Misc improvements

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 278 insertions, 202 deletions

diff --git a/src/config-ini.c b/src/config-ini.c
index df7d1a1..db94f22 100644
--- a/src/config-ini.c
+++ b/src/config-ini.c
@@ -1,257 +1,332 @@
 /* config-ini.c -- INI config file parser
-   This file is part of redshift-ng.
+ * This file is part of redshift-ng.
+ * 
+ * redshift-ng 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.
+ * 
+ * redshift-ng 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 redshift-ng.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ * Copyright (c) 2010-2018  Jon Lund Steffensen <jonlst@gmail.com>
+ * Copyright (c) 2025       Mattias Andrée <m@maandree.se>
+ */
+#include "common.h"
 
-   redshift-ng 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.
 
-   redshift-ng 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.
+/**
+ * Specification for a path that consists of a two parts:
+ * the first being defined by the environment, and the
+ * seocnd being a static string
+ */
+struct env_path {
+	/**
+	 * Whether the environment variable referenced by `.prefix`
+	 * should be split at each colon (:) into multiple paths to
+	 * test
+	 */
+	int multidir_env;
 
-   You should have received a copy of the GNU General Public License
-   along with redshift-ng.  If not, see <http://www.gnu.org/licenses/>.
+	/**
+	 * Environment variable to use as the first part of the path
+	 * 
+	 * `NULL` if the user's home directory should be used
+	 * 
+	 * The empty string if `.suffix` should be used as is
+	 */
+	const char *prefix_env;
 
-   Copyright (c) 2010-2018  Jon Lund Steffensen <jonlst@gmail.com>
-   Copyright (c) 2025       Mattias Andrée <m@maandree.se>
-*/
-#include "common.h"
+	/**
+	 * The second part of the path
+	 */
+	const char *suffix;
+};
 
-#define MAX_CONFIG_PATH  4096
-#define MAX_LINE_LENGTH   512
 
+/**
+ * Paths, in order of priority, to test when looking for
+ * the configuration file for redshift
+ */
+static const struct env_path paths[] = {
+	{0, "XDG_CONFIG_HOME", "/redshift-ng/redshift.conf"},
+	{0, "XDG_CONFIG_HOME", "/redshift/redshift.conf"},
+	{0, "XDG_CONFIG_HOME", "/redshift.conf"},
+#ifdef WINDOWS
+	{0, "localappdata", "/redshift-ng/redshift.conf"},
+	{0, "localappdata", "/redshift/redshift.conf"},
+	{0, "localappdata", "/redshift.conf"},
+#endif
+	{0, "HOME", "/.config/redshift-ng/redshift.conf"},
+	{0, "HOME", "/.config/redshift/redshift.conf"},
+	{0, "HOME", "/.config/redshift.conf"},
+	{0, "HOME", "/.redshift.conf"},
+	{0, NULL, "/.config/redshift-ng/redshift.conf"},
+	{0, NULL, "/.config/redshift/redshift.conf"},
+	{0, NULL, "/.config/redshift.conf"},
+	{0, NULL, "/.redshift.conf"},
+	{1, "XDG_CONFIG_DIRS", "/redshift-ng/redshift.conf"},
+	{1, "XDG_CONFIG_DIRS", "/redshift/redshift.conf"},
+	{1, "XDG_CONFIG_DIRS", "/redshift.conf"},
+	{0, "", "/etc/redshift-ng/redshift.conf"},
+	{0, "", "/etc/redshift/redshift.conf"},
+	{0, "", "/etc/redshift.conf"}
+};
 
-static FILE *
-open_config_file(const char *filepath)
-{
-	FILE *f = NULL;
 
-	/* If a path is not specified (filepath is NULL) then
-	   the configuration file is searched for in the directories
-	   specified by the XDG Base Directory Specification
-	   <http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html>.
+/**
+ * Remove trailing whitespace
+ * 
+ * @param   s    The string to trim, will be truncated
+ * @param   end  The current end of `s`; will be looked up if `NULL`
+ * @return       `s`
+ */
+static char *
+rtrim(char *s, char *end)
+{
+	end = end ? end : strchr(s, '\0');
+	while (end != s && (end[-1] == ' ' || end[-1] == '\t'))
+		end--;
+	*end = '\0';
+	return s;
+}
 
