On 26.07.23 09:02, Dan Carpenter wrote:
Hello Heinrich Schuchardt,
The patch 28cef9ca2e86: "fs: fat: create correct short names" from
Nov 20, 2020, leads to the following Smatch static
checker warning:
fs/fat/fat_write.c:61 str2fat()
warn: impossible condition '(c > 127) => ((-128)-127 > 127)'
fs/fat/fat_write.c:136 set_name()
warn: impossible condition '(*dirent.name == 229) => ((-128)-127 == 229)'
fs/fat/fat_write.c
105 static int set_name(fat_itr *itr, const char *filename, char
*shortname)
106 {
107 char *period;
108 char *pos;
109 int period_location;
110 char buf[13];
111 int i;
112 int ret;
113 struct nameext dirent;
114
115 if (!filename)
116 return -EIO;
117
118 /* Initialize buffer */
119 memset(&dirent, ' ', sizeof(dirent));
120
121 /* Convert filename to upper case short name */
122 period = strrchr(filename, '.');
123 pos = (char *)filename;
124 if (*pos == '.') {
125 pos = period + 1;
126 period = 0;
127 }
128 if (period)
129 str2fat(dirent.ext, period + 1, sizeof(dirent.ext));
130 period_location = str2fat(dirent.name, pos,
sizeof(dirent.name));
131 if (period_location < 0)
132 return period_location;
133 if (*dirent.name == ' ')
134 *dirent.name = '_';
135 /* 0xe5 signals a deleted directory entry. Replace it by 0x05.
*/
--> 136 if (*dirent.name == 0xe5)
dirent.name is a char type. Chars are signed on probably most people's
systems. The Linux kernel recently made char unsigned for everyone.
Anyway in a char 0xe5 is negative but as a literal, it's positive so
this condition cannot be true.
137 *dirent.name = 0x05;
Thanks for reporting the issue. In the same file we have:
fs/fat/fat_write.c:1493:
dent->nameext.name[0] = DELETED_FLAG;
include/fat.h:53:
#define DELETED_FLAG ((char)0xe5)
I will send a patch.
Best regards
Heinrich
138
139 /* If filename and short name are the same, quit. */
140 sprintf(buf, "%.*s.%.3s", period_location, dirent.name,
dirent.ext);
141 if (!strcmp(buf, filename)) {
142 ret = 1;
regards,
dan carpenter
