Android can't exec rm -r - java

I have an application that has a directory on the SD card. The application saves notes in a new subdirectory. I want to delete the whole subdirectory using shell command "rm -r" but the application throws an exception:
04-02 23:14:23.410: W/System.err(14891): java.io.IOException: Error running exec(). Command: [cd, /mnt/sdcard/mynote, &&, rm, -r, aaa] Working Directory: null Environment: null
Can anyone help me?

This happens because you used Runtime.exec(String). Never use this function. It's hard to predict and only works in trivial cases. Always use Runtime.exec(String[]).
Since cd and && are not commands but shell features, you need to manually invoke a shell for them to work:
Runtime.getRuntime().exec(new String[] {
"sh", "-c", "cd /mnt/sdcard/mynote && rm -r aaa"
});
On a related note, you should never pass String data unescaped to shells. For example, this is wrong:
// Insecure, buggy and wrong!
String target = "aaa";
Runtime.getRuntime().exec(new String[] {
"sh", "-c", "cd /mnt/sdcard/mynote && rm -r " + target
});
The correct way is to pass data as separate parameters to the shell, and reference them from your command:
// Secure and correct
String target = "aaa";
Runtime.getRuntime().exec(new String[] {
"sh", "-c", "cd /mnt/sdcard/mynote && rm -r \"$1\"", "--", target
});
For example, if a file is named * or My file, the incorrect version will delete a whole bunch of completely unrelated files. The correct version does not.

Related

ProcessBuilder can't find custom .exe

I am currently trying to write a small program in java which should take over the job of an old batch script I've been using.
This batch script executes a program called sum.exe (Supermicro Update Manager).
However, no matter which way I try, the program either does not respond, or straight up tells me it can't find the file in the directory where the file is.
boolean isWindows = System.getProperty("os.name").toLowerCase().startsWith("windows");
ProcessBuilder builder = new ProcessBuilder("C:\\Users\\[Username]\\SUM\\sum.exe");
if (isWindows) {
builder.command("sum.exe", "-i 192.168.4.10 -u ADMIN -p ADMIN -c CheckOOBSupport");
} else {
builder.command("sh", "-c", "ls");
}
builder.redirectErrorStream(true);
Process process = builder.start();
StreamGobbler streamGobbler = new StreamGobbler(process.getInputStream(), System.out::println);
StreamGobbler streamGobblerErrors = new StreamGobbler(process.getErrorStream(), System.out::println);
Executors.newSingleThreadExecutor().submit(streamGobbler);
Executors.newSingleThreadExecutor().submit(streamGobblerErrors);
int exitCode = process.waitFor();
assert exitCode == 0;
This is the code I currently have. The command I'm trying to call here will 100% give an error, so I made sure to redirect those as well.
As far as I understood, there are 3 different ways to set a Filepath for the Processbuilder.
Either you:
Set the path in the constructor
Set the path between your executable and arguments in the .command() method
Or you set the directory of the builder by creating a new file (and using System.Property)
I have a complete copy of the SUM-Folder under: C:\Users\[Username]\SUM, and I have tried all 3 options listed above with this, but always got the error message that the system could not find the file specified
Additionally, I'm still not sure if the command would even work this way. I have only ever used sum.exe via batch-Script or cmd.exe itself, so wouldn't the command need to be
builder.command("cmd.exe", "sum.exe -i 192.168.4.10 -u ADMIN -p ADMIN -c CheckOOBSupport)
instead?
Can anyone tell me what I'm doing wrong?
Thanks!
The ProcessBuilder command line is passed in the constructor or the command() method so in your example you've overridden the value used.
Choose the way you need:
ProcessBuilder builder = new ProcessBuilder("C:\\Users\\[Username]\\SUM\\sum.exe",
"-i", "192.168.4.10",
"-u", "ADMIN","-p", "ADMIN",
"-c", "CheckOOBSupport");
or
ProcessBuilder builder = new ProcessBuilder();
builder.command("sum.exe",
"-i", "192.168.4.10",
"-u", "ADMIN","-p", "ADMIN",
"-c", "CheckOOBSupport");
Note also that the arguments for the command need to supplied as separate string values rather than all concatenated together as one value, and you need absolute path to "sum.exe" if that is not found in the current directory or under a directory of environment variable "Path".

