conf-parser: add ini/.desktop file parser

3 files changed, 355 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index f7ed5ebbcd..6f41e8878c 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CFLAGS=-Wall -Wextra -O0 -g -pipe -D_GNU_SOURCE -fdiagnostics-show-option -Wno-unused-parameter
 LIBS=-lrt
 
-systemd: main.o name.o util.o set.o hashmap.o strv.o job.o manager.o
+systemd: main.o name.o util.o set.o hashmap.o strv.o job.o manager.o conf-parser.o
 	$(CC) $(CFLAGS) -o $@ $^  $(LIBS)
 
 clean:
diff --git a/conf-parser.c b/conf-parser.c
new file mode 100644
index 0000000000..c45acd7702
--- /dev/null
+++ b/conf-parser.c
@@ -0,0 +1,321 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <assert.h>
+#include <stdlib.h>
+
+#include "conf-parser.h"
+#include "util.h"
+#include "macro.h"
+
+#define WHITESPACE " \t\n"
+#define COMMENTS "#;\n"
+#define LINE_MAX 4096
+
+/* Run the user supplied parser for an assignment */
+static int next_assignment(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const ConfigItem *t,
+                const char *lvalue,
+                const char *rvalue,
+                void *userdata) {
+
+        assert(filename);
+        assert(t);
+        assert(lvalue);
+        assert(rvalue);
+
+        for (; t->parse; t++) {
+
+                if (t->lvalue && !streq(lvalue, t->lvalue))
+                        continue;
+
+                if (t->section && !section)
+                        continue;
+
+                if (t->section && !streq(section, t->section))
+                        continue;
+
+                return t->parse(filename, line, section, lvalue, rvalue, t->data, userdata);
+        }
+
+        fprintf(stderr, "[%s:%u] Unknown lvalue '%s' in section '%s'.", filename, line, lvalue, strna(section));
+        return -EBADMSG;
+}
+
+/* Returns non-zero when c is contained in s */
+static int in_string(char c, const char *s) {
+        assert(s);
+
+        for (; *s; s++)
+                if (*s == c)
+                        return 1;
+
+        return 0;
+}
+
+/* Remove all whitepsapce from the beginning and the end of *s. *s may
+ * be modified. */
+static char *strip(char *s) {
+        char *b = s+strspn(s, WHITESPACE);
+        char *e, *l = NULL;
+
+        for (e = b; *e; e++)
+                if (!in_string(*e, WHITESPACE))
+                        l = e;
+
+        if (l)
+                *(l+1) = 0;
+
+        return b;
+}
+
+/* Parse a variable assignment line */
+static int parse_line(const char *filename, unsigned line, char **section, const ConfigItem *t, char *l, void *userdata) {
+        char *e, *c, *b;
+
+        b = l+strspn(l, WHITESPACE);
+
+        if ((c = strpbrk(b, COMMENTS)))
+                *c = 0;
+
+        if (!*b)
+                return 0;
+
+        if (startswith(b, ".include ")) {
+                char *path = NULL, *fn;
+                int r;
+
+                fn = strip(b+9);
+                if (!is_path_absolute(fn)) {
+                        const char *k;
+
+                        if ((k = strrchr(filename, '/'))) {
+                                char *dir;
+
+                                if (!(dir = strndup(filename, k-filename)))
+                                        return -ENOMEM;
+
+                                if (asprintf(&path, "%s/%s", dir, fn) < 0)
+                                        return -errno;
+
+                                fn = path;
+                                free(dir);
+                        }
+                }
+
+                r = config_parse(fn, t, userdata);
+                free(path);
+                return r;
+        }
+
+        if (*b == '[') {
+                size_t k;
+                char *n;
+
+                k = strlen(b);
+                assert(k > 0);
+
+                if (b[k-1] != ']') {
+                        fprintf(stderr, "[%s:%u] Invalid section header.", filename, line);
+                        return -EBADMSG;
+                }
+
+                if (!(n = strndup(b+1, k-2)))
+                        return -ENOMEM;
+
+                free(*section);
+                *section = n;
+
+                return 0;
+        }
+
+        if (!(e = strchr(b, '='))) {
+                fprintf(stderr, "[%s:%u] Missing '='.", filename, line);
+                return -EBADMSG;
+        }
+
+        *e = 0;
+        e++;
+
+        return next_assignment(filename, line, *section, t, strip(b), strip(e), userdata);
+}
+
+/* Go through the file and parse each line */
+int config_parse(const char *filename, const ConfigItem *t, void *userdata) {
