make the config parser suck less

2 files changed, 195 insertions, 62 deletions

diff --git a/Makefile b/Makefile
index bee264c..85b47a9 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,8 @@ PREFIX ?= /usr/local
 MANPREFIX ?= $(PREFIX)/share/man
 
 # compiler flags
-CPPFLAGS := -DVERSION=\"$(VERSION)\" $(CPPFLAGS)
-CFLAGS   := -std=c99 -g -pedantic -Wall -Wextra $(CFLAGS)
+CPPFLAGS := -DVERSION=\"$(VERSION)\" -D_GNU_SOURCE $(CPPFLAGS)
+CFLAGS   := -std=c11 -g -pedantic -Wall -Wextra -Wno-missing-field-initializers $(CFLAGS)
 LDLIBS    = -lalpm
 
 DISTFILES = expac.c README.pod
diff --git a/expac.c b/expac.c
index 0c1a2e0..b94760c 100644
--- a/expac.c
+++ b/expac.c
@@ -24,10 +24,11 @@
  * OTHER DEALINGS IN THE SOFTWARE.
  */
 
-#define _GNU_SOURCE
 #include <alpm.h>
 #include <ctype.h>
+#include <errno.h>
 #include <getopt.h>
+#include <glob.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -66,6 +67,187 @@ int opt_pkgcounter = 0;
 
 typedef const char *(*extractfn)(void*);
 
+typedef struct config_t {
+  char **repos;
+  int size;
+  int capacity;
+} config_t;
+
+static inline void freep(void *p) { free(*(void **)p); }
+static inline void fclosep(FILE **p) { if (*p) fclose(*p); }
+static inline void globfreep(glob_t *p) { globfree(p); }
+#define _cleanup_(x) __attribute__((cleanup(x)))
+#define _cleanup_free_ _cleanup_(freep)
+
+static size_t strtrim(char *str) {
+  char *left = str, *right;
+
+  if (!str || *str == '\0') {
+    return 0;
+  }
+
+  while (isspace((unsigned char)*left)) {
+    left++;
+  }
+  if (left != str) {
+    memmove(str, left, (strlen(left) + 1));
+    left = str;
+  }
+
+  if (*str == '\0') {
+    return 0;
+  }
+
+  right = strchr(str, '\0') - 1;
+  while (isspace((unsigned char)*right)) {
+    right--;
+  }
+  *++right = '\0';
+
+  return right - left;
+}
+
+int is_section(const char *s, int n) {
+  return s[0] == '[' && s[n-1] == ']';
+}
+
+static int config_add_repo(config_t *config, char *reponame) {
+  /* first time setup */
+  if (config->repos == NULL) {
+    config->repos = calloc(10, sizeof(char*));
+    if (config->repos == NULL) {
+      return -ENOMEM;
+    }
+
+    config->size = 0;
+    config->capacity = 10;
+  }
+
+  /* grow when needed */
+  if (config->size == config->capacity) {
+    void *ptr;
+
+    ptr = realloc(config->repos, config->capacity * 2.5 * sizeof(char*));
+    if (ptr == NULL) {
+      return -ENOMEM;
+    }
+
+    config->repos = ptr;
+  }
+
+  config->repos[config->size] = strdup(reponame);
+  ++config->size;
+
+  return 0;
+}
+
+void config_reset(config_t *config) {
+  if (config == NULL)
+    return;
+
+  for (int i = 0; i < config->size; ++i)
+    free(config->repos[i]);
+
+  free(config->repos);
+}
+
+static int parse_one_file(config_t *config, const char *filename, char **section);
+
+static int parse_include(config_t *config, const char *include, char **section) {
+  _cleanup_(globfreep) glob_t globbuf = {};
+
+  if (glob(include, GLOB_NOCHECK, NULL, &globbuf) != 0) {
+    fprintf(stderr, "warning: globbing failed on '%s': out of memory\n",
+            include);
+    return -ENOMEM;
+  }
+
+  for (size_t i = 0; i < globbuf.gl_pathc; ++i)
+    parse_one_file(config, globbuf.gl_pathv[i], section);
+
+  return 0;
+}
+
+static char *split_keyval(char *line, const char *sep) {
+  strsep(&line, sep);
+  return line;
+}
+
+int parse_one_file(config_t *config, const char *filename, char **section) {
+  _cleanup_(fclosep) FILE *fp = NULL;
+  _cleanup_free_ char *line = NULL;
+  size_t n = 0;
+  int in_options = 0;
+
+  fp = fopen(filename, "r");
+  if (fp == NULL)
+    return -errno;
+
+  for (;;) {
+    ssize_t len;
+
+    errno = 0;
+    len = getline(&line, &n, fp);
+    if (len < 0) {
+      if (errno != 0)
+        return -errno;
+
+      /* EOF */
+      break;
+    }
+
+    len = strtrim(line);
+    if (len == 0 || line[0] == '#')
+      continue;
+
+    if (is_section(line, len)) {
+
+      free(*section);
+      *section = strndup(&line[1], len - 2);
+      if (*section == NULL)
+        return -ENOMEM;
+
+      in_options = strcmp(*section, "options") == 0;
+
+      if (!in_options) {
+        int r;
+
+        r = config_add_repo(config, *section);
+        if (r < 0)
+          return r;
+
+        continue;
+      }
+    }
+
+    if (in_options) {
+      char *val;
+
+      if (memchr(line, '=', len)) {
+        val = split_keyval(line, "=");
+
+        strtrim(val);
+        strtrim(line);
+
+        if (strcmp(line, "Include") == 0) {
+          int k;
+
+          k = parse_include(config, val, section);
+          if (k < 0)
+            return k;
+        }
+      }
+    }
+  }
+
+  return 0;
+}
+
+int config_parse(config_t *config, const char *filename) {
+  _cleanup_free_ char *section = NULL;
+
+  return parse_one_file(config, filename, &section);
+}
 static const char *alpm_backup_get_name(void *b)
 {
   alpm_backup_t *bkup = b;
@@ -110,33 +292,6 @@ static char *size_to_string(off_t pkgsize)
   return out;
 }
 
