July 2008 - Darwin-dev - lists.apple.com

Re: Interposing library calls
by Jernej Azarija 29 Jul '08

29 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=iglMZE2eP6ixefjRvpcaMeeuKBTyDfssbKFvw6PgIDg=; b=edTSUn7Mzmf+dFrLYDPbJ39GjB8Cf04uWdaijTqqMkbJQjGdQxAtfIXflmajrBbP6H 8A0YxfgHKM0n1gK1qvFmyyMmZrWIBLC4JuezPO1ahTpcxy8b+7ykIi4I846nN7JI7r/a mU97jyPgrx6BM4r4YIvaXPwxo85J1NjEdA3XI= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=FIS3O4VemxxB/uHx91Po9kckzUO3bWy+Y7QbSolOBWAjgV2PbG60dfSavwvyYqh9WY KmdlD0TX4JimX6RSIR7kinSirzZi/T+H0OB/L+TLfM+RxtRRF+0vq/Yd9MNcsJxpEtOb 3Wru8Hm8L1g19ECUJsTpvJt9+TiG3buBNuzBc= Thanks for all the help. I have another question before I stop annoying you. Suppose such library is created - is there any way it could be exported globally so that it affects every single binary on the system? As far as I can see, exporting DYLD_INSERT_LIBRARIES (through /etc/bashrc or whatever) doesn't affect applications running through the GUI which seems reasonable but makes me wonder how to preload the library in this cases. Jernej. On Fri, Jul 25, 2008 at 9:21 PM, Terry Lambert <tlambert(a)apple.com> wrote: > > On Jul 25, 2008, at 5:17 AM, Jernej Azarija wrote: >> >> Hello, >> >> this is a continuation of the previous thread located in darwin-kernel >> at : http://lists.apple.com/archives/Darwin-kernel/2008/Jul/msg00015.html >> . >> >> I assume my question is more on topic here. >> >> The conclusion reached in the above mentioned thread is that it's >> preferred to interpose library calls (in this case open/close) from a >> library loaded at runtime. I've therefore created a small example >> trying to intercept open, resolve the given path (using realpath()), >> print the resolved path and pass the work to open(). > > For these things to work, you need a relatively deep understanding of the ABI and linkage model. > > Quinn is correct that library interpostion is not officially supported by Apple. In general, this is because you will have to lock-step update your library with system library updates from Apple. The specific example I had in mind when I read Mike's suggestion on interposition is probably the same one Mike had in mind. Mine was "mallocdebug" (Mike used to maintain it, so that's why I'm guessing it's his example). > > It's possible to interpose, but you have to understand the lock-step nature of interposition, along with the nature of the library implementation, and the use of multi-level namespaces within libraries. The best source example is "mallocdebug", but again, you should be cautioned that what you want to do will have to be lock-stepped. > > Objective-C based code was intended to support runtime overrides as a language feature; you can still run into problems with library compatibility there, but it's less frequent when you follow the rules. > > [ ...] > >> I'm clueless about what is causing this issue. As far as I've checked >> libc' implementation, getcwd() is not using open() (at last not >> directly). I'd be glad to hear a hint on how to overcome this issue. > > __getcwd() uses open to get ".", then asks the system for the path to ".". Depending on the answer it gets, it may go and ask for ".." recursively until it gets all path components to the root of the volume. You appear to be interposing open at the wrong level in the symbol namespace, so getcwd() is calling your open() rather than the system open(). > > The difficulty in getting this type of detail right is another reason it's not supported. You are also unlikely to get it right to the point that multiple libraries can interpose the same set of calls, so if someone else tries to do what you are trying to do at the same time, one of you is going to be unhappy. > > >> Ps. I'm aware that this method is not officially "supported" by Apple, >> neither is any kernel "hacking" of this type. All this makes me >> wonder, how is someone able to deploy applications if it can't use >> internal information - in my opinion, forcing people not to mess with >> this stuff is just encouraging bad design of applications. > > The general cause of problems like the ones you are running into is usually that you are asking about how to implement a solution to a problem, when you've already arrived at the solution. Typically, it's better to ask "how do I solve this problem?" rather than "how do I implement this solution which I've already arrived at?", since you'll likely get more useful answers. > > -- Terry -- http://nd47.coderock.org/~azi _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: getutxent() not returning values when using 10.4u SDK
by Terry Lambert 25 Jul '08

