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Port current_zone to Red Hat

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Howard Hinnant
2016-06-10 21:15:59 -04:00
parent b38d20e126
commit 5aa704d5f7
1 changed files with 43 additions and 26 deletions
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69
tz.cpp
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@@ -2437,20 +2437,6 @@ current_zone()
const time_zone*
current_zone()
{
// On some versions of some linux distro's (e.g. Ubuntu),
// the current timezone might be in the first line of
// the /etc/timezone file. So we check that.
#if __linux
std::ifstream timezone_file("/etc/timezone");
if (timezone_file.is_open())
{
std::string line;
std::getline(timezone_file, line);
if (!line.empty())
return locate_zone(line);
// Fall through to try other means.
}
#endif
// On some OS's a file called /etc/localtime may
// exist and it may be either a real file
// containing time zone details or a symlink to such a file.
@@ -2466,25 +2452,56 @@ current_zone()
// "../usr/share/zoneinfo/America/Los_Angeles".
struct stat sb;
CONSTDATA auto timezone = "/etc/localtime";
if (lstat(timezone, &sb) == -1 || sb.st_size == 0)
throw std::runtime_error("Could not get lstat on /etc/localtime");
std::string result(sb.st_size, '\0');
while (true)
if (lstat(timezone, &sb) == 0 && S_ISLNK(sb.st_mode) && sb.st_size > 0)
{
std::string result(sb.st_size, '\0');
auto sz = readlink(timezone, &result.front(), result.size());
if (sz == -1)
throw std::runtime_error("readlink failure");
auto tmp = result.size();
result.resize(sz);
if (sz <= tmp)
break;
const char zonepath[] = "/usr/share/zoneinfo/";
const size_t zonepath_len = sizeof(zonepath)/sizeof(zonepath[0])-1;
const size_t pos = result.find(zonepath);
if (pos != result.npos)
result.erase(0, zonepath_len+pos);
return locate_zone(result);
}
const char zonepath[] = "/usr/share/zoneinfo/";
const size_t zonepath_len = sizeof(zonepath)/sizeof(zonepath[0])-1;
const size_t pos = result.find(zonepath);
if (pos != result.npos)
result.erase(0, zonepath_len+pos);
return locate_zone(result);
{
// On some versions of some linux distro's (e.g. Ubuntu),
// the current timezone might be in the first line of
// the /etc/timezone file.
std::ifstream timezone_file("/etc/timezone");
if (timezone_file.is_open())
{
std::string result;
std::getline(timezone_file, result);
if (!result.empty())
return locate_zone(result);
}
// Fall through to try other means.
}
{
// On some versions of some linux distro's (e.g. Red Hat),
// the current timezone might be in the first line of
// the /etc/sysconfig/clock file as:
// ZONE="US/Eastern"
std::ifstream timezone_file("/etc/sysconfig/clock");
std::string result;
while (timezone_file)
{
std::getline(timezone_file, result);
auto p = result.find("ZONE=\"");
if (p != std::string::npos)
{
result.erase(p, p+6);
result.erase(result.rfind('"'));
return locate_zone(result);
}
}
// Fall through to try other means.
}
throw std::runtime_error("Could not get current timezone");
}
#endif