-static char *strtrim(char *str) {
-  char *pch = str;
-
-  if (!str || *str == '\0') {
-    return str;
-  }
-
-  while (isspace((unsigned char)*pch)) {
-    pch++;
-  }
-  if (pch != str) {
-    memmove(str, pch, (strlen(pch) + 1));
-  }
-
-  if (*str == '\0') {
-    return str;
-  }
-
-  pch = (str + (strlen(str) - 1));
-  while (isspace((unsigned char)*pch)) {
-    pch--;
-  }
-  *++pch = '\0';
-
-  return str;
-}
-
 static char *format_optdep(alpm_depend_t *optdep) {
   char *out;
 
@@ -150,9 +305,8 @@ static char *format_optdep(alpm_depend_t *optdep) {
 static alpm_handle_t *alpm_init(void) {
   alpm_handle_t *alpm = NULL;
   enum _alpm_errno_t alpm_errno = 0;
-  FILE *fp;
-  char line[PATH_MAX];
-  char *ptr, *section = NULL;
+  config_t config = { NULL, 0, 0 };
+  int r;
 
   alpm = alpm_initialize("/", "/var/lib/pacman", &alpm_errno);
   if (!alpm) {
@@ -162,39 +316,18 @@ static alpm_handle_t *alpm_init(void) {
 
   db_local = alpm_get_localdb(alpm);
 
-  fp = fopen("/etc/pacman.conf", "r");
-  if (!fp) {
-    perror("fopen: /etc/pacman.conf");
-    return alpm;
+  r = config_parse(&config, "/etc/pacman.conf");
+  if (r < 0) {
+    fprintf(stderr, "error: failed to parse config: %s\n", strerror(-r));
+    return NULL;
   }
 
-  while (fgets(line, PATH_MAX, fp)) {
-    strtrim(line);
-
-    if (strlen(line) == 0 || line[0] == '#') {
-      continue;
-    }
-    if ((ptr = strchr(line, '#'))) {
-      *ptr = '\0';
-    }
-
-    if (line[0] == '[' && line[strlen(line) - 1] == ']') {
-      ptr = &line[1];
-      if (section) {
-        free(section);
-      }
-
-      section = strdup(ptr);
-      section[strlen(section) - 1] = '\0';
-
-      if (strcmp(section, "options") != 0) {
-        alpm_register_syncdb(alpm, section, 0);
-      }
-    }
+  for (int i = 0; i < config.size; ++i) {
+    alpm_register_syncdb(alpm, config.repos[i], 0);
   }
 
-  free(section);
-  fclose(fp);
+  config_reset(&config);
+
   return alpm;
 }