25 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com if ((ut = fopen(_PATH_UTMP, "r")) == NULL) err(1, "%s", _PATH_UTMP); This file utmp does not appear to exist on 10.5. - -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Jul 24, 2008, at 11:11 PM, Rosyna wrote: I tried using the utmp code in http://www.opensource.apple.com/darwinsource/10.5.4/shell_cmds-118/w/w.c but it gives an error, "/var/run/utmp: No such file or directory" when attempting: (Basically, my only goal here is to find how long the current user has been logged in and doing it from a daemon safe framework/library. The "w" source is bad example code for you to use, since it implies a dependency on underlying implementation, depending on the manifest constants you have in scope. You could make the code variant based on getting the current version by using the uname(3) library call and examining the "release" field of the returned "struct utsname", and make your function decide to either use utmp or utmpx based on that. But really, the easiest way to make the code portable (including to other platforms) is going to be to popen(3) the "last" command with appropriate arguments, and parse its output using whitespace as field/ token separators. Apropros the problem you are trying to solve, you are likely not going to be happy doing this from a daemon in any case, since it's possible to have multiple simultaneous sessions for the console user, it's possible to have non-console users (ssh, telnet, ftp, etc.), and, using Fast User Switching, its possible to have multiple concurrent (but non-simultaneous) console users. The problem is that daemons are effectively their own session, and are not specifically associated with any particular user session, including the one that started them (unless it's started by a particular session, and you grab the information before the daemon actually backgrounds itself to disassociate itself from the user session). Unless you have the session information about the user you are asking about, you are unlikely to get the answer you want. You may get *A* answer, but you won't get *THE* answer. This email sent to site_archiver(a)lists.apple.com

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Re: Interposing library calls
by Terry Lambert 25 Jul '08

25 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hello, this is a continuation of the previous thread located in darwin-kernel at : http://lists.apple.com/archives/Darwin-kernel/2008/Jul/msg00015.html . I assume my question is more on topic here. The conclusion reached in the above mentioned thread is that it's preferred to interpose library calls (in this case open/close) from a library loaded at runtime. I've therefore created a small example trying to intercept open, resolve the given path (using realpath()), print the resolved path and pass the work to open(). [ ...] I'm clueless about what is causing this issue. As far as I've checked libc' implementation, getcwd() is not using open() (at last not directly). I'd be glad to hear a hint on how to overcome this issue. Ps. I'm aware that this method is not officially "supported" by Apple, neither is any kernel "hacking" of this type. All this makes me wonder, how is someone able to deploy applications if it can't use internal information - in my opinion, forcing people not to mess with this stuff is just encouraging bad design of applications. -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Jul 25, 2008, at 5:17 AM, Jernej Azarija wrote: For these things to work, you need a relatively deep understanding of the ABI and linkage model. Quinn is correct that library interpostion is not officially supported by Apple. In general, this is because you will have to lock-step update your library with system library updates from Apple. The specific example I had in mind when I read Mike's suggestion on interposition is probably the same one Mike had in mind. Mine was "mallocdebug" (Mike used to maintain it, so that's why I'm guessing it's his example). It's possible to interpose, but you have to understand the lock-step nature of interposition, along with the nature of the library implementation, and the use of multi-level namespaces within libraries. The best source example is "mallocdebug", but again, you should be cautioned that what you want to do will have to be lock- stepped. Objective-C based code was intended to support runtime overrides as a language feature; you can still run into problems with library compatibility there, but it's less frequent when you follow the rules. __getcwd() uses open to get ".", then asks the system for the path to ".". Depending on the answer it gets, it may go and ask for ".." recursively until it gets all path components to the root of the volume. You appear to be interposing open at the wrong level in the symbol namespace, so getcwd() is calling your open() rather than the system open(). The difficulty in getting this type of detail right is another reason it's not supported. You are also unlikely to get it right to the point that multiple libraries can interpose the same set of calls, so if someone else tries to do what you are trying to do at the same time, one of you is going to be unhappy. The general cause of problems like the ones you are running into is usually that you are asking about how to implement a solution to a problem, when you've already arrived at the solution. Typically, it's better to ask "how do I solve this problem?" rather than "how do I implement this solution which I've already arrived at?", since you'll likely get more useful answers. This email sent to site_archiver(a)lists.apple.com

