From: zhuyan <zhuya...@huawei.com>
When I planned to print the command in read_line_input, I found that after
the system started, the command printed for the first time was always
garbled.
After analysis, it is found that in the init() function of ash, the
variable basepf.buf is not initialized after applying for memory, resulting
in garbled initial data. Then assign it to the global variable
g_parsefile->buf in ash.c, and then pass g_parsefile->buf to the parameter
command of the function read_line_input in the function preadfd(), and
finally cause it to be garbled when the command is printed by
read_line_input.
The call stack is as follows:
#0 read_line_input (st=0xb6fff220, prompt=0xb6ffc910 "\\[\\033[32m\\]\\h
\\w\\[\\033[m\\] \\$ ", command=command@entry=0xb6ffc230
"P\325\377\266P\325\377\266", maxsize=maxsize@entry=1024) at
libbb/lineedit.c:2461
#1 0x0043ef8c in preadfd () at shell/ash.c:10812
#2 preadbuffer () at shell/ash.c:10914
#3 pgetc () at shell/ash.c:10997
#4 0x00440c20 in pgetc_eatbnl () at shell/ash.c:11039
#5 0x00440cbc in xxreadtoken () at shell/ash.c:13157
#6 0x00440f40 in readtoken () at shell/ash.c:13268
#7 0x00441234 in list (nlflag=nlflag@entry=1) at shell/ash.c:11782
#8 0x004420e8 in parsecmd (interact=<optimized out>) at shell/ash.c:13344
#9 0x00442c34 in cmdloop (top=top@entry=1) at shell/ash.c:13549
#10 0x00444e4c in ash_main (argc=<optimized out>, argv=0x444e4c
<ash_main+1328>) at shell/ash.c:14747
#11 0x00407954 in run_applet_no_and_exit (applet_no=9, name=<optimized out>,
argv=0xbefffd34) at libbb/appletlib.c:1024
#12 0x00407b68 in run_applet_and_exit (name=0xbefffe56 "ash", argv=0x9) at
libbb/appletlib.c:1047
#13 0x00407f88 in main (argc=<optimized out>, argv=0xbefffd34) at
libbb/appletlib.c:1181
Fixes: 82dd14a510ca ("ash: use CONFIG_FEATURE_EDITING_MAX_LEN")
Signed-off-by: zhuyan <zhuya...@huawei.com>
---
shell/ash.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/shell/ash.c b/shell/ash.c
index e1d93da73..771fc8bf9 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -14484,7 +14484,7 @@ static NOINLINE void
init(void)
{
/* we will never free this */
- basepf.next_to_pgetc = basepf.buf = ckmalloc(IBUFSIZ);
+ basepf.next_to_pgetc = basepf.buf = ckzalloc(IBUFSIZ);
basepf.linno = 1;
sigmode[SIGCHLD - 1] = S_DFL; /* ensure we install handler even if it
is SIG_IGNed */
--
2.12.3
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