Use realpath() to canonicalize provided paths

The existing function choked in several corner cases:
* '/tmp/../tmp' was seen as absolute, so not cleaned up.
* '/tmp/' and '/tmp' were not equal, causing depmod to act differently
  when called with the -b option for the two paths.

Don't reinvent the wheel; just use the standard library function.

Signed-off-by: Dan McGee <dan@archlinux.org>

5 files changed, 18 insertions, 47 deletions

diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c
index 0af3e2e..adc055f 100644
--- a/libkmod/libkmod-module.c
+++ b/libkmod/libkmod-module.c
@@ -355,10 +355,10 @@ KMOD_EXPORT int kmod_module_new_from_path(struct kmod_ctx *ctx,
 	if (ctx == NULL || path == NULL || mod == NULL)
 		return -ENOENT;
 
-	abspath = path_make_absolute_cwd(path);
+	abspath = canonicalize_file_name(path);
 	if (abspath == NULL) {
-		DBG(ctx, "no absolute path for %s\n", path);
-		return -ENOMEM;
+		DBG(ctx, "no canonical filename returned for %s\n", path);
+		return -errno;
 	}
 
 	err = stat(abspath, &st);
diff --git a/libkmod/libkmod-util.c b/libkmod/libkmod-util.c
index f499578..ba89ecf 100644
--- a/libkmod/libkmod-util.c
+++ b/libkmod/libkmod-util.c
@@ -303,42 +303,6 @@ char *strchr_replace(char *s, int c, char r)
 	return s;
 }
 
-bool path_is_absolute(const char *p)
-{
-	assert(p != NULL);
-
-	return p[0] == '/';
-}
-
-char *path_make_absolute_cwd(const char *p)
-{
-	char *cwd, *r;
-	size_t plen;
-	size_t cwdlen;
-
-	if (path_is_absolute(p))
-		return strdup(p);
-
-	cwd = get_current_dir_name();
-	if (cwd == NULL)
-		return NULL;
-
-	plen = strlen(p);
-	cwdlen = strlen(cwd);
-
-	/* cwd + '/' + p + '\0' */
-	r = realloc(cwd, cwdlen + 1 + plen + 1);
-	if (r == NULL) {
-		free(cwd);
-		return NULL;
-	}
-
-	r[cwdlen] = '/';
-	memcpy(&r[cwdlen + 1], p, plen + 1);
-
-	return r;
-}
-
 #define USEC_PER_SEC  1000000ULL
 #define NSEC_PER_USEC 1000ULL
 unsigned long long stat_mstamp(const struct stat *st)
diff --git a/libkmod/libkmod-util.h b/libkmod/libkmod-util.h
index 317b2f7..655e8fb 100644
--- a/libkmod/libkmod-util.h
+++ b/libkmod/libkmod-util.h
@@ -19,8 +19,6 @@ ssize_t write_str_safe(int fd, const char *buf, size_t buflen) __attribute__((no
 int read_str_long(int fd, long *value, int base) __must_check __attribute__((nonnull(2)));
 int read_str_ulong(int fd, unsigned long *value, int base) __must_check __attribute__((nonnull(2)));
 char *strchr_replace(char *s, int c, char r);
-bool path_is_absolute(const char *p) __must_check __attribute__((nonnull(1)));
-char *path_make_absolute_cwd(const char *p) __must_check __attribute__((nonnull(1)));
 int alias_normalize(const char *alias, char buf[PATH_MAX], size_t *len) __must_check __attribute__((nonnull(1,2)));
 char *modname_normalize(const char *modname, char buf[PATH_MAX], size_t *len) __attribute__((nonnull(1, 2)));
 char *path_to_modname(const char *path, char buf[PATH_MAX], size_t *len) __attribute__((nonnull(2)));
diff --git a/libkmod/libkmod.c b/libkmod/libkmod.c
index 4990d3e..21297fb 100644
--- a/libkmod/libkmod.c
+++ b/libkmod/libkmod.c
@@ -195,13 +195,18 @@ static int log_priority(const char *priority)
 
 static const char *dirname_default_prefix = ROOTPREFIX "/lib/modules";
 
-static char *get_kernel_release(const char *dirname)
+static char *get_kernel_release(struct kmod_ctx *ctx, const char *dirname)
 {
 	struct utsname u;
 	char *p;
 
-	if (dirname != NULL)
-		return path_make_absolute_cwd(dirname);
+	if (dirname != NULL) {
+		p = canonicalize_file_name(dirname);
+		if (p)
+			return p;
+		INFO(ctx, "could not canonicalize directory %s: %m\n", dirname);
+		return strdup(dirname);
+	}
 
 	if (uname(&u) < 0)
 		return NULL;
@@ -250,7 +255,7 @@ KMOD_EXPORT struct kmod_ctx *kmod_new(const char *dirname,
 	ctx->log_data = stderr;
 	ctx->log_priority = LOG_ERR;
 
-	ctx->dirname = get_kernel_release(dirname);
+	ctx->dirname = get_kernel_release(ctx, dirname);
 
 	/* environment overwrites config */
 	env = getenv("KMOD_LOG");
diff --git a/tools/kmod-depmod.c b/tools/kmod-depmod.c
index 1871e18..c545916 100644
--- a/tools/kmod-depmod.c
+++ b/tools/kmod-depmod.c
@@ -1160,7 +1160,7 @@ static int depmod_module_add(struct depmod *depmod, struct kmod_module *kmod)
 		}
 	}
 
-	DBG("add %p kmod=%p, path=%s\n", mod, kmod, mod->path);
+	DBG("add %p kmod=%p, path=%s, relpath=%s\n", mod, kmod, mod->path, mod->relpath);
 
 	return 0;
 }
@@ -2549,7 +2549,11 @@ static int do_depmod(int argc, char *argv[])
 			maybe_all = 1;
 			break;
 		case 'b':
-			root = path_make_absolute_cwd(optarg);
+			root = canonicalize_file_name(optarg);
+			if (!root) {
+				CRIT("could not resolve path %s\n", optarg);
+				goto cmdline_failed;
+			}
 			break;
 		case 'C': {
 			size_t bytes = sizeof(char *) * (n_config_paths + 2);