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LibC: Fix and cleanup stdio mode string parsing

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The code is now much cleaner andd we are not as strict with the mode
string. Also add support for new 'e' and 'x' modifiers
This commit is contained in:
Bananymous
2026-07-04 19:13:26 +03:00
parent a41a3eeb66
commit 2957206718
1 changed files with 40 additions and 12 deletions
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52
userspace/libraries/LibC/stdio.cpp
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@@ -170,21 +170,49 @@ int fclose(FILE* file)
static mode_t parse_mode_string(const char* mode_str)
{
size_t len = strlen(mode_str);
if (len == 0 || len > 3)
return 0;
if (len == 3 && mode_str[1] == mode_str[2])
return 0;
if (strspn(mode_str + 1, "tb+") != len - 1)
return 0;
bool plus = (mode_str[1] == '+' || mode_str[2] == '+');
mode_t mode = 0;
switch (mode_str[0])
{
case 'r': return plus ? O_RDWR : O_RDONLY;
case 'w': return plus ? O_RDWR | O_CREAT | O_TRUNC : O_WRONLY | O_CREAT | O_TRUNC;
case 'a': return plus ? O_RDWR | O_CREAT | O_APPEND : O_WRONLY | O_CREAT | O_APPEND;
}
case 'r':
break;
case 'w':
mode |= O_CREAT | O_TRUNC;
break;
case 'a':
mode |= O_CREAT | O_APPEND;
break;
default:
return 0;
}
bool plus = false;
for (size_t i = 1; mode_str[i]; i++)
{
switch (mode_str[i])
{
case 'b':
case 't':
break;
case 'e':
mode |= O_CLOEXEC;
break;
case 'x':
mode |= O_CREAT | O_EXCL;
break;
case '+':
mode |= O_RDWR;
plus = true;
break;
default:
return 0;
}
}
if (!plus)
mode |= (mode_str[0] == 'r') ? O_RDONLY : O_WRONLY;
return mode;
}
FILE* fdopen(int fd, const char* mode_str)