| Message ID | 20191128114500.6289-1-y.karadz@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | kernel-shark: Retrieve the home of root from "/etc/passwd" | expand |
On Thu, Nov 28, 2019 at 1:46 PM Yordan Karadzhov (VMware) <y.karadz@gmail.com> wrote: [...] > + auto lamRootHome = [] () { > + QFile fPswd("/etc/passwd"); > + QString home("/root"); > + QStringList userInfo; > + > + fPswd.open(QIODevice::ReadOnly); > + if (!fPswd.isOpen()) > + return home; > + > + QTextStream s(&fPswd); > + while (!s.atEnd()) { > + userInfo = s.readLine().split(':'); > + > + /* Check the User Id. */ > + if (userInfo[2].toInt() == 0) { > + home = userInfo[5]; > + break; > + } > + } > + Another option is to use getpwent(3) [0] instead of parsing /etc/passwd by hand. Cheers, -- Slavi [0] http://man7.org/linux/man-pages/man3/getpwent.3.html
On Thu, 28 Nov 2019 16:27:11 +0200 Slavomir Kaslev <slavomir.kaslev@gmail.com> wrote: > On Thu, Nov 28, 2019 at 1:46 PM Yordan Karadzhov (VMware) > <y.karadz@gmail.com> wrote: > [...] > > + auto lamRootHome = [] () { > > + QFile fPswd("/etc/passwd"); > > + QString home("/root"); > > + QStringList userInfo; > > + > > + fPswd.open(QIODevice::ReadOnly); > > + if (!fPswd.isOpen()) > > + return home; > > + > > + QTextStream s(&fPswd); > > + while (!s.atEnd()) { > > + userInfo = s.readLine().split(':'); > > + > > + /* Check the User Id. */ > > + if (userInfo[2].toInt() == 0) { > > + home = userInfo[5]; > > + break; > > + } > > + } > > + > > Another option is to use getpwent(3) [0] instead of parsing /etc/passwd by hand. Thank you! My google fu is starting to show its age, as I did a bit of searching looking for a library function to parse passwd, knowing one had to be there, but came up empty. This is exactly what I was looking for. Yes, Yordan, I think using this would be the better option as if I had found it, it would have been what I would have suggested in the first place. -- Steve
On 28.11.19 г. 16:27 ч., Slavomir Kaslev wrote: > On Thu, Nov 28, 2019 at 1:46 PM Yordan Karadzhov (VMware) > <y.karadz@gmail.com> wrote: > [...] >> + auto lamRootHome = [] () { >> + QFile fPswd("/etc/passwd"); >> + QString home("/root"); >> + QStringList userInfo; >> + >> + fPswd.open(QIODevice::ReadOnly); >> + if (!fPswd.isOpen()) >> + return home; >> + >> + QTextStream s(&fPswd); >> + while (!s.atEnd()) { >> + userInfo = s.readLine().split(':'); >> + >> + /* Check the User Id. */ >> + if (userInfo[2].toInt() == 0) { >> + home = userInfo[5]; >> + break; >> + } >> + } >> + > > Another option is to use getpwent(3) [0] instead of parsing /etc/passwd by hand. > Hi Slavi, Thanks for pointing out this! This simplifies the patch a lot. I am sending a new version. cheers, Yordan > Cheers, > > -- Slavi > > [0] http://man7.org/linux/man-pages/man3/getpwent.3.html >
On Thu, Dec 12, 2019 at 3:30 PM Yordan Karadzhov (VMware) <y.karadz@gmail.com> wrote: [...] > Thanks for pointing out this! > This simplifies the patch a lot. I am sending a new version. I just saw the patch and I think I mislead you (sorry about that) by referring you to getpwent(3), since getpwuid(3) is a better match for this use-case and will make the patch even smaller.
On 12.12.19 г. 17:18 ч., Slavomir Kaslev wrote: > On Thu, Dec 12, 2019 at 3:30 PM Yordan Karadzhov (VMware) > <y.karadz@gmail.com> wrote: > [...] > >> Thanks for pointing out this! >> This simplifies the patch a lot. I am sending a new version. > > I just saw the patch and I think I mislead you (sorry about that) by > referring you to getpwent(3), since getpwuid(3) is a better match for > this use-case and will make the patch even smaller. Yes, getpwuid(3) is perfect. Thanks a lot! Sending v3. Y.
diff --git a/kernel-shark/src/KsMainWindow.cpp b/kernel-shark/src/KsMainWindow.cpp index bd6c338..fa887fc 100644 --- a/kernel-shark/src/KsMainWindow.cpp +++ b/kernel-shark/src/KsMainWindow.cpp @@ -422,6 +422,30 @@ QString KsMainWindow::_getCacheDir() QDir().mkpath(dir); }; + auto lamRootHome = [] () { + QFile fPswd("/etc/passwd"); + QString home("/root"); + QStringList userInfo; + + fPswd.open(QIODevice::ReadOnly); + if (!fPswd.isOpen()) + return home; + + QTextStream s(&fPswd); + while (!s.atEnd()) { + userInfo = s.readLine().split(':'); + + /* Check the User Id. */ + if (userInfo[2].toInt() == 0) { + home = userInfo[5]; + break; + } + } + + fPswd.close(); + return home; + }; + dir = getenv("KS_USER_CACHE_DIR"); if (!dir.isEmpty()) { if (!QDir(dir).exists()) @@ -432,7 +456,7 @@ QString KsMainWindow::_getCacheDir() dir += "/kernelshark"; if (geteuid() == 0) - dir.replace(QDir::homePath(), "/root"); + dir.replace(QDir::homePath(), lamRootHome()); if (!QDir(dir).exists()) lamMakePath(false);
Do not assume that root is always at "/root". Instead read the "/etc/passwd" file and searches for the user id of 0. Return the home path for that user. On any error just quietly default back to "/root". Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com> --- kernel-shark/src/KsMainWindow.cpp | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-)