Re: [PATCH v4] Replace fmemopen() with internal function in libsepol.

[Stephen Smalley <sds@tycho.nsa.gov>]

On 05/08/2015 10:51 AM, James Carter wrote:
> Created a new function, get_line(), to replace the use of fmemopen()
> and getline() in module_to_cil.c since fmemopen() is not available
> on Darwin.
> 
> Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>

Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>

> ---
>  libsepol/src/module_to_cil.c | 122 +++++++++++++++++++++++--------------------
>  1 file changed, 65 insertions(+), 57 deletions(-)
> 
> diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
> index d1d2efe..8d16d3e 100644
> --- a/libsepol/src/module_to_cil.c
> +++ b/libsepol/src/module_to_cil.c
> @@ -107,6 +107,44 @@ static void cil_println(int indent, const char *fmt, ...)
>  	}
>  }
>  
> +static int get_line(char **start, char *end, char **line)
> +{
> +	int rc = 1;
> +	char *p = NULL;
> +	size_t len = 0;
> +
> +	*line = NULL;
> +
> +	for (p = *start; p < end && isspace(*p); p++);
> +
> +	*start = p;
> +
> +	for (len = 0; p < end && *p != '\n' && *p != '\0'; p++, len++);
> +
> +	if (len == 0) {
> +		rc = 0;
> +		goto exit;
> +	}
> +
> +	*line = malloc(len+1);
> +	if (*line == NULL) {
> +		log_err("Out of memory");
> +		rc = -1;
> +		goto exit;
> +	}
> +
> +	memcpy(*line, *start, len);
> +	(*line)[len] = '\0';
> +
> +	*start = p;
> +
> +	return rc;
> +
> +exit:
> +	*start = NULL;
> +	return rc;
> +}
> +
>  struct map_args {
>  	struct policydb *pdb;
>  	struct avrule_block *block;
> @@ -2907,14 +2945,11 @@ exit:
>  static int seusers_to_cil(struct sepol_module_package *mod_pkg)
>  {
>  	int rc = -1;
> -	FILE *fp = NULL;
>  	char *seusers = sepol_module_package_get_seusers(mod_pkg);
>  	size_t seusers_len = sepol_module_package_get_seusers_len(mod_pkg);
> -	size_t len = 0;
> +	char *cur = seusers;
> +	char *end = seusers + seusers_len;
>  	char *line = NULL;
> -	ssize_t line_len = 0;
> -	char *buf = NULL;
> -
>  	char *user = NULL;
>  	char *seuser = NULL;
>  	char *level = NULL;
> @@ -2924,19 +2959,12 @@ static int seusers_to_cil(struct sepol_module_package *mod_pkg)
>  		return 0;
>  	}
>  
> -	fp = fmemopen(seusers, seusers_len, "r");
> -
> -	while ((line_len = getline(&line, &len, fp)) != -1) {
> -		buf = line;
> -		buf[line_len - 1] = '\0';
> -		while (*buf && isspace(buf[0])) {
> -			buf++;
> -		}
> -		if (buf[0] == '#' || buf[0] == '\0') {
> +	while ((rc = get_line(&cur, end, &line)) > 0) {
> +		if (line[0] == '#') {
>  			continue;
>  		}
>  
> -		matched = sscanf(buf, "%m[^:]:%m[^:]:%ms", &user, &seuser, &level);
> +		matched = sscanf(line, "%m[^:]:%m[^:]:%ms", &user, &seuser, &level);
>  
>  		if (matched < 2 || matched > 3) {
>  			log_err("Invalid seuser line: %s", line);
> @@ -2964,20 +2992,17 @@ static int seusers_to_cil(struct sepol_module_package *mod_pkg)
>  		free(user);
>  		free(seuser);
>  		free(level);
> +		free(line);
>  		user = seuser = level = NULL;
>  	}
> -	if (ferror(fp)) {
> +
> +	if (rc == -1) {
>  		cil_printf("Failed to read seusers\n");
> -		rc = -1;
>  		goto exit;
>  	}
>  
>  	rc = 0;
> -
>  exit:
> -	if (fp != NULL) {
> -		fclose(fp);
> -	}
>  	free(line);
>  	free(user);
>  	free(seuser);
