0ac77ec315
The motivation for this change is that system call failures are serious errors that should be reported to the user, but only few callers took the burden to decode the error codes that the functions returned into error messages. If at all, then only an unspecific error message was given. A prominent example is this: $ git upload-pack . | : fatal: unable to run 'git-upload-pack' In this example, git-upload-pack, the external command invoked through the git wrapper, dies due to SIGPIPE, but the git wrapper does not bother to report the real cause. In fact, this very error message is copied to the syslog if git-daemon's client aborts the connection early. With this change, system call failures are reported immediately after the failure and only a generic failure code is returned to the caller. In the above example the error is now to the point: $ git upload-pack . | : error: git-upload-pack died of signal Note that there is no error report if the invoked program terminated with a non-zero exit code, because it is reasonable to expect that the invoked program has already reported an error. (But many run_command call sites nevertheless write a generic error message.) There was one special return code that was used to identify the case where run_command failed because the requested program could not be exec'd. This special case is now treated like a system call failure with errno set to ENOENT. No error is reported in this case, because the call site in git.c expects this as a normal result. Therefore, the callers that carefully decoded the return value still check for this condition. Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
83 lines
2.5 KiB
C
83 lines
2.5 KiB
C
#ifndef RUN_COMMAND_H
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#define RUN_COMMAND_H
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struct child_process {
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const char **argv;
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pid_t pid;
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/*
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* Using .in, .out, .err:
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* - Specify 0 for no redirections (child inherits stdin, stdout,
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* stderr from parent).
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* - Specify -1 to have a pipe allocated as follows:
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* .in: returns the writable pipe end; parent writes to it,
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* the readable pipe end becomes child's stdin
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* .out, .err: returns the readable pipe end; parent reads from
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* it, the writable pipe end becomes child's stdout/stderr
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* The caller of start_command() must close the returned FDs
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* after it has completed reading from/writing to it!
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* - Specify > 0 to set a channel to a particular FD as follows:
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* .in: a readable FD, becomes child's stdin
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* .out: a writable FD, becomes child's stdout/stderr
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* .err > 0 not supported
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* The specified FD is closed by start_command(), even in case
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* of errors!
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*/
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int in;
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int out;
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int err;
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const char *dir;
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const char *const *env;
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unsigned no_stdin:1;
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unsigned no_stdout:1;
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unsigned no_stderr:1;
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unsigned git_cmd:1; /* if this is to be git sub-command */
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unsigned stdout_to_stderr:1;
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void (*preexec_cb)(void);
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};
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int start_command(struct child_process *);
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int finish_command(struct child_process *);
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int run_command(struct child_process *);
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extern int run_hook(const char *index_file, const char *name, ...);
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#define RUN_COMMAND_NO_STDIN 1
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#define RUN_GIT_CMD 2 /*If this is to be git sub-command */
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#define RUN_COMMAND_STDOUT_TO_STDERR 4
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int run_command_v_opt(const char **argv, int opt);
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/*
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* env (the environment) is to be formatted like environ: "VAR=VALUE".
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* To unset an environment variable use just "VAR".
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*/
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int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
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/*
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* The purpose of the following functions is to feed a pipe by running
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* a function asynchronously and providing output that the caller reads.
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*
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* It is expected that no synchronization and mutual exclusion between
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* the caller and the feed function is necessary so that the function
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* can run in a thread without interfering with the caller.
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*/
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struct async {
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/*
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* proc writes to fd and closes it;
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* returns 0 on success, non-zero on failure
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*/
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int (*proc)(int fd, void *data);
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void *data;
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int out; /* caller reads from here and closes it */
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#ifndef __MINGW32__
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pid_t pid;
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#else
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HANDLE tid;
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int fd_for_proc;
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#endif
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};
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int start_async(struct async *async);
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int finish_async(struct async *async);
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#endif
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