Execute bash in java

Wen i try to run this code :
String[] cmd = {"/bin/bash", "-c", "printf '%s'\n"+videoPath+"./"+"*.mp4 >"+"mylist.txt"};
processBuilder.command(cmd);
I get some error:
/bin/bash: line 1:
/home/gilles/eclipse-workspace/informationGewinnungApp/videotool/outputs/./info.mp4:
cannot execute binary file: Exec format error 126
The \n in your string is expanded into a newline. Hence bash sees two commands,
printf %s
..../info.mp4
Do it either as
String[] cmd = {"/bin/bash", "-c", "printf '%s' "+videoPath+"./"+"*.mp4 >"+"mylist.txt"};
Or
String[] cmd = {"/bin/bash", "-c", "echo "+videoPath+"./"+"*.mp4 >"+"mylist.txt"};
But: Why don't you want to use a bash child process, if you only want to create a new file containing a certain string? Wouldn't it be easier to do it directly from Java?

Java process command with file name space in it

I have below linux command running through java program , where input file name has space in it , while executing system fails
java.io.IOException: Cannot run program "tsp -I afmarker": error=2, No such file or directory
Command :
String[] commandArr = new String[] { "tsp -I afmarker", "/home/test/prad test.mpg" "-P afmarker -a 10 -v 20 -O file", "/home/prad/output.mpg};
Process process = Runtime.getRuntime().exec(commandArr);
How do I solve this problem?
When invoked with an array of Strings, Runtime.getRuntime().exec() expects the first element of the array to be the name of the executable, without any parameters. If I am not mistaken, your code is instructing your JVM to execute a command called tsp -I afmarker, and such command does not exist. All parameters to tsp should be specified separately as elements of the array passed to exec().
Try separating each argument instead:
String[] commandArr = new String[] {
"tsp", "-I", "afmarker",
"/home/test/prad test.mpg",
"-P", "afmarker", "-a", "10", "-v", "20",
"-O", "file", "/home/prad/output.mpg"
};

