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| author | Ian Rogers <irogers@google.com> | 2024-10-25 12:21:00 -0700 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2024-10-28 09:32:57 -0700 |
| commit | 5ce42b5de461c3154f61a023b191dd6b77ee66c0 (patch) | |
| tree | a4f49cc3673311c4de2bbb44232f22e02be99021 | |
| parent | 150dab31d5609f896fbfaa06b442ca314da79858 (diff) | |
| download | lwn-5ce42b5de461c3154f61a023b191dd6b77ee66c0.tar.gz lwn-5ce42b5de461c3154f61a023b191dd6b77ee66c0.zip | |
tools subcmd: Add non-waitpid check_if_command_finished()
Using waitpid can cause stdout/stderr of the child process to be
lost. Use Linux's /prod/<pid>/status file to determine if the process
has reached the zombie state. Use the 'status' file rather than 'stat'
to avoid issues around skipping the process name.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Veronika Molnarova <vmolnaro@redhat.com>
Link: https://lore.kernel.org/r/20241025192109.132482-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
| -rw-r--r-- | tools/lib/subcmd/run-command.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/tools/lib/subcmd/run-command.c b/tools/lib/subcmd/run-command.c index 4e3a557a2f37..0a764c25c384 100644 --- a/tools/lib/subcmd/run-command.c +++ b/tools/lib/subcmd/run-command.c @@ -2,6 +2,7 @@ #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> +#include <ctype.h> #include <fcntl.h> #include <string.h> #include <linux/string.h> @@ -217,8 +218,40 @@ static int wait_or_whine(struct child_process *cmd, bool block) int check_if_command_finished(struct child_process *cmd) { +#ifdef __linux__ + char filename[FILENAME_MAX + 12]; + char status_line[256]; + FILE *status_file; + + /* + * Check by reading /proc/<pid>/status as calling waitpid causes + * stdout/stderr to be closed and data lost. + */ + sprintf(filename, "/proc/%d/status", cmd->pid); + status_file = fopen(filename, "r"); + if (status_file == NULL) { + /* Open failed assume finish_command was called. */ + return true; + } + while (fgets(status_line, sizeof(status_line), status_file) != NULL) { + char *p; + + if (strncmp(status_line, "State:", 6)) + continue; + + fclose(status_file); + p = status_line + 6; + while (isspace(*p)) + p++; + return *p == 'Z' ? 1 : 0; + } + /* Read failed assume finish_command was called. */ + fclose(status_file); + return 1; +#else wait_or_whine(cmd, /*block=*/false); return cmd->finished; +#endif } int finish_command(struct child_process *cmd) |