From 20bcc774686078cf7f5c58ef058ca2458b01086d Mon Sep 17 00:00:00 2001 From: Daniel Friesel Date: Mon, 2 Nov 2009 21:21:10 +0100 Subject: Rewrite in C, release v2.0 (from branch 'v2') --- src/envstore.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 260 insertions(+) create mode 100644 src/envstore.c (limited to 'src/envstore.c') 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 + * License: WTFPL + * + * Function policy: Fail early (use err/errx if something goes wrong) + */ + +#include +#include +#include +#include +#include +#include +#include + +/* + * 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 "); + command_rm(store_file, argv[2]); + break; + case 's': + if (argc < 3) + errx(EXIT_FAILURE, "Usage: save [value]"); + command_save(store_file, argv[2], argv[3], argc); + break; + default: + errx(EXIT_FAILURE, "Unknown action: %s", argv[1]); + break; + } + + return EXIT_SUCCESS; +} -- cgit v1.2.3