-	   If HOME is not set, getpwuid() is consulted for the home directory. On
-	   windows platforms the %localappdata% is used in place of XDG_CONFIG_HOME.
-	*/
 
-	if (filepath == NULL) {
-		char cp[MAX_CONFIG_PATH];
-		char *env;
+/**
+ * Remove leading whitespace
+ * 
+ * @param   s  The string to trim (will not be modified)
+ * @return     An offset of `s`
+ */
+GCC_ONLY(__attribute__((__warn_unused_result__)))
+static char *
+ltrim(char *s)
+{
+	return &s[strspn(s, " \t")];
+}
 
-		if (f == NULL && (env = getenv("XDG_CONFIG_HOME")) != NULL &&
-		    env[0] != '\0') {
-			snprintf(cp, sizeof(cp), "%s/redshift/redshift.conf", env);
-			f = fopen(cp, "r");
-			if (f == NULL) {
-				/* Fall back to formerly used path. */
-				snprintf(cp, sizeof(cp), "%s/redshift.conf", env);
-				f = fopen(cp, "r");
-			}
-		}
 
+/**
+ * Get the user's home directory
+ *
+ * This function looks up the user's home directory
+ * once and caches the result, later calls to this
+ * function will use the cached result
+ * 
+ * @param  The user's home directory; the empty string if not found
+ */
+static const char *
+get_home(void)
+{
 #ifdef WINDOWS
-		if (f == NULL && (env = getenv("localappdata")) != NULL &&
-		    env[0] != '\0') {
-			snprintf(cp, sizeof(cp), "%s\\redshift.conf", env);
-			f = fopen(cp, "r");
+	return NULL;
+#else
+	static const char *home = NULL;
+	struct passwd *pw;
+	if (!home) {
+		pw = getpwuid(getuid());
+		if (pw) {
+			home = pw->pw_dir;
+			if (home && *home)
+				return home;
+			weprintf(_("Cannot determine your home directory, "
+			           "it is from the system's user table."));
+		} else if (errno) {
+			weprintf("getpwuid:");
+		} else {
+			weprintf(_("Cannot determine your home directory, your"
+			           " user ID is missing from the system's user table."));
+			/* `errno` can either be set to any number of error codes,
+			 * or be zero if the user does not have a passwd entry */
 		}
+		home = "";
+	}
+	return home;
 #endif
-		if (f == NULL && (env = getenv("HOME")) != NULL &&
-		    env[0] != '\0') {
-			snprintf(cp, sizeof(cp), "%s/.config/redshift/redshift.conf", env);
-			f = fopen(cp, "r");
-			if (f == NULL) {
-				/* Fall back to formerly used path. */
-				snprintf(cp, sizeof(cp), "%s/.config/redshift.conf", env);
-				f = fopen(cp, "r");
-			}
-		}
-#ifndef WINDOWS
+}
 
-		if (f == NULL) {
-			struct passwd *pwd = getpwuid(getuid());
-			if (pwd != NULL) {
-				char *home = pwd->pw_dir;
-				if ((home != NULL) && (*home != '\0')) {
-					snprintf(cp, sizeof(cp), "%s/.config/redshift/redshift.conf", home);
-					f = fopen(cp, "r");
-					if (!f) {
-						/* Fall back to formerly used path. */
-						snprintf(cp, sizeof(cp), "%s/.config/redshift.conf", home);
-						f = fopen(cp, "r");
-					}
-				} else {
-					weprintf(_("Cannot determine your home directory,"
-					           " it is from the system's user table."));
-				}
-			} else if (errno) {
-				weprintf("getpwuid:");
-			} else {
-				weprintf(_("Cannot determine your home directory, your"
-				           " user ID is missing from the system's user table."));
-				/* errno can either be set to any number of error codes,
-				   or be zero if the user does not have a passwd entry. */
-			}
-		}
 
-		if (f == NULL && (env = getenv("XDG_CONFIG_DIRS")) != NULL && *env) {
-			char *begin = env;
-			char *end;
-			int len;
-			for (;;) {
-				end = strchr(begin, ':');
-				if (end == NULL) end = strchr(begin, '\0');
+/**
+ * Search for a file and open it for reading
+ * 
+ * @param   path_spec  Specification for the path to try
+ * @param   path_out   Output parameter for the file path
+ * @return             `FILE` object for the reading the file; `NULL` if not found
+ */
+static FILE *
+try_path(const struct env_path *path_spec, char **path_out)
+{
+	const char *prefix, *p, *q;
+	char *path;
+	size_t len;
+	FILE *f;
+
+	if (!path_spec->prefix_env)
+		prefix = get_home();
+	else if (!*path_spec->prefix_env)
+		return fopen(path_spec->suffix, "r");
+	else
+		prefix = getenv(path_spec->prefix_env);
+	if (!prefix || !*prefix)
+		return NULL;
 
