Be ever so pedantic about escaping chars that the shell might not like...

2 files changed, 118 insertions, 34 deletions

diff --git a/findutils/xargs.c b/findutils/xargs.c
index 478e0ee6d..21bfb6bbe 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -29,6 +29,59 @@
 #include <getopt.h>
 #include <ctype.h>
 
+/* get_sh_safe_line_from_file() - This function reads an entire line from a text file
+ * up to a newline. It returns a malloc'ed char * which must be stored and
+ * free'ed  by the caller. */
+extern char *get_sh_safe_line_from_file(FILE *file)
+{
+	static const int GROWBY = 80; /* how large we will grow strings by */
+
+	char ch, last_ch = 0;
+	char tmp[]=" ";
+	int idx = 0;
+	char *linebuf = NULL;
+	int linebufsz = 0;
+
+	while (1) {
+		ch = fgetc(file);
+		if (ch == EOF)
+			break;
+		
+		/* grow the line buffer as necessary */
+		while (idx > linebufsz-4)
+			linebuf = xrealloc(linebuf, linebufsz += GROWBY);
+
+		/* Remove any extra spaces */
+		if (last_ch == ' ' && ch == ' ')
+			continue;
+
+		/* Replace any tabs with spaces */
+		if (ch == '\t')
+			ch=' ';
+
+		/* Escape any characters that are treated specially by /bin/sh */
+		*tmp=ch;
+		if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
+			linebuf[idx++] = '\\';
+		}
+
+		linebuf[idx++] = ch;
+		last_ch=ch;
+
+		if (ch == '\n')
+			break;
+	}
+	if (idx == 0 && last_ch!=0)
+		linebuf[idx++]=' ';
+
+	if (idx == 0)
+		return NULL;
+
+	linebuf[idx] = 0;
+	return linebuf;
+}
+
+
 
 int xargs_main(int argc, char **argv)
 {
@@ -54,7 +107,7 @@ int xargs_main(int argc, char **argv)
 	}
 
 	/* Store the command and arguments to be executed (from the command line) */
-	if (argc == 1) {
+	if (argc == 0) {
 		len_args_from_cmdline = 6;
 		args_from_cmdline = xmalloc(len_args_from_cmdline);
 		strcat(args_from_cmdline, "echo ");
@@ -72,6 +125,7 @@ int xargs_main(int argc, char **argv)
 			}
 			strcat(args_from_cmdline, *argv);
 			strcat(args_from_cmdline, " ");
+			++argv;
 		}
 	}
 
@@ -79,30 +133,19 @@ int xargs_main(int argc, char **argv)
 	len_cmd_to_be_executed=10;
 	cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
 	strcpy(cmd_to_be_executed, args_from_cmdline);
-	strcat(cmd_to_be_executed, " \"");
 
 	/* Now, read in one line at a time from stdin, and run command+args on it */
-	in_from_stdin = get_line_from_file(stdin);
+	in_from_stdin = get_sh_safe_line_from_file(stdin);
 	for (;in_from_stdin!=NULL;) {
 		char *tmp;
 		opt = strlen(in_from_stdin);
 		len = opt + len_args_from_cmdline;
 		len_cmd_to_be_executed+=len+3;
 		cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
-			
+
 		/* Strip out the final \n */
 		in_from_stdin[opt-1]=' ';
-		
-		/* Replace any tabs with spaces */
-		while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
-			*tmp=' ';
-
-		/* Strip out any extra intra-word spaces */
-		while( (tmp = strstr(in_from_stdin, "  ")) != NULL ) {
-			opt = strlen(in_from_stdin);
-			memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
-		}
-
+			
 		/* trim trailing whitespace */
 		opt = strlen(in_from_stdin) - 1;
 		while (isspace(in_from_stdin[opt]))
@@ -118,10 +161,9 @@ int xargs_main(int argc, char **argv)
 		strcat(cmd_to_be_executed, " ");
 	
 		free(in_from_stdin);
-		in_from_stdin = get_line_from_file(stdin);
+		in_from_stdin = get_sh_safe_line_from_file(stdin);
 	}
 
