diff options
| -rw-r--r-- | findutils/xargs.c | 135 |
1 files changed, 117 insertions, 18 deletions
diff --git a/findutils/xargs.c b/findutils/xargs.c index b4e3db02c..77e01ef6c 100644 --- a/findutils/xargs.c +++ b/findutils/xargs.c @@ -59,6 +59,11 @@ //config: depends on XARGS //config: help //config: Support -I STR and -i[STR] options. +//config: +//config:config FEATURE_XARGS_SUPPORT_PARALLEL +//config: bool "Enable -P N: processes to run in parallel" +//config: default y +//config: depends on XARGS //applet:IF_XARGS(APPLET_NOEXEC(xargs, xargs, BB_DIR_USR_BIN, BB_SUID_DROP, xargs)) @@ -99,38 +104,121 @@ struct globals { #endif const char *eof_str; int idx; +#if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL + int running_procs; + int max_procs; +#endif + smalluint xargs_exitcode; } FIX_ALIASING; #define G (*(struct globals*)bb_common_bufsiz1) #define INIT_G() do { \ setup_common_bufsiz(); \ G.eof_str = NULL; /* need to clear by hand because we are NOEXEC applet */ \ G.idx = 0; \ + IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.running_procs = 0;) \ + IF_FEATURE_XARGS_SUPPORT_PARALLEL(G.max_procs = 1;) \ + G.xargs_exitcode = 0; \ IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.repl_str = "{}";) \ IF_FEATURE_XARGS_SUPPORT_REPL_STR(G.eol_ch = '\n';) \ } while (0) +/* + * Returns 0 if xargs should continue (but may set G.xargs_exitcode to 123). + * Else sets G.xargs_exitcode to error code and returns nonzero. + * + * If G.max_procs == 0, performs final waitpid() loop for all children. + */ static int xargs_exec(void) { int status; +#if !ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL status = spawn_and_wait(G.args); +#else + if (G.max_procs == 1) { + status = spawn_and_wait(G.args); + } else { + pid_t pid; + int wstat; + again: + if (G.running_procs >= G.max_procs) + pid = safe_waitpid(-1, &wstat, 0); + else + pid = wait_any_nohang(&wstat); + if (pid > 0) { + /* We may have children we don't know about: + * sh -c 'sleep 1 & exec xargs ...' + * Do not make G.running_procs go negative. + */ + if (G.running_procs != 0) + G.running_procs--; + status = WIFSIGNALED(wstat) + ? 0x180 + WTERMSIG(wstat) + : WEXITSTATUS(wstat); + if (status > 0 && status < 255) { + /* See below why 123 does not abort */ + G.xargs_exitcode = 123; + status = 0; + } + if (status == 0) + goto again; /* maybe we have more children? */ + /* else: "bad" status, will bail out */ + } else if (G.max_procs != 0) { + /* Not in final waitpid() loop, + * and G.running_procs < G.max_procs: start more procs + */ + status = spawn(G.args); + /* here "status" actually holds pid, or -1 */ + if (status > 0) { + G.running_procs++; + status = 0; + } + /* else: status == -1 (failed to fork or exec) */ + } else { + /* final waitpid() loop: must be ECHILD "no more children" */ + status = 0; + } + } +#endif + /* Manpage: + * """xargs exits with the following status: + * 0 if it succeeds + * 123 if any invocation of the command exited with status 1-125 + * 124 if the command exited with status 255 + * ("""If any invocation of the command exits with a status of 255, + * xargs will stop immediately without reading any further input. + * An error message is issued on stderr when this happens.""") + * 125 if the command is killed by a signal + * 126 if the command cannot be run + * 127 if the command is not found + * 1 if some other error occurred.""" + */ if (status < 0) { bb_simple_perror_msg(G.args[0]); - return errno == ENOENT ? 127 : 126; - } - if (status == 255) { - bb_error_msg("%s: exited with status 255; aborting", G.args[0]); - return 124; + status = (errno == ENOENT) ? 127 : 126; } - if (status >= 0x180) { + else if (status >= 0x180) { bb_error_msg("'%s' terminated by signal %d", G.args[0], status - 0x180); - return 125; + status = 125; } - if (status) - return 123; - return 0; + else if (status != 0) { + if (status == 255) { + bb_error_msg("%s: exited with status 255; aborting", G.args[0]); + return 124; + } + /* "123 if any invocation of the command exited with status 1-125" + * This implies that nonzero exit code is remembered, + * but does not cause xargs to stop: we return 0. + */ + G.xargs_exitcode = 123; + status = 0; + } + + if (status != 0) + G.xargs_exitcode = status; + return status; } /* In POSIX/C locale isspace is only these chars: "\t\n\v\f\r" and space. @@ -436,6 +524,9 @@ static int xargs_ask_confirmation(void) //usage: IF_FEATURE_XARGS_SUPPORT_REPL_STR( //usage: "\n -I STR Replace STR within PROG ARGS with input line" //usage: ) +//usage: IF_FEATURE_XARGS_SUPPORT_PARALLEL( +//usage: "\n -P N Run up to N PROGs in parallel" +//usage: ) //usage: IF_FEATURE_XARGS_SUPPORT_TERMOPT( //usage: "\n -x Exit if size is exceeded" //usage: ) @@ -473,14 +564,14 @@ enum { IF_FEATURE_XARGS_SUPPORT_CONFIRMATION("p") \ IF_FEATURE_XARGS_SUPPORT_TERMOPT( "x") \ IF_FEATURE_XARGS_SUPPORT_ZERO_TERM( "0") \ - IF_FEATURE_XARGS_SUPPORT_REPL_STR( "I:i::") + IF_FEATURE_XARGS_SUPPORT_REPL_STR( "I:i::") \ + IF_FEATURE_XARGS_SUPPORT_PARALLEL( "P:+") int xargs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int xargs_main(int argc UNUSED_PARAM, char **argv) { int initial_idx; int i; - int child_error = 0; char *max_args; char *max_chars; char *buf; @@ -500,8 +591,14 @@ int xargs_main(int argc UNUSED_PARAM, char **argv) "no-run-if-empty\0" No_argument "r", &max_args, &max_chars, &G.eof_str, &G.eof_str IF_FEATURE_XARGS_SUPPORT_REPL_STR(, &G.repl_str, &G.repl_str) + IF_FEATURE_XARGS_SUPPORT_PARALLEL(, &G.max_procs) ); +#if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL + if (G.max_procs <= 0) /* -P0 means "run lots of them" */ + G.max_procs = 100; /* let's not go crazy high */ +#endif + /* -E ""? You may wonder why not just omit -E? * This is used for portability: * old xargs was using "_" as default for -E / -e */ @@ -620,11 +717,8 @@ int xargs_main(int argc UNUSED_PARAM, char **argv) } if (!(opt & OPT_INTERACTIVE) || xargs_ask_confirmation()) { - child_error = xargs_exec(); - } - - if (child_error > 0 && child_error != 123) { - break; + if (xargs_exec() != 0) + break; /* G.xargs_exitcode is set by xargs_exec() */ } overlapping_strcpy(buf, rem); @@ -635,7 +729,12 @@ int xargs_main(int argc UNUSED_PARAM, char **argv) free(buf); } - return child_error; +#if ENABLE_FEATURE_XARGS_SUPPORT_PARALLEL + G.max_procs = 0; + xargs_exec(); /* final waitpid() loop */ +#endif + + return G.xargs_exitcode; } |