complete CMD command not running from java

I am running the below query through Java on a Postgres DB using psql:
psql.exe -U <user> -w -h <host> -d <db_name> -a -f <file> 2> "<path_to_file>\psql.log"
Initially, for quite some time the java program did create the file. Then I ran into another problem, that it was not overwriting the log file. So i used file.delete() function after every time this log file got created via java.
Now, Java is not even creating the log file for some reason. If I run the above manually in command prompt, it runs absolutely fine, but not via java code. I can see this command getting run in the java log, but it does not create the log file even when i have removed the file.delete() function
I researched a lot on it but could not find any solution. Any help would be highly appreciated.
its a long code..so i will tell you the relevant part.
I am calling a function from a thread. Code is below for that function:
public static void SaveACopyfileToServer(int auditid,String filepath,String fname,String tb_name,String plpgsql_path) throws Exception
{
Map<String, String> env = System.getenv();
String plpgsql = "\""+plpgsql_path+"\" -U "+env.get("PG_USER")+" -w -h "+env.get("PG_HOST")+" -d "+env.get("PG_DB")+" -a -f "+"\""+filepath+"copy_"+tb_name+auditid+".sql\" 2> \"C:\\ER\\ETL\\logs\\psql.log\"";
System.out.println(plpgsql);
Process p = Runtime.getRuntime().exec(plpgsql);
p.getOutputStream().close();
p.waitFor();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSS");
Calendar cal10 = Calendar.getInstance();
System.out.println("Data loaded for "+tb_name+auditid+" at "+sdf.format(cal10.getTime()));
}
After this i am calling another function which is:
public static void extracterrorreason(String fname,int auditid,String sessionid,Connection con_pg) throws FileNotFoundException, IOException, InterruptedException{
File file = new File("C:\\ER\\ETL\\logs\\psql.log");
if(file.exists())
{
System.out.println("File present");
}
else
{
System.out.println(file+" not found");
}
if (file.length()!=0){
System.out.println("Log file being read is "+file);
BufferedReader br = new BufferedReader(new FileReader(file));
String line = br.readLine();
String out_err = line.substring(line.indexOf("ERROR"));
System.out.println(out_err);
System.out.println("Error while loading the file into Database for file "+fname);
String comment = "CopyToStage','"+out_err;
Utils.updateAuditDetailTable(auditid, sessionid, -1, comment, true, con_pg,"");
br.close();
//file.delete();
}
}
The first function used to create the psql.log file, but now it does not even create it. Not sure where is the problem. Every time i run the code and from the second function,i get the printline that log file not found. The part before the redirection of the output of the cmd command works fine.
I tried process builder also..
I even tried it with Process builder
String plpgsql = "\""+plpgsql_path+"\" -U "+env.get("PG_USER")+" -w -h "+env.get("PG_HOST")+" -d "+env.get("PG_DB")+" -a -f "+"\""+filepath+"copy_"+tb_name+auditid+".sql\" 2> \"C:\\ER\\ETL\\psql_" +auditid +".log\"";
ProcessBuilder pb = new ProcessBuilder("cmd.exe",plpgsql);
Process p =pb.start();
p.getOutputStream().close();
p.waitFor();
I expect that the problem is that Runtime.getRuntime().exec(plpgsql) is splitting the command line into arguments incorrectly. Basically, exec does not understand quoting. Instead, it splits wherever it sees one or more spaces ... even if those spaces are in quotes.
The solution is to use the exec(String[]) overload, and pass each individual argument as a separate string; e.g.
.exec(new String[]{plpgsql_path,
"-U",
env.get("PG_USER"),
"-w,
"-h",
// etcetera
});
UPDATE
I didn't notice that you were using > output redirection as well1.
That doesn't work with exec either. (And the same applies to all shell syntax.) To get redirection, you need to use ProcessBuilder and one of the redirect methods.
The other alternative is to run the command in a shell. Pass the command as a string, and let the shell take care of the quote handling, substitution of environment variables, globbing, redirection ... and so on.
For example (if you were running on UNIX, Linux or MacOSX):
.exec(new String[]{"/bin/sh", "-c", plpgsql});
For Windows
.exec(new String[]{"cmd.exe", "/C", plpgsql});
Note the "/C" option in the Windows case!
1 - It serves you right for not line-breaking that ~200 character line in your source code! Check out what Java coding standards say about source line lengths ...

Run linux command through java.

I want to run nm command in linux through java.
I tried this code :
command = "nm -l file1.o > file1.txt";
Process p = Runtime.getRuntime().exec(command);
But it's not working, what is wrong with the code?
That is not an executable, it is in fact a shell script.
If you invoke the shell with -c, then you can execute your command:
/bin/sh -c "command > here"
Here's what you need to do:
String command = "nm -l file1.o > file1.txt";
Process p = Runtime.getRuntime().exec(new String[]{"/bin/sh", "-c", command});
The following "simple answer" WON'T WORK :
String command = "/bin/sh -c 'nm -l file1.o > file1.txt'";
Process p = Runtime.getRuntime().exec(command);
because the exec(String) method splits its the string naively using whitespace as the separator and ignoring any quoting. So the above example is equivalent to supplying the following command / argument list.
new String[]{"/bin/sh", "-c", "'nm", "-l", "file1.o", ">", "file1.txt'"};
An alternative to pipe would be to read the stdout of your command, see Java exec() does not return expected result of pipes' connected commands for an example.
Instead of redirecting the output using "> file.txt" you would read whatever the output is and write it to a StringBuffer or OutputStream or whatever you like.
This would have the advantage that you could also read stderr and see if there were errors (like no space left on device etc.). (you can also do that using "2>" using your approach)

Categories

Resources