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Interposing library calls
by Jernej Azarija 25 Jul '08

25 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:mime-version:content-type:content-transfer-encoding :content-disposition; bh=BxOm6oSv1oE5rcf0Fk2YzfBV11R2hclYVmFz8T0mxI4=; b=LgTb6vVnSJlXq14UQCttHfUpFm2jx8gXmKUAI2MwIDeV6cfajTQ5d2Nt5kcjrSEuTR gkjrg3nE3HZIqhdsmmXhbDaSGJI2gD58IUK5Ek6Swar0XnrZ/kEki0uGVQGJvmN+NU/p KGb0tXifGKaKjY90O7s3GcgAx5rLNcuGmKZPU= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type :content-transfer-encoding:content-disposition; b=oKQlKGuJppaT6I4MQ5dG5dhBp8KdibRd69xSA/tX0MFP/kSU4GsGAH8QphNWwrx2CZ 78swG/epFB5CqhFflhi9tYjpnEJL06huutgy3xXU+QbALyKc4QFX8dq7pbh4ndmDAl2+ E6ebK+9LY8n0G8Q+BGzpvoGj+zPYwpE3bT/vE= Hello, this is a continuation of the previous thread located in darwin-kernel at : http://lists.apple.com/archives/Darwin-kernel/2008/Jul/msg00015.html . I assume my question is more on topic here. The conclusion reached in the above mentioned thread is that it's preferred to interpose library calls (in this case open/close) from a library loaded at runtime. I've therefore created a small example trying to intercept open, resolve the given path (using realpath()), print the resolved path and pass the work to open(). The code didn't always work (mostly, it ran out of file descriptors and/or segfaulted if some "complex" command was executed). Investigating the issue, I've noticed that the wrapped open function is recursively trying to open "." and segfaults (presumably after running out of stack). After some more investigation, I've noticed that getcwd() is the "showstopper". Here is a minimal example reassembling the issue : ==== /* gcc -Wall -Wextra -dynamiclib -o lib.dlyb lib.c*/ #include <fcntl.h> #include <sys/param.h> #include <stdio.h> #include <string.h> #include <errno.h> #include <unistd.h> struct interpose { void *old; void *new; }; int our_open(const char *path, int flags, mode_t mode); static const struct interpose func[] __attribute__((section("__DATA, __interpose"))) = { { (void *) our_open, (void *) open} }; int our_open(const char *path, int flags, mode_t mode) { char res_path[PATH_MAX]; fprintf(stderr, "Trying to open `%s'\n", path); if (getcwd(res_path,sizeof(res_path)) == NULL) { fprintf(stderr, "getcwd() failed. (%s)\n", strerror(errno)); } return open(path,flags,mode); } ==== And here the output : $ export DYLD_INSERT_LIBRARIES=lib.dlyb ... thousand of messages .... Trying to open `.' Trying to open `.' Segmentation fault I'm clueless about what is causing this issue. As far as I've checked libc' implementation, getcwd() is not using open() (at last not directly). I'd be glad to hear a hint on how to overcome this issue. Ps. I'm aware that this method is not officially "supported" by Apple, neither is any kernel "hacking" of this type. All this makes me wonder, how is someone able to deploy applications if it can't use internal information - in my opinion, forcing people not to mess with this stuff is just encouraging bad design of applications. Thanks, Jernej Azarija. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: getutxent() not returning values when using 10.4u SDK
by Rosyna 25 Jul '08

