util: avoid divide by zero FPE

[elogind.git] / src / shared / util.c

diff --git a/src/shared/util.c b/src/shared/util.c
index 462b541b41d6d7560b9ec0b792eb1f801633079b..9a45e6058e200813fed1bae7ff9d27f0ebb164a5 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -73,6 +73,7 @@ int saved_argc = 0;
 char **saved_argv = NULL;
 
 static volatile unsigned cached_columns = 0;
+static volatile unsigned cached_lines = 0;
 
 size_t page_size(void) {
         static __thread size_t pgsz = 0;
@@ -147,6 +148,10 @@ usec_t timespec_load(const struct timespec *ts) {
             ts->tv_nsec == (long) -1)
                 return (usec_t) -1;
 
+        if (ts->tv_sec > 0 &&
+            USEC_PER_SEC > ((UINT64_MAX - (ts->tv_nsec / NSEC_PER_USEC)) / (usec_t) ts->tv_sec))
+                return (usec_t) -1;
+
         return
                 (usec_t) ts->tv_sec * USEC_PER_SEC +
                 (usec_t) ts->tv_nsec / NSEC_PER_USEC;
@@ -174,6 +179,9 @@ usec_t timeval_load(const struct timeval *tv) {
             tv->tv_usec == (suseconds_t) -1)
                 return (usec_t) -1;
 
+        if (USEC_PER_SEC > (UINT64_MAX - tv->tv_usec) / (usec_t) tv->tv_sec)
+                return (usec_t) -1;
+
         return
                 (usec_t) tv->tv_sec * USEC_PER_SEC +
                 (usec_t) tv->tv_usec;
@@ -194,7 +202,7 @@ struct timeval *timeval_store(struct timeval *tv, usec_t u) {
         return tv;
 }
 
-bool endswith(const char *s, const char *postfix) {
+char* endswith(const char *s, const char *postfix) {
         size_t sl, pl;
 
         assert(s);
@@ -204,53 +212,49 @@ bool endswith(const char *s, const char *postfix) {
         pl = strlen(postfix);
 
         if (pl == 0)
-                return true;
+                return (char*) s + sl;
 
         if (sl < pl)
-                return false;
+                return NULL;
 
-        return memcmp(s + sl - pl, postfix, pl) == 0;
+        if (memcmp(s + sl - pl, postfix, pl) != 0)
+                return NULL;
+
+        return (char*) s + sl - pl;
 }
 
-bool startswith(const char *s, const char *prefix) {
-        size_t sl, pl;
+char* startswith(const char *s, const char *prefix) {
+        const char *a, *b;
 
         assert(s);
         assert(prefix);
 
-        sl = strlen(s);
-        pl = strlen(prefix);
-
-        if (pl == 0)
-                return true;
-
-        if (sl < pl)
-                return false;
+        a = s, b = prefix;
+        for (;;) {
+                if (*b == 0)
+                        return (char*) a;
+                if (*a != *b)
+                        return NULL;
 
-        return memcmp(s, prefix, pl) == 0;
+                a++, b++;
+        }
 }
 
-bool startswith_no_case(const char *s, const char *prefix) {
-        size_t sl, pl;
-        unsigned i;
+char* startswith_no_case(const char *s, const char *prefix) {
+        const char *a, *b;
 
         assert(s);
         assert(prefix);
 
-        sl = strlen(s);
-        pl = strlen(prefix);
-
-        if (pl == 0)
-                return true;
-
-        if (sl < pl)
-                return false;
-
-        for(i = 0; i < pl; ++i)
-                if (tolower(s[i]) != tolower(prefix[i]))
-                        return false;
+        a = s, b = prefix;
+        for (;;) {
+                if (*b == 0)
+                        return (char*) a;
+                if (tolower(*a) != tolower(*b))
+                        return NULL;
 
-        return true;
+                a++, b++;
+        }
 }
 
 bool first_word(const char *s, const char *word) {
@@ -2175,28 +2179,25 @@ int read_one_char(FILE *f, char *ret, usec_t t, bool *need_nl) {
 }
 
 int ask(char *ret, const char *replies, const char *text, ...) {
-        bool on_tty;
 
         assert(ret);
         assert(replies);
         assert(text);
 
