execute.c

ccache 是一个快速的编译器缓存。当您编译一个程序的时候

/*
   Copyright (C) Andrew Tridgell 2002
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "ccache.h"


/*
  execute a compiler backend, capturing all output to the given paths
  the full path to the compiler to run is in argv[0]
*/
int execute(char **argv, 
	    const char *path_stdout,
	    const char *path_stderr)
{
	pid_t pid;
	int status;

	pid = fork();
	if (pid == -1) fatal("Failed to fork");
	
	if (pid == 0) {
		int fd;

		unlink(path_stdout);
		fd = open(path_stdout, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0666);
		if (fd == -1) {
			exit(STATUS_NOCACHE);
		}
		dup2(fd, 1);
		close(fd);

		unlink(path_stderr);
		fd = open(path_stderr, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0666);
		if (fd == -1) {
			exit(STATUS_NOCACHE);
		}
		dup2(fd, 2);
		close(fd);

		exit(execv(argv[0], argv));
	}

	if (waitpid(pid, &status, 0) != pid) {
		fatal("waitpid failed");
	}

	if (WEXITSTATUS(status) == 0 && WIFSIGNALED(status)) {
		return -1;
	}

	return WEXITSTATUS(status);
}


/*
  find an executable by name in $PATH. Exclude any that are links to exclude_name 
*/
char *find_executable(const char *name, const char *exclude_name)
{
	char *path;
	char *tok;
	struct stat st1, st2;

	path = getenv("CCACHE_PATH");
	if (!path) {
		path = getenv("PATH");
	}
	if (!path) {
		cc_log("no PATH variable!?\n");
		return NULL;
	}

	path = x_strdup(path);
	
	/* search the path looking for the first compiler of the right name
	   that isn't us */
	for (tok=strtok(path,":"); tok; tok = strtok(NULL, ":")) {
		char *fname;
		x_asprintf(&fname, "%s/%s", tok, name);
		/* look for a normal executable file */
		if (access(fname, X_OK) == 0 &&
		    lstat(fname, &st1) == 0 &&
		    stat(fname, &st2) == 0 &&
		    S_ISREG(st2.st_mode)) {
			/* if its a symlink then ensure it doesn't
                           point at something called exclude_name */
			if (S_ISLNK(st1.st_mode)) {
				char *buf = x_realpath(fname);
				if (buf) {
					char *p = str_basename(buf);
					if (strcmp(p, exclude_name) == 0) {
						/* its a link to "ccache" ! */
						free(p);
						free(buf);
						continue;
					}
					free(buf);
					free(p);
				}
			}

			/* found it! */
			free(path);
			return fname;
		}
		free(fname);
	}

	return NULL;
}