25 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com if ((ut = fopen(_PATH_UTMP, "r")) == NULL) err(1, "%s", _PATH_UTMP); This file utmp does not appear to exist on 10.5. On Jul 24, 2008, at 4:22 PM, Terry Lambert wrote: --- Sincerely, Rosyna Keller Technical Support/Carbon troll/Always needs a hug Unsanity: Unsane Tools for Insanely Great People It's either this, or imagining Phil Schiller in a thong. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I tried using the utmp code in http://www.opensource.apple.com/darwinsource/10.5.4/shell_cmds-118/w/w.c but it gives an error, "/var/run/utmp: No such file or directory" when attempting: (Basically, my only goal here is to find how long the current user has been logged in and doing it from a daemon safe framework/library. If you want the same information back for both SDKs, then you need to limit yourself to utmp instead, since that was fully supported in 10.4, and is a common API (it's considered legacy on 10.5 and later, but it should give the same answers for both SDKs). This email sent to site_archiver(a)lists.apple.com

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Re: getutxent() not returning values when using 10.4u SDK
by Terry Lambert 24 Jul '08

24 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Jul 24, 2008, at 1:51 PM, Rosyna wrote: If I call setutxent()/getutxent()/endutxent() when using the 10.5 SDK while on 10.5, I correctly get the various fields filled out. If I use the 10.4u SDK only the username is filled out. The ut_type and ut_pid and ut_tv fields are all empty. Why would they be empty when the only change is the SDK? You are also changing the libraries you link against when you change your SDK. Prior to 10.5, the utmpx implementation was not fully UNIX conformant, so you get different answers with 10.5 than you did with 10.4; specifically, if you installed in the normal place, you are linking against /Developer/SDKs/MacOSX10.4u.sdk/usr/lib/ libSystem.B.dylib instead of /usr/lib/libSystem.B.dylib. The specific code that implements the UNIX conformat utmpx in 10.5 is in Libc project in gen/utmpx-darwin.[ch] (10.4 does not have these files). You are unlikely to be able to back-port this code to 10.4; for the components that were touched for UNIX conformance, there were as many lines of code that changed as were changed in all of the other changes between Tiger and Leopard combined, and there are dependencies on subsequent changes to the structure of libinfo (among others). If you want the same information back for both SDKs, then you need to limit yourself to utmp instead, since that was fully supported in 10.4, and is a common API (it's considered legacy on 10.5 and later, but it should give the same answers for both SDKs). This email sent to site_archiver(a)lists.apple.com

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getutxent() not returning values when using 10.4u SDK
by Rosyna 24 Jul '08

24 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Why would they be empty when the only change is the SDK? --- Sincerely, Rosyna Keller Technical Support/Carbon troll/Always needs a hug Unsanity: Unsane Tools for Insanely Great People It's either this, or imagining Phil Schiller in a thong. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… If I call setutxent()/getutxent()/endutxent() when using the 10.5 SDK while on 10.5, I correctly get the various fields filled out. If I use the 10.4u SDK only the username is filled out. The ut_type and ut_pid and ut_tv fields are all empty. #include <utmpx.h> #include <stdio.h> inline const char * getType(short type) { char * result = NULL; switch (type) { case BOOT_TIME: result = "Boot Time"; break; case DEAD_PROCESS: result = "Dead Process"; break; case EMPTY: result = "Empty"; break; case INIT_PROCESS: result = "Init Process"; break; case LOGIN_PROCESS: result = "Login Process"; break; case NEW_TIME: result = "New Time"; break; case OLD_TIME: result = "Old Time"; break; case RUN_LVL: result = "Run Level"; break; case USER_PROCESS: result = "User Process"; break; default: result = "Unknown"; break; } return result; } int main() { int nlines = 0; struct utmpx * ux = NULL; setutxent(); while (ux = getutxent()) { printf("Line[%i]: %s @ %s (%s)\n", nlines++, ux->ut_user, ux->ut_host, getType(ux->ut_type)); } endutxent(); return 0; } This email sent to site_archiver(a)lists.apple.com

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Re: "Kicking" the screensaver/display timers
by Ethan Bold 23 Jul '08

