Improve udev failure diagnostics.
A couple of folks had trouble understanding the existing message.
Before:
8XV7N15917000596 no permissions (udev requires plugdev group membership); see [http://developer.android.com/tools/device.html]
After:
8XV7N15917000596 no permissions (user buttmunch is not in the plugdev group); see [http://developer.android.com/tools/device.html]
This also fixes a libusb regression where we wouldn't show anything for
devices where we don't have permissions.
Bug: http://b/37707122
Test: ran "adb devices" as user buttmunch
Change-Id: I2fcd735ff4178145432b532a6e4dc8c93b2743fd
diff --git a/diagnose_usb.cpp b/diagnose_usb.cpp
index 0f067b0..9f721bf 100644
--- a/diagnose_usb.cpp
+++ b/diagnose_usb.cpp
@@ -25,13 +25,14 @@
#if defined(__linux__)
#include <grp.h>
+#include <pwd.h>
#endif
static const char kPermissionsHelpUrl[] = "http://developer.android.com/tools/device.html";
-// Returns a message describing any potential problems we find with udev, or nullptr if we can't
-// find plugdev information (i.e. udev is not installed).
-static const char* GetUdevProblem() {
+// Returns a message describing any potential problems we find with udev, or an empty string if we
+// can't find plugdev information (i.e. udev is not installed).
+static std::string GetUdevProblem() {
#if defined(__linux__)
errno = 0;
group* plugdev_group = getgrnam("plugdev");
@@ -41,43 +42,45 @@
perror("failed to read plugdev group info");
}
// We can't give any generally useful advice here, just let the caller print the help URL.
- return nullptr;
+ return "";
}
- // getgroups(2) indicates that the group_member() may not check the egid so we check it
+ // getgroups(2) indicates that the GNU group_member(3) may not check the egid so we check it
// additionally just to be sure.
if (group_member(plugdev_group->gr_gid) || getegid() == plugdev_group->gr_gid) {
// The user is in plugdev so the problem is likely with the udev rules.
- return "verify udev rules";
+ return "user in plugdev group; are your udev rules wrong?";
}
- return "udev requires plugdev group membership";
+ passwd* pwd = getpwuid(getuid());
+ return android::base::StringPrintf("user %s is not in the plugdev group",
+ pwd ? pwd->pw_name : "?");
#else
- return nullptr;
+ return "";
#endif
}
// Short help text must be a single line, and will look something like:
-// no permissions (reason); see <URL>
+//
+// no permissions (reason); see [URL]
std::string UsbNoPermissionsShortHelpText() {
std::string help_text = "no permissions";
- const char* problem = GetUdevProblem();
- if (problem != nullptr) {
- help_text += android::base::StringPrintf(" (%s)", problem);
- }
+ std::string problem(GetUdevProblem());
+ if (!problem.empty()) help_text += " (" + problem + ")";
return android::base::StringPrintf("%s; see [%s]", help_text.c_str(), kPermissionsHelpUrl);
}
-// Long help text can span multiple lines and should provide more detailed information.
+// Long help text can span multiple lines but doesn't currently provide more detailed information:
+//
+// insufficient permissions for device: reason
+// See [URL] for more information
std::string UsbNoPermissionsLongHelpText() {
std::string header = "insufficient permissions for device";
- const char* problem = GetUdevProblem();
- if (problem != nullptr) {
- header += android::base::StringPrintf(": %s", problem);
- }
+ std::string problem(GetUdevProblem());
+ if (!problem.empty()) header += ": " + problem;
- return android::base::StringPrintf("%s.\nSee [%s] for more information.",
- header.c_str(), kPermissionsHelpUrl);
+ return android::base::StringPrintf("%s\nSee [%s] for more information", header.c_str(),
+ kPermissionsHelpUrl);
}