htop: fix possible integer overflow in format strings

[GermanAizek]

%lf usage is redundant

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes correct format specifiers across CPU labels, user IDs, TTY paths, file descriptor meters, and pressure meters. CPU, user, and TTY values use unsigned decimal formatting. File descriptor and pressure values use float formatting. Unlimited file descriptor values remain displayed as unlimited.

Suggested reviewers: natoscott

Poem

Unsigned numbers march in line,
Float formats keep output fine.
TTY paths and meters align,
Pressure values render clear by design.

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[coderabbitai]

Actionable comments posted: 1

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 393e4d3f-e2de-4570-8c1d-0b7dfea94138

📥 Commits

Reviewing files that changed from the base of the PR and between c616dd6 and 325df04.

📒 Files selected for processing (6)

• AffinityPanel.c
• AvailableMetersPanel.c
• FileDescriptorMeter.c
• Process.c
• linux/LinuxProcessTable.c
• linux/PressureStallMeter.c

[coderabbitai]

🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
set -euo pipefail

rg -n -C 2 '\buid_t\b|\bST_UID\b' --glob '*.[ch]' .

Repository: htop-dev/htop

Length of output: 16019

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🏁 Script executed:

#!/bin/bash
set -euo pipefail

printf 'Relevant uid_t/user setup files:\n'
rg -n 'typedef|_uid_t|uid_t|UserId|getpwnam|getpwuid|ProcessTable_updateUid|UserTable' --glob '*.[ch]' .

printf '\nProcess.h context:\n'
sed -n '1,180p' Process.h

printf '\nRow.c width/print context:\n'
sed -n '1,175p' Row.c

printf '\nlibc/platform uid_t declarations and Process.c user handling:\n'
sed -n '1,120p' LinuxProcess.c
sed -n '1,120p' FreeBSDProcess.c
sed -n '1,120p' SolarisProcess.c
sed -n '1,120p' OpenBSDProcess.c
sed -n '1,120p' NetBSDProcess.c
sed -n '1,120p' DarwinProcess.c
sed -n '1,120p' DragonFlyBSDProcess.c
sed -n '1,120p' PCPProcess.c
sed -n '1,120p' UnsupportedProcess.c

printf '\nProcess.c UID formatting/compare/filter context:\n'
sed -n '730,815p' Process.c
sed -n '860,910p' Process.c
sed -n '1005,1035p' Process.c

Repository: htop-dev/htop

Length of output: 25794

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🌐 Web query:

POSIX uid_t format specifier printf %u unsigned int

💡 Result:

There is no specific POSIX printf format specifier for uid_t [1]. POSIX defines uid_t as an integer type, but it does not mandate whether it is signed or unsigned, nor does it define a specific width (e.g., 32-bit or 64-bit) [2][3][4]. Because of this, using a single format specifier like %u is not portable across all POSIX-compliant systems [3]. To print a uid_t portably, the recommended approach is to cast the value to a known, larger integer type that has a defined format specifier [1]. A common and safe practice is to cast it to (unsigned long) and use the %lu format specifier, as uid_t is guaranteed to be an integer type [1][2]. Example of portable usage: printf("User ID: %lu\n", (unsigned long)my_uid); This avoids potential issues where uid_t might be a signed type on some platforms (where %u could behave unexpectedly) or wider than a standard int [3][5].

Citations:

• 1: https://www.austingroupbugs.net/view.php?id=576
• 2: https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/basedefs/sys_types.h.html
• 3: https://stackoverflow.com/questions/21370094/is-the-uid-t-type-signed-or-unsigned
• 4: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html
• 5: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg480310.html

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Use a guaranteed-width format for UID output.

Process.c prints this->st_uid with %u, but POSIX only defines uid_t as an integer type and does not guarantee that it matches unsigned int. Cast it to a portable type such as unsigned long and use %lu, or a width-specific format that preserves the maximum uid_t range.