23 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com The 10.4u SDK version of IOPMAssertionCreate is not publicly supported. -Ethan On Jul 23, 2008, at 3:23 PM, Terry Lambert wrote: Are you sure about that? I just executed: I was looking in the linkages, not the headers: -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/ebold%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Moreover, 10.4.x does not respond to the NoDisplaySleep and NoIdleSleep assertions that 10.5 does. So these invocations of IOPMAssertionCreate() are only valid in 10.5 and later. On Jul 23, 2008, at 9:01 AM, Kevin Elliott wrote: On Jul 22, 2008, at 10:06 PM, Eli Bach wrote: find /Developer/SDKs -name '*.h' -print0|xargs -0 grep IOPMAssertionCreate and it only returned results in the 10.5 SDK [with no results for IOPMAssertionCreateWithName]. It's 10.5 only. You can read about it in the 10.5 IOKit release notes here: <http://developer.apple.com/releasenotes/Darwin/RN-IOKitPowerManagment/index… > nm -arch i386 /Developer/SDKs//MacOSX10.4u.sdk/System/Library/ Frameworks/IOKit.framework/Versions/A/IOKit | grep IOPMAssert 90c19ffc T _IOPMAssertionCreate 90c1a14e T _IOPMAssertionRelease But I'm guessing that without a published prototype, Ethan is not going to want you linking aqainst it, as it might do something nasty... This email sent to ebold(a)apple.com This email sent to site_archiver(a)lists.apple.com

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Re: "Kicking" the screensaver/display timers
by Terry Lambert 23 Jul '08

23 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Are you sure about that? I just executed: I was looking in the linkages, not the headers: -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Jul 23, 2008, at 9:01 AM, Kevin Elliott wrote: On Jul 22, 2008, at 10:06 PM, Eli Bach wrote: find /Developer/SDKs -name '*.h' -print0|xargs -0 grep IOPMAssertionCreate and it only returned results in the 10.5 SDK [with no results for IOPMAssertionCreateWithName]. It's 10.5 only. You can read about it in the 10.5 IOKit release notes here: <http://developer.apple.com/releasenotes/Darwin/RN-IOKitPowerManagment/index… > nm -arch i386 /Developer/SDKs//MacOSX10.4u.sdk/System/Library/ Frameworks/IOKit.framework/Versions/A/IOKit | grep IOPMAssert 90c19ffc T _IOPMAssertionCreate 90c1a14e T _IOPMAssertionRelease But I'm guessing that without a published prototype, Ethan is not going to want you linking aqainst it, as it might do something nasty... This email sent to site_archiver(a)lists.apple.com

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Re: "Kicking" the screensaver/display timers
by Ethan Bold 23 Jul '08

23 Jul '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com -Ethan On Jul 22, 2008, at 2:45 PM, Shayne Wissler wrote: Thanks again Ethan for your help. This code has the "kicking" effect I was after for *display sleep*, but has no effect on the screensaver: I can probably get by with just this by disabling the screensaver, but it'd be nice if the screensaver could be "kicked" as well. Any ideas? Shayne It's described in the 10.5 Darwin release notes here: http://developer.apple.com/releasenotes/Darwin/RN-IOKitPowerManagment/index… And discussed in practice here on a cocoa mailing list: http://www.cocoabuilder.com/archive/message/cocoa/2008/6/19/210697 -Ethan On Jul 18, 2008, at 4:24 PM, Shayne Wissler wrote: Hello, Any pointers to a relevant API would be appreciated. Shayne _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/ebold%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Correct - IOPMAssertionTypeNoDisplaySleep, as written today, will not keep the ScreenSaver off. This is a bug & an oversight. You can expect a future release of OS X to also keep the ScreenSaver off when NoDisplaySleep is asserted. IOPMAssertionID assertionID; IOReturn err = IOPMAssertionCreate(kIOPMAssertionTypeNoDisplaySleep, kIOPMAssertionLevelOn, &assertionID); err = IOPMAssertionRelease(assertionID); On Fri, Jul 18, 2008 at 5:49 PM, Ethan Bold <ebold(a)apple.com> wrote: Check out IOPMAssertionCreate() with type kIOPMAssertionTypeNoDisplaySleep. This is new in 10.5. I need an API call/approach for "kicking" the the display-sleep/screensaver timers, as if the user had moved the mouse or pressed a key. I need a program to be able to wake up the display and/or stop the screensaver, without having the user interact with the mouse or keyboard. (E.g., for an app used in a classroom situation to broadcast a message to a Mac hanging on a wall that happened to be in sleep mode). This email sent to ebold(a)apple.com This email sent to site_archiver(a)lists.apple.com

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