Rewrite in C, release v2.0 (from branch 'v2')2.0

1 files changed, 260 insertions, 0 deletions

diff --git a/src/envstore.c b/src/envstore.c
new file mode 100644
index 0000000..171b786
--- /dev/null
+++ b/src/envstore.c
@@ -0,0 +1,260 @@
+/*
+ * Copyright © 2009 by Daniel Friesel <derf@derf.homelinux.org>
+ * License: WTFPL <http://sam.zoy.org/wtfpl>
+ *
+ * Function policy: Fail early (use err/errx if something goes wrong)
+ */
+
+#include <err.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/*
+ * This struct is part of a linked list and contains one shell parameter
+ */
+
+struct parameter {
+	char *name;
+	char *content;
+	struct parameter *next;
+};
+
+
+/*
+ * Add element to linked list
+ *
+ * Parameters: list head (may be NULL), new list element
+ * Returns new list head
+ */
+
+static struct parameter * list_add(struct parameter *first, struct parameter *new) {
+	new->next = first;
+	first = new;
+	return first;
+}
+
+
+/*
+ * Remove element from linked list
+ *
+ * Parameters: list head, ->name part of element to remove
+ * Returns new list head (may be NULL)
+ */
+
+static struct parameter * list_remove(struct parameter *first, char *string) {
+	struct parameter *cur = first;
+	struct parameter *prev = NULL;
+
+	while (cur != NULL) {
+		if (strcmp(cur->name, string) == 0) {
+
+			if (prev == NULL)
+				return cur->next;
+
+			prev->next = cur->next;
+			return first;
+		}
+		prev = cur;
+		cur = cur->next;
+	}
+	return first;
+}
+
+
+static void store_save(struct parameter *first, char *file) {
+	struct parameter *cur = first;
+	FILE *fp;
+	char *tmpfile = malloc(strlen(file) + 5);
+
+	if (tmpfile == NULL)
+		err(EXIT_FAILURE, "malloc");
+
+	if (snprintf(tmpfile, strlen(file) + 5, "%s.tmp", file) < 3)
+		err(EXIT_FAILURE, "snprintf");
+
+	umask(0077);
+	fp = fopen(tmpfile, "w+");
+	if (fp == NULL)
+		err(EXIT_FAILURE, "Unable to save store to '%s'", file);
+
+	while (cur != NULL) {
+		fprintf(fp, "%s %s\n", cur->name, cur->content);
+		cur = cur->next;
+	}
+
+	if (fclose(fp) != 0)
+		err(EXIT_FAILURE, "fclose %s", file);
+
+	if (rename(tmpfile, file) != 0)
+		err(EXIT_FAILURE, "Unable to rename '%s' to '%s'", tmpfile, file);
+}
+
+
+static struct parameter * store_load(char *file) {
+	struct parameter *first = NULL;
+	struct parameter *new;
+	struct stat finfo;
+	uid_t self_uid = geteuid();
+	char vname[128];
+	char vcontent[256];
+	FILE *fp = fopen(file, "r");
+
+	/* Assume the store file does not exist and the store is empty
+	 *   (-> return NULL for empty list)
+	 * If it does in fact exist but has wrong permissions or similar,
+	 * the user will only notice if it happens with envstore save/rm (FIXME)
+	 */
+	if (fp == NULL)
+		return NULL;
+
+	if (fstat(fileno(fp), &finfo) != 0)
+		errx(EXIT_FAILURE, "Unable to verify store file permissions (%s)", file);
+
+	if (finfo.st_uid != self_uid)
+		errx(EXIT_FAILURE, "Store file '%s' is insecure (must be owned by you, not uid %d)", file, finfo.st_uid);
+
+	if ((finfo.st_mode & 077) > 0)
+		errx(EXIT_FAILURE, "Store file '%s' has insecure permissions %04o (recommended: 0600)", file, finfo.st_mode & 07777);
+
+	while (fscanf(fp, "%127s %255[^\n]\n", vname, vcontent) != EOF) {
+		new = malloc(sizeof (struct parameter));
+		if (new == NULL)
+			err(EXIT_FAILURE, "malloc");
+
+		new->name = strdup(vname);
+		new->content = strdup(vcontent);
+
+		if ((new->name == NULL) || (new->content) == NULL)
+			err(EXIT_FAILURE, "strdup");
+
+		first = list_add(first, new);
+	}
+
+	if (fclose(fp) != 0)
+		err(EXIT_FAILURE, "fclose %s", file);
+
+	return first;
+}
+
+
+static inline void command_clear(char *store_file) {
+	/*
+	 * No error checking - assume that the file didn't exist in the first place
+	 * if unlink fails.
