file: Add an abstraction to read files

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/Makefile.am b/Makefile.am
index ffcfc8c9338024502dd800520b578684c6b4baab..07a96607c2a21c80b7ae31dde1edbb025e17efde 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -101,6 +101,8 @@ dist_collectyd_SOURCES = \
        src/daemon/ctx.h \
        src/daemon/daemon.c \
        src/daemon/daemon.h \
+       src/daemon/file.c \
+       src/daemon/file.h \
        src/daemon/graph.c \
        src/daemon/graph.h \
        src/daemon/graph-bus.c \

diff --git a/src/daemon/file.c b/src/daemon/file.c
new file mode 100644 (file)
index 0000000..ff69356
--- /dev/null
+++ b/src/daemon/file.c
@@ -0,0 +1,148 @@
+/*#############################################################################
+#                                                                             #
+# collecty - A system statistics collection daemon for IPFire                 #
+# Copyright (C) 2025 IPFire Development Team                                  #
+#                                                                             #
+# This program is free software: you can redistribute it and/or modify        #
+# it under the terms of the GNU General Public License as published by        #
+# the Free Software Foundation, either version 3 of the License, or           #
+# (at your option) any later version.                                         #
+#                                                                             #
+# This program is distributed in the hope that it will be useful,             #
+# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
+# GNU General Public License for more details.                                #
+#                                                                             #
+# You should have received a copy of the GNU General Public License           #
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
+#                                                                             #
+#############################################################################*/
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ctx.h"
+#include "file.h"
+#include "string.h"
+
+struct collecty_file {
+       collecty_ctx* ctx;
+       int nrefs;
+
+       // File Handle
+       FILE* f;
+};
+
+static void collecty_file_free(collecty_file* self) {
+       if (self->f)
+               fclose(self->f);
+       if (self->ctx)
+               collecty_ctx_unref(self->ctx);
+       free(self);
+}
+
+static int collecty_file_create(collecty_file** file, collecty_ctx* ctx) {
+       collecty_file* self = NULL;
+
+       // Allocate some memory
+       self = calloc(1, sizeof(*self));
+       if (!self)
+               return -errno;
+
+       // Initialize the reference counter
+       self->nrefs = 1;
+
+       // Store a reference to the context
+       self->ctx = collecty_ctx_ref(ctx);
+
+       // Return the pointer
+       *file = self;
+       return 0;
+}
+
+int collecty_file_open_path(collecty_file** file, collecty_ctx* ctx, const char* path) {
+       collecty_file* self = NULL;
+       int r;
+
+       // Create a new object
+       r = collecty_file_create(&self, ctx);
+       if (r < 0)
+               goto ERROR;
+
+       // Open the file
+       self->f = fopen(path, "r");
+       if (!self->f) {
+               ERROR(ctx, "Failed to open %s: %m\n", path);
+               r = -errno;
+               goto ERROR;
+       }
+
+       // Return the pointer
+       *file = self;
+       return 0;
+
+ERROR:
+       if (self)
+               collecty_file_unref(self);
+
+       return r;
+}
+
+collecty_file* collecty_file_ref(collecty_file* self) {
+       ++self->nrefs;
+       return self;
+}
+
+collecty_file* collecty_file_unref(collecty_file* self) {
+       if (--self->nrefs > 0)
+               return self;
+
+       collecty_file_free(self);
+       return NULL;
+}
+
+int collecty_file_walk(collecty_file* self,
+               collecty_file_walk_callback callback, void* data) {
+       unsigned long lineno = 0;
+       char* line = NULL;
+       size_t length = 0;
+       size_t l = 0;
+       int r;
+
+       // Start at the beginning of the stream
+       r = fseek(self->f, 0L, SEEK_SET);
+       if (r < 0)
+               return -errno;
+
+       // Walk through all lines
+       for (;;) {
+               // Fetch the next line
+               r = getline(&line, &length, self->f);
+               if (r < 0) {
+                       // Reset r if have reached the end of the file
+                       if (feof(self->f))
+                               r = 0;
+
+                       break;
+               }
+
+               // Remove the trailing newline
+               collecty_string_rstrip(line);
+
+               // Determine the length of the line
+               l = strlen(line);
+
+               // Call the callback
+               r = callback(self->ctx, lineno++, line, l, data);
+               if (r < 0)
+                       break;
+       }
+
+       // Cleanup
+       if (line)
+               free(line);
+
+       return r;
+}

diff --git a/src/daemon/file.h b/src/daemon/file.h
new file mode 100644 (file)
index 0000000..4b50431
--- /dev/null
+++ b/src/daemon/file.h
@@ -0,0 +1,39 @@
+/*#############################################################################
+#                                                                             #
+# collecty - A system statistics collection daemon for IPFire                 #
+# Copyright (C) 2025 IPFire Development Team                                  #
+#                                                                             #
+# This program is free software: you can redistribute it and/or modify        #
+# it under the terms of the GNU General Public License as published by        #
+# the Free Software Foundation, either version 3 of the License, or           #
+# (at your option) any later version.                                         #
+#                                                                             #
+# This program is distributed in the hope that it will be useful,             #
+# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
+# GNU General Public License for more details.                                #
+#                                                                             #
+# You should have received a copy of the GNU General Public License           #
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
+#                                                                             #
+#############################################################################*/
+
+#ifndef COLLECTY_FILE_H
+#define COLLECTY_FILE_H
+
+typedef struct collecty_file collecty_file;
+
+#include "ctx.h"
+
+int collecty_file_open_path(collecty_file** file, collecty_ctx* ctx, const char* path);
+
+collecty_file* collecty_file_ref(collecty_file* self);
+collecty_file* collecty_file_unref(collecty_file* self);
+
+typedef int (*collecty_file_walk_callback)
+       (collecty_ctx* ctx, unsigned long lineno, char* line, size_t length, void* data);
+
+int collecty_file_walk(collecty_file* self,
+       collecty_file_walk_callback callback, void* data);
+
+#endif /* COLLECTY_FILE_H */