-        on_tty = isatty(STDOUT_FILENO);
-
         for (;;) {
                 va_list ap;
                 char c;
                 int r;
                 bool need_nl = true;
 
-                if (on_tty)
+                if (on_tty())
                         fputs(ANSI_HIGHLIGHT_ON, stdout);
 
                 va_start(ap, text);
                 vprintf(text, ap);
                 va_end(ap);
 
-                if (on_tty)
+                if (on_tty())
                         fputs(ANSI_HIGHLIGHT_OFF, stdout);
 
                 fflush(stdout);
@@ -3815,11 +3816,6 @@ unsigned columns(void) {
         return c;
 }
 
-/* intended to be used as a SIGWINCH sighandler */
-void columns_cache_reset(int signum) {
-        cached_columns = 0;
-}
-
 int fd_lines(int fd) {
         struct winsize ws;
         zero(ws);
@@ -3834,23 +3830,40 @@ int fd_lines(int fd) {
 }
 
 unsigned lines(void) {
-        static __thread int parsed_lines = 0;
         const char *e;
+        unsigned l;
 
-        if (_likely_(parsed_lines > 0))
-                return parsed_lines;
+        if (_likely_(cached_lines > 0))
+                return cached_lines;
 
+        l = 0;
         e = getenv("LINES");
         if (e)
-                parsed_lines = atoi(e);
+                safe_atou(e, &l);
 
-        if (parsed_lines <= 0)
-                parsed_lines = fd_lines(STDOUT_FILENO);
+        if (l <= 0)
+                l = fd_lines(STDOUT_FILENO);
 
-        if (parsed_lines <= 0)
-                parsed_lines = 25;
+        if (l <= 0)
+                l = 24;
+
+        cached_lines = l;
+        return cached_lines;
+}
 
-        return parsed_lines;
+/* intended to be used as a SIGWINCH sighandler */
+void columns_lines_cache_reset(int signum) {
+        cached_columns = 0;
+        cached_lines = 0;
+}
+
+bool on_tty(void) {
+        static int cached_on_tty = -1;
+
+        if (_unlikely_(cached_on_tty < 0))
+                cached_on_tty = isatty(STDOUT_FILENO) > 0;
+
+        return cached_on_tty;
 }
 
 int running_in_chroot(void) {
@@ -5685,6 +5698,30 @@ int can_sleep(const char *type) {
         return false;
 }
 
+int can_sleep_disk(const char *type) {
+        char *w, *state;
+        size_t l, k;
+        int r;
+        _cleanup_free_ char *p = NULL;
+
+        assert(type);
+
+        r = read_one_line_file("/sys/power/disk", &p);
+        if (r < 0)
+                return r == -ENOENT ? 0 : r;
+
+        k = strlen(type);
+        FOREACH_WORD_SEPARATOR(w, l, p, WHITESPACE, state) {
+                if (l == k && memcmp(w, type, l) == 0)
+                        return true;
+
+                if (l == k + 2 && w[0] == '[' && memcmp(w + 1, type, l - 2) == 0 && w[l-1] == ']')
+                        return true;
+        }
+
+        return false;
+}
+
 bool is_valid_documentation_url(const char *url) {
         assert(url);
 
@@ -6056,3 +6093,26 @@ finish:
 
         return 0;
 }
+
+/* hey glibc, APIs with callbacks without a user pointer are so useless */
+void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
+                 int (*compar) (const void *, const void *, void *), void *arg) {
+        size_t l, u, idx;
+        const void *p;
+        int comparison;
+
+        l = 0;
+        u = nmemb;
+        while (l < u) {
+                idx = (l + u) / 2;
+                p = (void *)(((const char *) base) + (idx * size));
+                comparison = compar(key, p, arg);
+                if (comparison < 0)
+                        u = idx;
+                else if (comparison > 0)
+                        l = idx + 1;
+                else
+                        return (void *)p;
+        }
+        return NULL;
+}