VFS: Initial procfs support #88
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This patch contains changes for procfs support, as well as fixing some bugs in the VFS system: - Fixed some more buffer overflow bugs. - Fixed traversing across mount boundaries. - Fixed `errno` when doing an unsupported operation on a device. (`EPERM`, not `EOPNOTSUPP`). Currently only a few static files (`filesystems`, `meminfo`, `mounts`, `self`, `uptime`), as well as the folder corresponding to the current process and its static contents (`cwd`, `exe`, `mounts`, `root`) are supported. For further support, `blink` must have some method to register, manage and query shared process information.
jart
approved these changes
Mar 17, 2023
| struct HostfsDevice *hostfsdevice = (struct HostfsDevice *)device->data; | ||
| *spec = strdup(hostfsdevice->source); | ||
| if (*spec == NULL) { | ||
| return enomem(); |
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You can just return -1 in cases like this, because strdup already set the errno.
| @@ -128,6 +128,21 @@ int HostfsInit(const char *source, u64 flags, const void *data, | |||
| return -1; | |||
| } | |||
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| int HostfsReadmountentry(struct VfsDevice *device, char **spec, char **type, char **mntops) { | |||
| struct HostfsDevice *hostfsdevice = (struct HostfsDevice *)device->data; | |||
| *spec = strdup(hostfsdevice->source); | |||
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One best practice for API design in C is that the output parameters should only be modified on success. There's very few exceptions to this rule. But it's mostly an issue for public APIs.
| // TODO(trungnt): This should be dynamically allocated when we support | ||
| // more processes. | ||
| (*info)->ino = PROCFS_FIRST_PID_INO; | ||
| sprintf((*info)->name, "%d", pid); |
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I recommend against using sprintf() because it's one of those functions that triggers security people and attracts attention from scanners.
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I used sprintf at that once instance as I wonder how a 32-bit int can take more than 16 chars to represent.
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This patch contains changes for procfs support, as well as fixing some bugs in the VFS system:
errnowhen doing an unsupported operation on a device. (EPERM, notEOPNOTSUPP).Currently only a few static files (
filesystems,meminfo,mounts,self,uptime), as well as the folder corresponding to the current process and its static contents (cwd,exe,mounts,root) are supported. For further support,blinkmust have some method to register, manage and query shared process information.