-				len = (int)(end - begin);
-				if (len > 0) {
-					snprintf(cp, sizeof(cp), "%.*s/redshift/redshift.conf", len, begin);
-					f = fopen(cp, "r");
-					if (f == NULL) {
-						/* Fall back to formerly used path. */
-						snprintf(cp, sizeof(cp), "%.*s/redshift.conf", len, begin);
-						f = fopen(cp, "r");
-					}
-					if (f != NULL)
-						break;
-				}
+	path = emalloc(strlen(prefix) + strlen(path_spec->suffix) + 1U);
+
+	if (path_spec->multidir_env) {
+		for (p = prefix; *p; p = &q[!!*q]) {
+#ifdef strchrnul
+			q = strchrnul(p, ':');
+#else
+			q = strchr(p, ':');
+			q = q ? q : strchr(p, '\0');
+#endif
+			len = (size_t)(q - p);
+			if (!len)
+				continue;
 
-				if (*end)
-					break;
-				begin = &end[1];
+			memcpy(path, p, len);
+			stpcpy(&path[len], path_spec->suffix);
+			f = fopen(path, "r");
+			if (f) {
+				weprintf(_("Found configuration file `%s'."));
+				break;
+			} else if (errno != ENOENT) {
+				eprintf("fopen %s \"%s\":", path);
 			}
 		}
+	} else {
+		stpcpy(stpcpy(path, prefix), path_spec->suffix);
+		f = fopen(path, "r");
+		if (f)
+			weprintf(_("Found configuration file `%s'."));
+		else if (errno != ENOENT)
+			eprintf("fopen %s \"%s\":", path);
+	}
 
-		if (f == NULL) {
-			snprintf(cp, sizeof(cp), "%s/redshift.conf", "/etc");
-			f = fopen(cp, "r");
-		}
-#endif
+	if (f) {
+		*path_out = path;
 	} else {
-		f = fopen(filepath, "r");
-		if (f == NULL) {
-			weprintf("fopen:");
-			return NULL;
-		}
+		free(path);
+		*path_out = NULL;
+	}
+	return f;
+}
+
+
+/**
+ * Open the configuration file for reading
+ * 
+ * @param   path         The path to the configuration file, or `NULL` if the
+ *                       application should look for it in the default paths
+ * @param   path_out     Output parameter for the configuration file
+ * @param   pathbuf_out  Output parameter for the memory allocation for `*path_out`;
+ *                       will be set to `NULL` unless `path` is `NULL`
+ * @return               `FILE` object for the reading the file; `NULL` if not
+ *                       found and `path` is `NULL`
+ */
+static FILE *
+open_config_file(const char *path, const char **path_out, char **pathbuf_out)
+{
+	FILE *f = NULL;
+	size_t i;
+
+	if (!path) {
+		for (i = 0; !f && i < ELEMSOF(paths); i++)
+			f = try_path(&paths[i], pathbuf_out);
+		if (!f)
+			weprintf(_("No configuration file found."));
+		*path_out = *pathbuf_out;
+	} else {
+		f = fopen(path, "r");
+		if (!f)
+			eprintf("fopen %s \"r\":", path);
+		*path_out = path;
+		*pathbuf_out = NULL;
 	}
 
 	return f;
 }
 
-int
-config_ini_init(struct config_ini_state *state, const char *filepath)
+
+void
+config_ini_init(struct config_ini_state *state, const char *path)
 {
 	struct config_ini_section *section = NULL;
-	char line[MAX_LINE_LENGTH];
-	char *s;
+	struct config_ini_setting *setting;
+	char *line = NULL, *s, *p, *value, *end, *pathbuf;
+	char *next_line = NULL, *name;
+	size_t size = 0;
+	ssize_t len;
 	FILE *f;
 
 	state->sections = NULL;
 
