From 21b7bd73ae88ba2ce9a5bfeedf67bc204d10fd08 Mon Sep 17 00:00:00 2001 From: Yousong Zhou Date: Wed, 12 Jun 2019 04:19:02 +0000 Subject: [PATCH] alternatives: special-case busybox as alternatives provider Almost all busybox applets are alternatives to some other existing "full" utilities. To lift the maintenance burden of enumerating CONFIG symbols, symlink path of each applet, we special case busybox here as a known alternatives provider. All file pathes provided by busybox will serve as fallback alternatives with -inf priority. Packages intending to switch to using alternatives mechanism will also not need to depend on the same kind of change be applied on busybox in base system v3 <- v2 continue to next when fetching provider pkg failed v2 <- v1 Move busybox-specific part into data section Signed-off-by: Yousong Zhou Acked-by: Jo-Philipp Wich --- libopkg/pkg_alternatives.c | 49 +++++++++++++++++++++++++++++++++++--- 1 file changed, 46 insertions(+), 3 deletions(-) diff --git a/libopkg/pkg_alternatives.c b/libopkg/pkg_alternatives.c index 50e9d12..5891616 100644 --- a/libopkg/pkg_alternatives.c +++ b/libopkg/pkg_alternatives.c @@ -27,6 +27,42 @@ #include "pkg_alternatives.h" #include "sprintf_alloc.h" +struct alternative_provider { + char *name; + char *altpath; +}; + +static const struct alternative_provider const providers[] = { + { + .name = "busybox", + .altpath = "/bin/busybox", + }, +}; + +static const char *pkg_alternatives_check_providers(const char *path) +{ + pkg_t *pkg; + str_list_t *files; + str_list_elt_t *iter; + int i; + + for (i = 0; i < ARRAY_SIZE(providers); i++) { + pkg = pkg_hash_fetch_installed_by_name(providers[i].name); + if (!pkg) { + continue; + } + files = pkg_get_installed_files(pkg); + for (iter = str_list_first(files); iter; iter = str_list_next(files, iter)) { + if (!strcmp(path, (char *)(iter->data))) { + pkg_free_installed_files(pkg); + return providers[i].altpath; + } + } + pkg_free_installed_files(pkg); + } + return NULL; +} + static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, const char *path) { struct pkg_alternatives *pkg_alts; @@ -35,6 +71,7 @@ static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, int i, j; int r; char *path_in_dest; + const char *target_path = NULL; for (i = 0; i < installed->len; i++) { pkg_t *pkg = installed->pkgs[i]; @@ -60,6 +97,12 @@ static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, return -1; if (the_alt) { + target_path = the_alt->altpath; + } else { + target_path = pkg_alternatives_check_providers(path); + } + + if (target_path) { struct stat sb; r = lstat(path_in_dest, &sb); @@ -72,7 +115,7 @@ static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, goto out; } realpath = xreadlink(path_in_dest); - if (realpath && strcmp(realpath, the_alt->altpath)) + if (realpath && strcmp(realpath, target_path)) unlink(path_in_dest); free(realpath); } else if (errno != ENOENT) { @@ -87,7 +130,7 @@ static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, if (r) { goto out; } - r = symlink(the_alt->altpath, path_in_dest); + r = symlink(target_path, path_in_dest); if (r && errno == EEXIST) { /* * the strcmp & unlink check above will make sure that if EEXIST @@ -96,7 +139,7 @@ static int pkg_alternatives_update_path(pkg_t *pkg, const pkg_vec_t *installed, r = 0; } if (r) { - opkg_perror(ERROR, "failed symlinking %s -> %s", path_in_dest, the_alt->altpath); + opkg_perror(ERROR, "failed symlinking %s -> %s", path_in_dest, target_path); } } } else { -- 2.25.1