pretty-print: make conf_files_cat() not show files outside of the specified root.

Then, make the function show the original and resolved path if they are
different.

With this change, procfs needs to be mounted on /proc/, hence the test
code is slightly updated.

src/shared/pretty-print.c

@@ -6,6 +6,7 @@
 #include <unistd.h>
 
 #include "alloc-util.h"
+#include "chase.h"
 #include "color-util.h"
 #include "conf-files.h"
 #include "constants.h"
@@ -13,6 +14,7 @@
 #include "errno-util.h"
 #include "fd-util.h"
 #include "fileio.h"
+#include "fs-util.h"
 #include "log.h"
 #include "path-util.h"
 #include "pretty-print.h"
@@ -184,12 +186,15 @@ int terminal_urlify_man(const char *page, const char *section, char **ret) {
         return terminal_urlify(url, text, ret);
 }
 
-static int cat_file(const char *filename, bool *newline, CatFlags flags) {
+static int cat_file(const ConfFile *c, bool *newline, CatFlags flags) {
         _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *urlified = NULL, *section = NULL, *old_section = NULL;
         int r;
 
-        assert(filename);
+        assert(c);
+        assert(c->original_path);
+        assert(c->resolved_path);
+        assert(c->fd >= 0);
 
         if (newline) {
                 if (*newline)
@@ -197,25 +202,29 @@ static int cat_file(const char *filename, bool *newline, CatFlags flags) {
                 *newline = true;
         }
 
-        r = terminal_urlify_path(filename, NULL, &urlified);
-        if (r < 0)
-                return log_error_errno(r, "Failed to urlify path \"%s\": %m", filename);
+        bool resolved = !path_equal(c->original_path, c->resolved_path);
 
-        printf("%s# %s%s\n",
+        r = terminal_urlify_path(c->resolved_path, NULL, &urlified);
+        if (r < 0)
+                return log_error_errno(r, "Failed to urlify path \"%s\": %m", c->resolved_path);
+
+        printf("%s# %s%s%s%s\n",
                ansi_highlight_blue(),
+               resolved ? c->original_path : "",
+               resolved ? " -> " : "",
                urlified,
                ansi_normal());
 
-        f = fopen(filename, "re");
+        f = fopen(FORMAT_PROC_FD_PATH(c->fd), "re");
         if (!f)
-                return log_error_errno(errno, "Failed to open \"%s\": %m", filename);
+                return log_error_errno(errno, "Failed to open \"%s\": %m", c->resolved_path);
 
         for (bool continued = false;;) {
                 _cleanup_free_ char *line = NULL;
 
                 r = read_line(f, LONG_LINE_MAX, &line);
                 if (r < 0)
-                        return log_error_errno(r, "Failed to read \"%s\": %m", filename);
+                        return log_error_errno(r, "Failed to read \"%s\": %m", c->resolved_path);
                 if (r == 0)
                         break;
 
@@ -296,15 +305,43 @@ static int cat_file(const char *filename, bool *newline, CatFlags flags) {
         return 0;
 }
 
+int cat_files_full(const ConfFile *file, ConfFile * const *dropins, size_t n_dropins, CatFlags flags) {
+        bool newline = false;
+        int ret = 0;
+
+        assert(dropins || n_dropins == 0);
+
+        if (file)
+                ret = cat_file(file, &newline, flags);
+
+        FOREACH_ARRAY(i, dropins, n_dropins)
+                RET_GATHER(ret, cat_file(*i, &newline, flags));
+
+        return ret;
+}
+
+static int cat_file_by_path(const char *p, bool *newline, CatFlags flags) {
+        _cleanup_(conf_file_freep) ConfFile *c = NULL;
+        int r;
+
+        assert(p);
+
+        r = conf_file_new(p, /* root = */ NULL, CHASE_MUST_BE_REGULAR, &c);
+        if (r < 0)
+                return log_error_errno(r, "Failed to chase '%s': %m", p);
+
+        return cat_file(c, newline, flags);
+}
+
 int cat_files(const char *file, char **dropins, CatFlags flags) {
         bool newline = false;
         int ret = 0;
 
         if (file)
-                ret = cat_file(file, &newline, flags);
+                ret = cat_file_by_path(file, &newline, flags);
 