> @@ -3002,10 +3027,9 @@ static int user_extra_to_cil(struct sepol_module_package *mod_pkg)
>  	int rc = -1;
>  	char *userx = sepol_module_package_get_user_extra(mod_pkg);
>  	size_t userx_len = sepol_module_package_get_user_extra_len(mod_pkg);
> -	FILE *fp = NULL;
> -	size_t len = 0;
> -	char *line = NULL;
> -	ssize_t line_len = 0;
> +	char *cur = userx;
> +	char *end = userx + userx_len;
> +	char *line;
>  	int matched;
>  	char *user = NULL;
>  	char *prefix = NULL;
> @@ -3014,10 +3038,10 @@ static int user_extra_to_cil(struct sepol_module_package *mod_pkg)
>  		return 0;
>  	}
>  
> -	fp = fmemopen(userx, userx_len, "r");
> -
> -	while ((line_len = getline(&line, &len, fp)) != -1) {
> -		line[line_len - 1] = '\0';
> +	while ((rc = get_line(&cur, end, &line)) > 0) {
> +		if (line[0] == '#') {
> +			continue;
> +		}
>  
>  		matched = sscanf(line, "user %ms prefix %m[^;];", &user, &prefix);
>  		if (matched != 2) {
> @@ -3029,20 +3053,17 @@ static int user_extra_to_cil(struct sepol_module_package *mod_pkg)
>  		cil_println(0, "(userprefix %s %s)", user, prefix);
>  		free(user);
>  		free(prefix);
> -		user = prefix = NULL;
> +		free(line);
> +		user = prefix = line = NULL;
>  	}
>  
> -	if (ferror(fp)) {
> +	if (rc == -1) {
>  		cil_printf("Failed to read user_extra\n");
> -		rc = -1;
>  		goto exit;
>  	}
>  
>  	rc = 0;
>  exit:
> -	if (fp != NULL) {
> -		fclose(fp);
> -	}
>  	free(line);
>  	free(user);
>  	free(prefix);
> @@ -3055,11 +3076,9 @@ static int file_contexts_to_cil(struct sepol_module_package *mod_pkg)
>  	int rc = -1;
>  	char *fc = sepol_module_package_get_file_contexts(mod_pkg);
>  	size_t fc_len = sepol_module_package_get_file_contexts_len(mod_pkg);
> -	FILE *fp = NULL;
> -	size_t len = 0;
> +	char *cur = fc;
> +	char *end = fc + fc_len;
>  	char *line = NULL;
> -	char *buf = NULL;
> -	ssize_t line_len = 0;
>  	int matched;
>  	char *regex = NULL;
>  	char *mode = NULL;
> @@ -3070,20 +3089,12 @@ static int file_contexts_to_cil(struct sepol_module_package *mod_pkg)
>  		return 0;
>  	}
>  
> -	fp = fmemopen(fc, fc_len, "r");
> -	while ((line_len = getline(&line, &len, fp)) != -1) {
> -		buf = line;
> -		if (buf[line_len - 1] == '\n') {
> -			buf[line_len - 1] = '\0';
> -		}
> -		while (*buf && isspace(buf[0])) {
> -			buf++;
> -		}
> -		if (buf[0] == '#' || buf[0] == '\0') {
> +	while ((rc = get_line(&cur, end, &line)) > 0) {
> +		if (line[0] == '#') {
>  			continue;
>  		}
>  
> -		matched = sscanf(buf, "%ms %ms %ms", &regex, &mode, &context);
> +		matched = sscanf(line, "%ms %ms %ms", &regex, &mode, &context);
>  		if (matched < 2 || matched > 3) {
>  			rc = -1;
>  			log_err("Invalid file context line: %s", line);
> @@ -3130,12 +3141,12 @@ static int file_contexts_to_cil(struct sepol_module_package *mod_pkg)
>  		free(regex);
>  		free(mode);
>  		free(context);
> -		regex = mode = context = NULL;
> +		free(line);
> +		regex = mode = context = line = NULL;
>  	}
>  
> -	if (ferror(fp)) {
> -		cil_printf("Failed to read user_extra\n");
> -		rc = -1;
> +	if (rc == -1) {
> +		cil_printf("Failed to read file_contexts_to_cil\n");
>  		goto exit;
>  	}
>  
> @@ -3145,9 +3156,6 @@ exit:
>  	free(regex);
>  	free(mode);
>  	free(context);
> -	if (fp != NULL) {
> -		fclose(fp);
> -	}
>  
>  	return rc;
>  }
>