Commit 01b5cbe7 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

fixdep: use malloc() and read() to load dep_file to buffer 



Commit dee81e98 ("fixdep: faster CONFIG_ search") changed how to
read files in which CONFIG options are searched.  It used malloc()
and read() instead of mmap() because it needed to zero-terminate the
buffer in order to use strstr().  print_deps() was left untouched
since there was no reason to change it.

Now, I have two motivations to change it in the same way.

 - do_config_file() and print_deps() do quite similar things; they
   open a file, load it onto memory, and pass it to a parser function.
   If we use malloc() and read() for print_deps() too, we can factor
   out the common code.  (I will do this in the next commit.)

 - parse_dep_file() copies each token to a temporary buffer because
   it needs to zero-terminate it to be passed to printf().  It is not
   possible to modify the buffer directly because it is mmap'ed with
   O_RDONLY.  If we load the file content into a malloc'ed buffer, we
   can insert '\0' after each token, and save memcpy().  (I will do
   this in the commit after next.)

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent 41f92cff

scripts/basic/fixdep.c

+32 −24
Original line number Diff line number Diff line
@@ -104,7 +104,6 @@ 


#include <sys/types.h>

#include <sys/stat.h>

#include <sys/mman.h>

#include <unistd.h>

#include <fcntl.h>

#include <string.h>
@@ -308,24 +307,27 @@ static void do_config_file(const char *filename) 
 * assignments are parsed not only by make, but also by the rather simple

 * parser in scripts/mod/sumversion.c.

 */

static void parse_dep_file(void *map, size_t len)

static void parse_dep_file(char *m)

{

	char *m = map;

	char *end = m + len;

	char *p;

	char s[PATH_MAX];

	int is_target;

	int is_last, is_target;

	int saw_any_target = 0;

	int is_first_dep = 0;



	while (m < end) {

	while (1) {

		/* Skip any "white space" */

		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))

		while (*m == ' ' || *m == '\\' || *m == '\n')

			m++;



		if (!*m)

			break;



		/* Find next "white space" */

		p = m;

		while (p < end && *p != ' ' && *p != '\\' && *p != '\n')

		while (*p && *p != ' ' && *p != '\\' && *p != '\n')

			p++;

		is_last = (*p == '\0');

		/* Is the token we found a target name? */

		is_target = (*(p-1) == ':');

		/* Don't write any target names into the dependency file */
@@ -373,6 +375,10 @@ static void parse_dep_file(void *map, size_t len) 
				do_config_file(s);

			}

		}



		if (is_last)

			break;



		/*

		 * Start searching for next token immediately after the first

		 * "whitespace" character that follows this token.
@@ -391,40 +397,42 @@ static void parse_dep_file(void *map, size_t len) 
	printf("$(deps_%s):\n", target);

}



static void print_deps(void)

static void print_deps(const char *filename)

{

	struct stat st;

	int fd;

	void *map;

	char *buf;



	fd = open(depfile, O_RDONLY);

	fd = open(filename, O_RDONLY);

	if (fd < 0) {

		fprintf(stderr, "fixdep: error opening depfile: ");

		perror(depfile);

		perror(filename);

		exit(2);

	}

	if (fstat(fd, &st) < 0) {

		fprintf(stderr, "fixdep: error fstat'ing depfile: ");

		perror(depfile);

		perror(filename);

		exit(2);

	}

	if (st.st_size == 0) {

		fprintf(stderr,"fixdep: %s is empty\n",depfile);

		close(fd);

		return;

	}

	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);

	if ((long) map == -1) {

		perror("fixdep: mmap");

		close(fd);

		return;

	buf = malloc(st.st_size + 1);

	if (!buf) {

		perror("fixdep: malloc");

		exit(2);

	}

	if (read(fd, buf, st.st_size) != st.st_size) {

		perror("fixdep: read");

		exit(2);

	}

	buf[st.st_size] = '\0';

	close(fd);



	parse_dep_file(map, st.st_size);



	munmap(map, st.st_size);

	parse_dep_file(buf);



	close(fd);

	free(buf);

}



int main(int argc, char *argv[])
@@ -440,7 +448,7 @@ int main(int argc, char *argv[]) 
	cmdline = argv[3];



	print_cmdline();

	print_deps();

	print_deps(depfile);



	return 0;

}

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