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/usr/bin/mysqldump: Permission denied问题分析

news 来源：原创 2025/6/18 17:27:45

今天碰到SpringBoot调用mysqldump数据库备份报Permission denied，第一眼看到感觉很简单，添加权限就行，mysqldump和备份目录都加载权限，还是问题依旧。

认为是mysql版本问题，因为另一台机器可以。
手动执行备份是正常的，只有报个Warning，说密码不能放到命令中。
备份目录权限问题。

但最终发现都不是

这里直接strace看结果，主要是找到这个方法：

sudo strace -f -e trace=execve /home/app/jdk-17.0.9/bin/java TestPermission

结果：发现是/home/app/jdk-17.0.9/lib/jspawnhelper没有权限

execve("/home/app/jdk-17.0.9/bin/java", ["/home/app/jdk-17.0.9/bin/j"..., "TestPermission"], 0x7ffcda3fd620 /* 13 vars */) = 0
strace: Process 26967 attached
[pid 26967] --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---
strace: Process 26968 attached
...
[pid 26985] execve("/home/app/jdk-17.0.9/lib/jspawnhelper", ["10:13"], 0x7fff76f01b30 /* 13 vars */) = -1 EACCES (Permission denied)
[pid 26985] +++ exited with 127 +++
[pid 26966] --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=26985, si_uid=0, si_status=127, si_utime=0, si_stime=0} ---
Exception in thread "main" java.io.IOException: Cannot run program "/usr/bin/mysqldump": error=13, Permission denied
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1143)
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1073)
        at TestPermission.main(TestPermission.java:8)
Caused by: java.io.IOException: error=13, Permission denied
        at java.base/java.lang.ProcessImpl.forkAndExec(Native Method)
        at java.base/java.lang.ProcessImpl.<init>(ProcessImpl.java:314)
        at java.base/java.lang.ProcessImpl.start(ProcessImpl.java:244)
        at java.base/java.lang.ProcessBuilder.start(ProcessBuilder.java:1110)
        ... 2 more
[pid 26983] +++ exited with 0 +++
...

TestPermission 代码：

public class TestPermission {
    public static void main(String[] args) throws Exception {
        ProcessBuilder pb = new ProcessBuilder("/usr/bin/mysqldump", "--version");
        pb.redirectErrorStream(true);
        Process p = pb.start();
        BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        p.waitFor();
    }
}