-	f = open_config_file(filepath);
-	if (f == NULL) {
-		/* Only a serious error if a file was explicitly requested. */
-		return filepath ? 0 : -1;
-	}
+	f = open_config_file(path, &path, &pathbuf);
+	if (!f)
+		return;
+	while ((s = next_line) || (len = getline(&line, &size, f)) >= 0) {
+		if (!s && (s = line, strlen(s) != (size_t)len))
+			eprintf(_("Config file contains NUL byte."));
 
-	for (;;) {
-		/* Handle the file input linewise. */
-		char *r = fgets(line, sizeof(line), f);
-		if (!r)
-			break;
-
-		/* Strip leading blanks and trailing newline. */
-		s = line + strspn(line, " \t");
-		s[strcspn(s, "\r\n")] = '\0';
-
-		/* Skip comments and empty lines. */
-		if (s[0] == ';' || s[0] == '#' || s[0] == '\0')
-			continue;
+		s = ltrim(s);
+		next_line = NULL;
+		end = &s[strcspn(s, "\r\n")];
+		if (*end) {
+			p = end;
+			do {
+				*p++ = '\0';
+			} while (*p == '\r' || *p == '\n');
+			if (*p)
+				next_line = p;
+		}
+		rtrim(s, end);
 
-		if (s[0] == '[') {
-			/* Read name of section. */
-			const char *name = &s[1];
-			char *end = strchr(s, ']');
-			if (end == NULL || end[1] != '\0' || end == name) {
-				weprintf(_("Malformed section header in config file."));
-				fclose(f);
-				config_ini_free(state);
-				return -1;
-			}
+		switch (*s) {
+		case ';': /* comment line */
+		case '#': /* comment line */
+		case '\0': /* blank line */
+			break;
 
+		case '[': /* "[%s]", section */
+			end = strchr(name = &s[1], ']');
+			if (!end || end[1] || end == name)
+				eprintf(_("Malformed section header in config file."));
 			*end = '\0';
-
-			/* Create section. */
 			section = emalloc(sizeof(*section));
-
-			/* Insert into section list. */
-			section->name = NULL;
+			section->name = estrdup(name);
 			section->settings = NULL;
 			section->next = state->sections;
 			state->sections = section;
+			break;
 
-			/* Copy section name. */
-			section->name = malloc(end - name + 1);
-			if (section->name == NULL) {
-				fclose(f);
-				config_ini_free(state);
-				return -1;
-			}
-
-			memcpy(section->name, name, end - name + 1);
-		} else {
-			char *value, *end;
-			size_t value_len;
-			struct config_ini_setting *setting;
-
-			/* Split assignment at equals character. */
-			end = strchr(s, '=');
-			if (!end || end == s) {
-				weprintf(_("Malformed assignment in config file."));
-				fclose(f);
-				config_ini_free(state);
-				return -1;
-			}
-
-			*end++ = '\0';
-			value = end;
-
-			if (!section) {
-				weprintf(_("Assignment outside section in config file."));
-				fclose(f);
-				config_ini_free(state);
-				return -1;
-			}
-
-			/* Create section. */
+		default: /* "%s = %s", name, value */
+			value = p = strchr(name = s, '=');
+			if (!value || value == name)
+				eprintf(_("Malformed assignment in config file."));
+			*value++ = '\0';
+			if (!section)
+				eprintf(_("Assignment outside section in config file."));
 			setting = emalloc(sizeof(*setting));
-
-			/* Insert into section list. */
-			setting->name = NULL;
-			setting->value = NULL;
+			setting->name = estrdup(rtrim(name, p));
+			setting->value = estrdup(rtrim(ltrim(value), NULL));
 			setting->next = section->settings;
 			section->settings = setting;
-
-			/* Copy name of setting. */
-			setting->name = emalloc(end - s);
-
-			memcpy(setting->name, s, end - s);
-
-			/* Copy setting value. */
-			value_len = strlen(value) + 1;
-			setting->value = emalloc(value_len);
-
-			memcpy(setting->value, value, value_len);
+			break;
 		}
 	}
-
+	if (ferror(f))
+		eprintf("getline %s:", path);
+	free(pathbuf);
+	free(line);
 	fclose(f);
-
-	return 0;
 }
 
+
 void
 config_ini_free(struct config_ini_state *state)
 {
@@ -270,6 +345,7 @@ config_ini_free(struct config_ini_state *state)
 	}
 }
 
+
 struct config_ini_section *
 config_ini_get_section(struct config_ini_state *state, const char *name)
 {