         STRV_FOREACH(path, dropins)
-                RET_GATHER(ret, cat_file(*path, &newline, flags));
+                RET_GATHER(ret, cat_file_by_path(*path, &newline, flags));
 
         return ret;
 }
@@ -384,8 +421,7 @@ static int guess_type(const char **name, char ***ret_prefixes, bool *ret_is_coll
 }
 
 int conf_files_cat(const char *root, const char *name, CatFlags flags) {
-        _cleanup_strv_free_ char **dirs = NULL, **files = NULL;
-        _cleanup_free_ char *path = NULL;
+        _cleanup_strv_free_ char **dirs = NULL;
         char **prefixes = NULL; /* explicit initialization to appease gcc */
         bool is_collection;
         const char *extension;
@@ -416,17 +452,18 @@ int conf_files_cat(const char *root, const char *name, CatFlags flags) {
         }
 
         /* First locate the main config file, if any */
+        _cleanup_(conf_file_freep) ConfFile *c = NULL;
         if (!is_collection) {
                 STRV_FOREACH(prefix, prefixes) {
-                        path = path_join(root, *prefix, name);
-                        if (!path)
+                        _cleanup_free_ char *p = path_join(*prefix, name);
+                        if (!p)
                                 return log_oom();
-                        if (access(path, F_OK) == 0)
+
+                        if (conf_file_new(p, root, CHASE_MUST_BE_REGULAR, &c) >= 0)
                                 break;
-                        path = mfree(path);
                 }
 
-                if (!path)
+                if (!c)
                         printf("%s# Main configuration file %s not found%s\n",
                                ansi_highlight_magenta(),
                                name,
@@ -434,7 +471,10 @@ int conf_files_cat(const char *root, const char *name, CatFlags flags) {
         }
 
         /* Then locate the drop-ins, if any */
-        r = conf_files_list_strv(&files, extension, root, 0, (const char* const*) dirs);
+        ConfFile **dropins = NULL;
+        size_t n_dropins = 0;
+        CLEANUP_ARRAY(dropins, n_dropins, conf_file_free_many);
+        r = conf_files_list_strv_full(extension, root, CONF_FILES_REGULAR | CONF_FILES_FILTER_MASKED, (const char* const*) dirs, &dropins, &n_dropins);
         if (r < 0)
                 return log_error_errno(r, "Failed to query file list: %m");
 
@@ -442,7 +482,7 @@ int conf_files_cat(const char *root, const char *name, CatFlags flags) {
         if (is_collection)
                 flags |= CAT_FORMAT_HAS_SECTIONS;
 
-        return cat_files(path, files, flags);
+        return cat_files_full(c, dropins, n_dropins, flags);
 }
 
 int terminal_tint_color(double hue, char **ret) {

src/shared/pretty-print.h

@@ -30,6 +30,7 @@ typedef enum CatFlags {
         CAT_TLDR                = 1 << 2,  /* Only print comments and relevant section headers */
 } CatFlags;
 
+int cat_files_full(const ConfFile *file, ConfFile * const *dropins, size_t n_dropins, CatFlags flags);
 int cat_files(const char *file, char **dropins, CatFlags flags);
 int conf_files_cat(const char *root, const char *name, CatFlags flags);
 

test/units/TEST-65-ANALYZE.sh

@@ -313,6 +313,7 @@ if [[ ! -v ASAN_OPTIONS ]]; then
     # check that systemd-analyze cat-config paths work in a chroot
     mkdir -p /tmp/root
     mount --bind / /tmp/root
+    mount -t proc proc /tmp/root/proc
     if mountpoint -q /usr; then
         mount --bind /usr /tmp/root/usr
     fi