From b2a5fec5f8b8b6bf1313d8474448cd8b50057d1b Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Tue, 12 May 2009 17:17:19 +0100
Subject: [PATCH] Refactor line splitting code in the daemon, and fix it so it
works.
---
daemon/command.c | 27 +++------------------------
daemon/daemon.h | 2 ++
daemon/guestfsd.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
daemon/strings.c | 23 +++--------------------
4 files changed, 62 insertions(+), 44 deletions(-)
diff --git a/daemon/command.c b/daemon/command.c
index 1daccf6..1a50264 100644
--- a/daemon/command.c
+++ b/daemon/command.c
@@ -84,37 +84,16 @@ char **
do_command_lines (char * const * const argv)
{
char *out;
- char **lines = NULL;
- int size = 0, alloc = 0;
- char *p, *pend;
+ char **lines;
out = do_command (argv);
if (out == NULL)
return NULL;
- /* Now convert the output to a list of lines. */
- p = out;
- while (p) {
- pend = strchr (p, '\n');
- if (pend) {
- *pend = '\0';
- pend++;
-
- /* Final \n? Don't return an empty final element. */
- if (*pend == '\0') break;
- }
-
- if (add_string (&lines, &size, &alloc, p) == -1) {
- free (out);
- return NULL;
- }
-
- p = pend;
- }
-
+ lines = split_lines (out);
free (out);
- if (add_string (&lines, &size, &alloc, NULL) == -1)
+ if (lines == NULL)
return NULL;
return lines; /* Caller frees. */
diff --git a/daemon/daemon.h b/daemon/daemon.h
index 001c703..8ad7b7c 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -47,6 +47,8 @@ extern int commandv (char **stdoutput, char **stderror,
extern int commandrv (char **stdoutput, char **stderror,
char * const* const argv);
+extern char **split_lines (char *str);
+
extern int shell_quote (char *out, int len, const char *in);
extern int verbose;
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index eeb84bd..406c104 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -587,6 +587,60 @@ commandrv (char **stdoutput, char **stderror, char * const* const argv)
return -1;
}
+/* Split an output string into a NULL-terminated list of lines.
+ * Typically this is used where we have run an external command
+ * which has printed out a list of things, and we want to return
+ * an actual list.
+ *
+ * The corner cases here are quite tricky. Note in particular:
+ *
+ * "" -> []
+ * "\n" -> [""]
+ * "a\nb" -> ["a"; "b"]
+ * "a\nb\n" -> ["a"; "b"]
+ * "a\nb\n\n" -> ["a"; "b"; ""]
+ *
+ * The original string is written over and destroyed by this
+ * function (which is usually OK because it's the 'out' string
+ * from command()). You can free the original string, because
+ * add_string() strdups the strings.
+ */
+char **
+split_lines (char *str)
+{
+ char **lines = NULL;
+ int size = 0, alloc = 0;
+ char *p, *pend;
+
+ if (strcmp (str, "") == 0)
+ goto empty_list;
+
+ p = str;
+ while (p) {
+ /* Empty last line? */
+ if (p[0] == '\0')
+ break;
+
+ pend = strchr (p, '\n');
+ if (pend) {
+ *pend = '\0';
+ pend++;
+ }
+
+ if (add_string (&lines, &size, &alloc, p) == -1) {
+ return NULL;
+ }
+
+ p = pend;
+ }
+
+ empty_list:
+ if (add_string (&lines, &size, &alloc, NULL) == -1)
+ return NULL;
+
+ return lines;
+}
+
/* Quote 'in' for the shell, and write max len-1 bytes to out. The
* result will be NUL-terminated, even if it is truncated.
*
diff --git a/daemon/strings.c b/daemon/strings.c
index 5e9c3a8..b26691d 100644
--- a/daemon/strings.c
+++ b/daemon/strings.c
@@ -32,9 +32,7 @@ do_strings_e (const char *encoding, const char *path)
char *buf;
int r;
char *out, *err;
- char **lines = NULL;
- int size = 0, alloc = 0;
- char *p, *pend;
+ char **lines;
NEED_ROOT (NULL);
ABS_PATH (path, NULL);
@@ -60,25 +58,10 @@ do_strings_e (const char *encoding, const char *path)
free (err);
/* Now convert the output to a list of lines. */
- p = out;
- while (p && *p) {
- pend = strchr (p, '\n');
- if (pend) {
- *pend = '\0';
- pend++;
- }
-
- if (add_string (&lines, &size, &alloc, p) == -1) {
- free (out);
- return NULL;
- }
-
- p = pend;
- }
-
+ lines = split_lines (out);
free (out);
- if (add_string (&lines, &size, &alloc, NULL) == -1)
+ if (lines == NULL)
return NULL;
return lines; /* Caller frees. */
--
1.8.3.1