-	strcat(cmd_to_be_executed, "\"");
 	if (traceflag==1)
 		fputs(cmd_to_be_executed, stderr);
 
diff --git a/xargs.c b/xargs.c
index 478e0ee6d..21bfb6bbe 100644
--- a/xargs.c
+++ b/xargs.c
@@ -29,6 +29,59 @@
 #include <getopt.h>
 #include <ctype.h>
 
+/* get_sh_safe_line_from_file() - This function reads an entire line from a text file
+ * up to a newline. It returns a malloc'ed char * which must be stored and
+ * free'ed  by the caller. */
+extern char *get_sh_safe_line_from_file(FILE *file)
+{
+	static const int GROWBY = 80; /* how large we will grow strings by */
+
+	char ch, last_ch = 0;
+	char tmp[]=" ";
+	int idx = 0;
+	char *linebuf = NULL;
+	int linebufsz = 0;
+
+	while (1) {
+		ch = fgetc(file);
+		if (ch == EOF)
+			break;
+		
+		/* grow the line buffer as necessary */
+		while (idx > linebufsz-4)
+			linebuf = xrealloc(linebuf, linebufsz += GROWBY);
+
+		/* Remove any extra spaces */
+		if (last_ch == ' ' && ch == ' ')
+			continue;
+
+		/* Replace any tabs with spaces */
+		if (ch == '\t')
+			ch=' ';
+
+		/* Escape any characters that are treated specially by /bin/sh */
+		*tmp=ch;
+		if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
+			linebuf[idx++] = '\\';
+		}
+
+		linebuf[idx++] = ch;
+		last_ch=ch;
+
+		if (ch == '\n')
+			break;
+	}
+	if (idx == 0 && last_ch!=0)
+		linebuf[idx++]=' ';
+
+	if (idx == 0)
+		return NULL;
+
+	linebuf[idx] = 0;
+	return linebuf;
+}
+
+
 
 int xargs_main(int argc, char **argv)
 {
@@ -54,7 +107,7 @@ int xargs_main(int argc, char **argv)
 	}
 
 	/* Store the command and arguments to be executed (from the command line) */
-	if (argc == 1) {
+	if (argc == 0) {
 		len_args_from_cmdline = 6;
 		args_from_cmdline = xmalloc(len_args_from_cmdline);
 		strcat(args_from_cmdline, "echo ");
@@ -72,6 +125,7 @@ int xargs_main(int argc, char **argv)
 			}
 			strcat(args_from_cmdline, *argv);
 			strcat(args_from_cmdline, " ");
+			++argv;
 		}
 	}
 
@@ -79,30 +133,19 @@ int xargs_main(int argc, char **argv)
 	len_cmd_to_be_executed=10;
 	cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
 	strcpy(cmd_to_be_executed, args_from_cmdline);
-	strcat(cmd_to_be_executed, " \"");
 
 	/* Now, read in one line at a time from stdin, and run command+args on it */
-	in_from_stdin = get_line_from_file(stdin);
+	in_from_stdin = get_sh_safe_line_from_file(stdin);
 	for (;in_from_stdin!=NULL;) {
 		char *tmp;
 		opt = strlen(in_from_stdin);
 		len = opt + len_args_from_cmdline;
 		len_cmd_to_be_executed+=len+3;
 		cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
-			
+
 		/* Strip out the final \n */
 		in_from_stdin[opt-1]=' ';
-		
-		/* Replace any tabs with spaces */
-		while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
-			*tmp=' ';
-
-		/* Strip out any extra intra-word spaces */
-		while( (tmp = strstr(in_from_stdin, "  ")) != NULL ) {
-			opt = strlen(in_from_stdin);
-			memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
-		}
-
+			
 		/* trim trailing whitespace */
 		opt = strlen(in_from_stdin) - 1;
 		while (isspace(in_from_stdin[opt]))
@@ -118,10 +161,9 @@ int xargs_main(int argc, char **argv)
 		strcat(cmd_to_be_executed, " ");
 	
 		free(in_from_stdin);
-		in_from_stdin = get_line_from_file(stdin);
+		in_from_stdin = get_sh_safe_line_from_file(stdin);
 	}
 
-	strcat(cmd_to_be_executed, "\"");
 	if (traceflag==1)
 		fputs(cmd_to_be_executed, stderr);