+        unsigned line = 0;
+        char *section = NULL;
+        FILE *f;
+        int r;
+
+        assert(filename);
+        assert(t);
+
+        if (!(f = fopen(filename, "re"))) {
+                r = -errno;
+                fprintf(stderr, "Failed to open configuration file '%s': %s", filename, strerror(-r));
+                goto finish;
+        }
+
+        while (!feof(f)) {
+                char l[LINE_MAX];
+
+                if (!fgets(l, sizeof(l), f)) {
+                        if (feof(f))
+                                break;
+
+                        r = -errno;
+                        fprintf(stderr, "Failed to read configuration file '%s': %s", filename, strerror(-r));
+                        goto finish;
+                }
+
+                if ((r = parse_line(filename, ++line, &section, t, l, userdata)) < 0)
+                        goto finish;
+        }
+
+        r = 0;
+
+finish:
+        free(section);
+
+        if (f)
+                fclose(f);
+
+        return r;
+}
+
+int config_parse_int(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        int *i = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if ((r = safe_atoi(rvalue, i)) < 0) {
+                fprintf(stderr, "[%s:%u] Failed to parse numeric value: %s", filename, line, rvalue);
+                return r;
+        }
+
+        return 0;
+}
+
+int config_parse_unsigned(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        unsigned *u = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if ((r = safe_atou(rvalue, u)) < 0) {
+                fprintf(stderr, "[%s:%u] Failed to parse numeric value: %s", filename, line, rvalue);
+                return r;
+        }
+
+        return 0;
+}
+
+int config_parse_size(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        size_t *sz = data;
+        unsigned u;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if ((r = safe_atou(rvalue, &u)) < 0) {
+                fprintf(stderr, "[%s:%u] Failed to parse numeric value: %s", filename, line, rvalue);
+                return r;
+        }
+
+        *sz = (size_t) u;
+        return 0;
+}
+
+int config_parse_bool(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        int k;
+        bool *b = data;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if ((k = parse_boolean(rvalue)) < 0) {
+                fprintf(stderr, "[%s:%u] Failed to parse boolean value: %s", filename, line, rvalue);
+                return k;
+        }
+
+        *b = !!k;
+        return 0;
+}
+
+int config_parse_string(
+                const char *filename,
+                unsigned line,
+                const char *section,
+                const char *lvalue,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        char **s = data;
+        char *n;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (*rvalue) {
+                if (!(n = strdup(rvalue)))
+                        return -ENOMEM;
+        } else
+                n = NULL;
+
+        free(*s);
+        *s = n;
+
+        return 0;
+}
diff --git a/conf-parser.h b/conf-parser.h
new file mode 100644
index 0000000000..11f537918f
--- /dev/null
+++ b/conf-parser.h
@@ -0,0 +1,33 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+#ifndef fooconfparserhfoo
+#define fooconfparserhfoo
+
+#include <stdio.h>
+
+/* An abstract parser for simple, line based, shallow configuration
+ * files consisting of variable assignments only. */
+
+typedef int (*config_parser_cb_t)(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+
+/* Wraps info for parsing a specific configuration variable */
+typedef struct ConfigItem {
+        const char *lvalue; /* name of the variable */
+        config_parser_cb_t parse; /* Function that is called to parse the variable's value */
+        void *data; /* Where to store the variable's data */
+        const char *section;
+} ConfigItem;
+
+/* The configuration file parsing routine. Expects a table of
+ * config_items in *t that is terminated by an item where lvalue is
+ * NULL */
+int config_parse(const char *filename, const ConfigItem *t, void *userdata);
+
+/* Generic parsers */
+int config_parse_int(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+int config_parse_unsigned(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+int config_parse_size(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+int config_parse_bool(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+int config_parse_string(const char *filename, unsigned line, const char *section, const char *lvalue, const char *rvalue, void *data, void *userdata);
+
+#endif