From a17363e992943244987dbab754b112c77d938b5d Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Sat, 14 Oct 2023 17:06:51 +0200
Subject: [PATCH] common: New function scan_secondsstr.

* common/gettime.c (scan_secondsstr): New.

* common/t-gettime.c (test_scan_secondsstr):
(main): Call it.
---
 common/gettime.c    | 23 ++++++++++++++++++++
 common/gettime.h    |  1 +
 common/stringhelp.c |  2 +-
 common/t-gettime.c  | 52 ++++++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/common/gettime.c b/common/gettime.c
index 2a9b71779..c3b0c6c6c 100644
--- a/common/gettime.c
+++ b/common/gettime.c
@@ -37,6 +37,7 @@
 #ifdef HAVE_LANGINFO_H
 #include <langinfo.h>
 #endif
+#include <stdint.h>    /* We use uint64_t.  */
 
 #include "util.h"
 #include "i18n.h"
@@ -172,6 +173,28 @@ make_timestamp (void)
 }
 
 
+/* Specialized version of atoi which returns an u32 instead of an int
+ * and caps the result at 2^32-2.  Leading white space is skipped,
+ * scanning stops at at the first non-convertable byte.  Note that we
+ * do not cap at 2^32-1 because that value is often used as error
+ * return. */
+u32
+scan_secondsstr (const char *string)
+{
+  uint64_t value = 0;
+
+  while (*string == ' ' || *string == '\t')
+    string++;
+  for (; *string >= '0' && *string <= '9'; string++)
+    {
+      value *= 10;
+      value += atoi_1 (string);
+      if (value >= (u32)(-1))
+        return (u32)(-1) - 1;
+    }
+  return (u32)value;
+}
+
 
 /****************
  * Scan a date string and return a timestamp.
diff --git a/common/gettime.h b/common/gettime.h
index 4f7199f92..18f65ab1a 100644
--- a/common/gettime.h
+++ b/common/gettime.h
@@ -51,6 +51,7 @@ int    gnupg_faked_time_p (void);
 u32    make_timestamp (void);
 char *elapsed_time_string (time_t since, time_t now);
 
+u32    scan_secondsstr (const char *string);
 u32    scan_isodatestr (const char *string);
 int    isotime_p (const char *string);
 int    isotime_human_p (const char *string, int date_only);
diff --git a/common/stringhelp.c b/common/stringhelp.c
index 5407653de..9a2265258 100644
--- a/common/stringhelp.c
+++ b/common/stringhelp.c
@@ -725,7 +725,7 @@ compare_filenames (const char *a, const char *b)
 
 /* Convert a base-10 number in STRING into a 64 bit unsigned int
  * value.  Leading white spaces are skipped but no error checking is
- * done.  Thus it is similar to atoi(). */
+ * done.  Thus it is similar to atoi().  See also scan_secondsstr.  */
 uint64_t
 string_to_u64 (const char *string)
 {
diff --git a/common/t-gettime.c b/common/t-gettime.c
index 13cb1a2f7..76c305204 100644
--- a/common/t-gettime.c
+++ b/common/t-gettime.c
@@ -43,6 +43,56 @@ static int errcount;
 #define INVALID ((time_t)(-1))
 
 
+static void
+test_scan_secondsstr (void)
+{
+  struct { const char *string; u32 expected; } array [] = {
+    { "",  0 },
+    { "0",  0 },
+    { " 0",  0 },
+    { " 0x",  0 },
+    { " 1",  1 },
+    { "-1",  0 },
+    { " -1",  0 },
+    { "2",  2 },
+    { "11",  11 },
+    { "011",  11 },
+    { "3600 ",  3600 },
+    { "65535",  65535 },
+    { "65536",  65536 },
+    { "65537",  65537 },
+    { "4294967289", 4294967289 },
+    { "4294967290", 4294967290 },
+    { "4294967293", 4294967293 },
+    { "4294967295", 4294967294 },
+    { "4294967296", 4294967294 },
+    { "4294967297", 4294967294 },
+    { "4294967298", 4294967294 },
+    { "4294967299", 4294967294 },
+    { "4294967300", 4294967294 },
+    { "5294967300", 4294967294 },
+    { "9999999999", 4294967294 },
+    { "99999999999",4294967294 },
+    { NULL, 0 }
+  };
+  int idx;
+  u32 val;
+
+  for (idx=0; array[idx].string; idx++)
+    {
+      val = scan_secondsstr (array[idx].string);
+      if (val != array[idx].expected )
+        {
+          fail (idx);
+          if (verbose)
+            fprintf (stderr, "string '%s' exp: %ld got: %ld\n",
+                     array[idx].string, (unsigned long)array[idx].expected,
+                     (unsigned long)val);
+        }
+    }
+}
+
+
 static void
 test_isotime2epoch (void)
 {
@@ -103,7 +153,6 @@ test_isotime2epoch (void)
 }
 
 
-
 static void
 test_string2isotime (void)
 {
@@ -269,6 +318,7 @@ main (int argc, char **argv)
   if (argc > 1 && !strcmp (argv[1], "--verbose"))
     verbose = 1;
 
+  test_scan_secondsstr ();
   test_isotime2epoch ();
   test_string2isotime ();
   test_isodate_human_to_tm ();