *g, const char *dir, ...); static int contains_old_style_appliance (guestfs_h *g, const char *path, void *data); static int contains_fixed_appliance (guestfs_h *g, const char *path, void *data); static int contains_supermin_appliance (guestfs_h *g, const char *path, void *data); -static int build_supermin_appliance (guestfs_h *g, const char *supermin_path, char **kernel, char **initrd, char **appliance); +static int build_supermin_appliance (guestfs_h *g, const char *supermin_path, struct appliance_files *appliance); static int run_supermin_build (guestfs_h *g, const char *lockfile, const char *appliancedir, const char *supermin_path); /** @@ -59,12 +64,12 @@ static int run_supermin_build (guestfs_h *g, const char *lockfile, const char *a * appliances, or using either a fixed or old-style appliance. * * The return value is C<0> = good, C<-1> = error. Returned in - * C<*kernel> will be the name of the kernel to use, C<*initrd> the - * name of the initrd, C<*appliance> the name of the ext2 root - * filesystem. C<*appliance> can be C<NULL>, meaning that we are - * using an old-style (non-ext2) appliance. All three strings must be - * freed by the caller. However the referenced files themselves must - * I<not> be deleted. + * C<appliance.kernel> will be the name of the kernel to use, + * C<appliance.initrd> the name of the initrd, C<appliance.image> the name of + * the ext2 root filesystem. C<appliance.image> can be C<NULL>, meaning that + * we are using an old-style (non-ext2) appliance. All three strings must be + * freed by the caller. However the referenced files themselves must I<not> be + * deleted. * * The process is as follows: * @@ -72,9 +77,8 @@ static int run_supermin_build (guestfs_h *g, const char *lockfile, const char *a * * =item 1. * - * Look for the first element of C<g-E<gt>path> which contains a - * supermin appliance skeleton. If no element has this, skip straight - * to step 3. + * Look in C<path> which contains a supermin appliance skeleton. If no element + * has this, skip straight to step 3. * * =item 2. * @@ -83,13 +87,12 @@ static int run_supermin_build (guestfs_h *g, const char *lockfile, const char *a * * =item 3. * - * Check each element of C<g-E<gt>path>, looking for a fixed - * appliance. If one is found, return it. + * Check C<path>, looking for a fixed appliance. If one is found, return it. * * =item 4. * - * Check each element of C<g-E<gt>path>, looking for an old-style - * appliance. If one is found, return it. + * Check C<path>, looking for an old-style appliance. If one is found, + * return it. * * =back * @@ -112,74 +115,108 @@ guestfs_int_build_appliance (guestfs_h *g, char **initrd_rtn, char **appliance_rtn) { - char *kernel = NULL, *initrd = NULL, *appliance = NULL; - if (build_appliance (g, &kernel, &initrd, &appliance) == -1) + struct appliance_files appliance; + + if (search_appliance (g, &appliance) != 1) return -1; /* Don't assign these until we know we're going to succeed, to avoid * the caller double-freeing (RHBZ#983218). */ - *kernel_rtn = kernel; - *initrd_rtn = initrd; - *appliance_rtn = appliance; + *kernel_rtn = appliance.kernel; + *initrd_rtn = appliance.initrd; + *appliance_rtn = appliance.image; return 0; } +/** + * Check C<path>, looking for one of appliances: supermin appliance, + * fixed appliance or old-style appliance. If one of the fixed appliances is + * found, return it. If the supermin appliance skeleton is found, build and + * return appliance. + * + * Return values: + * + * 1 = appliance is found, returns C<appliance>, + * 0 = appliance not found, + * -1 = error which aborts the launch process. + */ static int -build_appliance (guestfs_h *g, - char **kernel, - char **initrd, - char **appliance) +locate_or_build_appliance (guestfs_h *g, + struct appliance_files *appliance, + const char *path) { int r; - CLEANUP_FREE char *supermin_path = NULL; - CLEANUP_FREE char *path = NULL; /* Step (1). */ - r = find_path (g, contains_supermin_appliance, NULL, &supermin_path); - if (r == -1) - return -1; - - if (r == 1) + r = contains_supermin_appliance(g, path, NULL); + if (r == 1) { /* Step (2): build supermin appliance. */ - return build_supermin_appliance (g, supermin_path, - kernel, initrd, appliance); + r = build_supermin_appliance (g, path, appliance); + return r < 0 ? r : 1; + } /* Step (3). */ - r = find_path (g, contains_fixed_appliance, NULL, &path); - if (r == -1) - return -1; - + r = contains_fixed_appliance (g, path, NULL); if (r == 1) { - const size_t len = strlen (path); - *kernel = safe_malloc (g, len + 6 /* "kernel" */ + 2); - *initrd = safe_malloc (g, len + 6 /* "initrd" */ + 2); - *appliance = safe_malloc (g, len + 4 /* "root" */ + 2); - sprintf (*kernel, "%s/kernel", path); - sprintf (*initrd, "%s/initrd", path); - sprintf (*appliance, "%s/root", path); - return 0; + appliance->kernel = safe_asprintf (g, "%s/kernel", path); + appliance->initrd = safe_asprintf (g, "%s/initrd", path); + appliance->image = safe_asprintf(g, "%s/root", path); + return 1; } /* Step (4). */ - r = find_path (g, contains_old_style_appliance, NULL, &path); - if (r == -1) - return -1; - + r = contains_old_style_appliance (g, path, NULL); if (r == 1) { - const size_t len = strlen (path); - *kernel = safe_malloc (g, len + strlen (kernel_name) + 2); - *initrd = safe_malloc (g, len + strlen (initrd_name) + 2); - sprintf (*kernel, "%s/%s", path, kernel_name); - sprintf (*initrd, "%s/%s", path, initrd_name); - *appliance = NULL; - return 0; + appliance->kernel = safe_asprintf(g, "%s/%s", path, kernel_name); + appliance->initrd = safe_asprintf(g, "%s/%s", path, initrd_name); + appliance->image = NULL; + return 1; } + return 0; +} + + +/** + * Search elements of C<g-E<gt>path>, returning the first C<appliance> element + * which matches the predicate function C<locate_or_build_appliance>. + * + * Return values: + * + * 1 = a path element matched, returns C<appliance>, + * 0 = no path element matched, + * -1 = error which aborts the launch process. + */ +static int +search_appliance (guestfs_h *g, struct appliance_files *appliance) +{ + const char *pelem = g->path; + + /* Note that if g->path is an empty string, we want to check the + * current directory (for backwards compatibility with + * libguestfs < 1.5.4). + */ + do { + size_t len = strcspn (pelem, PATH_SEPARATOR); + /* Empty element or "." means current directory. */ + CLEANUP_FREE char *path = (len == 0) ? safe_strdup (g, ".") : + safe_strndup (g, pelem, len); + int r = locate_or_build_appliance (g, appliance, path); + if (r != 0) + return r; /* error or predicate matched */ + + if (pelem[len] == PATH_SEPARATOR[0]) + pelem += len + 1; + else + pelem += len; + } while (*pelem); + + /* Predicate didn't match on any path element. */ error (g, _("cannot find any suitable libguestfs supermin, fixed or old-style appliance on LIBGUESTFS_PATH (search path: %s)"), g->path); - return -1; + return 0; } static int @@ -213,8 +250,7 @@ contains_supermin_appliance (guestfs_h *g, const char *path, void *data) static int build_supermin_appliance (guestfs_h *g, const char *supermin_path, - char **kernel, char **initrd, - char **appliance) + struct appliance_files *appliance) { CLEANUP_FREE char *cachedir = NULL, *lockfile = NULL, *appliancedir = NULL; @@ -236,13 +272,13 @@ build_supermin_appliance (guestfs_h *g, debug (g, "finished building supermin appliance"); /* Return the appliance filenames. */ - *kernel = safe_asprintf (g, "%s/kernel", appliancedir); - *initrd = safe_asprintf (g, "%s/initrd", appliancedir); - *appliance = safe_asprintf (g, "%s/root", appliancedir); + appliance->kernel = safe_asprintf (g, "%s/kernel", appliancedir); + appliance->initrd = safe_asprintf (g, "%s/initrd", appliancedir); + appliance->image = safe_asprintf (g, "%s/root", appliancedir); /* Touch the files so they don't get deleted (as they are in /var/tmp). */ - (void) utimes (*kernel, NULL); - (void) utimes (*initrd, NULL); + (void) utimes (appliance->kernel, NULL); + (void) utimes (appliance->initrd, NULL); /* Checking backend != "uml" is a big hack. UML encodes the mtime * of the original backing file (in this case, the appliance) in the @@ -257,7 +293,7 @@ build_supermin_appliance (guestfs_h *g, * XXX */ if (STRNEQ (g->backend, "uml")) - (void) utimes (*appliance, NULL); + (void) utimes (appliance->image, NULL); return 0; } @@ -317,65 +353,6 @@ run_supermin_build (guestfs_h *g, } /** - * Search elements of C<g-E<gt>path>, returning the first path element - * which matches the predicate function C<pred>. - * - * Function C<pred> must return a true or false value. If it returns - * C<-1> then the entire search is aborted. - * - * Return values: - * - * 1 = a path element matched, it is returned in *pelem_ret and must be - * freed by the caller, - * 0 = no path element matched, *pelem_ret is set to NULL, or - * -1 = error which aborts the launch process - */ -static int -find_path (guestfs_h *g, - int (*pred) (guestfs_h *g, const char *pelem, void *data), - void *data, - char **pelem_ret) -{ - size_t len; - int r; - const char *pelem = g->path; - - /* Note that if g->path is an empty string, we want to check the - * current directory (for backwards compatibility with - * libguestfs < 1.5.4). - */ - do { - len = strcspn (pelem, PATH_SEPARATOR); - - /* Empty element or "." means current directory. */ - if (len == 0) - *pelem_ret = safe_strdup (g, "."); - else - *pelem_ret = safe_strndup (g, pelem, len); - - r = pred (g, *pelem_ret, data); - if (r == -1) { - free (*pelem_ret); - return -1; - } - - if (r != 0) /* predicate matched */ - return 1; - - free (*pelem_ret); - - if (pelem[len] == PATH_SEPARATOR[0]) - pelem += len + 1; - else - pelem += len; - } while (*pelem); - - /* Predicate didn't match on any path element. */ - *pelem_ret = NULL; - return 0; -} - -/** * Returns true iff C<file> is contained in C<dir>. */ static int -- 2.11.0