+	 */
+	unlink(store_file);
+}
+
+
+static inline void command_eval(char *store_file) {
+	struct parameter *first = store_load(store_file);
+	struct parameter *cur = first;
+	unsigned long int i;
+
+	while (cur != NULL) {
+
+		printf("export %s='", cur->name);
+		for (i = 0; i < strlen(cur->content); i++) {
+			if (cur->content[i] == '\'')
+				fputs("'\"'\"'", stdout);
+			else
+				putchar(cur->content[i]);
+		}
+		fputs("'\n", stdout);
+		cur = cur->next;
+	}
+}
+
+
+static inline void command_list(char *store_file) {
+	struct parameter *first = store_load(store_file);
+	struct parameter *cur = first;
+
+	while (cur != NULL) {
+		printf("%-15s = %s\n", cur->name, cur->content);
+		cur = cur->next;
+	}
+}
+
+
+static inline void command_rm(char *store_file, char *param) {
+	struct parameter *first = store_load(store_file);
+	first = list_remove(first, param);
+	store_save(first, store_file);
+}
+
+
+static inline void command_save(char *store_file, char *param, char *value, int argc) {
+	struct parameter *first = store_load(store_file);
+	struct parameter new;
+	char *newvalue;
+	first = list_remove(first, param);
+
+	if (argc > 3)
+		newvalue = value;
+	else
+		newvalue = getenv(param);
+
+	if (newvalue == NULL)
+		errx(EXIT_FAILURE, "parameter '%s' has no value", param);
+
+	if ((strlen(param) > 127) || (strlen(newvalue) > 255))
+		errx(EXIT_FAILURE, "parameter or value too long (see man envstore -> LIMITATIONS)");
+
+	new.name = param;
+	new.content = newvalue;
+
+	first = list_add(first, &new);
+	store_save(first, store_file);
+}
+
+
+int main(int argc, char **argv) {
+	char *store_file;
+	uid_t my_uid = geteuid();
+
+	if (argc < 2)
+		errx(EXIT_FAILURE, "Insufficient arguments");
+
+	store_file = getenv("ENVSTORE_FILE");
+	if (store_file == NULL) {
+		store_file = malloc(64);
+		if (store_file == NULL) {
+			err(EXIT_FAILURE, "malloc");
+		}
+		if (snprintf(store_file, 63, "/tmp/envstore-%d", (int)my_uid) < 10) {
+			err(EXIT_FAILURE, "snprintf");
+		}
+	}
+
+	switch (argv[1][0]) {
+		case 'c':
+			command_clear(store_file);
+			break;
+		case 'e':
+			command_eval(store_file);
+			break;
+		case 'l':
+			command_list(store_file);
+			break;
+		case 'r':
+			if (argc < 3)
+				errx(EXIT_FAILURE, "Usage: rm <parameter>");
+			command_rm(store_file, argv[2]);
+			break;
+		case 's':
+			if (argc < 3)
+				errx(EXIT_FAILURE, "Usage: save <parameter> [value]");
+			command_save(store_file, argv[2], argv[3], argc);
+			break;
+		default:
+			errx(EXIT_FAILURE, "Unknown action: %s", argv[1]);
+			break;
+	}
+
+	return EXIT_SUCCESS;
+}