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      1 /* system/core/include/logwrap/logwrap.h
      2  *
      3  * Copyright 2013, The Android Open Source Project
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 #ifndef __LIBS_LOGWRAP_H
     19 #define __LIBS_LOGWRAP_H
     20 
     21 #include <stdbool.h>
     22 
     23 __BEGIN_DECLS
     24 
     25 /*
     26  * Run a command while logging its stdout and stderr
     27  *
     28  * WARNING: while this function is running it will clear all SIGCHLD handlers
     29  * if you rely on SIGCHLD in the caller there is a chance zombies will be
     30  * created if you're not calling waitpid after calling this. This function will
     31  * log a warning when it clears SIGCHLD for processes other than the child it
     32  * created.
     33  *
     34  * Arguments:
     35  *   argc:   the number of elements in argv
     36  *   argv:   an array of strings containing the command to be executed and its
     37  *           arguments as separate strings. argv does not need to be
     38  *           NULL-terminated
     39  *   status: the equivalent child status as populated by wait(status). This
     40  *           value is only valid when logwrap successfully completes. If NULL
     41  *           the return value of the child will be the function's return value.
     42  *   ignore_int_quit: set to true if you want to completely ignore SIGINT and
     43  *           SIGQUIT while logwrap is running. This may force the end-user to
     44  *           send a signal twice to signal the caller (once for the child, and
     45  *           once for the caller)
     46  *   log_target: Specify where to log the output of the child, either LOG_NONE,
     47  *           LOG_ALOG (for the Android system log) or LOG_KLOG (for the kernel
     48  *           log).
     49  *   abbreviated: If true, capture up to the first 100 lines and last 4K of
     50  *           output from the child.  The abbreviated output is not dumped to
     51  *           the specified log until the child has exited.
     52  *
     53  * Return value:
     54  *   0 when logwrap successfully run the child process and captured its status
     55  *   -1 when an internal error occurred
     56  *   -ECHILD if status is NULL and the child didn't exit properly
     57  *   the return value of the child if it exited properly and status is NULL
     58  *
     59  */
     60 
     61 /* Values for the log_target parameter android_fork_exec_ext() */
     62 #define LOG_NONE        0
     63 #define LOG_ALOG        1
     64 #define LOG_KLOG        2
     65 
     66 int android_fork_execvp_ext(int argc, char* argv[], int *status, bool ignore_int_quit,
     67         int log_target, bool abbreviated);
     68 
     69 /* Similar to above, except abbreviated logging is not available, and if logwrap
     70  * is true, logging is to the Android system log, and if false, there is no
     71  * logging.
     72  */
     73 static inline int android_fork_execvp(int argc, char* argv[], int *status,
     74                                      bool ignore_int_quit, bool logwrap)
     75 {
     76     return android_fork_execvp_ext(argc, argv, status, ignore_int_quit,
     77                                    (logwrap ? LOG_ALOG : LOG_NONE), false);
     78 }
     79 
     80 
     81 __END_DECLS
     82 
     83 #endif /* __LIBS_LOGWRAP_H */
     84