149 lines
4.1 KiB
C
149 lines
4.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* wait_error.c
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* Convert a wait/waitpid(2) result code to a human-readable string
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*
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*
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* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/common/wait_error.c
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef FRONTEND
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#include "postgres.h"
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#else
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#include "postgres_fe.h"
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#endif
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#include <signal.h>
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#include <sys/wait.h>
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/*
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* Return a human-readable string explaining the reason a child process
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* terminated. The argument is a return code returned by wait(2) or
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* waitpid(2), which also applies to pclose(3) and system(3). The result is a
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* translated, palloc'd or malloc'd string.
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*/
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char *
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wait_result_to_str(int exitstatus)
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{
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char str[512];
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/*
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* To simplify using this after pclose() and system(), handle status -1
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* first. In that case, there is no wait result but some error indicated
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* by errno.
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*/
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if (exitstatus == -1)
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{
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snprintf(str, sizeof(str), "%m");
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}
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else if (WIFEXITED(exitstatus))
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{
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/*
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* Give more specific error message for some common exit codes that
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* have a special meaning in shells.
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*/
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switch (WEXITSTATUS(exitstatus))
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{
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case 126:
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snprintf(str, sizeof(str), _("command not executable"));
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break;
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case 127:
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snprintf(str, sizeof(str), _("command not found"));
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break;
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default:
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snprintf(str, sizeof(str),
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_("child process exited with exit code %d"),
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WEXITSTATUS(exitstatus));
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}
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}
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else if (WIFSIGNALED(exitstatus))
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{
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#if defined(WIN32)
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snprintf(str, sizeof(str),
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_("child process was terminated by exception 0x%X"),
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WTERMSIG(exitstatus));
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#else
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snprintf(str, sizeof(str),
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_("child process was terminated by signal %d: %s"),
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WTERMSIG(exitstatus), pg_strsignal(WTERMSIG(exitstatus)));
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#endif
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}
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else
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snprintf(str, sizeof(str),
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_("child process exited with unrecognized status %d"),
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exitstatus);
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return pstrdup(str);
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}
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/*
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* Return true if a wait(2) result indicates that the child process
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* died due to the specified signal.
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*
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* The reason this is worth having a wrapper function for is that
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* there are two cases: the signal might have been received by our
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* immediate child process, or there might've been a shell process
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* between us and the child that died. The shell will, per POSIX,
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* report the child death using exit code 128 + signal number.
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*
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* If there is no possibility of an intermediate shell, this function
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* need not (and probably should not) be used.
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*/
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bool
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wait_result_is_signal(int exit_status, int signum)
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{
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if (WIFSIGNALED(exit_status) && WTERMSIG(exit_status) == signum)
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return true;
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if (WIFEXITED(exit_status) && WEXITSTATUS(exit_status) == 128 + signum)
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return true;
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return false;
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}
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/*
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* Return true if a wait(2) result indicates that the child process
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* died due to any signal. We consider either direct child death
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* or a shell report of child process death as matching the condition.
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*
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* If include_command_not_found is true, also return true for shell
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* exit codes indicating "command not found" and the like
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* (specifically, exit codes 126 and 127; see above).
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*/
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bool
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wait_result_is_any_signal(int exit_status, bool include_command_not_found)
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{
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if (WIFSIGNALED(exit_status))
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return true;
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if (WIFEXITED(exit_status) &&
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WEXITSTATUS(exit_status) > (include_command_not_found ? 125 : 128))
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return true;
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return false;
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}
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/*
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* Return the shell exit code (normally 0 to 255) that corresponds to the
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* given wait status. The argument is a wait status as returned by wait(2)
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* or waitpid(2), which also applies to pclose(3) and system(3). To support
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* the latter two cases, we pass through "-1" unchanged.
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*/
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int
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wait_result_to_exit_code(int exit_status)
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{
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if (exit_status == -1)
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return -1; /* failure of pclose() or system() */
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if (WIFEXITED(exit_status))
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return WEXITSTATUS(exit_status);
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if (WIFSIGNALED(exit_status))
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return 128 + WTERMSIG(exit_status);
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/* On many systems, this is unreachable */
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return -1;
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}
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